Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering so...Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering solutions.Similar technology,particularly photo-cured bioprinting strategies,plays an important role in the field of tissue engineering research.The successful implementation of 3D bioprinting is based on the properties of photopolymerized materials.Photocrosslinkable hydrogel is an attractive biomaterial that is polymerized rapidly and enables process control in space and time.Photopolymerization is frequently initiated by ultraviolet(UV)or visible light.However,UV light may cause cell damage and thereby,affect cell viability.Thus,visible light is considered to be more biocompatible than UV light for bioprinting.In this review,we provide an overview of photo curing-based bioprinting technologies,and describe a visible light crosslinkable bioink,including its crosslinking mechanisms,types of visible light initiator,and biomedical applications.We also discuss existing challenges and prospects of visible light-induced 3D bioprinting devices and hydrogels in biomedical areas.展开更多
Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resol...Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resolution of conventional bioprinting techniques such as extrusion-and inkjet-based printing.Recently,an electrohydrodynamic(EHD)bioprinting strategy was reported for the precise deposition of well-organized cell-laden constructs with microscale filament size,whereas few studies have been devoted to developing bioinks that can be applied for EHD bioprinting and simultaneously support cell spreading.This study describes functionalized alginate-based bioinks for microscale EHD bioprinting using peptide grafting and fibrin incorporation,which leads to high cell viability(>90%)and cell spreading.The printed filaments can be further refined to as small as 30μm by incorporating polyoxyethylene and remained stable over one week when exposed to an aqueous environment.By utilizing the presented alginate-based bioinks,layer-specific cell alignment along the printing struts could be observed inside the EHD-printed microscale filaments,which allows fabricating living constructs with cell-scale filament resolution for guided cellular orientation.展开更多
The significance of bioink suitability for the extrusion bioprinting of tissue-like constructs cannot be overemphasized.Gelatin,derived from the hydrolysis of collagen,not only can mimic the extracellular matrix to imm...The significance of bioink suitability for the extrusion bioprinting of tissue-like constructs cannot be overemphasized.Gelatin,derived from the hydrolysis of collagen,not only can mimic the extracellular matrix to immensely support cell function,but also is suitable for extrusion under certain conditions.Thus,gelatin has been recognized as a promising bioink for extrusion bioprinting.However,the development of a gelatin-based bioink with satisfactory printability and bioactivity to fabricate complex tissue-like constructs with the desired physicochemical properties and biofunctions for a specific biomedical application is still in its infancy.Therefore,in this review,we aim to comprehensively summarize the state-of-the-art methods of gelatin-based bioink application for extrusion bioprinting.Wefirstly outline the properties and requirements of gelatin-based bioinks for extrusion bioprinting,highlighting the strategies to overcome their main limitations in terms of printability,structural stability and cell viability.Then,the challenges and prospects are further discussed regarding the development of ideal gelatin-based bioinks for extrusion bioprinting to create complex tissue-like constructs with preferable physicochemical properties and biofunctions.展开更多
Three-dimensional(3D)bioprinting has revolutionized tissue engineering by enabling precise fabrication with bioinks.Among these techniques,digital light processing(DLP)stands out due to its exceptional resolution,spee...Three-dimensional(3D)bioprinting has revolutionized tissue engineering by enabling precise fabrication with bioinks.Among these techniques,digital light processing(DLP)stands out due to its exceptional resolution,speed,and biocompatibility.However,the progress of DLP is hindered by the limited availability of suitable bioinks.Currently,some studies involve simple mixing of different materials,resulting in bioinks that lack uniformity and photopolymerization characteristics.To address this challenge,we present an innovative one-pot synthesis method for bioinks based on methacrylated gelatin/alginate with hydroxyapatite(HAP).This approach offers significant advantages in terms of efficiency and uniformity.The synthesized bioinks demonstrate excellent printability,stability,and notably enhanced mechanical properties,facilitating optimal in vitro compatibility.Additionally,the HAP-hybrid bioinks printed scaffolds demonstrated impressive bone repair capabilities in vivo compared with pure organic bioinks.In conclusion,the Gel/Alg/HAP bioinks presented herein offer an innovative solution for DLP bioprinting within the field of bone tissue engineering.Their multifaceted advantages help overcome the limitations of restricted bioink choices,pushing forward the boundaries of bioprinting technology and contributing to the progress of regenerative medicine and tissue engineering.展开更多
Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of g...Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of great importance for successful application of 3D bioprinting. Research efforts have been made to develop new bioinks as "raw materials" with better biocompatibility and biofunctionality, but the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting. This article aims to introduce a recent published review (Appl. Phys. Rev. 2018, 5, 041304) on the evaluation of bioink printability by Huang's research group from University of Florida. Huang et al. comprehensively reviewed the bioink printability based on the physical point of view during inkjet printing, laser printing, and microextrusion, and a series of self-consistent time scales and dimensi on less quantities were utilized to physically understand and evaluate bioink printability. This article would be helpful to know the trends on physical understanding of bioink printability.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
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
Three-dimensional(3D)bioprinting technology has great potential for application in the treatment of cartilage defects.However,the preparation of biocompatible and stable bioinks is still a major challenge.In this stud...Three-dimensional(3D)bioprinting technology has great potential for application in the treatment of cartilage defects.However,the preparation of biocompatible and stable bioinks is still a major challenge.In this study,decellularized extracellular matrix(dECM)of soft tissue was used as the basic material to prepare the bioink.Our results showed that this novel dECM-derived bioink had good printing performance and comprised a large number of fine nanofibers.Biological characterization revealed that the bioink was compatible with the growth of chondrocytes and that the nanofibrous structure greatly promoted cell proliferation.Histological and immunohistochemical analyses showed that the in vitro printed cartilage displayed the presence of characteristic cartilage lacunae.Thus,a new preparation method for dECM-derived bioink with potential application in generation of cartilage was developed in this study.展开更多
Ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural regeneration.Variation in oxygen concentration among diverse tissues necessita...Ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural regeneration.Variation in oxygen concentration among diverse tissues necessitates the precise recreation of tissue-specific oxygen levels in imprinted constructs to support the survival of targeted cells.Although oxygen-releasing biomaterials,such as oxygen-generating microparticles(OMPs),have shown promise for enhancing the oxygen supply of microenvironments in injured tissues,whether this approach is scalable for large tissues and whether tissue-specific bioinks with varying OMP concentrations remain printable remain unknown.This study addresses this critical gap by introducing an innovative class of engineered oxygenated bioinks that combine colloidal-based microgels with OMPs.We report that incorporating nanosized calcium peroxide(nCaO_(2))and manganese oxide nanosheets(nMnO_(2))into hydrophobic polymeric microparticles enables precise modulation of oxygen release while controlling hydrogen peroxide release.Moreover,the fabrication of oxygenating and cytocompatible colloidal gels is achieved using an aqueous two-phase system.This study thoroughly evaluates the fundamental characteristics of the resulting bioink,including its rheological behaviors,printability,shape fidelity,mechanical properties,and oxygen release properties.Moreover,this study demonstrates the macroscopic scalability and cytocompatibility of printed constructs produced via cell-laden oxygenating colloidal bioinks.By showcasing the effectiveness of extrusion-based bioprinting,this study underscores how it can be used to fabricate biomimetic tissues,indicating its potential for new applications.The findings presented here advance the bioprinting field by achieving scalability with both high cell viability and the possibility of mimicking specifically oxygenated tissues.This work thereby offers a promising avenue for the development of functional tissues with enhanced physiological relevance.展开更多
Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-en...Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-engineered structures are intended to integrate with the patient’s body.Vascular tissue engineering(TE)is relevant in TE because it supports the sustained oxygenization and nutrition of all tissue-engineered constructs.Bioinks have a specific role,representingthenecessarymedium for printability and vascular cell growth.This review aims to understand the requirements for the design of vascular bioinks.First,an in-depth analysis of vascular cell interaction with their native environment must be gained.A physiological bioink suitable for a tissue-engineered vascular graft(TEVG)must not only ensure good printability but also induce cells to behave like in a native vascular vessel,including self-regenerative and growth functions.This review describes the general structure of vascular walls with wall-specific cell and extracellular matrix(ECM)components and biomechanical properties and functions.Furthermore,the physiological role of vascular ECM components for their interaction with vascular cells and the mode of interaction is introduced.Diverse currently available or imaginable bioinks are described from physiological matrix proteins to nonphysiologically occurring but natural chemical compounds useful for vascular bioprinting.The physiological performance of these bioinks is evaluated with regard to biomechanical properties postprinting,with a view to current animal studies of 3D printed vascular structures.Finally,the main challenges for further bioink development,suitable bioink components to create a self-assembly bioink concept,and future bioprinting strategies are outlined.These concepts are discussed in terms of their suitability to be part of a TEVG with a high potential for later clinical use.展开更多
Geometric and structural integrity often deteriorate in 3D printed cell-laden constructs over time due to cellular compaction and hydrogel shrinkage.This study introduces a new approach that synergizes the advantages ...Geometric and structural integrity often deteriorate in 3D printed cell-laden constructs over time due to cellular compaction and hydrogel shrinkage.This study introduces a new approach that synergizes the advantages of cell compatibility of biological hydrogels and mechanical stability of elastomeric polymers for structure fidelity maintenance upon stereolithography and extrusion 3D printing.Enabling this advance is the composite bioink,formulated by integrating elastomeric microparticles from poly(octamethylene maleate(anhydride)citrate)(POMaC)into biologically derived hydrogels(fibrin,gelatin methacryloyl(GelMA),and alginate).The composite bioink enhanced the elasticity and plasticity of the 3D printed constructs,effectively mitigating tissue compaction and swelling.It exhibited a low shear modulus and a rapid crosslinking time,along with a high ultimate compressive strength and resistance to deformation from cellular forces and physical handling;this was attributed to packing and stress dissipation of elastomeric particles,which was confirmed via mathematical modelling.Enhanced functional assembly and stability of human iPSC-derived cardiac tissues and primary vasculature proved the utility of the composite bioink in tissue engineering.In vivo implantation studies revealed that constructs containing POMaC particles exhibited improved resilience against host tissue stress,enhanced angiogenesis,and infiltration of pro-reparative macrophages.展开更多
Extrusion-based 3D bioprinting is being increasingly adopted as a versatile biofabrication method for making biomimetic constructs in tissue engineering.However,the lack of ideal bioinks continues to limit its broader...Extrusion-based 3D bioprinting is being increasingly adopted as a versatile biofabrication method for making biomimetic constructs in tissue engineering.However,the lack of ideal bioinks continues to limit its broader application.Conventional hydrogel-based bioinks typically possess a densely crosslinked nanoporous structure that hinders their ability to fully support cell behavior.Microgel-based bioinks have recently emerged as a promising alternative due to their enhanced printability and functionality.This review will begin with the evolution of the“bioink"concept,followed by a discussion on bioink categories and the requirements of ideal bioinks.It will then introduce hydrogel-based bioinks and their limitations,followed by a definition of microgels and microgel-based bioinks and a discussion of their key properties,highlighting their differences compared to conventional hydrogel-based bioinks.Topics on microgel-based bioinks are then presented in order of the printing process:pre-printing(fabrication of microgels and formulation of microgel-based bioinks),during printing and post-printing(microgel assembly kinetics).Uniquely,this review will examine the various appli-cations of microgel-based bioinks in tissue engineering,summarizing their advantages and limitations.Finally,the current challenges and future perspectives of using microgel-based bioinks are discussed.This review comprehensively examines microgel-based bioinks for 3D bioprinting,highlighting their potential to overcome current challenges and setting the stage for their future applications in creating complex,functional tissue en-gineering scaffolds.展开更多
Tissue-engineered anisotropic cell constructs are promising candidates for treating volumetric muscle loss(VML).However,achieving successful cell alignment within macroscale 3D cell constructs for skeletal muscle tiss...Tissue-engineered anisotropic cell constructs are promising candidates for treating volumetric muscle loss(VML).However,achieving successful cell alignment within macroscale 3D cell constructs for skeletal muscle tissue regeneration remains challenging,owing to difficulties in controlling cell arrangement within a low-viscosity hydrogel.Herein,we propose the concept of a magnetorheological bioink to manipulate the cellular arrangement within a low-viscosity hydrogel.This bioink consisted of gelatin methacrylate(GelMA),iron oxide nanoparticles,and human adipose stem cells(hASCs).The cell arrangement is regulated by the responsiveness of iron oxide nanoparticles to external magnetic fields.A bioprinting process using ring magnets was developed for in situ bioprinting,resulting in well-aligned 3D cell structures and enhanced mechanotransduction effects on hASCs.In vitro analyses revealed upregulation of cellular activities,including myogenic-related gene expression,in hASCs.When implanted into a VML mouse model,the bioconstructs improved muscle functionality and regeneration,validating the effectiveness of the proposed approach.展开更多
The scarcity of human donor corneal graft tissue worldwide available for corneal transplantation necessitates the development of alternative therapeutic strategies for treating patients with corneal blindness.Corneal ...The scarcity of human donor corneal graft tissue worldwide available for corneal transplantation necessitates the development of alternative therapeutic strategies for treating patients with corneal blindness.Corneal stromal stem cells(CSSCs)have the potential to address this global shortage by allowing a single donor cornea to treat multiple patients.To directly deliver CSSCs to corneal defects within an engineered biomatrix,we developed a UNIversal Orthogonal Network(UNION)collagen bioink that crosslinks in situ with a bioorthogonal,covalent chemistry.This cell-gel therapy is optically transparent,stable against contraction forces exerted by CSSCs,and permissive to the efficient growth of corneal epithelial cells.Furthermore,CSSCs remain viable within the UNION collagen gel precursor solution under standard storage and transportation conditions.This approach promoted corneal transparency and re-epithelialization in a rabbit anterior lamellar keratoplasty model,indi-cating that the UNION collagen bioink serves effectively as an in situ-forming,suture-free therapy for delivering CSSCs to corneal wounds.展开更多
Tissue engineering provides a promising strategy for auricular reconstruction.Although the first international clinical breakthrough of tissue-engineered auricular reconstruction has been realized based on polymer sca...Tissue engineering provides a promising strategy for auricular reconstruction.Although the first international clinical breakthrough of tissue-engineered auricular reconstruction has been realized based on polymer scaffolds,this approach has not been recognized as a clinically available treatment because of its unsatisfactory clinical efficacy.This is mainly since reconstruction constructs easily cause inflammation and deformation.In this study,we present a novel strategy for the development of biological auricle equivalents with precise shapes,low immunogenicity,and excellent mechanics using auricular chondrocytes and a bioactive bioink based on biomimetic microporous methacrylate-modified acellular cartilage matrix(ACMMA)with the assistance of gelatin methacrylate(GelMA),poly(ethylene oxide)(PEO),and polycaprolactone(PCL)by integrating multi-nozzle bioprinting technology.Photocrosslinkable ACMMA is used to emulate the intricacy of the cartilage-specific microenvironment for active cellular behavior,while GelMA,PEO,and PCL are used to balance printability and physical properties for precise structural stability,form the microporous structure for unhindered nutrient exchange,and provide mechanical support for higher shape fidelity,respectively.Finally,mature auricular cartilage-like tissues with high morphological fidelity,excellent elasticity,abundant cartilage lacunae,and cartilage-specific ECM deposition are successfully regenerated in vivo,which provides new opportunities and novel strategies for the fabrication and regeneration of patient-specific auricular cartilage.展开更多
Bioinks are formulations of biomaterials and living cells, sometimes with growth factors or other biomolecules, while extrusion bioprinting is an emerging technique to apply or deposit these bioinks or biomaterial sol...Bioinks are formulations of biomaterials and living cells, sometimes with growth factors or other biomolecules, while extrusion bioprinting is an emerging technique to apply or deposit these bioinks or biomaterial solutions to create three-dimensional (3D) constructs with architectures and mechanical/biological properties that mimic those of native human tissue or organs. Printed constructs have found wide applications in tissue engineering for repairing or treating tissue/organ injuries, as well as in vitro tissue modelling for testing or validating newly developed therapeutics and vaccines prior to their use in humans. Successful printing of constructs and their subsequent applications rely on the properties of the formulated bioinks, including the rheological, mechanical, and biological properties, as well as the printing process. This article critically reviews the latest developments in bioinks and biomaterial solutions for extrusion bioprinting, focusing on bioink synthesis and characterization, as well as the influence of bioink properties on the printing process. Key issues and challenges are also discussed along with recommendations for future research.展开更多
Extrusion-based bioprinting (EBB) holds potential for regenerative medicine. However, the widely-used bioinks of EBB exhibit some limitations for skin regeneration, such as unsatisfactory bio-physical (i.e., mechanica...Extrusion-based bioprinting (EBB) holds potential for regenerative medicine. However, the widely-used bioinks of EBB exhibit some limitations for skin regeneration, such as unsatisfactory bio-physical (i.e., mechanical, structural, biodegradable) properties and compromised cellular compatibilities, and the EBB-based bioinks with therapeutic effects targeting cutaneous wounds still remain largely undiscussed. In this review, the printability considerations for skin bioprinting were discussed. Then, current strategies for improving the physical properties of bioinks and for reinforcing bioinks in EBB approaches were introduced, respectively. Notably, we highlighted the applications and effects of current EBB-based bioinks on wound healing, wound scar formation, vasculari-zation and the regeneration of skin appendages (i.e., sweat glands and hair follicles) and discussed the challenges and future perspectives. This review aims to provide an overall view of the applications, challenges and promising solutions about the EBB-based bioinks for cutaneous wound healing and skin regeneration.展开更多
3-dimensional(3D)bioprinting technology provides promising strategy in the fabrication of artificial tissues and organs.As the fundamental element in bioprinting process,preparation of bioink with ideal mechanical pro...3-dimensional(3D)bioprinting technology provides promising strategy in the fabrication of artificial tissues and organs.As the fundamental element in bioprinting process,preparation of bioink with ideal mechanical properties without sacrifice of biocompatibility is a great challenge.In this study,a supramolecular hydrogel-based bioink is prepared by polyethylene glycol(PEG)grafted chitosan,α-cyclodextrin(α-CD)and gelatin.It has a primary crosslinking structure through the aggregation of the pseudo-polyrotaxane-like side chains,which are formed from the host-vip interactions betweenα-CD and PEG side chain.Apparent viscosity measurement shows the shear-shinning property of this bioink,which might be due to the reversibility of the physical crosslinking.Moreover,withβ-glycerophosphate at different concentrations as the secondary crosslinking agent,the printed constructs demonstrate different Young's modulus(p<0.001).They could also maintain the Young's modulus in cell culture condition for at least 21 days(p<0.05).By co-culturing each component with fibroblasts,CCK-8 assay demonstrate cellular viability is higher than 80%.After bioprinting and culturing,immunofluorescence staining with quantification indicate the expression of Ki-67,Paxillin,and N-cadherin is higher in day 14 than those in day 3(p<0.05).Oil red O and Nissl body specific staining reflect strength tunable bioink may have impact on the cell fate of mesenchymal stem cells(p<0.05).This work might provide new idea for advanced bioink in the application of re-establishing complicated tissues and organs.展开更多
In the field of regenerative medicine,the importance of 3D bioprinting is self-evident and nonnegligible.However,3D bioprinting technology also requires bioink with excellent performance as support material to fabrica...In the field of regenerative medicine,the importance of 3D bioprinting is self-evident and nonnegligible.However,3D bioprinting technology also requires bioink with excellent performance as support material to fabricate a multi-functional bioinspired scaffold.Collagen-based bioink is regarded as an ideal 3D bioprinting ink for its excellent biocompatibility,controllable printability and cell loading property.It is an important breakthrough in regenerative medicine with the progress of collagen-based bioink,which fabricates bioinspired scaffolds with different functions and is applied in different repair scenarios.This review summarizes the different applications of collagen-based bioink and classifies them as soft tissue and hard tissue according to the target region.The applications of target region in soft tissues include skin,cartilage,heart and blood vessels,while in hard tissues include femur,skull,teeth and spine.When the collagen-based bioink is applied in repairing soft tissue,the requirements of function are higher,while the mechanical properties must be further improved in repairing hard tissue.We further summarize the characteristics of collagen-based bioink and point out the most important properties that should be considered in different repair scenarios,which can provide reference for the preparation of bioinks with different functions.Finally,we point out the main challenges faced by collagen-based bioink and prospect the future research directions.展开更多
The ready-to-use,structure-supporting hydrogel bioink can shorten the time for ink preparation,ensure cell dispersion,and maintain the preset shape/microstructure without additional assistance during printing.Meanwhil...The ready-to-use,structure-supporting hydrogel bioink can shorten the time for ink preparation,ensure cell dispersion,and maintain the preset shape/microstructure without additional assistance during printing.Meanwhile,ink with high permeability might facilitate uniform cell growth in biological constructs,which is beneficial to homogeneous tissue repair.Unfortunately,current bioinks are hard to meet these requirements simultaneously in a simple way.Here,based on the fast dynamic crosslinking of aldehyde hyaluronic acid(AHA)/N-carboxymethyl chitosan(CMC)and the slow stable crosslinking of gelatin(GEL)/4-arm poly(ethylene glycol)succinimidyl glutarate(PEG-SG),we present a time-sharing structure-supporting(TSHSP)hydrogel bioink with high permeability,containing 1%AHA,0.75%CMC,1%GEL and 0.5%PEG-SG.The TSHSP hydrogel can facilitate printing with proper viscoelastic property and self-healing behavior.By crosslinking with 4%PEG-SG for only 3 min,the integrity of the cell-laden construct can last for 21 days due to the stable internal and external GEL/PEG-SG networks,and cells manifested long-term viability and spreading morphology.Nerve-like,muscle-like,and cartilage-like in vitro constructs exhibited homogeneous cell growth and remarkable biological specificities.This work provides not only a convenient and practical bioink for tissue engineering,targeted cell therapy,but also a new direction for hydrogel bioink development.展开更多
基金supported by the Key-Area Research and Development Program of Guangdong Province(2019B010941001)the Shenzhen Double Chain Project for Innovation and Development Industry supported by the Bureau of Industry and Information Technology of Shenzhen(201908141541)Shenzhen Fundamental Research Foundation(GJHZ20170314154845576 and GJHS20170314161106706).
文摘Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering solutions.Similar technology,particularly photo-cured bioprinting strategies,plays an important role in the field of tissue engineering research.The successful implementation of 3D bioprinting is based on the properties of photopolymerized materials.Photocrosslinkable hydrogel is an attractive biomaterial that is polymerized rapidly and enables process control in space and time.Photopolymerization is frequently initiated by ultraviolet(UV)or visible light.However,UV light may cause cell damage and thereby,affect cell viability.Thus,visible light is considered to be more biocompatible than UV light for bioprinting.In this review,we provide an overview of photo curing-based bioprinting technologies,and describe a visible light crosslinkable bioink,including its crosslinking mechanisms,types of visible light initiator,and biomedical applications.We also discuss existing challenges and prospects of visible light-induced 3D bioprinting devices and hydrogels in biomedical areas.
基金This work was financially supported by the National Key Research and Development Program of China(No.2018YFA0703003)the National Natural Science Foundation of China(No.52125501)+1 种基金the Key Research Project of Shaanxi Province(Nos.2021LLRH-08,2020GXLH-Y-021,and 2021GXLH-Z-028)the Youth InnovationTeam of Shaanxi Universities and the Fundamental Research Funds for the Central Universities.
文摘Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resolution of conventional bioprinting techniques such as extrusion-and inkjet-based printing.Recently,an electrohydrodynamic(EHD)bioprinting strategy was reported for the precise deposition of well-organized cell-laden constructs with microscale filament size,whereas few studies have been devoted to developing bioinks that can be applied for EHD bioprinting and simultaneously support cell spreading.This study describes functionalized alginate-based bioinks for microscale EHD bioprinting using peptide grafting and fibrin incorporation,which leads to high cell viability(>90%)and cell spreading.The printed filaments can be further refined to as small as 30μm by incorporating polyoxyethylene and remained stable over one week when exposed to an aqueous environment.By utilizing the presented alginate-based bioinks,layer-specific cell alignment along the printing struts could be observed inside the EHD-printed microscale filaments,which allows fabricating living constructs with cell-scale filament resolution for guided cellular orientation.
基金support for this work from the National Key R&D Program of China(No.2018YFA0703100)the National Natural Sci-ence Foundation of China(Nos.32122046,82072082,and 32000959)+2 种基金the Youth Innovation Promotion Association of CAS(No.2019350)the Guangdong Natural Science Foundation(No.2019A1515111197)the Shenzhen Fundamental Research Foun-dation(Nos.JCYJ20190812162809131,JCYJ20200109114006014,JCYJ20210324113001005,and JCYJ20210324115814040).
文摘The significance of bioink suitability for the extrusion bioprinting of tissue-like constructs cannot be overemphasized.Gelatin,derived from the hydrolysis of collagen,not only can mimic the extracellular matrix to immensely support cell function,but also is suitable for extrusion under certain conditions.Thus,gelatin has been recognized as a promising bioink for extrusion bioprinting.However,the development of a gelatin-based bioink with satisfactory printability and bioactivity to fabricate complex tissue-like constructs with the desired physicochemical properties and biofunctions for a specific biomedical application is still in its infancy.Therefore,in this review,we aim to comprehensively summarize the state-of-the-art methods of gelatin-based bioink application for extrusion bioprinting.Wefirstly outline the properties and requirements of gelatin-based bioinks for extrusion bioprinting,highlighting the strategies to overcome their main limitations in terms of printability,structural stability and cell viability.Then,the challenges and prospects are further discussed regarding the development of ideal gelatin-based bioinks for extrusion bioprinting to create complex tissue-like constructs with preferable physicochemical properties and biofunctions.
基金financial support from the National Natural Science Foundation of China(Nos.82202335,82230071,and 82172098)the Shanghai Sailing Program(No.22YF1414000).
文摘Three-dimensional(3D)bioprinting has revolutionized tissue engineering by enabling precise fabrication with bioinks.Among these techniques,digital light processing(DLP)stands out due to its exceptional resolution,speed,and biocompatibility.However,the progress of DLP is hindered by the limited availability of suitable bioinks.Currently,some studies involve simple mixing of different materials,resulting in bioinks that lack uniformity and photopolymerization characteristics.To address this challenge,we present an innovative one-pot synthesis method for bioinks based on methacrylated gelatin/alginate with hydroxyapatite(HAP).This approach offers significant advantages in terms of efficiency and uniformity.The synthesized bioinks demonstrate excellent printability,stability,and notably enhanced mechanical properties,facilitating optimal in vitro compatibility.Additionally,the HAP-hybrid bioinks printed scaffolds demonstrated impressive bone repair capabilities in vivo compared with pure organic bioinks.In conclusion,the Gel/Alg/HAP bioinks presented herein offer an innovative solution for DLP bioprinting within the field of bone tissue engineering.Their multifaceted advantages help overcome the limitations of restricted bioink choices,pushing forward the boundaries of bioprinting technology and contributing to the progress of regenerative medicine and tissue engineering.
文摘Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of great importance for successful application of 3D bioprinting. Research efforts have been made to develop new bioinks as "raw materials" with better biocompatibility and biofunctionality, but the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting. This article aims to introduce a recent published review (Appl. Phys. Rev. 2018, 5, 041304) on the evaluation of bioink printability by Huang's research group from University of Florida. Huang et al. comprehensively reviewed the bioink printability based on the physical point of view during inkjet printing, laser printing, and microextrusion, and a series of self-consistent time scales and dimensi on less quantities were utilized to physically understand and evaluate bioink printability. This article would be helpful to know the trends on physical understanding of bioink printability.
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.
基金the National Key Research and Development Program of China(Nos.2018YFB1105600,and 2018YFA0703000)the National Natural Science Foundation of China(No.81802131)the China Postdoctoral Science Foundation(No.2019T120347)。
文摘Three-dimensional(3D)bioprinting technology has great potential for application in the treatment of cartilage defects.However,the preparation of biocompatible and stable bioinks is still a major challenge.In this study,decellularized extracellular matrix(dECM)of soft tissue was used as the basic material to prepare the bioink.Our results showed that this novel dECM-derived bioink had good printing performance and comprised a large number of fine nanofibers.Biological characterization revealed that the bioink was compatible with the growth of chondrocytes and that the nanofibrous structure greatly promoted cell proliferation.Histological and immunohistochemical analyses showed that the in vitro printed cartilage displayed the presence of characteristic cartilage lacunae.Thus,a new preparation method for dECM-derived bioink with potential application in generation of cartilage was developed in this study.
基金funded by the National Insti-tutes of Health(No.R01 AR074234)AHA collaborative award(No.944227)the Gillian Reny Stepping Strong Center for Trauma Inno-vation at Brigham and Women's Hospital.
文摘Ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural regeneration.Variation in oxygen concentration among diverse tissues necessitates the precise recreation of tissue-specific oxygen levels in imprinted constructs to support the survival of targeted cells.Although oxygen-releasing biomaterials,such as oxygen-generating microparticles(OMPs),have shown promise for enhancing the oxygen supply of microenvironments in injured tissues,whether this approach is scalable for large tissues and whether tissue-specific bioinks with varying OMP concentrations remain printable remain unknown.This study addresses this critical gap by introducing an innovative class of engineered oxygenated bioinks that combine colloidal-based microgels with OMPs.We report that incorporating nanosized calcium peroxide(nCaO_(2))and manganese oxide nanosheets(nMnO_(2))into hydrophobic polymeric microparticles enables precise modulation of oxygen release while controlling hydrogen peroxide release.Moreover,the fabrication of oxygenating and cytocompatible colloidal gels is achieved using an aqueous two-phase system.This study thoroughly evaluates the fundamental characteristics of the resulting bioink,including its rheological behaviors,printability,shape fidelity,mechanical properties,and oxygen release properties.Moreover,this study demonstrates the macroscopic scalability and cytocompatibility of printed constructs produced via cell-laden oxygenating colloidal bioinks.By showcasing the effectiveness of extrusion-based bioprinting,this study underscores how it can be used to fabricate biomimetic tissues,indicating its potential for new applications.The findings presented here advance the bioprinting field by achieving scalability with both high cell viability and the possibility of mimicking specifically oxygenated tissues.This work thereby offers a promising avenue for the development of functional tissues with enhanced physiological relevance.
文摘Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-engineered structures are intended to integrate with the patient’s body.Vascular tissue engineering(TE)is relevant in TE because it supports the sustained oxygenization and nutrition of all tissue-engineered constructs.Bioinks have a specific role,representingthenecessarymedium for printability and vascular cell growth.This review aims to understand the requirements for the design of vascular bioinks.First,an in-depth analysis of vascular cell interaction with their native environment must be gained.A physiological bioink suitable for a tissue-engineered vascular graft(TEVG)must not only ensure good printability but also induce cells to behave like in a native vascular vessel,including self-regenerative and growth functions.This review describes the general structure of vascular walls with wall-specific cell and extracellular matrix(ECM)components and biomechanical properties and functions.Furthermore,the physiological role of vascular ECM components for their interaction with vascular cells and the mode of interaction is introduced.Diverse currently available or imaginable bioinks are described from physiological matrix proteins to nonphysiologically occurring but natural chemical compounds useful for vascular bioprinting.The physiological performance of these bioinks is evaluated with regard to biomechanical properties postprinting,with a view to current animal studies of 3D printed vascular structures.Finally,the main challenges for further bioink development,suitable bioink components to create a self-assembly bioink concept,and future bioprinting strategies are outlined.These concepts are discussed in terms of their suitability to be part of a TEVG with a high potential for later clinical use.
文摘Geometric and structural integrity often deteriorate in 3D printed cell-laden constructs over time due to cellular compaction and hydrogel shrinkage.This study introduces a new approach that synergizes the advantages of cell compatibility of biological hydrogels and mechanical stability of elastomeric polymers for structure fidelity maintenance upon stereolithography and extrusion 3D printing.Enabling this advance is the composite bioink,formulated by integrating elastomeric microparticles from poly(octamethylene maleate(anhydride)citrate)(POMaC)into biologically derived hydrogels(fibrin,gelatin methacryloyl(GelMA),and alginate).The composite bioink enhanced the elasticity and plasticity of the 3D printed constructs,effectively mitigating tissue compaction and swelling.It exhibited a low shear modulus and a rapid crosslinking time,along with a high ultimate compressive strength and resistance to deformation from cellular forces and physical handling;this was attributed to packing and stress dissipation of elastomeric particles,which was confirmed via mathematical modelling.Enhanced functional assembly and stability of human iPSC-derived cardiac tissues and primary vasculature proved the utility of the composite bioink in tissue engineering.In vivo implantation studies revealed that constructs containing POMaC particles exhibited improved resilience against host tissue stress,enhanced angiogenesis,and infiltration of pro-reparative macrophages.
基金supported by the RMIT Vice-Chancellor’s Senior Research Fellowship 2020.K.S L.acknowledges RMIT HDR Scholarshipthe Australian Research Council Discovery Early Career Researcher Fellowship(DE190101514).
文摘Extrusion-based 3D bioprinting is being increasingly adopted as a versatile biofabrication method for making biomimetic constructs in tissue engineering.However,the lack of ideal bioinks continues to limit its broader application.Conventional hydrogel-based bioinks typically possess a densely crosslinked nanoporous structure that hinders their ability to fully support cell behavior.Microgel-based bioinks have recently emerged as a promising alternative due to their enhanced printability and functionality.This review will begin with the evolution of the“bioink"concept,followed by a discussion on bioink categories and the requirements of ideal bioinks.It will then introduce hydrogel-based bioinks and their limitations,followed by a definition of microgels and microgel-based bioinks and a discussion of their key properties,highlighting their differences compared to conventional hydrogel-based bioinks.Topics on microgel-based bioinks are then presented in order of the printing process:pre-printing(fabrication of microgels and formulation of microgel-based bioinks),during printing and post-printing(microgel assembly kinetics).Uniquely,this review will examine the various appli-cations of microgel-based bioinks in tissue engineering,summarizing their advantages and limitations.Finally,the current challenges and future perspectives of using microgel-based bioinks are discussed.This review comprehensively examines microgel-based bioinks for 3D bioprinting,highlighting their potential to overcome current challenges and setting the stage for their future applications in creating complex,functional tissue en-gineering scaffolds.
基金supported by the’Korea National Institute of Health’research project(2022ER130502)a grant from by SMC-SKKU Future Convergence Academic Research Program,2024.In additionsupported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2024-00336758).
文摘Tissue-engineered anisotropic cell constructs are promising candidates for treating volumetric muscle loss(VML).However,achieving successful cell alignment within macroscale 3D cell constructs for skeletal muscle tissue regeneration remains challenging,owing to difficulties in controlling cell arrangement within a low-viscosity hydrogel.Herein,we propose the concept of a magnetorheological bioink to manipulate the cellular arrangement within a low-viscosity hydrogel.This bioink consisted of gelatin methacrylate(GelMA),iron oxide nanoparticles,and human adipose stem cells(hASCs).The cell arrangement is regulated by the responsiveness of iron oxide nanoparticles to external magnetic fields.A bioprinting process using ring magnets was developed for in situ bioprinting,resulting in well-aligned 3D cell structures and enhanced mechanotransduction effects on hASCs.In vitro analyses revealed upregulation of cellular activities,including myogenic-related gene expression,in hASCs.When implanted into a VML mouse model,the bioconstructs improved muscle functionality and regeneration,validating the effectiveness of the proposed approach.
基金supported by the National Science Foundation,grants DGE-165618(L.G.B.),DMR-2103812(S.C.H.),DMR-2427971(S.C.H.),and CBET-2033302(S C H)the National Institutes of Health,grants F31-EY034785(L G B),F31-EY030731(S.M.H.),R01-EY035697(S C H.,D.M.),R01-EY033363(D.M.),and P30-EY026877(D.M.)+3 种基金the ARCS Foundation Scholarship(L.G.B.)the Stanford Bio-X Interdisci-plinary Graduate Fellowship(B.C.,S.M.H.)the Stanford Knight-Hennessy Scholars Program(B.C.)and a departmental core grant from Research to Prevent Blindness(D.M.).
文摘The scarcity of human donor corneal graft tissue worldwide available for corneal transplantation necessitates the development of alternative therapeutic strategies for treating patients with corneal blindness.Corneal stromal stem cells(CSSCs)have the potential to address this global shortage by allowing a single donor cornea to treat multiple patients.To directly deliver CSSCs to corneal defects within an engineered biomatrix,we developed a UNIversal Orthogonal Network(UNION)collagen bioink that crosslinks in situ with a bioorthogonal,covalent chemistry.This cell-gel therapy is optically transparent,stable against contraction forces exerted by CSSCs,and permissive to the efficient growth of corneal epithelial cells.Furthermore,CSSCs remain viable within the UNION collagen gel precursor solution under standard storage and transportation conditions.This approach promoted corneal transparency and re-epithelialization in a rabbit anterior lamellar keratoplasty model,indi-cating that the UNION collagen bioink serves effectively as an in situ-forming,suture-free therapy for delivering CSSCs to corneal wounds.
基金supported by the National Key Research and Development Program of China(2017YFC1103900)the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(2017-I2M-1-007,2021-I2M-1-052)the National Natural Science Foundation of China(81871502,81871575).
文摘Tissue engineering provides a promising strategy for auricular reconstruction.Although the first international clinical breakthrough of tissue-engineered auricular reconstruction has been realized based on polymer scaffolds,this approach has not been recognized as a clinically available treatment because of its unsatisfactory clinical efficacy.This is mainly since reconstruction constructs easily cause inflammation and deformation.In this study,we present a novel strategy for the development of biological auricle equivalents with precise shapes,low immunogenicity,and excellent mechanics using auricular chondrocytes and a bioactive bioink based on biomimetic microporous methacrylate-modified acellular cartilage matrix(ACMMA)with the assistance of gelatin methacrylate(GelMA),poly(ethylene oxide)(PEO),and polycaprolactone(PCL)by integrating multi-nozzle bioprinting technology.Photocrosslinkable ACMMA is used to emulate the intricacy of the cartilage-specific microenvironment for active cellular behavior,while GelMA,PEO,and PCL are used to balance printability and physical properties for precise structural stability,form the microporous structure for unhindered nutrient exchange,and provide mechanical support for higher shape fidelity,respectively.Finally,mature auricular cartilage-like tissues with high morphological fidelity,excellent elasticity,abundant cartilage lacunae,and cartilage-specific ECM deposition are successfully regenerated in vivo,which provides new opportunities and novel strategies for the fabrication and regeneration of patient-specific auricular cartilage.
文摘Bioinks are formulations of biomaterials and living cells, sometimes with growth factors or other biomolecules, while extrusion bioprinting is an emerging technique to apply or deposit these bioinks or biomaterial solutions to create three-dimensional (3D) constructs with architectures and mechanical/biological properties that mimic those of native human tissue or organs. Printed constructs have found wide applications in tissue engineering for repairing or treating tissue/organ injuries, as well as in vitro tissue modelling for testing or validating newly developed therapeutics and vaccines prior to their use in humans. Successful printing of constructs and their subsequent applications rely on the properties of the formulated bioinks, including the rheological, mechanical, and biological properties, as well as the printing process. This article critically reviews the latest developments in bioinks and biomaterial solutions for extrusion bioprinting, focusing on bioink synthesis and characterization, as well as the influence of bioink properties on the printing process. Key issues and challenges are also discussed along with recommendations for future research.
基金This study was supported by the Beijing Natural Science Foundation(7204306)National Natural Science Foundation of China(82002056,81830064,81721092,32000969,81974019)+9 种基金National Key Research and Development Program of China(2018YFA0108700,2017YFA0105602)NSFC Projects of International Cooperation and Exchanges(81720108004)China Postdoctoral Science Foundation(2020M673672)Key Support Program for Growth Factor Research(SZYZ-TR-03)Chinese PLA General Hospital for Military Medical Innovation Research Project(CX19026)the CAMS Innovation Fund for Medical Sciences(CIFMS,2019-I2M-5-059)the Military Medical Research and Development Projects(AWS17J005)the Research Team Project of Natural Science Foundation of Guangdong Province of China(2017A030312007)the key program of guangzhou science research plan(201904020047)The Special Project of Dengfeng Program of Guangdong Provincial People’s Hospital(DFJH201812,KJ012019119,KJ012019423).
文摘Extrusion-based bioprinting (EBB) holds potential for regenerative medicine. However, the widely-used bioinks of EBB exhibit some limitations for skin regeneration, such as unsatisfactory bio-physical (i.e., mechanical, structural, biodegradable) properties and compromised cellular compatibilities, and the EBB-based bioinks with therapeutic effects targeting cutaneous wounds still remain largely undiscussed. In this review, the printability considerations for skin bioprinting were discussed. Then, current strategies for improving the physical properties of bioinks and for reinforcing bioinks in EBB approaches were introduced, respectively. Notably, we highlighted the applications and effects of current EBB-based bioinks on wound healing, wound scar formation, vasculari-zation and the regeneration of skin appendages (i.e., sweat glands and hair follicles) and discussed the challenges and future perspectives. This review aims to provide an overall view of the applications, challenges and promising solutions about the EBB-based bioinks for cutaneous wound healing and skin regeneration.
基金supported by the National Key Research Development Plan of China(2017YFC1103300)the National Nature Science Foundation of China(81571909,81701906,81830064,81721092,51703230,and 31971303)+4 种基金the CAMS Innovation Fund for Medical Sciences(CIFMS,2019-I2M-5-059)the Military Medical Research and Development Projects(AWS17J005)Fostering Funds of Chinese PLA General Hospital for National Distinguished Young Scholar Science Fund(2017-JQPY-002)Chinese PLA General Hospital for Military Medical Innovation Research Project(CX19026)the Presidential Foundation of Technical Institute of Physics and Chemistry,Chinese Academy of Sciences.
文摘3-dimensional(3D)bioprinting technology provides promising strategy in the fabrication of artificial tissues and organs.As the fundamental element in bioprinting process,preparation of bioink with ideal mechanical properties without sacrifice of biocompatibility is a great challenge.In this study,a supramolecular hydrogel-based bioink is prepared by polyethylene glycol(PEG)grafted chitosan,α-cyclodextrin(α-CD)and gelatin.It has a primary crosslinking structure through the aggregation of the pseudo-polyrotaxane-like side chains,which are formed from the host-vip interactions betweenα-CD and PEG side chain.Apparent viscosity measurement shows the shear-shinning property of this bioink,which might be due to the reversibility of the physical crosslinking.Moreover,withβ-glycerophosphate at different concentrations as the secondary crosslinking agent,the printed constructs demonstrate different Young's modulus(p<0.001).They could also maintain the Young's modulus in cell culture condition for at least 21 days(p<0.05).By co-culturing each component with fibroblasts,CCK-8 assay demonstrate cellular viability is higher than 80%.After bioprinting and culturing,immunofluorescence staining with quantification indicate the expression of Ki-67,Paxillin,and N-cadherin is higher in day 14 than those in day 3(p<0.05).Oil red O and Nissl body specific staining reflect strength tunable bioink may have impact on the cell fate of mesenchymal stem cells(p<0.05).This work might provide new idea for advanced bioink in the application of re-establishing complicated tissues and organs.
基金the financial support from the National Natural Science Foundation of China(No.32122046,12272032,82072082,32101102)the National Key R&D Program of China(No.2020YFC0122204,2018YFA0703100)+2 种基金the Youth Innovation Promotion Association of CAS[No.2019350]the Shenzhen Fundamental Research Foundation[No.JCYJ20210324115814040]the 111 Project(No.B13003).
文摘In the field of regenerative medicine,the importance of 3D bioprinting is self-evident and nonnegligible.However,3D bioprinting technology also requires bioink with excellent performance as support material to fabricate a multi-functional bioinspired scaffold.Collagen-based bioink is regarded as an ideal 3D bioprinting ink for its excellent biocompatibility,controllable printability and cell loading property.It is an important breakthrough in regenerative medicine with the progress of collagen-based bioink,which fabricates bioinspired scaffolds with different functions and is applied in different repair scenarios.This review summarizes the different applications of collagen-based bioink and classifies them as soft tissue and hard tissue according to the target region.The applications of target region in soft tissues include skin,cartilage,heart and blood vessels,while in hard tissues include femur,skull,teeth and spine.When the collagen-based bioink is applied in repairing soft tissue,the requirements of function are higher,while the mechanical properties must be further improved in repairing hard tissue.We further summarize the characteristics of collagen-based bioink and point out the most important properties that should be considered in different repair scenarios,which can provide reference for the preparation of bioinks with different functions.Finally,we point out the main challenges faced by collagen-based bioink and prospect the future research directions.
基金This work was supported by the National Natural Science Foundation of China[grant number 52075285]the Science and Technology Program of Guangzhou,China[grant number 201604040002]+1 种基金the Key-Area Research and Development Program of Guangdong Province,China[grant number 2020B090923003]the Key Research and Development Projects of People’s Liberation Army,China[grant number.BWS17J036].
文摘The ready-to-use,structure-supporting hydrogel bioink can shorten the time for ink preparation,ensure cell dispersion,and maintain the preset shape/microstructure without additional assistance during printing.Meanwhile,ink with high permeability might facilitate uniform cell growth in biological constructs,which is beneficial to homogeneous tissue repair.Unfortunately,current bioinks are hard to meet these requirements simultaneously in a simple way.Here,based on the fast dynamic crosslinking of aldehyde hyaluronic acid(AHA)/N-carboxymethyl chitosan(CMC)and the slow stable crosslinking of gelatin(GEL)/4-arm poly(ethylene glycol)succinimidyl glutarate(PEG-SG),we present a time-sharing structure-supporting(TSHSP)hydrogel bioink with high permeability,containing 1%AHA,0.75%CMC,1%GEL and 0.5%PEG-SG.The TSHSP hydrogel can facilitate printing with proper viscoelastic property and self-healing behavior.By crosslinking with 4%PEG-SG for only 3 min,the integrity of the cell-laden construct can last for 21 days due to the stable internal and external GEL/PEG-SG networks,and cells manifested long-term viability and spreading morphology.Nerve-like,muscle-like,and cartilage-like in vitro constructs exhibited homogeneous cell growth and remarkable biological specificities.This work provides not only a convenient and practical bioink for tissue engineering,targeted cell therapy,but also a new direction for hydrogel bioink development.
