Damage to the adult mammalian central nervous system （CNS） often results in persistent neurological deficits with limited recovery of functions. The past decade has seen in- creasing research efforts in neural regen...Damage to the adult mammalian central nervous system （CNS） often results in persistent neurological deficits with limited recovery of functions. The past decade has seen in- creasing research efforts in neural regeneration research with the ultimate goal of achieving functional recovery. Many studies have focused on prevention of further neural damage and restoration of functional connections that are com- promised after iniurY or pathological damage.展开更多
In recent years,organoid technology,i.e.,in vitro three-dimensional(3D)tissue culture,has attracted increasing attention in biomedical engineering.Organoids are cell complexes induced by differentiation of stem cells ...In recent years,organoid technology,i.e.,in vitro three-dimensional(3D)tissue culture,has attracted increasing attention in biomedical engineering.Organoids are cell complexes induced by differentiation of stem cells or organ-progenitor cells in vitro using 3D culture technology.They can replicate the key structural and functional characteristics of the target organs in vivo.With the opening up of this new field of health engineering,there is a need for engineering-system approaches to the production,control,and quantitative analysis of organoids and their microenvironment.Traditional organoid technology has limitations,including lack of physical and chemical microenvironment control,high heterogeneity,complex manual operation,imperfect nutritional supply system,and lack of feasible online analytical technology for the organoids.The introduction of microfluidic chip technology into organoids has overcome many of these limitations and greatly expanded the scope of applications.Engineering organoid microfluidic system has become an interdisciplinary field in biomedical and health engineering.In this review,we summarize the development and culture system of organoids,discuss how microfluidic technology has been used to solve the main technical challenges in organoid research and development,and point out new opportunities and prospects for applications of organoid microfluidic system in drug development and screening,food safety,precision medicine,and other biomedical and health engineering fields.展开更多
To adapt to a complex and variable environment,self-adaptive camouflage technology is becoming more and more important in all kinds of military applications by overcoming the weakness of the static camouflage.In natur...To adapt to a complex and variable environment,self-adaptive camouflage technology is becoming more and more important in all kinds of military applications by overcoming the weakness of the static camouflage.In nature,the chameleon can achieve self-adaptive camouflage by changing its skin color in real time with the change of the background color.To imitate the chameleon skin,a camouflaged film controlled by a color-changing microfluidic system is proposed in this paper.The film with microfluidic channels fabricated by soft materials can achieve dynamic cloaking and camouflage by circulating color liquids through channels inside the film.By sensing and collecting environmental color change information,the control signal of the microfluidic system can be adjusted in real time to imitate chameleon skin.The microstructure of the film and the working principle of the microfluidic color-changing system are introduced.The mechanism to generate the control signal by information processing of background colors is illustrated.“Canny”double-threshold edge detection algorithm and color similarity are used to analyze and evaluate the camouflage.The tested results show that camouflaged images have a relatively high compatibility with environmental backgrounds and the dynamic cloaking eff ect can be achieved.展开更多
Exosomes are now raising focus as a prospective biomarker for cancer diagnostics and prognosis owing to its unique bio-origin and composition.Exosomes take part in cellular communication and receptor mediation and tra...Exosomes are now raising focus as a prospective biomarker for cancer diagnostics and prognosis owing to its unique bio-origin and composition.Exosomes take part in cellular communication and receptor mediation and transfer their cargos(e.g.,proteins,m RNA and DNA).Quantitative analysis of tumor-related nucleic acid mutations can be a potential method to cancer diagnosis and prognosis in early stages.Here we present an integrated microfluidic system for exosome on-chip isolation and lung cancer RNA analysis through droplet digital PCR(dd PCR).Gradient dilution experiments show great linearity over a large concentration range with R^(2)=0.9998.Utilizing the system,four cell lines and two mutation targets were parallelly detected for mutation analysis.The experiments demonstrated mutation heterogeneity and the results were agree with cell researches.These results proved our integrated microfluidic system as a promising means for early cancer diagnosis and prognosis in the era of liquid biopsy.展开更多
A microfluidic system was developed for the synthesis of trigonal selenium（t-Se） nanowires, which was composed of a glass microchip coupled with a poly（methyl methacrylate）（PMMA） microchip. In the glass microchi...A microfluidic system was developed for the synthesis of trigonal selenium（t-Se） nanowires, which was composed of a glass microchip coupled with a poly（methyl methacrylate）（PMMA） microchip. In the glass microchip, amorphous selenium（a-Se） colloid was prepared by reducing selenious acid with an excess amount of hydrazine at a temperature of 100 ℃. In the coupled PMMA microchip, a-Se was transformed into more stable t-Se seeds via sonication at room temperature. The residence time of the reactants in both microchips was optimized by varying the dimension and length of the microchannel each. The t-Se nanowires were formed by anisotropic growth of selenium crystallite during sonication and aging under the assistance of β-cyclodextrin（β-CD）. Various stages of the nanowires＇ growth were investigated. The as-synthesized products were characterized by powder X-Ray diffraction（XRD）, Raman spectroscopy, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and selected-area electron diffraction（SAED）.展开更多
To improve the performance of real-time recombinase polymerase amplification(RPA),a microfluidic system with active mixing is developed to optimize the reaction dynamics.Instead of adopting a single typical reaction c...To improve the performance of real-time recombinase polymerase amplification(RPA),a microfluidic system with active mixing is developed to optimize the reaction dynamics.Instead of adopting a single typical reaction chamber,a specific reactor including a relatively large chamber in center with two adjacent zig-zag channels at two sides is integrated into the microfluidic chip.Active mixing is achieved by driving the viscous reagent between the chamber and the channel back and forth periodically with an outside compact peristaltic pump.To avoid reagent evapora-tion,one end of the reactor is sealed with paraffin oil.A hand-held companion device is developed to facilitate real-time RPA amplification within 20 min.The whole area of the reactor is heated with a resistance heater to provide uniform reaction temperature.To achieve real-time monitoring,a compact fluorescence detection module is integrated into the hand-held device.A smartphone with custom application software is adopted to control the hand-held device and display the real-time fluorescence curves.The performances of two cases with and without active on-chip mixing are compared between each other by detecting African swine fever viruses.It has been demonstrated that,with active on-chip mixing,the amplification efficiency and detection sensitivity can be signifi-cantly improved.展开更多
Combining deep-learning image inpainting algorithms with the microfluidic technology,the paper proposes a method to achieve dynamic stealth and camouflage by using a microfluidic vision camouflage system simulating th...Combining deep-learning image inpainting algorithms with the microfluidic technology,the paper proposes a method to achieve dynamic stealth and camouflage by using a microfluidic vision camouflage system simulating the chameleon skin.The basic principle is to perceive color changes in the external environment and collect ambient image information,and then utilize the image inpainting algorithm to adjust the control signals of the microfluidic system in real time.The detailed working principle of the microfluidic vision camouflage system is presented,and the mechanism of generating control signals for the system through deep-learning image inpainting algorithms and image-processing techniques is elucidated.The camouflage effect of the chameleon skin is analyzed and evaluated using color similarity.Results indicate that the camouflaged images are consistent with the background environment,thereby improving the target’s stealth and maneuvering characteristics.The camouflage technology developed in the paper based on the microfluidic vision camouflage system can be applied to several situations,such as military camouflage uniforms,robot skins,and weapon equipment.展开更多
Thrombosis remains a major global health concern mainly characterized by high rates of morbidity and mortality.Animal models serve as an indispensable tool to understand the underlying pathogenesis of thrombosis and a...Thrombosis remains a major global health concern mainly characterized by high rates of morbidity and mortality.Animal models serve as an indispensable tool to understand the underlying pathogenesis of thrombosis and assess the efficacy of novel antithrombotic drugs.Currently,zebrafish has emerged as a valuable model organism for thrombosis research.However,the traditional method of studying zebrafish thrombosis requires a laborious and time-consuming procedure,including anesthesia and manual immobilization of zebrafish.In this study,based on hydrodynamic force,a lateral-immobilization zebrafish microfluidic chip(LIZMC)was designed to evaluate the cardiovascular system of multiple larvae within a single microscope field of view.Specifically,coupling with microscope imaging,real-time monitoring of the peripheral blood circulation in the tail of phenylhydrazine(PHZ)-induced zebrafish thrombosis was enabled.Furthermore,the reliability of LIZMC for in vivo evaluation of antithrombotic agents in zebrafish was verified using aspirin.Collectively,this novel LIZMC-based system can be used for in vivo zebrafish thrombosis studies and rapid screening of antithrombotic agents.展开更多
Surface engineering plays a crucial role in improving the performance of high energy materials,and polydopamine(PDA)is widely used in the field of energetic materials for surface modification and functionalization.In ...Surface engineering plays a crucial role in improving the performance of high energy materials,and polydopamine(PDA)is widely used in the field of energetic materials for surface modification and functionalization.In order to obtain high-quality HMX@PDA-based PBX explosives with high sphericity and a narrow particle size distribution,composite microspheres were prepared using co-axial droplet microfluidic technology.The formation mechanism,thermal behavior,mechanical sensitivity,electrostatic spark sensitivity,compressive strength,and combustion performance of the microspheres were investigated.The results show that PDA can effectively enhance the interfacial interaction between the explosive particles and the binder under the synergistic effect of chemical bonds and the physical"mechanical interlocking"structure.Interface reinforcement causes the thermal decomposition temperature of the sample microspheres to move to a higher temperature,with the sensitivity to impact,friction,and electrostatic sparks(for S-1)increasing by 12.5%,31.3%,and 81.5%respectively,and the compressive strength also increased by 30.7%,effectively enhancing the safety performance of the microspheres.Therefore,this study provides an effective and universal strategy for preparing high-quality functional explosives,and also provides some reference for the safe use of energetic materials in practical applications.展开更多
Point-of-care testing(POCT)refers to a category of diagnostic tests that are performed at or near to the site of the patients(also called bedside testing)and is capable of obtaining accurate results in a short time by...Point-of-care testing(POCT)refers to a category of diagnostic tests that are performed at or near to the site of the patients(also called bedside testing)and is capable of obtaining accurate results in a short time by using portable diagnostic devices,avoiding sending samples to the medical laboratories.It has been extensively explored for diagnosing and monitoring patients’diseases and health conditions with the assistance of development in biochemistry and microfluidics.Microfluidic paper-based analytical devices(μPADs)have gained dramatic popularity in POCT because of their simplicity,user-friendly,fast and accurate result reading and low cost.SeveralμPADs have been successfully commercialized and received excellent feedback during the past several decades.This review briefly discusses the main types ofμPADs,preparation methods and their detection principles,followed by a few representative examples.The future perspectives of the development inμPADs are also provided.展开更多
Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been wide...Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been widely employed for liposome preparation.Although some studies have explored factors affecting liposomal size in microfluidic processes,most focus on small-sized liposomes,predominantly through experimental data analysis.However,the production of larger liposomes,which are equally significant,remains underexplored.In this work,we thoroughly investigate multiple variables influencing liposome size during microfluidic preparation and develop a machine learning(ML)model capable of accurately predicting liposomal size.Experimental validation was conducted using a staggered herringbone micromixer(SHM)chip.Our findings reveal that most investigated variables significantly influence liposomal size,often interrelating in complex ways.We evaluated the predictive performance of several widely-used ML algorithms,including ensemble methods,through cross-validation(CV)for both lipo-some size and polydispersity index(PDI).A standalone dataset was experimentally validated to assess the accuracy of the ML predictions,with results indicating that ensemble algorithms provided the most reliable predictions.Specifically,gradient boosting was selected for size prediction,while random forest was employed for PDI prediction.We successfully produced uniform large(600 nm)and small(100 nm)liposomes using the optimised experimental conditions derived from the ML models.In conclusion,this study presents a robust methodology that enables precise control over liposome size distribution,of-fering valuable insights for medicinal research applications.展开更多
Droplet microfluidics,which encapsulates individual cells within separate microreactors,has become an essential tool for single-cell phenotypic and genotypic analysis.However,the efficiency of single-cell encapsulatio...Droplet microfluidics,which encapsulates individual cells within separate microreactors,has become an essential tool for single-cell phenotypic and genotypic analysis.However,the efficiency of single-cell encapsulation is limited by the Poisson distribution governing the encapsulation process,resulting in most droplets being either empty or containing multiple cells.Traditional single-cell sorting methods typically rely on fluorescence labeling for identification,but this approach not only increases experimental costs and complexity but can also impact cell viability.Additionally,current label-free sorting methods still encounter difficulties in accurately detecting multicellular droplets and small cellular aggregates.To address these challenges,this paper proposes an intelligent sorting system that combines YOLOv8 object detection and BoTSORT tracking algorithms.This system enables real-time analysis of droplet images,facilitating precise identification,counting,and automated sorting of target droplets.To validate the system’s performance,polystyrene microspheres were used to simulate real cells in sorting tests.The results demonstrated that,under label-free conditions,the system significantly outperformed traditional fluorescence labeling methods in both classification accuracy and sorting efficiency.This system provides an effective,label-free solution for cell sorting,with potential applications in precision medicine,single-cell sequencing,and drug screening.展开更多
Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characteri...Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characterized by the loss of oligodendrocytes(OLs)and the disintegration of myelin sheaths,leading to impaired neural connectivity and motor dysfunction.Neural stem cells(NSCs)represent a promising regenerative source for replenishing lost OLs;however,conventional twodimensional(2D)in vitro culture systems lack the three-dimensional(3D)physiological microenvironment.Microfluidic chip technology has emerged as a powerful tool to overcome this limitation by enabling precise spatial and temporal control over 3D microenvironmental conditions,including the establishment of stable concentration gradients of bioactive molecules.Catalpol,an iridoid glycoside derived from traditional medicinal plants,exhibits dual antioxidant and anti-apoptotic properties.Despite its therapeutic potential,the capacity of catalpol to drive NSC differentiation toward OLs under biomimetic 3D conditions,as well as the underlying molecular mechanisms,remains poorly understood.This study aims to develop a microfluidic-based 3D biomimetic platform to systematically investigate the concentration-dependent effects of catalpol on promoting NSCs-to-OLs differentiation and to elucidate the role of the caveolin-1(Cav-1)signaling pathway in this process.Methods We developed a novel multiplexed microfluidic device featuring parallel microchannels with integrated gradient generators capable of establishing and maintaining precise linear concentration gradients(0-3 g/L catalpol)across 3D NSCs cultures.This platform facilitated the continuous perfusion culture of NSC-derived 3D spheroids,mimicking the dynamic in vivo microenvironment.Real-time cell viability was assessed using Calcein-AM/propidium iodide(PI)dual staining,with fluorescence imaging quantifying live/dead cell ratios.Oligodendrocyte differentiation was evaluated through quantitative reverse transcription polymerase chain reaction(qRT-PCR)for MBP and SOX10 gene expression,complemented by immunofluorescence staining to visualize corresponding protein changes.To dissect the molecular mechanism,the Cav-1-specific pharmacological inhibitor methyl‑β‑cyclodextrin(MCD)was employed to perturb the pathway,and its effects on differentiation markers were analyzed.Results Catalpol demonstrated excellent biocompatibility,with cell viability exceeding 96%across the entire tested concentration range(0-3 g/L),confirming its non-cytotoxic nature.At the optimal concentration of 0-3 g/L,catalpol significantly upregulated both MBP and SOX10 expression(P<0.05,P<0.01),indicating robust promotion of oligodendroglial differentiation.Intriguingly,Cav-1 mRNA expression was progressively downregulated during NSC differentiation into OLs.Further inhibition of Cav-1 with MCD further enhanced this effect,leading to a statistically significant increase in OL-specific gene expression(P<0.05,P<0.01),suggesting Cav-1 acts as a negative regulator of OLs differentiation.Conclusion This study established an integrated microfluidic gradient chip-3D NSC spheroid culture system,which combines the advantages of precise chemical gradient control with physiologically relevant 3D cell culture.The findings demonstrate that 3 g/L catalpol effectively suppresses Cav-1 signaling to drive NSC differentiation into functional OLs.This work not only provides novel insights into the Cav-1-dependent mechanisms of myelination but also delivers a scalable technological platform for future research on remyelination therapies,with potential applications in cerebral palsy and other white matter disorders.The platform’s modular design permits adaptation for screening other neurogenic compounds or investigating additional signaling pathways involved in OLs maturation.展开更多
Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still...Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still undesirable under certain circumstances.Encouragingly,laminar microfluidic reactor offers prospective options that possess controllable flow characteristics such as enhanced mass transport,precise laminar flow control and the ability to expand production scale progressively.In this comprehensive review,the underlying fundamentals of the paired electrosynthesis are initially summarized,followed by categorizing the paired electrosynthesis including parallel paired electrosynthesis,divergent paired electrosynthesis,convergent paired electrosynthesis,sequential paired electrosynthesis and linear paired electrosynthesis.Thereafter,a holistic overview of microfluidic reactor equipment,integral fundamentals and research methodology as well as channel extension and scale-up strategies is proposed.The established fundamentals and evaluated metrics further inspired the applications of microfluidic reactors in paired electrosynthesis.This work stimulated the overwhelming investigation of mechanism discovery,material screening strategies,and device assemblies.展开更多
There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct...There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct constant volume depletion experiments and investigate the microscopic mechanisms of condensate gas recovery.The aim of the experiments was to reveal the phase-behavior differences between bulk-phase gas and gas contained in porous media.The results revealed that condensate oil recovery in microfluidics experiments was higher than that in PVT cell tests,and nonuniform condensation and evaporation were exclusively observed in the microfluidics experiments.Furthermore,lower pore connectivity resulted in higher depletion recovery,while more developed fractures led to reduced recovery.Specifically,the chip with fewer fractures achieved the highest recovery(71.15%),whereas the highly fractured chip exhibited the lowest recovery(56.11%).These findings demonstrate that oil saturation during the process of constant volume depletion(CVD)of gas condensate within porous media is lower than that observed in the PVT cell,thus providing experimental evidence for optimizing condensate gas development in field applications.展开更多
The real-time screening of biomolecules and single cells in biochips is extremely important for disease prediction and diagnosis,cellular analysis,and life science research.Barcode biochip technology,which is integrat...The real-time screening of biomolecules and single cells in biochips is extremely important for disease prediction and diagnosis,cellular analysis,and life science research.Barcode biochip technology,which is integrated with microfluidics,typically comprises barcode array,sample loading,and reaction unit array chips.Here,we present a review of microfluidics barcode biochip analytical approaches for the high-throughput screening of biomolecules and single cells,including protein biomarkers,microRNA(miRNA),circulating tumor DNA(ctDNA),single-cell secreted proteins,single-cell exosomes,and cell interactions.We begin with an overview of current high-throughput detection and analysis approaches.Following this,we outline recent improvements in microfluidic devices for biomolecule and single-cell detection,highlighting the benefits and limitations of these devices.This paper focuses on the research and development of microfluidic barcode biochips,covering their self-assembly substrate materials and their specific applications with biomolecules and single cells.Looking forward,we explore the prospects and challenges of this technology,with the aim of contributing toward the use of microfluidic barcode detection biochips in medical diagnostics and therapies,and their large-scale commercialization.展开更多
Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fl...Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fluids and facilitate droplet formation at the microscale,enables precise control of chemical reactions.Recent scholarly endeavors have increasingly harnessed microfluidic reactors in the realm of energetic materials,yielding morphologically controllable particles with enhanced uniformity and explosive efficacy.However,crucial insights into microfluidic-based methodologies are dispersed across various publications,necessitating a systematic compilation.Accordingly,this review addresses this gap by concentrating on the synthesis of energetic materials through microfluidics.Specifically,the methods based on micro-mixing and droplets in the previous papers are summarized and the strategies to control the critical parameters within chemical reactions are discussed in detail.Then,the comparison in terms of advantages and disadvantages is attempted.As demonstrated in the last section regarding perspectives,challenges such as clogging,dead zones,and suboptimal production yields are non-ignoble in the promising fields and they might be addressed by integrating sound,optics,or electrical energy to meet heightened requirements.This comprehensive overview aims to consolidate and analyze the diverse array of microfluidic approaches in energetic material synthesis,offering valuable insights for future research directions.展开更多
Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for de...Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for detecting Ni ions.The microfluidic paper-based analytical devices(µPADs)are potential candidates for the detection of water quality parameters including pH,heavy ions,nitrite and so on.However,it suffers from a huge error caused by the environment and artificial mistakes.In this study,we proposed an improved technique route to increase the stability and reliability of microfluidic paper-based analytical devices.The main technique points include a stable light source,a matched camera,improved reliability of the devices,and effective calculated methods.Finally,we established 15 standard curves that could be used to detect nickel ions and obtained uniform colorimetric results with reliability and repeatability.With those improvements,the relative errors for the five types of real water samples from the Zhongshan industrial parks were reduced to 0.26%,14.78%,24.20%,50.29%and 3.53%,respectively.These results were conducive to exploring this technique for the detection of nickel ions in wastewater from the Zhongshan industrial parks.The results demonstrated that the above technique route is promising for the detection of other heavy metal ions in industrial effluent.展开更多
Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-...Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas−liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α1 and α2 are influenced by the viscous force. The values of pre-factors m_(1) and m_(2) are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.展开更多
Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was c...Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was constructed based on microfluidics.A microscopic and mesoscopic observation technique was proposed to simultaneously capture gas-liquid interface morphology of pores and throat and the two-phase flow characteristics in entire cleat system.The local contact characteristics of cleats reduced absolute permeability,which resulted in a sharp increase in the starting pressure.The reduced gas flow capacity narrowed the co-infiltration area and decreased water saturation at the isotonic point in a hydrophilic environment.The increased local contact area of cleats weakened gas phase flow capacity and narrowed the co-infiltration area.Jumping events occurred in methane-water flow due to altered porosity caused by local contact in cleats.The distribution of residual phases changed the jumping direction on the micro-scale as well as the dominant channel on the mesoscale.Besides,jumping events caused additional energy dissipation,which was ignored in traditional two-phase flow models.This might contribute to the overestimation of relative permeability.The work provides new methods and insights for investigating unsaturated flow in complex porous media.展开更多
基金supported by grants from NIH National Institute of Mental Health MH085267National Institute of Neurological Disorders and Stroke NS060017
文摘Damage to the adult mammalian central nervous system （CNS） often results in persistent neurological deficits with limited recovery of functions. The past decade has seen in- creasing research efforts in neural regeneration research with the ultimate goal of achieving functional recovery. Many studies have focused on prevention of further neural damage and restoration of functional connections that are com- promised after iniurY or pathological damage.
基金This work was supported by the Key Areas Research Development Projects of Guangdong Province(No.2019B020210001)the Tsinghua-U Tokyo Collaborative Research Fund(No.20193080052)the Key Areas Research Development Projects of Hebei Province(No.20375502D).
文摘In recent years,organoid technology,i.e.,in vitro three-dimensional(3D)tissue culture,has attracted increasing attention in biomedical engineering.Organoids are cell complexes induced by differentiation of stem cells or organ-progenitor cells in vitro using 3D culture technology.They can replicate the key structural and functional characteristics of the target organs in vivo.With the opening up of this new field of health engineering,there is a need for engineering-system approaches to the production,control,and quantitative analysis of organoids and their microenvironment.Traditional organoid technology has limitations,including lack of physical and chemical microenvironment control,high heterogeneity,complex manual operation,imperfect nutritional supply system,and lack of feasible online analytical technology for the organoids.The introduction of microfluidic chip technology into organoids has overcome many of these limitations and greatly expanded the scope of applications.Engineering organoid microfluidic system has become an interdisciplinary field in biomedical and health engineering.In this review,we summarize the development and culture system of organoids,discuss how microfluidic technology has been used to solve the main technical challenges in organoid research and development,and point out new opportunities and prospects for applications of organoid microfluidic system in drug development and screening,food safety,precision medicine,and other biomedical and health engineering fields.
基金the National Natural Science Foundation of China for the support(No.51175101)on this paper.
文摘To adapt to a complex and variable environment,self-adaptive camouflage technology is becoming more and more important in all kinds of military applications by overcoming the weakness of the static camouflage.In nature,the chameleon can achieve self-adaptive camouflage by changing its skin color in real time with the change of the background color.To imitate the chameleon skin,a camouflaged film controlled by a color-changing microfluidic system is proposed in this paper.The film with microfluidic channels fabricated by soft materials can achieve dynamic cloaking and camouflage by circulating color liquids through channels inside the film.By sensing and collecting environmental color change information,the control signal of the microfluidic system can be adjusted in real time to imitate chameleon skin.The microstructure of the film and the working principle of the microfluidic color-changing system are introduced.The mechanism to generate the control signal by information processing of background colors is illustrated.“Canny”double-threshold edge detection algorithm and color similarity are used to analyze and evaluate the camouflage.The tested results show that camouflaged images have a relatively high compatibility with environmental backgrounds and the dynamic cloaking eff ect can be achieved.
基金National Natural Science Foundation of China(Nos.61971410,and 62001458)Shanghai Sailing Program(No.20YF1457100)。
文摘Exosomes are now raising focus as a prospective biomarker for cancer diagnostics and prognosis owing to its unique bio-origin and composition.Exosomes take part in cellular communication and receptor mediation and transfer their cargos(e.g.,proteins,m RNA and DNA).Quantitative analysis of tumor-related nucleic acid mutations can be a potential method to cancer diagnosis and prognosis in early stages.Here we present an integrated microfluidic system for exosome on-chip isolation and lung cancer RNA analysis through droplet digital PCR(dd PCR).Gradient dilution experiments show great linearity over a large concentration range with R^(2)=0.9998.Utilizing the system,four cell lines and two mutation targets were parallelly detected for mutation analysis.The experiments demonstrated mutation heterogeneity and the results were agree with cell researches.These results proved our integrated microfluidic system as a promising means for early cancer diagnosis and prognosis in the era of liquid biopsy.
基金Supported by the Natural Science Foundation of Zhejiang Province,China(No.Z407029)the Hangzhou Qianjiang Scholar Foundation,China(No.HZ2010-41)
文摘A microfluidic system was developed for the synthesis of trigonal selenium（t-Se） nanowires, which was composed of a glass microchip coupled with a poly（methyl methacrylate）（PMMA） microchip. In the glass microchip, amorphous selenium（a-Se） colloid was prepared by reducing selenious acid with an excess amount of hydrazine at a temperature of 100 ℃. In the coupled PMMA microchip, a-Se was transformed into more stable t-Se seeds via sonication at room temperature. The residence time of the reactants in both microchips was optimized by varying the dimension and length of the microchannel each. The t-Se nanowires were formed by anisotropic growth of selenium crystallite during sonication and aging under the assistance of β-cyclodextrin（β-CD）. Various stages of the nanowires＇ growth were investigated. The as-synthesized products were characterized by powder X-Ray diffraction（XRD）, Raman spectroscopy, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and selected-area electron diffraction（SAED）.
基金supported by the National Natural Science Foundation of China(Nos.81871505,61971026)the Fundamental Research Fund for the Central Universities(No.XK1802-4)+1 种基金the National Science and Technology Major Project(No.2018ZX10732101-001-009)the Research Fund to the Top Scientific and Technological Innovation Team from Beijing University of Chemical Technology(No.buctylkjcx06).
文摘To improve the performance of real-time recombinase polymerase amplification(RPA),a microfluidic system with active mixing is developed to optimize the reaction dynamics.Instead of adopting a single typical reaction chamber,a specific reactor including a relatively large chamber in center with two adjacent zig-zag channels at two sides is integrated into the microfluidic chip.Active mixing is achieved by driving the viscous reagent between the chamber and the channel back and forth periodically with an outside compact peristaltic pump.To avoid reagent evapora-tion,one end of the reactor is sealed with paraffin oil.A hand-held companion device is developed to facilitate real-time RPA amplification within 20 min.The whole area of the reactor is heated with a resistance heater to provide uniform reaction temperature.To achieve real-time monitoring,a compact fluorescence detection module is integrated into the hand-held device.A smartphone with custom application software is adopted to control the hand-held device and display the real-time fluorescence curves.The performances of two cases with and without active on-chip mixing are compared between each other by detecting African swine fever viruses.It has been demonstrated that,with active on-chip mixing,the amplification efficiency and detection sensitivity can be signifi-cantly improved.
基金the National Natural Science Foundation of China for the support(No.51175101)on this paper.
文摘Combining deep-learning image inpainting algorithms with the microfluidic technology,the paper proposes a method to achieve dynamic stealth and camouflage by using a microfluidic vision camouflage system simulating the chameleon skin.The basic principle is to perceive color changes in the external environment and collect ambient image information,and then utilize the image inpainting algorithm to adjust the control signals of the microfluidic system in real time.The detailed working principle of the microfluidic vision camouflage system is presented,and the mechanism of generating control signals for the system through deep-learning image inpainting algorithms and image-processing techniques is elucidated.The camouflage effect of the chameleon skin is analyzed and evaluated using color similarity.Results indicate that the camouflaged images are consistent with the background environment,thereby improving the target’s stealth and maneuvering characteristics.The camouflage technology developed in the paper based on the microfluidic vision camouflage system can be applied to several situations,such as military camouflage uniforms,robot skins,and weapon equipment.
基金supported in part by the National Natural Science Foundation of China(Nos.81825020 and 82150208)the Shanghai Science and Technology Commission Biomedical Science and Technology Support Special Project(Nos.21S11907900 and 20S11901000)+3 种基金the Fundamental Research Funds for the Central Universitiesthe Shanghai“Beyond Limits Manufacturing”Projectsponsored by National Program for Special Supports of Eminent ProfessionalsNational Program for Support of Top-notch Young Professionals。
文摘Thrombosis remains a major global health concern mainly characterized by high rates of morbidity and mortality.Animal models serve as an indispensable tool to understand the underlying pathogenesis of thrombosis and assess the efficacy of novel antithrombotic drugs.Currently,zebrafish has emerged as a valuable model organism for thrombosis research.However,the traditional method of studying zebrafish thrombosis requires a laborious and time-consuming procedure,including anesthesia and manual immobilization of zebrafish.In this study,based on hydrodynamic force,a lateral-immobilization zebrafish microfluidic chip(LIZMC)was designed to evaluate the cardiovascular system of multiple larvae within a single microscope field of view.Specifically,coupling with microscope imaging,real-time monitoring of the peripheral blood circulation in the tail of phenylhydrazine(PHZ)-induced zebrafish thrombosis was enabled.Furthermore,the reliability of LIZMC for in vivo evaluation of antithrombotic agents in zebrafish was verified using aspirin.Collectively,this novel LIZMC-based system can be used for in vivo zebrafish thrombosis studies and rapid screening of antithrombotic agents.
基金supported by the National Natural Science Foundation of China(Grant No.22005275).
文摘Surface engineering plays a crucial role in improving the performance of high energy materials,and polydopamine(PDA)is widely used in the field of energetic materials for surface modification and functionalization.In order to obtain high-quality HMX@PDA-based PBX explosives with high sphericity and a narrow particle size distribution,composite microspheres were prepared using co-axial droplet microfluidic technology.The formation mechanism,thermal behavior,mechanical sensitivity,electrostatic spark sensitivity,compressive strength,and combustion performance of the microspheres were investigated.The results show that PDA can effectively enhance the interfacial interaction between the explosive particles and the binder under the synergistic effect of chemical bonds and the physical"mechanical interlocking"structure.Interface reinforcement causes the thermal decomposition temperature of the sample microspheres to move to a higher temperature,with the sensitivity to impact,friction,and electrostatic sparks(for S-1)increasing by 12.5%,31.3%,and 81.5%respectively,and the compressive strength also increased by 30.7%,effectively enhancing the safety performance of the microspheres.Therefore,this study provides an effective and universal strategy for preparing high-quality functional explosives,and also provides some reference for the safe use of energetic materials in practical applications.
文摘Point-of-care testing(POCT)refers to a category of diagnostic tests that are performed at or near to the site of the patients(also called bedside testing)and is capable of obtaining accurate results in a short time by using portable diagnostic devices,avoiding sending samples to the medical laboratories.It has been extensively explored for diagnosing and monitoring patients’diseases and health conditions with the assistance of development in biochemistry and microfluidics.Microfluidic paper-based analytical devices(μPADs)have gained dramatic popularity in POCT because of their simplicity,user-friendly,fast and accurate result reading and low cost.SeveralμPADs have been successfully commercialized and received excellent feedback during the past several decades.This review briefly discusses the main types ofμPADs,preparation methods and their detection principles,followed by a few representative examples.The future perspectives of the development inμPADs are also provided.
基金supported by the National Key Research and Development Plan of the Ministry of Science and Technology,China(Grant No.:2022YFE0125300)the National Natural Science Foundation of China(Grant No:81690262)+2 种基金the National Science and Technology Major Project,China(Grant No.:2017ZX09201004-021)the Open Project of National facility for Translational Medicine(Shanghai),China(Grant No.:TMSK-2021-104)Shanghai Jiao Tong University STAR Grant,China(Grant Nos.:YG2022ZD024 and YG2022QN111).
文摘Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been widely employed for liposome preparation.Although some studies have explored factors affecting liposomal size in microfluidic processes,most focus on small-sized liposomes,predominantly through experimental data analysis.However,the production of larger liposomes,which are equally significant,remains underexplored.In this work,we thoroughly investigate multiple variables influencing liposome size during microfluidic preparation and develop a machine learning(ML)model capable of accurately predicting liposomal size.Experimental validation was conducted using a staggered herringbone micromixer(SHM)chip.Our findings reveal that most investigated variables significantly influence liposomal size,often interrelating in complex ways.We evaluated the predictive performance of several widely-used ML algorithms,including ensemble methods,through cross-validation(CV)for both lipo-some size and polydispersity index(PDI).A standalone dataset was experimentally validated to assess the accuracy of the ML predictions,with results indicating that ensemble algorithms provided the most reliable predictions.Specifically,gradient boosting was selected for size prediction,while random forest was employed for PDI prediction.We successfully produced uniform large(600 nm)and small(100 nm)liposomes using the optimised experimental conditions derived from the ML models.In conclusion,this study presents a robust methodology that enables precise control over liposome size distribution,of-fering valuable insights for medicinal research applications.
文摘Droplet microfluidics,which encapsulates individual cells within separate microreactors,has become an essential tool for single-cell phenotypic and genotypic analysis.However,the efficiency of single-cell encapsulation is limited by the Poisson distribution governing the encapsulation process,resulting in most droplets being either empty or containing multiple cells.Traditional single-cell sorting methods typically rely on fluorescence labeling for identification,but this approach not only increases experimental costs and complexity but can also impact cell viability.Additionally,current label-free sorting methods still encounter difficulties in accurately detecting multicellular droplets and small cellular aggregates.To address these challenges,this paper proposes an intelligent sorting system that combines YOLOv8 object detection and BoTSORT tracking algorithms.This system enables real-time analysis of droplet images,facilitating precise identification,counting,and automated sorting of target droplets.To validate the system’s performance,polystyrene microspheres were used to simulate real cells in sorting tests.The results demonstrated that,under label-free conditions,the system significantly outperformed traditional fluorescence labeling methods in both classification accuracy and sorting efficiency.This system provides an effective,label-free solution for cell sorting,with potential applications in precision medicine,single-cell sequencing,and drug screening.
基金supported by grants from the Liaoning Province Excellent Talent Program Project(XLYC1902031)Dalian Science and Technology Talent Innovation Plan Grant(2022RG18)Basic Research Project of the Department of Education of Liaoning Province(LJKQZ20222395)。
文摘Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characterized by the loss of oligodendrocytes(OLs)and the disintegration of myelin sheaths,leading to impaired neural connectivity and motor dysfunction.Neural stem cells(NSCs)represent a promising regenerative source for replenishing lost OLs;however,conventional twodimensional(2D)in vitro culture systems lack the three-dimensional(3D)physiological microenvironment.Microfluidic chip technology has emerged as a powerful tool to overcome this limitation by enabling precise spatial and temporal control over 3D microenvironmental conditions,including the establishment of stable concentration gradients of bioactive molecules.Catalpol,an iridoid glycoside derived from traditional medicinal plants,exhibits dual antioxidant and anti-apoptotic properties.Despite its therapeutic potential,the capacity of catalpol to drive NSC differentiation toward OLs under biomimetic 3D conditions,as well as the underlying molecular mechanisms,remains poorly understood.This study aims to develop a microfluidic-based 3D biomimetic platform to systematically investigate the concentration-dependent effects of catalpol on promoting NSCs-to-OLs differentiation and to elucidate the role of the caveolin-1(Cav-1)signaling pathway in this process.Methods We developed a novel multiplexed microfluidic device featuring parallel microchannels with integrated gradient generators capable of establishing and maintaining precise linear concentration gradients(0-3 g/L catalpol)across 3D NSCs cultures.This platform facilitated the continuous perfusion culture of NSC-derived 3D spheroids,mimicking the dynamic in vivo microenvironment.Real-time cell viability was assessed using Calcein-AM/propidium iodide(PI)dual staining,with fluorescence imaging quantifying live/dead cell ratios.Oligodendrocyte differentiation was evaluated through quantitative reverse transcription polymerase chain reaction(qRT-PCR)for MBP and SOX10 gene expression,complemented by immunofluorescence staining to visualize corresponding protein changes.To dissect the molecular mechanism,the Cav-1-specific pharmacological inhibitor methyl‑β‑cyclodextrin(MCD)was employed to perturb the pathway,and its effects on differentiation markers were analyzed.Results Catalpol demonstrated excellent biocompatibility,with cell viability exceeding 96%across the entire tested concentration range(0-3 g/L),confirming its non-cytotoxic nature.At the optimal concentration of 0-3 g/L,catalpol significantly upregulated both MBP and SOX10 expression(P<0.05,P<0.01),indicating robust promotion of oligodendroglial differentiation.Intriguingly,Cav-1 mRNA expression was progressively downregulated during NSC differentiation into OLs.Further inhibition of Cav-1 with MCD further enhanced this effect,leading to a statistically significant increase in OL-specific gene expression(P<0.05,P<0.01),suggesting Cav-1 acts as a negative regulator of OLs differentiation.Conclusion This study established an integrated microfluidic gradient chip-3D NSC spheroid culture system,which combines the advantages of precise chemical gradient control with physiologically relevant 3D cell culture.The findings demonstrate that 3 g/L catalpol effectively suppresses Cav-1 signaling to drive NSC differentiation into functional OLs.This work not only provides novel insights into the Cav-1-dependent mechanisms of myelination but also delivers a scalable technological platform for future research on remyelination therapies,with potential applications in cerebral palsy and other white matter disorders.The platform’s modular design permits adaptation for screening other neurogenic compounds or investigating additional signaling pathways involved in OLs maturation.
基金supported by the National Natural Science Foundation of China(22178361,22378402,52302310)the International Partnership Project of CAS(039GJHZ2022029GC)+5 种基金the National Key R&D Program of China(2020YFA0710200)the foundation of the Innovation Academy for Green Manufacture Institute,Chinese Academy of Sciences(IAGM2022D07)the China Postdoctoral Science Foundation(2022M722597)QinChuangYuan Cites High-level Innovation and Entrepreneurship Talent Programs(QCYRCXM-2022-335)the Fundamental Research Funds for the Central Universities(G2022KY05111)the Open Project Program of Anhui Province International Research Center on Advanced Building Materials(JZCL2303KF)。
文摘Paired electrosynthesis has received considerable attention as a consequence of simultaneously synthesizing target products at both cathode and anode,whereas the related synthetic efficiency in batch reactors is still undesirable under certain circumstances.Encouragingly,laminar microfluidic reactor offers prospective options that possess controllable flow characteristics such as enhanced mass transport,precise laminar flow control and the ability to expand production scale progressively.In this comprehensive review,the underlying fundamentals of the paired electrosynthesis are initially summarized,followed by categorizing the paired electrosynthesis including parallel paired electrosynthesis,divergent paired electrosynthesis,convergent paired electrosynthesis,sequential paired electrosynthesis and linear paired electrosynthesis.Thereafter,a holistic overview of microfluidic reactor equipment,integral fundamentals and research methodology as well as channel extension and scale-up strategies is proposed.The established fundamentals and evaluated metrics further inspired the applications of microfluidic reactors in paired electrosynthesis.This work stimulated the overwhelming investigation of mechanism discovery,material screening strategies,and device assemblies.
基金supported by the National Natural Science Foundation of China(grant number 52404044).
文摘There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct constant volume depletion experiments and investigate the microscopic mechanisms of condensate gas recovery.The aim of the experiments was to reveal the phase-behavior differences between bulk-phase gas and gas contained in porous media.The results revealed that condensate oil recovery in microfluidics experiments was higher than that in PVT cell tests,and nonuniform condensation and evaporation were exclusively observed in the microfluidics experiments.Furthermore,lower pore connectivity resulted in higher depletion recovery,while more developed fractures led to reduced recovery.Specifically,the chip with fewer fractures achieved the highest recovery(71.15%),whereas the highly fractured chip exhibited the lowest recovery(56.11%).These findings demonstrate that oil saturation during the process of constant volume depletion(CVD)of gas condensate within porous media is lower than that observed in the PVT cell,thus providing experimental evidence for optimizing condensate gas development in field applications.
基金supported by the National Key Research and Development Plan of China(2023YFB3210400)the Natural Science Innovation Group Foundation of China(T2321004)+3 种基金the National Natural Science Foundation of China(62174101)Shandong University Integrated Research and Cultivation Project(2022JC001)Key Research and Development Plan of Shandong Province(Major Science and Technology Innovation Project2022CXGC020501).
文摘The real-time screening of biomolecules and single cells in biochips is extremely important for disease prediction and diagnosis,cellular analysis,and life science research.Barcode biochip technology,which is integrated with microfluidics,typically comprises barcode array,sample loading,and reaction unit array chips.Here,we present a review of microfluidics barcode biochip analytical approaches for the high-throughput screening of biomolecules and single cells,including protein biomarkers,microRNA(miRNA),circulating tumor DNA(ctDNA),single-cell secreted proteins,single-cell exosomes,and cell interactions.We begin with an overview of current high-throughput detection and analysis approaches.Following this,we outline recent improvements in microfluidic devices for biomolecule and single-cell detection,highlighting the benefits and limitations of these devices.This paper focuses on the research and development of microfluidic barcode biochips,covering their self-assembly substrate materials and their specific applications with biomolecules and single cells.Looking forward,we explore the prospects and challenges of this technology,with the aim of contributing toward the use of microfluidic barcode detection biochips in medical diagnostics and therapies,and their large-scale commercialization.
基金financially supported by Science and Technology on Applied Physical Chemistry Laboratory,China(Grant No.61426022220303)supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.52305617)。
文摘Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fluids and facilitate droplet formation at the microscale,enables precise control of chemical reactions.Recent scholarly endeavors have increasingly harnessed microfluidic reactors in the realm of energetic materials,yielding morphologically controllable particles with enhanced uniformity and explosive efficacy.However,crucial insights into microfluidic-based methodologies are dispersed across various publications,necessitating a systematic compilation.Accordingly,this review addresses this gap by concentrating on the synthesis of energetic materials through microfluidics.Specifically,the methods based on micro-mixing and droplets in the previous papers are summarized and the strategies to control the critical parameters within chemical reactions are discussed in detail.Then,the comparison in terms of advantages and disadvantages is attempted.As demonstrated in the last section regarding perspectives,challenges such as clogging,dead zones,and suboptimal production yields are non-ignoble in the promising fields and they might be addressed by integrating sound,optics,or electrical energy to meet heightened requirements.This comprehensive overview aims to consolidate and analyze the diverse array of microfluidic approaches in energetic material synthesis,offering valuable insights for future research directions.
基金funded by the Beijing Natural Science Foundation[Grant No.Z210006]the National Natural Science Foundation of China[Grant No.62275061].
文摘Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for detecting Ni ions.The microfluidic paper-based analytical devices(µPADs)are potential candidates for the detection of water quality parameters including pH,heavy ions,nitrite and so on.However,it suffers from a huge error caused by the environment and artificial mistakes.In this study,we proposed an improved technique route to increase the stability and reliability of microfluidic paper-based analytical devices.The main technique points include a stable light source,a matched camera,improved reliability of the devices,and effective calculated methods.Finally,we established 15 standard curves that could be used to detect nickel ions and obtained uniform colorimetric results with reliability and repeatability.With those improvements,the relative errors for the five types of real water samples from the Zhongshan industrial parks were reduced to 0.26%,14.78%,24.20%,50.29%and 3.53%,respectively.These results were conducive to exploring this technique for the detection of nickel ions in wastewater from the Zhongshan industrial parks.The results demonstrated that the above technique route is promising for the detection of other heavy metal ions in industrial effluent.
基金supports for this project from State Key Laboratory of Chemical Safety(SKLCS–2024001)are gratefully acknowledged。
文摘Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas−liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α1 and α2 are influenced by the viscous force. The values of pre-factors m_(1) and m_(2) are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.
基金the financial support from the National Natural Science Foundation of China (No.42102127)the Postdoctoral Research Foundation of China (No.2024 M751860)。
文摘Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was constructed based on microfluidics.A microscopic and mesoscopic observation technique was proposed to simultaneously capture gas-liquid interface morphology of pores and throat and the two-phase flow characteristics in entire cleat system.The local contact characteristics of cleats reduced absolute permeability,which resulted in a sharp increase in the starting pressure.The reduced gas flow capacity narrowed the co-infiltration area and decreased water saturation at the isotonic point in a hydrophilic environment.The increased local contact area of cleats weakened gas phase flow capacity and narrowed the co-infiltration area.Jumping events occurred in methane-water flow due to altered porosity caused by local contact in cleats.The distribution of residual phases changed the jumping direction on the micro-scale as well as the dominant channel on the mesoscale.Besides,jumping events caused additional energy dissipation,which was ignored in traditional two-phase flow models.This might contribute to the overestimation of relative permeability.The work provides new methods and insights for investigating unsaturated flow in complex porous media.
