The constraints of traditional 3D bioprinting are overcome by 4D bioprinting integrating with adaptable materials over time,resulting in dynamic,compliant,and functional biological structures.This innovative approach ...The constraints of traditional 3D bioprinting are overcome by 4D bioprinting integrating with adaptable materials over time,resulting in dynamic,compliant,and functional biological structures.This innovative approach to bioprinting holds great promise for tissue engineering,regenerative medicine,and advanced drug delivery systems.4D bioprinting is a technology that allows for the extension of 3D bioprinting technology by making predesigned structures change after they are fabricated using smart materials that can alter their characteristics via stimulus,leading to transformation in healthcare,which is able to provide precise personalized effective medical treatment without any side effects.This review article concentrates on some recent developments and applications in the field of 4D bioprinting,which can pave the way for groundbreaking advancements in biomedical sciences.4D printing is a new chapter in bioprinting that introduces dynamism and functional living biological structures.Therefore,smart materials and sophisticated printing techniques can eliminate the challenges associated with printing complex organs and tissues.However,the problems with this process are biocompatibility,immunogenicity,and scalability,which need to be addressed.Moreover,numerous obstacles have been encountered during its widespread adoption in clinical practice.Therefore,4D bioprinting requires improvements in future material science innovations and further development in printers and manufacturing techniques to unlock its potential for better patient care and outcomes.展开更多
Bioprinting is a revolutionary technology within the field of tissue engineering that enables the precise fabrication of three-dimensional(3D)tissue constructs.It combines the principles of engineering and biology to ...Bioprinting is a revolutionary technology within the field of tissue engineering that enables the precise fabrication of three-dimensional(3D)tissue constructs.It combines the principles of engineering and biology to create structures that closely mimic the complexity of native human tissues,facilitating advancements in regenerative medicine and personalized healthcare.This review paper systematically explores the challenges and design requirements in the fabrication of 3D biomimetic tissue constructs,emphasizing the need for advanced bioprinting strategies.Achieving biomimicry involves creating 3D anatomically relevant structures,biomimetic microenvironments,and vascularization.The focus is on overcoming existing bottlenecks through advancements in both fabrication techniques and bio-inks.Future directions in bioprinting are outlined,including multi-modal bioprinting systems,in-situ bioprinting,and the integration of machine learning into bioprinting processes.The critical role of bio-inks and printing methodologies in influencing cell viability is highlighted,providing insights into strategies for enhancing cellular functionality throughout the bioprinting process.Furthermore,the paper addresses post-fabrication considerations,particularly in accelerating tissue maturation,as a pivotal component for advancing the clinical applicability of bioprinted tissues.By navigating through the challenges,innovations,and prospects of advanced bioprinting strategies,this review highlights the transformative impact on tissue engineering.Pushing the boundaries of technological capabilities,these strategies hold the promise of groundbreaking advancements in regenerative medicine and personalized healthcare.Ultimately,the integration of these advanced techniques into bioprinting processes will pave the way for the development of more highly biomimetic and functional bioprinted tissues.展开更多
Biomanufacturing of tissues/organs in vitro is our big dream,driven by two needs:organ transplantation and accurate tissue models.Over the last decades,3D bioprinting has been widely applied in the construction of man...Biomanufacturing of tissues/organs in vitro is our big dream,driven by two needs:organ transplantation and accurate tissue models.Over the last decades,3D bioprinting has been widely applied in the construction of many tissues/organs such as skins,vessels,hearts,etc.,which can not only lay a foundation for the grand goal of organ replacement,but also be served as in vitro models committed to pharmacokinetics,drug screening and so on.As organs are so complicated,many bioprinting methods are exploited to figure out the challenges of different applications.So the question is how to choose the suitable bioprinting method?Herein,we systematically review the evolution,process and classification of 3D bioprinting with an emphasis on the fundamental printing principles and commercialized bioprinters.We summarize and classify extrusion-based,dropletbased,and photocuring-based bioprinting methods and give some advices for applications.Among them,coaxial and multi-material bioprinting are highlighted and basic principles of designing bioinks are also discussed.展开更多
This comprehensive review explores the multifaceted landscape of skin bioprinting,revolutionizing dermatological research.The applications of skin bioprinting utilizing techniques like extrusion-,droplet-,laser-and li...This comprehensive review explores the multifaceted landscape of skin bioprinting,revolutionizing dermatological research.The applications of skin bioprinting utilizing techniques like extrusion-,droplet-,laser-and light-based methods,with specialized bioinks for skin biofabrication have been critically reviewed along with the intricate aspects of bioprinting hair follicles,sweat glands,and achieving skin pigmentation.Challenges remain with the need for vascularization,safety concerns,and the integration of automated processes for effective clinical translation.The review further investigates the incorporation of biosensor technologies,emphasizing their role in monitoring and enhancing the wound healing process.While highlighting the remarkable progress in the field,critical limitations and concerns are critically examined to provide a balanced perspective.This synthesis aims to guide scientists,engineers,and healthcare providers,fostering a deeper understanding of the current state,challenges,and future directions in skin bioprinting for transformative applications in tissue engineering and regenerative medicine.展开更多
The global demand for effective skin injury treatments has prompted the exploration of tissue engineering solutions.While three-dimensional(3D)bioprinting has shown promise,challenges persist with respect to achieving...The global demand for effective skin injury treatments has prompted the exploration of tissue engineering solutions.While three-dimensional(3D)bioprinting has shown promise,challenges persist with respect to achieving timely and compatible solutions to treat diverse skin injuries.In situ bioprinting has emerged as a key new technology,since it reduces risks during the implantation of printed scaffolds and demonstrates superior therapeutic effects.However,maintaining printing fidelity during in situ bioprinting remains a critical challenge,particularly with respect to model layering and path planning.This study proposes a novel optimization-based conformal path planning strategy for in situ bioprinting-based repair of complex skin injuries.This strategy employs constrained optimization to identify optimal waypoints on a point cloud-approximated curved surface,thereby ensuring a high degree of similarity between predesigned planar and surface-mapped 3D paths.Furthermore,this method is applicable for skin wound treatments,since it generates 3D-equidistant zigzag curves along surface tangents and enables multi-layer conformal path planning to facilitate the treatment of volumetric injuries.Furthermore,the proposed algorithm was found to be a feasible and effective treatment in a murine back injury model as well as in other complex models,thereby showcasing its potential to guide in situ bioprinting,enhance bioprinting fidelity,and facilitate improvement of clinical outcomes.展开更多
Three-dimensional(3D)bioprinting is widely used in ophthalmic clinic,including in diagnosis,surgery,prosthetics,medications,drug development and delivery,and medical education.Articles published in 2011–2022 into bio...Three-dimensional(3D)bioprinting is widely used in ophthalmic clinic,including in diagnosis,surgery,prosthetics,medications,drug development and delivery,and medical education.Articles published in 2011–2022 into bioinks,printing technologies,and bioprinting applications in ophthalmology were reviewed and the strengths and limitations of bioprinting in ophthalmology highlighted.The review highlighted the trade-offs of printing technologies and bioinks in respect to,among others,material type cost,throughput,gelation technique,cell density,cell viability,resolution,and printing speed.There is already widespread ophthalmological application of bioprinting outside clinical settings,including in educational modelling,retinal imaging/visualization techniques and drug design/testing.In clinical settings,bioprinting has already found application in pre-operatory planning.Even so,the findings showed that even with its immense promise,actual translation to clinical applications remains distant,but relatively closer for the corneal(except stromal)tissues,epithelium,endothelium,and conjunctiva,than it was for the retina.This review similarly reflected on the critical on the technical,practical,ethical,and cost barrier to rapid progress of bioprinting in ophthalmology,including accessibility to the most sophisticated bioprinting technologies,choice,and suitability of bioinks,tissue viability and storage conditions.The extant research is encouraging,but more work is clearly required for the push towards clinical translation of research.展开更多
The global demand for in vitro respiratory airway models has surged due to the coronavirus disease 2019(COVID-19)pandemic.Current state-of-the-art models use polymer membranes to separate epithelial cells from other c...The global demand for in vitro respiratory airway models has surged due to the coronavirus disease 2019(COVID-19)pandemic.Current state-of-the-art models use polymer membranes to separate epithelial cells from other cell types,creating a nonphysiological barrier.In this study,we applied three-dimensional(3D)printing and bioprinting to develop an in vitro model where endothelial and epithelial cells were in direct contact,mimicking their natural arrangement.This proof-ofconcept model includes a culture chamber,with an endothelial bioink printed and perfused through an epithelial channel.In silico simulations of the air velocity within the channel revealed shear stress values ranging from 0.13 to 0.39 Pa,aligning with the desired in vivo shear stress observed in the bronchi regions(0.1–0.4 Pa).Biomechanical movements during resting breathing were mimicked by incorporating a textile mesh positioned away from the cell–cell interface.The epithelial channel demonstrated a capacity for compression and expansion of up to−14.7%and+6.4%,respectively.Microscopic images showed that the epithelial cells formed a uniform monolayer within the lumen of the channel close to the bioprinted endothelial cells.Our novel model offers a valuable tool for future research into respiratory diseases and potential treatments under conditions closely mimicking those in the lung.展开更多
Osteoarthritis is a common aging-related disorder that is confined mostly to the chondral layer of joints(e.g., the knee) but can spread to bony layers over time. In its early stages, osteoarthritis has minimal sympto...Osteoarthritis is a common aging-related disorder that is confined mostly to the chondral layer of joints(e.g., the knee) but can spread to bony layers over time. In its early stages, osteoarthritis has minimal symptoms;however, these gradually worsen over time and include joint pain, stiffness, loss of mobility, and inflammation. The exposed subchondral bone of a Grade 4 osteoarthritic knee is highly prone to erosion if left untreated due to persistent rubbing between the bones, which can lead to painful bone spurs. However, treating osteoarthritis is especially challenging due to the poor mitotic potential and low metabolic activity of chondrocytes. Although currently available tissue-engineered products(e.g., BST-CarGel■, TruFit■, and Atelocollagen■) can achieve structural reconstruction and tissue regeneration, final clinical outcomes can still be improved. Major challenges faced during clinical studies of tissue-engineered constructs include chondrocyte hypertrophy and the development of mechanically inferior fibrous tissue, among others. These issues can be addressed by selecting suitable biomaterial combinations, mimicking the three-dimensional(3D) architecture of the tissue matrix, and better controlling inflammation. Furthermore, it is crucial to generate essential signaling molecules within the articular cartilage ecosystem. This approach must also account for the microarchitecture of the affected joint and support the chondrogenic differentiation of mesenchymal stem cells. The use of tissue-engineered constructs has the potential to overcome each of these challenges, since materials can be modified for drug/biomolecule delivery while simultaneously facilitating the regeneration of robust articular cartilage. Three-dimensional printing has been successfully used in tissue engineering to achieve bioprinting. By manipulating conventional 3D printing techniques and the types of bioink used, many different types of bioprinting have emerged. Overall, these bioprinting techniques can be used to address various challenges associated with osteoarthritis treatment.展开更多
Bioprinting is a widely used technique for creating three-dimensional,complex,and heterogeneous artificial tissue constructs that are biologically and biophysically similar to natural tissues.The skin is composed of s...Bioprinting is a widely used technique for creating three-dimensional,complex,and heterogeneous artificial tissue constructs that are biologically and biophysically similar to natural tissues.The skin is composed of several layers including the epidermis,basement membrane(BM),and dermis.However,the unique undulating structure of basement membranes(i.e.rete ridges)and the function of BM have not been extensively studied in the fabrication of engineered skin substitutes.In this study,a novel engineered skin substitute incorporating an artificially designed rete ridge(i.e.mogul-shape)was developed using bioprinting and bioinks prepared using collagen and fibrinogen.To mimic the structure of the rete ridges of skin tissue,we developed a modified bioprinting technique,controlling rheological property of bioink to create a mogul-shaped layer.In vitro cellular activities,including the expression of specific genes(those encoding vimentin,laminin-5,collagen IV,and cytokeratins),demonstrated that the engineered skin substitute exhibited more potent cellular responses than the normally bioprinted control owing to the favorable biophysical BM structure and the bioink microenvironment.Additionally,the feasibility of utilizing the bioprinted skin-structure was evaluated in a mouse model,and in vivo results demonstrated that the bioprinted skin substitutes effectively promoted wound healing capabilities.Based on these results,we suggest that bioprinted skin tissues and the bioprinting technique for mimicking rete ridges can be used not only as potential lab-chip models for testing cosmetic materials and drugs,but also as complex physiological models for understanding human skin.展开更多
Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidel...Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidelines has limited their optimal engineering,as the factors influencing their mechanical performance and printability remain largely unexamined.In this study,we developed GC hydrogels by integrating microgels with interstitial matrices of photocrosslinkable gelatin methacrylate(GelMA).We utilized confocal microscopy and nanoindentation analyses to investigate the spatial distribution and mechanical behavior of these hydrogels.Our findings indicate that the mechanical and rheological properties of GC hydrogels can be precisely tailored by adjusting the volume fraction and size of the microgels.Furthermore,hydrogen bonds were identified as significant contributors to compressive performance,although they had minimal effect on cyclic mechanical behavior.Compared to bulk GelMA hydrogels,GC hydrogels demonstrated enhanced printability and remarkable superelasticity.As a proof of concept,we illustrated their dual printability in embedded printing to create prosthetic liver models for preoperative planning.This study provides valuable insights into the design and optimization of GC hydrogels for advanced biomedical applications.展开更多
Three-dimensional(3D)bioprinting provides a rapid and efficient method for fabricating customized bioprinted tissues that replicate the complex architecture of native tissues.However,in 3D bioprinting,the need for den...Three-dimensional(3D)bioprinting provides a rapid and efficient method for fabricating customized bioprinted tissues that replicate the complex architecture of native tissues.However,in 3D bioprinting,the need for dense biomaterial networks to ensure mechanical strength and structural fidelity often restricts the spreading,migration,and proliferation of encapsulated cells,as well as the transport of materials.This review summarizes effective strategies for manufacturing microporous bioprinted tissues via 3D bioprinting.The term“microporous”refers to interconnected,micrometer-sized pore-like structures within the internal materials of bioprinted tissues,including the microstructure of a single extruded fiber in extrusion printing.This differs from the macroscopic pore structure formed between fibers composed of print tracks or computer-aided design presets.These micropores play a crucial role in advancing biomanufacturing and 3D bioprinting by providing space for cell adhesion and proliferation while facilitating the timely transport of nutrients and metabolic waste essential for cell growth.Additionally,microporous bioprinted tissues offer the mechanical support needed for cell seeding and serve as sites for extracellular matrix deposition.As microporous 3D bioprinting continues to advance,it has the potential to address unresolved challenges in fields such as organ transplantation,tissue regeneration,and tissue replacement.展开更多
Bioprinting of cell-laden hydrogels is a rapidly growing field in tissue engineering.The advent of digital light processing(DLP)three-dimensional(3D)bioprinting technique has revolutionized the fabrication of complex ...Bioprinting of cell-laden hydrogels is a rapidly growing field in tissue engineering.The advent of digital light processing(DLP)three-dimensional(3D)bioprinting technique has revolutionized the fabrication of complex 3D structures.By adjusting light exposure,it becomes possible to control the mechanical properties of the structure,a critical factor in modulating cell activities.To better mimic cell densities in real tissues,recent progress has been made in achieving high-cell-density(HCD)printing with high resolution.However,regulating the stiffness in HCD constructs remains challenging.The large volume of cells greatly affects the light-based DLP bioprinting by causing light absorption,reflection,and scattering.Here,we introduce a neural network-based machine learning technique to predict the stiffness of cell-laden hydrogel scaffolds.Using comprehensive mechanical testing data from 3D bioprinted samples,the model was trained to deliver accurate predictions.To address the demand of working with precious and costly cell types,we employed various methods to ensure the generalizability of the model,even with limited datasets.We demonstrated a transfer learning method to achieve good performance for a precious cell type with a reduced amount of data.The chosen method outperformed many other machine learning techniques,offering a reliable and efficient solution for stiffness prediction in cell-laden scaffolds.This breakthrough paves the way for the next generation of precision bioprinting and more customized tissue engineering.展开更多
Prostate cancer(PCa),one of the leading causes of cancer-related mortality in men worldwide,presents significant challenges due to its heterogeneity and the presence of cancer stem cells(CSCs),which contribute to ther...Prostate cancer(PCa),one of the leading causes of cancer-related mortality in men worldwide,presents significant challenges due to its heterogeneity and the presence of cancer stem cells(CSCs),which contribute to therapy resistance and metastasis.Advances in three-dimensional(3D)bioprinting have ushered in a new era of precision medicine by enabling the recreation of complex tumor mi-croenvironments.This review highlights the transformative potential of 3D bioprinting technology in modelling prostate cancer stem cells(PCSCs)to identify therapeutic vulnerabilities and develop targeted treatments.By integrating bioinks with PCSCs and their niche components,3D bioprinting offers a robust platform to investigate the molecular and cellular mechanisms underlying PCa progression and resistance.Furthermore,it allows high-throughput drug scree-ning,cellular cross talks,facilitating the discovery of novel interventions aimed at eradicating CSCs while preserving healthy tissue.The review also discusses the challenges of scalability,bioink optimization,and clinical translation,alongside emerging technologies such as organ-on-chip systems and bioprinted metastatic models.This review underscores the promise of bioprinting as a disruptive in-novation in cancer care,capable of redefining therapeutic approaches and offering hope for better patient outcomes in PCa.展开更多
Vascular networks inside organs provide the means for metabolic exchange and adequate nutrition.Similarly,vascular or nutrient networks are needed when building tissue constructs>500μm in vitro due to the hydrogel...Vascular networks inside organs provide the means for metabolic exchange and adequate nutrition.Similarly,vascular or nutrient networks are needed when building tissue constructs>500μm in vitro due to the hydrogel compact pore size of bioinks.As the hydrogel used in bioinks is rather soft,it is a great challenge to reconstruct effective vascular networks.Recently,coaxial 3 D bioprinting was developed to print tissue constructs directly using hollow hydrogel fibers,which can be treated as built-in microchannels for nutrient delivery.Furthermore,vascular networks could be printed directly through coaxial 3 D bioprinting.This review summarizes recent advances in coaxial bioprinting for the fabrication of complex vascularized tissue constructs including methods,the effectiveness of varying strategies,and the use of sacrificial bioink.The limitations and challenges of coaxial 3 D bioprinting are also summarized.展开更多
Among the different bioprinting techniques,the drop-on-demand(DOD)jetting-based bioprinting approach facilitates contactless deposition of pico/nanoliter droplets ofmaterials and cells for optimal cell–matrix and cel...Among the different bioprinting techniques,the drop-on-demand(DOD)jetting-based bioprinting approach facilitates contactless deposition of pico/nanoliter droplets ofmaterials and cells for optimal cell–matrix and cell–cell interactions.Although bioinks play a critical role in the bioprinting process,there is a poor understanding of the influence of bioink properties on printing performance(such as filament elongation,formation of satellite droplets,and droplet splashing)and cell health(cell viability and proliferation)during the DOD jetting-based bioprinting process.An inert polyvinylpyrrolidone(PVP360,molecular weight=360 kDa)polymerwas used in this study to manipulate the physical properties of the bioinks and investigate the influence of bioink properties on printing performance and cell health.Our experimental results showed that a higher bioink viscoelasticity helps to stabilize droplet filaments before rupturing from the nozzle orifice.The highly stretched droplet filament resulted in the formation of highly aligned“satellite droplets,”which minimized the displacement of the satellite droplets away from the predefined positions.Next,a significant increase in the bioink viscosity facilitated droplet deposition on the wetted substrate surface in the absence of splashing and significantly improved the accuracy of the deposited main droplet.Further analysis showed that cell-laden bioinks with higher viscosity exhibited higher measured average cell viability(%),as the presence of polymer within the printed droplets provides an additional cushioning effect(higher energy dissipation)for the encapsulated cells during droplet impact on the substrate surface,improves the measured average cell viability even at higher droplet impact velocity and retains the proliferation capability of the printed cells.Understanding the influence of bioink properties(e.g.,bioink viscoelasticity and viscosity)on printing performance and cell proliferation is important for the formulation of new bioinks,and we have demonstrated precise DOD deposition of living cells and fabrication of tunable cell spheroids(nL–μL range)using multiple types of cells in a facile manner.展开更多
Articular cartilage damage caused by trauma or degenerative pathologies such as osteoarthritis can result in significant pain,mobility issues,and disability.Current surgical treatments have a limited capacity for effi...Articular cartilage damage caused by trauma or degenerative pathologies such as osteoarthritis can result in significant pain,mobility issues,and disability.Current surgical treatments have a limited capacity for efficacious cartilage repair,and long-term patient outcomes are not satisfying.Three-dimensional bioprinting has been used to fabricate biochemical and biophysical environments that aim to recapitulate the native microenvironment and promote tissue regeneration.However,conventional in vitro bioprinting has limitations due to the challenges associated with the fabrication and implantation of bioprinted constructs and their integration with the native cartilage tissue.In situ bioprinting is a novel strategy to directly deliver bioinks to the desired anatomical site and has the potential to overcome major shortcomings associated with conventional bioprinting.In this review,we focus on the new frontier of robotic-assisted in situ bioprinting surgical systems for cartilage regeneration.We outline existing clinical approaches and the utilization of robotic-assisted surgical systems.Handheld and robotic-assisted in situ bioprinting techniques including minimally invasive and non-invasive approaches are defined and presented.Finally,we discuss the challenges and potential future perspectives of in situ bioprinting for cartilage applications.展开更多
Cryobioprinting has tremendous potential to solve problems to do with lack of shelf availability in traditional bioprinting by combining extrusion bioprinting and cryopreservation.In order to ensure the viability of c...Cryobioprinting has tremendous potential to solve problems to do with lack of shelf availability in traditional bioprinting by combining extrusion bioprinting and cryopreservation.In order to ensure the viability of cells in the frozen state and avoid the possible toxicity of dimethyl sulfoxide(DMSO),DMSO-free bioink design is critical for achieving successful cryobioprinting.A nontoxic gelatin methacryloyl-based bioink used in cryobioprinting is composed of cryoprotective agents(CPAs)and a buffer solution.The selection and ratio of CPAs in the bioink directly affect the survival of cells in the frozen state.However,the development of universal and efficient cryoprotective bioinks requires extensive experimentation.We first compared two commonly used CPA formulations via experiments in this study.Results show that the effect of using ethylene glycol as the permeable CPA was 6.07%better than that of glycerol.Two datasets were obtained and four machinelearning models were established to predict experimental outcomes.The predictive powers of multiple linear regression(MLR),decision tree(DT),random forest(RF),and artificial neural network(ANN)approaches were compared,suggesting an order of ANN>RF>DT>MLR.The final selected ANN model was then applied to another dataset.Results reveal that this machine-learning method can accurately predict the effects of cryoprotective bioinks composed of different CPAs.Outcomes also suggest that the formulations presented here have universality.Our findings are likely to greatly accelerate research and development on the use of bioinks for cryobioprinting.展开更多
The review focuses on the most important areas of cell therapy for spinal cord injuries.Olfactory mucosa cells are promising for transplantation.Obtaining these cells is safe for patients.The use of olfactory mucosa c...The review focuses on the most important areas of cell therapy for spinal cord injuries.Olfactory mucosa cells are promising for transplantation.Obtaining these cells is safe for patients.The use of olfactory mucosa cells is effective in restoring motor function due to the remyelination and regeneration of axons after spinal cord injuries.These cells express neurotrophic factors that play an important role in the functional recovery of nerve tissue after spinal cord injuries.In addition,it is possible to increase the content of neurotrophic factors,at the site of injury,exogenously by the direct injection of neurotrophic factors or their delivery using gene therapy.The advantages of olfactory mucosa cells,in combination with neurotrophic factors,open up wide possibilities for their application in threedimensional and four-dimensional bioprinting technology treating spinal cord injuries.展开更多
Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for th...Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for the preparation of the microspheres.The microspheres can be automatically and high-throughput produced with this cutting-edge system.Introduction and Methods:This paper mainly introduced a novel,efficient,and cost-effective approach for the microsphere fabrication with the MBT system.In this work,the whole microsphere production equipment was built and the optimal conditions(like concentration,drying temperature,frequency,and voltage)for generating uniform hydroxypropyl cellulose-cyclosporine A(HPC-CsA)and poly-l-lactic acid(PLLA)microspheres were explored.Results:Results demonstrated that the optimal uniformity of HPC-CsA microspheres was achieved at 2%(w/v)HPC-CsA mixture,45°C(drying temperature),1,000 Hz(frequency),and 25 V(voltage amplitude).CsA microspheres[coefficient of variation(CV):~9%]are successfully synthesized,and the drug encapsulation rate was 84.8%.The methodology was further used to produce PLLA microspheres with a diameter of~2.55μm,and the best CV value achieved 6.84%.Conclusion:This investigation fully highlighted the integration of MEMS and bioprinting as a promising tool for the microsphere fabrication,and this MBT system had huge potential applications in pharmaceutical formulations and medical aesthetics.展开更多
Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods...Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods for neural regeneration.This study was designed to fabricate a type of three-dimensional collagen/silk fibroin scaffold (3D-CF) with cavities that simulate the anatomy of normal spinal cord.This scaffold allows cell growth in vitro and in vivo.To observe the effects of combined transplantation of neural stem cells (NSCs) and 3D-CF on the repair of spinal cord injury.Forty Sprague-Dawley rats were divided into four groups: sham (only laminectomy was performed),spinal cord injury (transection injury of T10 spinal cord without any transplantation),3D-CF (3D scaffold was transplanted into the local injured cavity),and 3D-CF + NSCs (3D scaffold co-cultured with NSCs was transplanted into the local injured cavity.Neuroelectrophysiology,imaging,hematoxylin-eosin staining,argentaffin staining,immunofluorescence staining,and western blot assay were performed.Apart from the sham group,neurological scores were significantly higher in the 3D-CF + NSCs group compared with other groups.Moreover,latency of the 3D-CF + NSCs group was significantly reduced,while the amplitude was significantly increased in motor evoked potential tests.The results of magnetic resonance imaging and diffusion tensor imaging showed that both spinal cord continuity and the filling of injury cavity were the best in the 3D-CF + NSCs group.Moreover,regenerative axons were abundant and glial scarring was reduced in the 3D-CF + NSCs group compared with other groups.These results confirm that implantation of 3D-CF combined with NSCs can promote the repair of injured spinal cord.This study was approved by the Institutional Animal Care and Use Committee of People’s Armed Police Force Medical Center in 2017 (approval No.2017-0007.2).展开更多
基金the Scientific and Technological Research Council of Turkey (TÜBİTAK) for their support through the TÜBİTAK 2211-A National PhD Fellowship Program
文摘The constraints of traditional 3D bioprinting are overcome by 4D bioprinting integrating with adaptable materials over time,resulting in dynamic,compliant,and functional biological structures.This innovative approach to bioprinting holds great promise for tissue engineering,regenerative medicine,and advanced drug delivery systems.4D bioprinting is a technology that allows for the extension of 3D bioprinting technology by making predesigned structures change after they are fabricated using smart materials that can alter their characteristics via stimulus,leading to transformation in healthcare,which is able to provide precise personalized effective medical treatment without any side effects.This review article concentrates on some recent developments and applications in the field of 4D bioprinting,which can pave the way for groundbreaking advancements in biomedical sciences.4D printing is a new chapter in bioprinting that introduces dynamism and functional living biological structures.Therefore,smart materials and sophisticated printing techniques can eliminate the challenges associated with printing complex organs and tissues.However,the problems with this process are biocompatibility,immunogenicity,and scalability,which need to be addressed.Moreover,numerous obstacles have been encountered during its widespread adoption in clinical practice.Therefore,4D bioprinting requires improvements in future material science innovations and further development in printers and manufacturing techniques to unlock its potential for better patient care and outcomes.
基金support from NTU Presidential Postdoctoral Fellowshipthe support from the National Research Foundation,Singapore,under its NRF Investigatorship(NRFNRFI07-2021-007,Funding Awardee:Wai Yee Yeong)。
文摘Bioprinting is a revolutionary technology within the field of tissue engineering that enables the precise fabrication of three-dimensional(3D)tissue constructs.It combines the principles of engineering and biology to create structures that closely mimic the complexity of native human tissues,facilitating advancements in regenerative medicine and personalized healthcare.This review paper systematically explores the challenges and design requirements in the fabrication of 3D biomimetic tissue constructs,emphasizing the need for advanced bioprinting strategies.Achieving biomimicry involves creating 3D anatomically relevant structures,biomimetic microenvironments,and vascularization.The focus is on overcoming existing bottlenecks through advancements in both fabrication techniques and bio-inks.Future directions in bioprinting are outlined,including multi-modal bioprinting systems,in-situ bioprinting,and the integration of machine learning into bioprinting processes.The critical role of bio-inks and printing methodologies in influencing cell viability is highlighted,providing insights into strategies for enhancing cellular functionality throughout the bioprinting process.Furthermore,the paper addresses post-fabrication considerations,particularly in accelerating tissue maturation,as a pivotal component for advancing the clinical applicability of bioprinted tissues.By navigating through the challenges,innovations,and prospects of advanced bioprinting strategies,this review highlights the transformative impact on tissue engineering.Pushing the boundaries of technological capabilities,these strategies hold the promise of groundbreaking advancements in regenerative medicine and personalized healthcare.Ultimately,the integration of these advanced techniques into bioprinting processes will pave the way for the development of more highly biomimetic and functional bioprinted tissues.
基金sponsored by the National Natural Science Foundation of China(No.U1609207)。
文摘Biomanufacturing of tissues/organs in vitro is our big dream,driven by two needs:organ transplantation and accurate tissue models.Over the last decades,3D bioprinting has been widely applied in the construction of many tissues/organs such as skins,vessels,hearts,etc.,which can not only lay a foundation for the grand goal of organ replacement,but also be served as in vitro models committed to pharmacokinetics,drug screening and so on.As organs are so complicated,many bioprinting methods are exploited to figure out the challenges of different applications.So the question is how to choose the suitable bioprinting method?Herein,we systematically review the evolution,process and classification of 3D bioprinting with an emphasis on the fundamental printing principles and commercialized bioprinters.We summarize and classify extrusion-based,dropletbased,and photocuring-based bioprinting methods and give some advices for applications.Among them,coaxial and multi-material bioprinting are highlighted and basic principles of designing bioinks are also discussed.
基金supported by National Institutes of Health Award(Nos.R01DE028614(I T O)and R21AR082668(I T O)),and 2236 CoCirculation2 of TUBITAK award(No.121C359(I T O))supported by The Assistant Secretary of Defense for Health Affairs endorsed by the Department of Defense,in the amount of($1986275)through the Peer Reviewed Medical Research Program under Award Number(No.HT9425-23-1-0487)。
文摘This comprehensive review explores the multifaceted landscape of skin bioprinting,revolutionizing dermatological research.The applications of skin bioprinting utilizing techniques like extrusion-,droplet-,laser-and light-based methods,with specialized bioinks for skin biofabrication have been critically reviewed along with the intricate aspects of bioprinting hair follicles,sweat glands,and achieving skin pigmentation.Challenges remain with the need for vascularization,safety concerns,and the integration of automated processes for effective clinical translation.The review further investigates the incorporation of biosensor technologies,emphasizing their role in monitoring and enhancing the wound healing process.While highlighting the remarkable progress in the field,critical limitations and concerns are critically examined to provide a balanced perspective.This synthesis aims to guide scientists,engineers,and healthcare providers,fostering a deeper understanding of the current state,challenges,and future directions in skin bioprinting for transformative applications in tissue engineering and regenerative medicine.
基金supported in part by the National Natural Science Foundation of China(Nos.52205532 and 624B2077)the National Key Research and Development Program of China(No.2023YFB4302003).
文摘The global demand for effective skin injury treatments has prompted the exploration of tissue engineering solutions.While three-dimensional(3D)bioprinting has shown promise,challenges persist with respect to achieving timely and compatible solutions to treat diverse skin injuries.In situ bioprinting has emerged as a key new technology,since it reduces risks during the implantation of printed scaffolds and demonstrates superior therapeutic effects.However,maintaining printing fidelity during in situ bioprinting remains a critical challenge,particularly with respect to model layering and path planning.This study proposes a novel optimization-based conformal path planning strategy for in situ bioprinting-based repair of complex skin injuries.This strategy employs constrained optimization to identify optimal waypoints on a point cloud-approximated curved surface,thereby ensuring a high degree of similarity between predesigned planar and surface-mapped 3D paths.Furthermore,this method is applicable for skin wound treatments,since it generates 3D-equidistant zigzag curves along surface tangents and enables multi-layer conformal path planning to facilitate the treatment of volumetric injuries.Furthermore,the proposed algorithm was found to be a feasible and effective treatment in a murine back injury model as well as in other complex models,thereby showcasing its potential to guide in situ bioprinting,enhance bioprinting fidelity,and facilitate improvement of clinical outcomes.
文摘Three-dimensional(3D)bioprinting is widely used in ophthalmic clinic,including in diagnosis,surgery,prosthetics,medications,drug development and delivery,and medical education.Articles published in 2011–2022 into bioinks,printing technologies,and bioprinting applications in ophthalmology were reviewed and the strengths and limitations of bioprinting in ophthalmology highlighted.The review highlighted the trade-offs of printing technologies and bioinks in respect to,among others,material type cost,throughput,gelation technique,cell density,cell viability,resolution,and printing speed.There is already widespread ophthalmological application of bioprinting outside clinical settings,including in educational modelling,retinal imaging/visualization techniques and drug design/testing.In clinical settings,bioprinting has already found application in pre-operatory planning.Even so,the findings showed that even with its immense promise,actual translation to clinical applications remains distant,but relatively closer for the corneal(except stromal)tissues,epithelium,endothelium,and conjunctiva,than it was for the retina.This review similarly reflected on the critical on the technical,practical,ethical,and cost barrier to rapid progress of bioprinting in ophthalmology,including accessibility to the most sophisticated bioprinting technologies,choice,and suitability of bioinks,tissue viability and storage conditions.The extant research is encouraging,but more work is clearly required for the push towards clinical translation of research.
基金supported by the Volkswagen Foundation(Grant No.Az 99078 to DDC,ALT,and MT)funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy–2082/1–390761711(to DDC)part of the research training group GRK 2415–Mechanobiology in Epithelial 3D Tissue Constructs(project number 363055819,to ALT and SJ).
文摘The global demand for in vitro respiratory airway models has surged due to the coronavirus disease 2019(COVID-19)pandemic.Current state-of-the-art models use polymer membranes to separate epithelial cells from other cell types,creating a nonphysiological barrier.In this study,we applied three-dimensional(3D)printing and bioprinting to develop an in vitro model where endothelial and epithelial cells were in direct contact,mimicking their natural arrangement.This proof-ofconcept model includes a culture chamber,with an endothelial bioink printed and perfused through an epithelial channel.In silico simulations of the air velocity within the channel revealed shear stress values ranging from 0.13 to 0.39 Pa,aligning with the desired in vivo shear stress observed in the bronchi regions(0.1–0.4 Pa).Biomechanical movements during resting breathing were mimicked by incorporating a textile mesh positioned away from the cell–cell interface.The epithelial channel demonstrated a capacity for compression and expansion of up to−14.7%and+6.4%,respectively.Microscopic images showed that the epithelial cells formed a uniform monolayer within the lumen of the channel close to the bioprinted endothelial cells.Our novel model offers a valuable tool for future research into respiratory diseases and potential treatments under conditions closely mimicking those in the lung.
基金Open access funding provided by Manipal Academy of Higher Education,Manipal.
文摘Osteoarthritis is a common aging-related disorder that is confined mostly to the chondral layer of joints(e.g., the knee) but can spread to bony layers over time. In its early stages, osteoarthritis has minimal symptoms;however, these gradually worsen over time and include joint pain, stiffness, loss of mobility, and inflammation. The exposed subchondral bone of a Grade 4 osteoarthritic knee is highly prone to erosion if left untreated due to persistent rubbing between the bones, which can lead to painful bone spurs. However, treating osteoarthritis is especially challenging due to the poor mitotic potential and low metabolic activity of chondrocytes. Although currently available tissue-engineered products(e.g., BST-CarGel■, TruFit■, and Atelocollagen■) can achieve structural reconstruction and tissue regeneration, final clinical outcomes can still be improved. Major challenges faced during clinical studies of tissue-engineered constructs include chondrocyte hypertrophy and the development of mechanically inferior fibrous tissue, among others. These issues can be addressed by selecting suitable biomaterial combinations, mimicking the three-dimensional(3D) architecture of the tissue matrix, and better controlling inflammation. Furthermore, it is crucial to generate essential signaling molecules within the articular cartilage ecosystem. This approach must also account for the microarchitecture of the affected joint and support the chondrogenic differentiation of mesenchymal stem cells. The use of tissue-engineered constructs has the potential to overcome each of these challenges, since materials can be modified for drug/biomolecule delivery while simultaneously facilitating the regeneration of robust articular cartilage. Three-dimensional printing has been successfully used in tissue engineering to achieve bioprinting. By manipulating conventional 3D printing techniques and the types of bioink used, many different types of bioprinting have emerged. Overall, these bioprinting techniques can be used to address various challenges associated with osteoarthritis treatment.
基金supported by the‘Korea National Institute of Health’(KNIH)research project(Project No.2022ER130502)the National Research Foundation of Korea(NRF)Grant funded by the Korea Government(MSIT)(No.2021R1A2C20060331222182102840102)。
文摘Bioprinting is a widely used technique for creating three-dimensional,complex,and heterogeneous artificial tissue constructs that are biologically and biophysically similar to natural tissues.The skin is composed of several layers including the epidermis,basement membrane(BM),and dermis.However,the unique undulating structure of basement membranes(i.e.rete ridges)and the function of BM have not been extensively studied in the fabrication of engineered skin substitutes.In this study,a novel engineered skin substitute incorporating an artificially designed rete ridge(i.e.mogul-shape)was developed using bioprinting and bioinks prepared using collagen and fibrinogen.To mimic the structure of the rete ridges of skin tissue,we developed a modified bioprinting technique,controlling rheological property of bioink to create a mogul-shaped layer.In vitro cellular activities,including the expression of specific genes(those encoding vimentin,laminin-5,collagen IV,and cytokeratins),demonstrated that the engineered skin substitute exhibited more potent cellular responses than the normally bioprinted control owing to the favorable biophysical BM structure and the bioink microenvironment.Additionally,the feasibility of utilizing the bioprinted skin-structure was evaluated in a mouse model,and in vivo results demonstrated that the bioprinted skin substitutes effectively promoted wound healing capabilities.Based on these results,we suggest that bioprinted skin tissues and the bioprinting technique for mimicking rete ridges can be used not only as potential lab-chip models for testing cosmetic materials and drugs,but also as complex physiological models for understanding human skin.
基金support from the National Natural Science Foundation of China(Nos.U21A20394 and 52305314)the Beijing Natural Science Foundation(Nos.7252285 and L246001)the National Key Research and Development Program of China(No.2023YFB4605800)。
文摘Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidelines has limited their optimal engineering,as the factors influencing their mechanical performance and printability remain largely unexamined.In this study,we developed GC hydrogels by integrating microgels with interstitial matrices of photocrosslinkable gelatin methacrylate(GelMA).We utilized confocal microscopy and nanoindentation analyses to investigate the spatial distribution and mechanical behavior of these hydrogels.Our findings indicate that the mechanical and rheological properties of GC hydrogels can be precisely tailored by adjusting the volume fraction and size of the microgels.Furthermore,hydrogen bonds were identified as significant contributors to compressive performance,although they had minimal effect on cyclic mechanical behavior.Compared to bulk GelMA hydrogels,GC hydrogels demonstrated enhanced printability and remarkable superelasticity.As a proof of concept,we illustrated their dual printability in embedded printing to create prosthetic liver models for preoperative planning.This study provides valuable insights into the design and optimization of GC hydrogels for advanced biomedical applications.
基金supported by the National Natural Science Foundation of China(Nos.82302786 and 82172394)the China Postdoctoral Science Foundation(Nos.BX20230245 and 2023M742478)+4 种基金the Sichuan Science and Technology Program(No.2023YFH0068)the Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows(No.BX202203)the Sichuan University Postdoctoral Interdisciplinary Innovation Fund(No.JCXK2226)1·3·5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(No.ZYGD23033)the Postdoctoral Research Fund of West China Hospital,Sichuan University(No.2023HXBH012).
文摘Three-dimensional(3D)bioprinting provides a rapid and efficient method for fabricating customized bioprinted tissues that replicate the complex architecture of native tissues.However,in 3D bioprinting,the need for dense biomaterial networks to ensure mechanical strength and structural fidelity often restricts the spreading,migration,and proliferation of encapsulated cells,as well as the transport of materials.This review summarizes effective strategies for manufacturing microporous bioprinted tissues via 3D bioprinting.The term“microporous”refers to interconnected,micrometer-sized pore-like structures within the internal materials of bioprinted tissues,including the microstructure of a single extruded fiber in extrusion printing.This differs from the macroscopic pore structure formed between fibers composed of print tracks or computer-aided design presets.These micropores play a crucial role in advancing biomanufacturing and 3D bioprinting by providing space for cell adhesion and proliferation while facilitating the timely transport of nutrients and metabolic waste essential for cell growth.Additionally,microporous bioprinted tissues offer the mechanical support needed for cell seeding and serve as sites for extracellular matrix deposition.As microporous 3D bioprinting continues to advance,it has the potential to address unresolved challenges in fields such as organ transplantation,tissue regeneration,and tissue replacement.
基金supported in part by the National Institutes of Health(Nos.R01HD112026 and R21ES034455)National Science Foundation(NSF,Nos.2135720 and 2223669)performed at San Diego Nanotechnology Infrastructure(SDNI)of UCSD,a member of the National Nanotechnology Coordinated Infrastructure(NNCI),which is supported by NSF(Grant No.ECCS-2025752).
文摘Bioprinting of cell-laden hydrogels is a rapidly growing field in tissue engineering.The advent of digital light processing(DLP)three-dimensional(3D)bioprinting technique has revolutionized the fabrication of complex 3D structures.By adjusting light exposure,it becomes possible to control the mechanical properties of the structure,a critical factor in modulating cell activities.To better mimic cell densities in real tissues,recent progress has been made in achieving high-cell-density(HCD)printing with high resolution.However,regulating the stiffness in HCD constructs remains challenging.The large volume of cells greatly affects the light-based DLP bioprinting by causing light absorption,reflection,and scattering.Here,we introduce a neural network-based machine learning technique to predict the stiffness of cell-laden hydrogel scaffolds.Using comprehensive mechanical testing data from 3D bioprinted samples,the model was trained to deliver accurate predictions.To address the demand of working with precious and costly cell types,we employed various methods to ensure the generalizability of the model,even with limited datasets.We demonstrated a transfer learning method to achieve good performance for a precious cell type with a reduced amount of data.The chosen method outperformed many other machine learning techniques,offering a reliable and efficient solution for stiffness prediction in cell-laden scaffolds.This breakthrough paves the way for the next generation of precision bioprinting and more customized tissue engineering.
基金Supported by GSBTM,DST Government of Gujarat for Financial Support to the Prostate Cancer Research Project at GSFC University,Vadodara,No.GSBTM/RSS/E-FILE/30/2024/0021/04306791.
文摘Prostate cancer(PCa),one of the leading causes of cancer-related mortality in men worldwide,presents significant challenges due to its heterogeneity and the presence of cancer stem cells(CSCs),which contribute to therapy resistance and metastasis.Advances in three-dimensional(3D)bioprinting have ushered in a new era of precision medicine by enabling the recreation of complex tumor mi-croenvironments.This review highlights the transformative potential of 3D bioprinting technology in modelling prostate cancer stem cells(PCSCs)to identify therapeutic vulnerabilities and develop targeted treatments.By integrating bioinks with PCSCs and their niche components,3D bioprinting offers a robust platform to investigate the molecular and cellular mechanisms underlying PCa progression and resistance.Furthermore,it allows high-throughput drug scree-ning,cellular cross talks,facilitating the discovery of novel interventions aimed at eradicating CSCs while preserving healthy tissue.The review also discusses the challenges of scalability,bioink optimization,and clinical translation,alongside emerging technologies such as organ-on-chip systems and bioprinted metastatic models.This review underscores the promise of bioprinting as a disruptive in-novation in cancer care,capable of redefining therapeutic approaches and offering hope for better patient outcomes in PCa.
基金the National Key Research and Development Program of China(No.2018YFA0703000)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.51521064)。
文摘Vascular networks inside organs provide the means for metabolic exchange and adequate nutrition.Similarly,vascular or nutrient networks are needed when building tissue constructs>500μm in vitro due to the hydrogel compact pore size of bioinks.As the hydrogel used in bioinks is rather soft,it is a great challenge to reconstruct effective vascular networks.Recently,coaxial 3 D bioprinting was developed to print tissue constructs directly using hollow hydrogel fibers,which can be treated as built-in microchannels for nutrient delivery.Furthermore,vascular networks could be printed directly through coaxial 3 D bioprinting.This review summarizes recent advances in coaxial bioprinting for the fabrication of complex vascularized tissue constructs including methods,the effectiveness of varying strategies,and the use of sacrificial bioink.The limitations and challenges of coaxial 3 D bioprinting are also summarized.
文摘Among the different bioprinting techniques,the drop-on-demand(DOD)jetting-based bioprinting approach facilitates contactless deposition of pico/nanoliter droplets ofmaterials and cells for optimal cell–matrix and cell–cell interactions.Although bioinks play a critical role in the bioprinting process,there is a poor understanding of the influence of bioink properties on printing performance(such as filament elongation,formation of satellite droplets,and droplet splashing)and cell health(cell viability and proliferation)during the DOD jetting-based bioprinting process.An inert polyvinylpyrrolidone(PVP360,molecular weight=360 kDa)polymerwas used in this study to manipulate the physical properties of the bioinks and investigate the influence of bioink properties on printing performance and cell health.Our experimental results showed that a higher bioink viscoelasticity helps to stabilize droplet filaments before rupturing from the nozzle orifice.The highly stretched droplet filament resulted in the formation of highly aligned“satellite droplets,”which minimized the displacement of the satellite droplets away from the predefined positions.Next,a significant increase in the bioink viscosity facilitated droplet deposition on the wetted substrate surface in the absence of splashing and significantly improved the accuracy of the deposited main droplet.Further analysis showed that cell-laden bioinks with higher viscosity exhibited higher measured average cell viability(%),as the presence of polymer within the printed droplets provides an additional cushioning effect(higher energy dissipation)for the encapsulated cells during droplet impact on the substrate surface,improves the measured average cell viability even at higher droplet impact velocity and retains the proliferation capability of the printed cells.Understanding the influence of bioink properties(e.g.,bioink viscoelasticity and viscosity)on printing performance and cell proliferation is important for the formulation of new bioinks,and we have demonstrated precise DOD deposition of living cells and fabrication of tunable cell spheroids(nL–μL range)using multiple types of cells in a facile manner.
基金the funding provided by the United Kingdom(UK)Engineering and Physical Sciences Research Council(EPSRC)Doctoral Prize Fellowship(EP/R513131/1)。
文摘Articular cartilage damage caused by trauma or degenerative pathologies such as osteoarthritis can result in significant pain,mobility issues,and disability.Current surgical treatments have a limited capacity for efficacious cartilage repair,and long-term patient outcomes are not satisfying.Three-dimensional bioprinting has been used to fabricate biochemical and biophysical environments that aim to recapitulate the native microenvironment and promote tissue regeneration.However,conventional in vitro bioprinting has limitations due to the challenges associated with the fabrication and implantation of bioprinted constructs and their integration with the native cartilage tissue.In situ bioprinting is a novel strategy to directly deliver bioinks to the desired anatomical site and has the potential to overcome major shortcomings associated with conventional bioprinting.In this review,we focus on the new frontier of robotic-assisted in situ bioprinting surgical systems for cartilage regeneration.We outline existing clinical approaches and the utilization of robotic-assisted surgical systems.Handheld and robotic-assisted in situ bioprinting techniques including minimally invasive and non-invasive approaches are defined and presented.Finally,we discuss the challenges and potential future perspectives of in situ bioprinting for cartilage applications.
基金supported by the Major Science and Technology Special Project of Henan Province,China(No.171100210600)the Program of China Scholarship Council(No.201807045057)+2 种基金the High Level Talent Internationalization Training Program of Henan Province,China(No.2019004)the Scientific and Technological Research Project of Henan Province,China(Nos.212102310854 and 222102310526)the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202105)。
文摘Cryobioprinting has tremendous potential to solve problems to do with lack of shelf availability in traditional bioprinting by combining extrusion bioprinting and cryopreservation.In order to ensure the viability of cells in the frozen state and avoid the possible toxicity of dimethyl sulfoxide(DMSO),DMSO-free bioink design is critical for achieving successful cryobioprinting.A nontoxic gelatin methacryloyl-based bioink used in cryobioprinting is composed of cryoprotective agents(CPAs)and a buffer solution.The selection and ratio of CPAs in the bioink directly affect the survival of cells in the frozen state.However,the development of universal and efficient cryoprotective bioinks requires extensive experimentation.We first compared two commonly used CPA formulations via experiments in this study.Results show that the effect of using ethylene glycol as the permeable CPA was 6.07%better than that of glycerol.Two datasets were obtained and four machinelearning models were established to predict experimental outcomes.The predictive powers of multiple linear regression(MLR),decision tree(DT),random forest(RF),and artificial neural network(ANN)approaches were compared,suggesting an order of ANN>RF>DT>MLR.The final selected ANN model was then applied to another dataset.Results reveal that this machine-learning method can accurately predict the effects of cryoprotective bioinks composed of different CPAs.Outcomes also suggest that the formulations presented here have universality.Our findings are likely to greatly accelerate research and development on the use of bioinks for cryobioprinting.
文摘The review focuses on the most important areas of cell therapy for spinal cord injuries.Olfactory mucosa cells are promising for transplantation.Obtaining these cells is safe for patients.The use of olfactory mucosa cells is effective in restoring motor function due to the remyelination and regeneration of axons after spinal cord injuries.These cells express neurotrophic factors that play an important role in the functional recovery of nerve tissue after spinal cord injuries.In addition,it is possible to increase the content of neurotrophic factors,at the site of injury,exogenously by the direct injection of neurotrophic factors or their delivery using gene therapy.The advantages of olfactory mucosa cells,in combination with neurotrophic factors,open up wide possibilities for their application in threedimensional and four-dimensional bioprinting technology treating spinal cord injuries.
基金sponsored by Shanghai Pujiang Program(23PJ1423400)Shanghai Rising-Star Program(23QB1405100)National Key Research and Development Program of China(2019YFA0707004 and SQ2021YFF0700202).
文摘Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for the preparation of the microspheres.The microspheres can be automatically and high-throughput produced with this cutting-edge system.Introduction and Methods:This paper mainly introduced a novel,efficient,and cost-effective approach for the microsphere fabrication with the MBT system.In this work,the whole microsphere production equipment was built and the optimal conditions(like concentration,drying temperature,frequency,and voltage)for generating uniform hydroxypropyl cellulose-cyclosporine A(HPC-CsA)and poly-l-lactic acid(PLLA)microspheres were explored.Results:Results demonstrated that the optimal uniformity of HPC-CsA microspheres was achieved at 2%(w/v)HPC-CsA mixture,45°C(drying temperature),1,000 Hz(frequency),and 25 V(voltage amplitude).CsA microspheres[coefficient of variation(CV):~9%]are successfully synthesized,and the drug encapsulation rate was 84.8%.The methodology was further used to produce PLLA microspheres with a diameter of~2.55μm,and the best CV value achieved 6.84%.Conclusion:This investigation fully highlighted the integration of MEMS and bioprinting as a promising tool for the microsphere fabrication,and this MBT system had huge potential applications in pharmaceutical formulations and medical aesthetics.
基金supported by the National Natural Science Foundation of China,No.11672332(to XYC)the National Key Research and Development Plan of China,No.2016YFC1101500(to SZ)
文摘Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods for neural regeneration.This study was designed to fabricate a type of three-dimensional collagen/silk fibroin scaffold (3D-CF) with cavities that simulate the anatomy of normal spinal cord.This scaffold allows cell growth in vitro and in vivo.To observe the effects of combined transplantation of neural stem cells (NSCs) and 3D-CF on the repair of spinal cord injury.Forty Sprague-Dawley rats were divided into four groups: sham (only laminectomy was performed),spinal cord injury (transection injury of T10 spinal cord without any transplantation),3D-CF (3D scaffold was transplanted into the local injured cavity),and 3D-CF + NSCs (3D scaffold co-cultured with NSCs was transplanted into the local injured cavity.Neuroelectrophysiology,imaging,hematoxylin-eosin staining,argentaffin staining,immunofluorescence staining,and western blot assay were performed.Apart from the sham group,neurological scores were significantly higher in the 3D-CF + NSCs group compared with other groups.Moreover,latency of the 3D-CF + NSCs group was significantly reduced,while the amplitude was significantly increased in motor evoked potential tests.The results of magnetic resonance imaging and diffusion tensor imaging showed that both spinal cord continuity and the filling of injury cavity were the best in the 3D-CF + NSCs group.Moreover,regenerative axons were abundant and glial scarring was reduced in the 3D-CF + NSCs group compared with other groups.These results confirm that implantation of 3D-CF combined with NSCs can promote the repair of injured spinal cord.This study was approved by the Institutional Animal Care and Use Committee of People’s Armed Police Force Medical Center in 2017 (approval No.2017-0007.2).
