A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(D...A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(DC)sputtering,vacuum evaporation and liftoff process.The thermal annealing test was conducted in the temperature range of 200-800℃for obtaining an appropriate property of the multilayer.Based on the experimental results,400℃was selected as the experimental annealing temperature for the Ti/Pt/Cr/Au layer.The redistribution of structural imperfections and recrystallization promote the density and adhesion of multilayer during the annealing process.With the annealing temperature rising,the annealing process leads to through-thickness migration of chromium and partial depletion of the adhesive layer.The Ti also diffuses into the Pt,which makes the interface disappear.Nevertheless,the layer remains continuous.The temperature coefficient of resistance(TCR)of the sensors was investigated through the microfluidic testing system.The excellent stability and sensitivity of the Ti/Pt/Cr/Au thin-film temperature sensor are verified.Furthermore,the capability of the Ti/Pt/Cr/Au thin-film temperature sensor detecting the sudden temperature change caused by bubble effect is very meaningful to the microfluidic devices.展开更多
This device is aimed at ensuring that the sample is uniformly and equivalently reacted with the antibody on the NC membrane in each test when the microfluidic liquid system is introduced to the chip.In this study,the ...This device is aimed at ensuring that the sample is uniformly and equivalently reacted with the antibody on the NC membrane in each test when the microfluidic liquid system is introduced to the chip.In this study,the developed microfluidic chip can avoid the presence of the sample and conjugate pads in the chip,while the precision of the chro matography system can be greatly improved using the same particles,NC membrane and antibody alongside the traditional strip.The results,taking the detection of cTnI as an example,revealed that the coefficient of variation(CV)is controlled within 4%,while the maximum record of the contrast chromatographic reagent strip can reach 15%.Additionally,the detection sensitivity can maintain the same order of magnitudes with that of the traditional chromatographic strip.With the results,the determination correlation of the developed microfluidic chip has been greatly improved.In addition,the CV of the chip in this study is greatly improved in comparison with that of the traditional strip.The biggest improvement lies in the mixing between the sample and the microspheres,indicating that this is a new approach to improve the CV of the traditional strip.展开更多
Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glas...Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.展开更多
Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and diffi...Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and difficult to use in generating multilayered structure.As an alternative,3D printing allows rapid and cost-effective prototyping and customization of complex microfluidic structures.However,3Dprinted devices are typically opaque and are challenging to create small channels.Herein,we introduce a novel“programmable optical window bonding”3D printing method that incorporates the bonding of an optical window during the printing process,facilitating the fabrication of transparent microfluidic devices with high printing fidelity.Our approach allows direct and rapid manufacturing of complex microfluidic structure without the use of molds for PDMS casting.We successfully demonstrated the applications of this method by fabricating a variety of microfluidic devices,including perfusable chips for cell culture,droplet generators for spheroid formation,and high-resolution droplet microfluidic devices involving different channel width and height for rapid antibiotic susceptibility testing.Overall,our 3D printing method demonstrates a rapid and cost-effective approach for manufacturing microfluidic devices,particularly in the biomedical field,where rapid prototyping and high-quality optical analysis are crucial.展开更多
Reservoir simulation uses numerical models to study how reservoir properties impact oil recovery.However, numerical modelling is insufficient and is often paired with physical simulation, where physical models are use...Reservoir simulation uses numerical models to study how reservoir properties impact oil recovery.However, numerical modelling is insufficient and is often paired with physical simulation, where physical models are used to verify and improve simulation results. Historically, physical simulation was conducted using difficult-to-extract reservoir rock samples;however, microfluidic devices(MFDs) have emerged as viable substitutes. Unfortunately, conventional approaches to MFD fabrication leads to devices with physical and chemical properties dissimilar to that of reservoir rock-which can decrease simulation accuracy. Thanks to significant advancements in three-dimensional printing, it can be used to fabricate MFDs with properties and dimensions close to those of reservoir rocks thanks to high resolution, good dimensional accuracy, and a wide range of printable substrates, resulting in more accurate simulation aimed at maximizing oil recovery.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
Nanomaterials show promising opportunities to address clinical problems （such as insufficient capture of circulating tumor cells; CTCs） via the high surface area-to-volume ratio and high affinity for biological cell...Nanomaterials show promising opportunities to address clinical problems （such as insufficient capture of circulating tumor cells; CTCs） via the high surface area-to-volume ratio and high affinity for biological cells. However, how to apply these nanomaterials as a nano-bio interface in a microfluidic device for efficient CTC capture with high specificity remains a challenge. In the present work, we first found that a titanium dioxide （TiO2） nanorod array that can be conveniently prepared on multiple kinds of substrates has high affinity for tumor cells. Then, the TiO2 nanorod array was vertically grown on the surface of a microchannel with hexagonally patterned Si micropillars via a hydrothermal reaction, forming a new kind of a micro-nano 3D hierarchically structured microfluidic device. The vertically grown TiO2 nanorod array was used as a sensitive nano-bio interface of this 3D hierarchically structured microfluidic device, which showed high efficiency of CTC capture （76.7% ± 7.1%） in an artificial whole-blood sample.展开更多
With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow c...With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow characteristics of compressible flow through micro-channels and micronozzles.An improved surface roughness viscosity model is used to simulate the effect of surface roughness on micro-channels flow characteristics.Using this model,better agreements between the computational results and the experimental data are found.The result indicates that the surface roughness is one of the important factors affecting the flow characteristics of gas through micro-channels.The numerical investigation on the expansion channel shows that by using the laminar model that considers surface roughness,the computational results and experimental data are consistent when Re<450,whereas deviation increases when Re>450.Based on the synthetic model with considerations of turbulence viscosity and surface roughness,the numerical results and the experimental data are identical.展开更多
Molecularly imprinted polymers are generated by curing a cross-linked polymer in the presence of a template. During the curing process, noncovalent bonds form between the polymer and the template. The interaction site...Molecularly imprinted polymers are generated by curing a cross-linked polymer in the presence of a template. During the curing process, noncovalent bonds form between the polymer and the template. The interaction sites for the noncovalent bonds become "frozen" in the cross-linking polymer and maintain their shape even after the template is removed. The resulting cavities reproduce the size and shape of the template and can selectively reincorporate the template when a mixture containing it flows over the imprinted surface. In the last few decades the field of molecular imprinting has evolved from being able to selectively capture only small molecules to dealing with all kinds of samples. Molecularly imprinted polymers (MIPs) have been generated for analytes as diverse as metal ions, drug molecules, environmental pollutants, proteins and viruses to entire cells. We review here the relatively new field of surface imprinting, which creates imprints of large, biologically relevant templates. The traditional bulk imprinting, where a template is simply added to a prepolymer before curing, cannot be applied if the analyte is too large to diffuse from the cured polymer. Special methods must be used to generate binding sites only on a surface. Those techniques have solved crucial problems in separation science as well as chemical and biochemical sensing. The implementation of imprinted polymers into microfluidic chips has greatly improved the applicability of microfluidics. We present the latest advances and different approaches of surface imprinting and their applications for microfluidic devices.展开更多
Microfluidic devices, as a new miniaturized platform stemming from the field of micro-electromechanical sys-tems, have been used in many disciplines. In the field of chemical reactions, microfluidic device-based micro...Microfluidic devices, as a new miniaturized platform stemming from the field of micro-electromechanical sys-tems, have been used in many disciplines. In the field of chemical reactions, microfluidic device-based microreac-tors have shown great promise in building new chemical technologies and processes with increased speed and reli- ability and reduced sample consumption and cost. This technology has also become a new and effective tool for precise, high-throughput, and automatic analysis of chemical synthesis processes. Compared with conventional chemical laboratory batch methodologies, microfluidic reactors have a number of features, such as high mixing ef- ficiency, short reaction time, high heat-transfer coefficient, small reactant volume, controllable residence time, and high surface-to-volume ratio, among others. Combined with recent advances in microfluidic devices for chemical reactions, this review aims to give an overview of the features and applications of microfluidic devices in the field of chemical synthesis. It also aims to stimulate the development of microfluidic device applications in the field of chemical reactions.展开更多
Circulating tumor cells(CTCs)are cancer cells that have propagated from primary tumor sites,spreading into the bloodstream as the cellular origin of fatal metastasis,and to secondary tumor sites.Capturing and analyzin...Circulating tumor cells(CTCs)are cancer cells that have propagated from primary tumor sites,spreading into the bloodstream as the cellular origin of fatal metastasis,and to secondary tumor sites.Capturing and analyzing CTCs is a kind of‘‘liquid biopsy'of the tumor that provides information about cancer changes over time and tailoring treatment[1].CTC enrichment and detection remains technologically challenging due to their extremely low concentra-展开更多
Central nervous system(CNS)neurons typically fail to regenerate their axons after injury leading to neurological impairment.Axonal regeneration is a highly energy-demanding cellular program that requires local mitocho...Central nervous system(CNS)neurons typically fail to regenerate their axons after injury leading to neurological impairment.Axonal regeneration is a highly energy-demanding cellular program that requires local mitochondria to supply most energy within injured axons.Recent emerging lines of evidence have started to reveal that injury-triggered acute mitochondrial damage and local energy crisis contribute to the intrinsic energetic restriction that accounts for axon regeneration failure in the CNS.Characterizing and reprogramming bioenergetic signaling and mitochondrial maintenance after axon injury-ischemia is fundamental for developing therapeutic strategies that can restore local energy metabolism and thus facilitate axon regeneration.Therefore,establishing reliable and reproduc-ible neuronal model platforms is critical for assessing axonal energetic metabolism and regeneration capacity after injury-ischemia.In this focused methodology article,we discuss recent advances in applying cutting-edge microflu-idic chamber devices in combination with state-of-the-art live-neuron imaging tools to monitor axonal regeneration,mitochondrial transport,bioenergetic metabolism,and local protein synthesis in response to injury-ischemic stress in mature CNS neurons.展开更多
We report a functionalisation strategy which is able to generate Ricinus communis agglutinin 1 （RCA 120） modified PMMA microfluidic device for binding and culturing living cells. The functionalisation is achieved by...We report a functionalisation strategy which is able to generate Ricinus communis agglutinin 1 （RCA 120） modified PMMA microfluidic device for binding and culturing living cells. The functionalisation is achieved by standard aminealdehyde （Schiff base） reaction through the crosslinker, glutaraldehyde. To prove the ability of the RCA 120 modified PMMA surface, the PC 12 cell line （rat pheochromocytoma ceils） has been captured and cultured by the microfluidic device. In the presence of tunicamycin, the dose/timedependence on decreasing of binding affinity of RCA 120 modified device with PC 12 cell is also observed. The experimental results demonstrate that the lectin-functionalized microfluidic device can be employed as efficient cell culturing platform, and has a great promise of being used as a powerful tool for monitoring the interaction of drug with living cell.展开更多
The selection of the most motile and functionally competent sperm is an essential basis for in vitro fertilization(IVF)and normal embryonic development.Widely adopted clinical approaches for sperm sample processing in...The selection of the most motile and functionally competent sperm is an essential basis for in vitro fertilization(IVF)and normal embryonic development.Widely adopted clinical approaches for sperm sample processing intensely rely on centrifugation and wash steps that may induce mechanical damage and oxidative stress to sperm.Although a few microfluidic sperm sorting devices may avoid these adverse effects by exploiting intrinsic guidance mechanisms of sperm swimming,none of these approaches have been fully validated by clinical-grade assessment criteria.In this study,a microfluidic sperm sorting device that enables the selection of highly motile and functional sperm via their intrinsic thermotaxis is presented.Bioinspired by the temperature microenvironment in the fallopian tube during natural sperm selection,a microfluidic device with controllable temperature gradients along the sperm separation channel was designed and fabricated.This study investigated the optimal temperature conditions for human sperm selection and fully characterized thermotaxis-selected sperm with 45 human sperm samples.Results indicated that a temperature range of 35–36.5℃along the separation channel significantly improves human sperm motility rate((85.25±6.28)%vs.(60.72±1.37)%;P=0.0484),increases normal sperm morphology rate((16.42±1.43)%vs.(12.55±0.88)%;P<0.0001),and reduces DNA fragmentation((7.44±0.79)%vs.(10.36±0.72)%;P=0.0485)compared to the nonthermotaxis group.Sperm thermotaxis is species-specific,and selected mouse sperm displayed the highest motility in response to a temperature range of 36–37.5℃ along the separation channel.Furthermore,IVF experiments indicated that the selected sperm permitted an increased fertilization rate and improved embryonic development from zygote to blastocyst.This microfluidic thermotaxic selection approach will be translated into clinical practice to improve the IVF success rate for patients with oligozoospermia and asthenozoospermia.展开更多
We conducted experiments on specially designed microfluidic chips that generate droplets through a microfluidic ow-focusing approach. The fluid flow in the microfluidic channel produced a shear flow field at low Reyno...We conducted experiments on specially designed microfluidic chips that generate droplets through a microfluidic ow-focusing approach. The fluid flow in the microfluidic channel produced a shear flow field at low Reynolds numbers. The droplets in the microfluidic system exhibited special droplet pattern formations similar to periodic crystal-like lattices because of the competition between shear forces and surface tension. By adjusting the flow rate ratio of the water （droplet phase） to oil （continuous phase） phases and changing the outlet channel widths, the droplets formed monolayer dispersion to double-layer formation to monolayer squeezing when the outlet channel widths were 250 or 300 μm. We also obtained droplets with monolayer dispersion, three-layer arrangements, double-layer squeezing, and monolayer squeezing when the outlet channel width was 350 μm. The outlet channel width was increased to 400 μm, and four-layer arrangements were observed. We also studied the translation of droplet formation, which resulted in a detailed strategy to control drop size and droplet pattern formation for emulsi cation in microfluidic devices. We expect that our strategy can provide theoretical guidance to synthesize dispersion or polydisperse colloid particles.展开更多
Abstract A new microfluidic system with four different microchambers （a circle and three equilateral concave polygons） was designed and fabricated using poly（dimethylsiloxane） （PDMS） and the soft lithography met...Abstract A new microfluidic system with four different microchambers （a circle and three equilateral concave polygons） was designed and fabricated using poly（dimethylsiloxane） （PDMS） and the soft lithography method. Using this microfluidic device at six flow rates （5, 10, 20, 30, 40, and 50 μL/h）, the effects of microenvironmental geometry and aqueous flow on bacterial adhesion behaviors were investigated. Escherichia coli HB101 pGLO, which could produce a green fluorescent protein induced by L-arabinose, was utilized as the model bacteria. The results demonstrated that bacterial adhesion was significantly related to culture time, microenvironment geometry, and aqueous flow rates. Adhered bacterial density increased with the culture time. Initially, the adhesion occurred at the microchamber sides, and then the entire chamber was gradually covered with increased culture time. Adhesion densities in the side zones were larger than those in the center zones because of the lower shearing force in the side zone. Also, the adhesion densities in the complex chambers were larger than those in the simple chambers. At low flow rates, the orientation of adhered bacteria was random and disorderly. At high flow rates, bacterial orientation became close to the streamline and oriented toward the flow direction; All these results implied that bacterial adhesion tended to occur in complicated aqueous flow areas.The present study provided an on-chip flow system for physiological behavior of biological cells, as well as provided a strategic cue for the prevention of bacterial infection and biofilm formation.展开更多
The research on microfluidic droplet size prediction has been extensive and fruitful, while the droplet deforming process has been seldom studied. In this paper, a frying-oil-assessing microfluidic device was designed...The research on microfluidic droplet size prediction has been extensive and fruitful, while the droplet deforming process has been seldom studied. In this paper, a frying-oil-assessing microfluidic device was designed to study the droplet deforming and recovering processes, which were dominated by channel geometry, flow rates,sheath flow viscosity and interfacial tension of the two phases. Theoretical expressions of the deforming process and its extreme value were obtained for the first time, supported by simulation and experiments. Theoretical,simulation and experimental results indicated that the steady-state droplet length could be a useful parameter for frying oil assessment.展开更多
Neurodegeneration is a catastrophic process that develops progressive damage leading to functional andstructural loss of the cells of the nervous system and is among the biggest unavoidable problems of our age.Animalm...Neurodegeneration is a catastrophic process that develops progressive damage leading to functional andstructural loss of the cells of the nervous system and is among the biggest unavoidable problems of our age.Animalmodels do not reflect the pathophysiology observed in humans due to distinct differences between the neuralpathways,gene expression patterns,neuronal plasticity,and other disease-related mechanisms in animals andhumans.Classical in vitro cell culture models are also not sufficient for pre-clinical drug testing in reflecting thecomplex pathophysiology of neurodegenerative diseases.Today,modern,engineered techniques are applied to developmulticellular,intricate in vitro models and to create the closest microenvironment simulating biological,biochemical,and mechanical characteristics of the in vivo degenerating tissue.In THIS review,the capabilities and shortcomings ofscaffold-based and scaffold-free techniques,organoids,and microfluidic models that best reflect neurodegeneration invitro in the biomimetic framework are discussed.展开更多
To enhance the efficiency of vaccine manufacturing,this study focuses on optimizing the microfluidic conditions and lipid mix ratios of messenger RNA-lipid nanoparticles(mRNA-LNP).Different mRNA-LNP formulations(n=24)...To enhance the efficiency of vaccine manufacturing,this study focuses on optimizing the microfluidic conditions and lipid mix ratios of messenger RNA-lipid nanoparticles(mRNA-LNP).Different mRNA-LNP formulations(n=24)were developed using an I-optimal design,where machine learning tools(XGBoost/Bayesian optimization and self-validated ensemble(SVEM))were used to optimize the process and predict lipid mix ratio.The investigation included material attributes,their respective ratios,and process attributes.The critical responses like particle size(PS),polydispersity index(PDI),Zeta potential,pKa,heat trend cycle,encapsulation efficiency(EE),recovery ratio,and encapsulated mRNA were evaluated.Overall prediction of SVEM(>97%)was comparably better than that of XGBoost/Bayesian optimization(>94%).Moreover,in actual experimental outcomes,SVEM prediction is close to the actual data as confirmed by the experimental PS(94-96 nm)is close to the predicted one(95-97 nm).The other parameters including PDI and EE were also close to the actual experimental data.展开更多
Low-temperature energy harvest,delivery,and utilization pose significant challenges for thermal management in extreme environments owing to heat loss during transport and difficulty in temperature control.Herein,we pr...Low-temperature energy harvest,delivery,and utilization pose significant challenges for thermal management in extreme environments owing to heat loss during transport and difficulty in temperature control.Herein,we propose a light-driven photo-energy delivery device with a series of photo-responsive alkoxy-grafted azobenzene-based phase-change materials(a-g-Azo PCMs).These a-g-Azo PCMs store and release crystallization and isomerization enthalpies,reaching a high energy density of 380.76 J/g even at a low temperature of-63.92℃.On this basis,we fabricate a novel three-branch light-driven microfluidic control device for distributed energy recycling that achieves light absorption,energy storage,controlled movement,and selective release cyclically over a wide range of temperatures.The a-g-Azo PCMs move remote-controllably in the microfluidic device at an average velocity of 0.11-0.53 cm/s owing to the asymmetric thermal expansion effect controlled by the temperature difference.During movement,the optically triggered heat release of a-g-Azo PCMs achieves a temperature difference of 6.6℃ even at a low temperature of-40℃.These results provide a new technology for energy harvest,delivery,and utilization in low-temperature environments via a remote manipulator.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51602039)the Central University Support Project(No.ZYGX2016J051)。
文摘A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(DC)sputtering,vacuum evaporation and liftoff process.The thermal annealing test was conducted in the temperature range of 200-800℃for obtaining an appropriate property of the multilayer.Based on the experimental results,400℃was selected as the experimental annealing temperature for the Ti/Pt/Cr/Au layer.The redistribution of structural imperfections and recrystallization promote the density and adhesion of multilayer during the annealing process.With the annealing temperature rising,the annealing process leads to through-thickness migration of chromium and partial depletion of the adhesive layer.The Ti also diffuses into the Pt,which makes the interface disappear.Nevertheless,the layer remains continuous.The temperature coefficient of resistance(TCR)of the sensors was investigated through the microfluidic testing system.The excellent stability and sensitivity of the Ti/Pt/Cr/Au thin-film temperature sensor are verified.Furthermore,the capability of the Ti/Pt/Cr/Au thin-film temperature sensor detecting the sudden temperature change caused by bubble effect is very meaningful to the microfluidic devices.
基金financially supported by National Natural Science Foundation of China(Nos.81902153,61871180,62071119 and 61971187)Jiangsu Provincial Key Research and Development Program(No.BE 2018695)。
文摘This device is aimed at ensuring that the sample is uniformly and equivalently reacted with the antibody on the NC membrane in each test when the microfluidic liquid system is introduced to the chip.In this study,the developed microfluidic chip can avoid the presence of the sample and conjugate pads in the chip,while the precision of the chro matography system can be greatly improved using the same particles,NC membrane and antibody alongside the traditional strip.The results,taking the detection of cTnI as an example,revealed that the coefficient of variation(CV)is controlled within 4%,while the maximum record of the contrast chromatographic reagent strip can reach 15%.Additionally,the detection sensitivity can maintain the same order of magnitudes with that of the traditional chromatographic strip.With the results,the determination correlation of the developed microfluidic chip has been greatly improved.In addition,the CV of the chip in this study is greatly improved in comparison with that of the traditional strip.The biggest improvement lies in the mixing between the sample and the microspheres,indicating that this is a new approach to improve the CV of the traditional strip.
文摘Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.
文摘Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and difficult to use in generating multilayered structure.As an alternative,3D printing allows rapid and cost-effective prototyping and customization of complex microfluidic structures.However,3Dprinted devices are typically opaque and are challenging to create small channels.Herein,we introduce a novel“programmable optical window bonding”3D printing method that incorporates the bonding of an optical window during the printing process,facilitating the fabrication of transparent microfluidic devices with high printing fidelity.Our approach allows direct and rapid manufacturing of complex microfluidic structure without the use of molds for PDMS casting.We successfully demonstrated the applications of this method by fabricating a variety of microfluidic devices,including perfusable chips for cell culture,droplet generators for spheroid formation,and high-resolution droplet microfluidic devices involving different channel width and height for rapid antibiotic susceptibility testing.Overall,our 3D printing method demonstrates a rapid and cost-effective approach for manufacturing microfluidic devices,particularly in the biomedical field,where rapid prototyping and high-quality optical analysis are crucial.
基金supported by the Russian Ministry of Science and Higher Education “Science and Universities” National Project state task N°FSER-2022-0002.E.F.K.also acknowledges the Priority 2030 Federal Academic Leadership Program for infrastructural support
文摘Reservoir simulation uses numerical models to study how reservoir properties impact oil recovery.However, numerical modelling is insufficient and is often paired with physical simulation, where physical models are used to verify and improve simulation results. Historically, physical simulation was conducted using difficult-to-extract reservoir rock samples;however, microfluidic devices(MFDs) have emerged as viable substitutes. Unfortunately, conventional approaches to MFD fabrication leads to devices with physical and chemical properties dissimilar to that of reservoir rock-which can decrease simulation accuracy. Thanks to significant advancements in three-dimensional printing, it can be used to fabricate MFDs with properties and dimensions close to those of reservoir rocks thanks to high resolution, good dimensional accuracy, and a wide range of printable substrates, resulting in more accurate simulation aimed at maximizing oil recovery.
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The authors are thankful for funding from the National Natural Science Foundation of China （Nos. 51402063, 51432005, 61405040, 61505010, 51502018, 31270022, and 81471784）, the ＂100 Talents Program＂ of the Chinese Academy of Sciences, Beijing City Committee of science and technology （No. Z151100003315010）, Beijing Natural Science Foundation （Nos. 2164077 and 2164076）, the Fundamental Research Funds of Shandong University （No. 2014QY003）, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences （No. 2015023）. The authors also acknowledge the support from the＂thousands talents＂ program for pioneer researchers and his innovation team, and support from the President Funding of the Chinese Academy of Sciences.
文摘Nanomaterials show promising opportunities to address clinical problems （such as insufficient capture of circulating tumor cells; CTCs） via the high surface area-to-volume ratio and high affinity for biological cells. However, how to apply these nanomaterials as a nano-bio interface in a microfluidic device for efficient CTC capture with high specificity remains a challenge. In the present work, we first found that a titanium dioxide （TiO2） nanorod array that can be conveniently prepared on multiple kinds of substrates has high affinity for tumor cells. Then, the TiO2 nanorod array was vertically grown on the surface of a microchannel with hexagonally patterned Si micropillars via a hydrothermal reaction, forming a new kind of a micro-nano 3D hierarchically structured microfluidic device. The vertically grown TiO2 nanorod array was used as a sensitive nano-bio interface of this 3D hierarchically structured microfluidic device, which showed high efficiency of CTC capture （76.7% ± 7.1%） in an artificial whole-blood sample.
基金supported by the National Natural Science Foundation of China(Grant No. 10872106)
文摘With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow characteristics of compressible flow through micro-channels and micronozzles.An improved surface roughness viscosity model is used to simulate the effect of surface roughness on micro-channels flow characteristics.Using this model,better agreements between the computational results and the experimental data are found.The result indicates that the surface roughness is one of the important factors affecting the flow characteristics of gas through micro-channels.The numerical investigation on the expansion channel shows that by using the laminar model that considers surface roughness,the computational results and experimental data are consistent when Re<450,whereas deviation increases when Re>450.Based on the synthetic model with considerations of turbulence viscosity and surface roughness,the numerical results and the experimental data are identical.
文摘Molecularly imprinted polymers are generated by curing a cross-linked polymer in the presence of a template. During the curing process, noncovalent bonds form between the polymer and the template. The interaction sites for the noncovalent bonds become "frozen" in the cross-linking polymer and maintain their shape even after the template is removed. The resulting cavities reproduce the size and shape of the template and can selectively reincorporate the template when a mixture containing it flows over the imprinted surface. In the last few decades the field of molecular imprinting has evolved from being able to selectively capture only small molecules to dealing with all kinds of samples. Molecularly imprinted polymers (MIPs) have been generated for analytes as diverse as metal ions, drug molecules, environmental pollutants, proteins and viruses to entire cells. We review here the relatively new field of surface imprinting, which creates imprints of large, biologically relevant templates. The traditional bulk imprinting, where a template is simply added to a prepolymer before curing, cannot be applied if the analyte is too large to diffuse from the cured polymer. Special methods must be used to generate binding sites only on a surface. Those techniques have solved crucial problems in separation science as well as chemical and biochemical sensing. The implementation of imprinted polymers into microfluidic chips has greatly improved the applicability of microfluidics. We present the latest advances and different approaches of surface imprinting and their applications for microfluidic devices.
基金The present work was supported by the National Natural Science Foundation of China （Nos. 21175107, 20975082 and 31100726）, the Ministry of Education of the People＇s Republic of China （No. NCET-08-0464）, the State Forestry Administration of the People＇s Re-public of China （No. 200904004）, the Scientific Re-search Foundation for the Returned Overseas Chinese Scholars of the State Education Ministry, and Northwest A＆F University.
文摘Microfluidic devices, as a new miniaturized platform stemming from the field of micro-electromechanical sys-tems, have been used in many disciplines. In the field of chemical reactions, microfluidic device-based microreac-tors have shown great promise in building new chemical technologies and processes with increased speed and reli- ability and reduced sample consumption and cost. This technology has also become a new and effective tool for precise, high-throughput, and automatic analysis of chemical synthesis processes. Compared with conventional chemical laboratory batch methodologies, microfluidic reactors have a number of features, such as high mixing ef- ficiency, short reaction time, high heat-transfer coefficient, small reactant volume, controllable residence time, and high surface-to-volume ratio, among others. Combined with recent advances in microfluidic devices for chemical reactions, this review aims to give an overview of the features and applications of microfluidic devices in the field of chemical synthesis. It also aims to stimulate the development of microfluidic device applications in the field of chemical reactions.
基金supported by the National Basic Research Program of China(2015CB932100,2013CB932703)the National Natural Science Foundation of China(11405185)
文摘Circulating tumor cells(CTCs)are cancer cells that have propagated from primary tumor sites,spreading into the bloodstream as the cellular origin of fatal metastasis,and to secondary tumor sites.Capturing and analyzing CTCs is a kind of‘‘liquid biopsy'of the tumor that provides information about cancer changes over time and tailoring treatment[1].CTC enrichment and detection remains technologically challenging due to their extremely low concentra-
基金This work was supported by grants from the“Young Talent Support Plan”of Xi’an Jiaotong University(71211222010704)to N.Huangthe Intramural Research Program of NINDS,NIH(ZIA NS003029 and ZIA NS002946)to Z.-H.Sheng.
文摘Central nervous system(CNS)neurons typically fail to regenerate their axons after injury leading to neurological impairment.Axonal regeneration is a highly energy-demanding cellular program that requires local mitochondria to supply most energy within injured axons.Recent emerging lines of evidence have started to reveal that injury-triggered acute mitochondrial damage and local energy crisis contribute to the intrinsic energetic restriction that accounts for axon regeneration failure in the CNS.Characterizing and reprogramming bioenergetic signaling and mitochondrial maintenance after axon injury-ischemia is fundamental for developing therapeutic strategies that can restore local energy metabolism and thus facilitate axon regeneration.Therefore,establishing reliable and reproduc-ible neuronal model platforms is critical for assessing axonal energetic metabolism and regeneration capacity after injury-ischemia.In this focused methodology article,we discuss recent advances in applying cutting-edge microflu-idic chamber devices in combination with state-of-the-art live-neuron imaging tools to monitor axonal regeneration,mitochondrial transport,bioenergetic metabolism,and local protein synthesis in response to injury-ischemic stress in mature CNS neurons.
基金supported by National Basic Research Program of China (2011CB935800)the Jilin Provincial Science and Technology Department (20100701)
文摘We report a functionalisation strategy which is able to generate Ricinus communis agglutinin 1 （RCA 120） modified PMMA microfluidic device for binding and culturing living cells. The functionalisation is achieved by standard aminealdehyde （Schiff base） reaction through the crosslinker, glutaraldehyde. To prove the ability of the RCA 120 modified PMMA surface, the PC 12 cell line （rat pheochromocytoma ceils） has been captured and cultured by the microfluidic device. In the presence of tunicamycin, the dose/timedependence on decreasing of binding affinity of RCA 120 modified device with PC 12 cell is also observed. The experimental results demonstrate that the lectin-functionalized microfluidic device can be employed as efficient cell culturing platform, and has a great promise of being used as a powerful tool for monitoring the interaction of drug with living cell.
基金supported by the Key Research and Development Project of Hubei Province,China(No.2021BCA111)。
文摘The selection of the most motile and functionally competent sperm is an essential basis for in vitro fertilization(IVF)and normal embryonic development.Widely adopted clinical approaches for sperm sample processing intensely rely on centrifugation and wash steps that may induce mechanical damage and oxidative stress to sperm.Although a few microfluidic sperm sorting devices may avoid these adverse effects by exploiting intrinsic guidance mechanisms of sperm swimming,none of these approaches have been fully validated by clinical-grade assessment criteria.In this study,a microfluidic sperm sorting device that enables the selection of highly motile and functional sperm via their intrinsic thermotaxis is presented.Bioinspired by the temperature microenvironment in the fallopian tube during natural sperm selection,a microfluidic device with controllable temperature gradients along the sperm separation channel was designed and fabricated.This study investigated the optimal temperature conditions for human sperm selection and fully characterized thermotaxis-selected sperm with 45 human sperm samples.Results indicated that a temperature range of 35–36.5℃along the separation channel significantly improves human sperm motility rate((85.25±6.28)%vs.(60.72±1.37)%;P=0.0484),increases normal sperm morphology rate((16.42±1.43)%vs.(12.55±0.88)%;P<0.0001),and reduces DNA fragmentation((7.44±0.79)%vs.(10.36±0.72)%;P=0.0485)compared to the nonthermotaxis group.Sperm thermotaxis is species-specific,and selected mouse sperm displayed the highest motility in response to a temperature range of 36–37.5℃ along the separation channel.Furthermore,IVF experiments indicated that the selected sperm permitted an increased fertilization rate and improved embryonic development from zygote to blastocyst.This microfluidic thermotaxic selection approach will be translated into clinical practice to improve the IVF success rate for patients with oligozoospermia and asthenozoospermia.
基金This work was supported by the National Natural Science Foundation of China （No.20934004 and No.91127046） and the National Basic Research Program of China （No.2012CB821500 and No.2010CB934500）.
文摘We conducted experiments on specially designed microfluidic chips that generate droplets through a microfluidic ow-focusing approach. The fluid flow in the microfluidic channel produced a shear flow field at low Reynolds numbers. The droplets in the microfluidic system exhibited special droplet pattern formations similar to periodic crystal-like lattices because of the competition between shear forces and surface tension. By adjusting the flow rate ratio of the water （droplet phase） to oil （continuous phase） phases and changing the outlet channel widths, the droplets formed monolayer dispersion to double-layer formation to monolayer squeezing when the outlet channel widths were 250 or 300 μm. We also obtained droplets with monolayer dispersion, three-layer arrangements, double-layer squeezing, and monolayer squeezing when the outlet channel width was 350 μm. The outlet channel width was increased to 400 μm, and four-layer arrangements were observed. We also studied the translation of droplet formation, which resulted in a detailed strategy to control drop size and droplet pattern formation for emulsi cation in microfluidic devices. We expect that our strategy can provide theoretical guidance to synthesize dispersion or polydisperse colloid particles.
基金supported by the National Natural Science Foundation of China (Nos.20975082 and 20775059)the Ministry of Education of the People’s Republic of China (NCET-08-0464),the Scientific Research Foundation for Returned Overseas Chinese Scholars,by the State Education Ministry,by the Northwest A&F University
文摘Abstract A new microfluidic system with four different microchambers （a circle and three equilateral concave polygons） was designed and fabricated using poly（dimethylsiloxane） （PDMS） and the soft lithography method. Using this microfluidic device at six flow rates （5, 10, 20, 30, 40, and 50 μL/h）, the effects of microenvironmental geometry and aqueous flow on bacterial adhesion behaviors were investigated. Escherichia coli HB101 pGLO, which could produce a green fluorescent protein induced by L-arabinose, was utilized as the model bacteria. The results demonstrated that bacterial adhesion was significantly related to culture time, microenvironment geometry, and aqueous flow rates. Adhered bacterial density increased with the culture time. Initially, the adhesion occurred at the microchamber sides, and then the entire chamber was gradually covered with increased culture time. Adhesion densities in the side zones were larger than those in the center zones because of the lower shearing force in the side zone. Also, the adhesion densities in the complex chambers were larger than those in the simple chambers. At low flow rates, the orientation of adhered bacteria was random and disorderly. At high flow rates, bacterial orientation became close to the streamline and oriented toward the flow direction; All these results implied that bacterial adhesion tended to occur in complicated aqueous flow areas.The present study provided an on-chip flow system for physiological behavior of biological cells, as well as provided a strategic cue for the prevention of bacterial infection and biofilm formation.
基金the National Natural Science Foundation of China(No.51205245)Innovation Program of Shanghai Municipal Education Commission(No.14ZZ092)+1 种基金Shanghai Municipal Natural Science Foundation(No.15ZR1415800)College Students’Joint Operation of Shanghai University(No.201618)
文摘The research on microfluidic droplet size prediction has been extensive and fruitful, while the droplet deforming process has been seldom studied. In this paper, a frying-oil-assessing microfluidic device was designed to study the droplet deforming and recovering processes, which were dominated by channel geometry, flow rates,sheath flow viscosity and interfacial tension of the two phases. Theoretical expressions of the deforming process and its extreme value were obtained for the first time, supported by simulation and experiments. Theoretical,simulation and experimental results indicated that the steady-state droplet length could be a useful parameter for frying oil assessment.
文摘Neurodegeneration is a catastrophic process that develops progressive damage leading to functional andstructural loss of the cells of the nervous system and is among the biggest unavoidable problems of our age.Animalmodels do not reflect the pathophysiology observed in humans due to distinct differences between the neuralpathways,gene expression patterns,neuronal plasticity,and other disease-related mechanisms in animals andhumans.Classical in vitro cell culture models are also not sufficient for pre-clinical drug testing in reflecting thecomplex pathophysiology of neurodegenerative diseases.Today,modern,engineered techniques are applied to developmulticellular,intricate in vitro models and to create the closest microenvironment simulating biological,biochemical,and mechanical characteristics of the in vivo degenerating tissue.In THIS review,the capabilities and shortcomings ofscaffold-based and scaffold-free techniques,organoids,and microfluidic models that best reflect neurodegeneration invitro in the biomimetic framework are discussed.
基金supported by the Advance Production of Vaccine Raw Materials(Grant Nos.:20022404 and 20018168)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Grant No.:NRF-2018R1A5A2023127)Dongguk University Research Fund of 2023(Grant No.:S-2023-G0001-00099)。
文摘To enhance the efficiency of vaccine manufacturing,this study focuses on optimizing the microfluidic conditions and lipid mix ratios of messenger RNA-lipid nanoparticles(mRNA-LNP).Different mRNA-LNP formulations(n=24)were developed using an I-optimal design,where machine learning tools(XGBoost/Bayesian optimization and self-validated ensemble(SVEM))were used to optimize the process and predict lipid mix ratio.The investigation included material attributes,their respective ratios,and process attributes.The critical responses like particle size(PS),polydispersity index(PDI),Zeta potential,pKa,heat trend cycle,encapsulation efficiency(EE),recovery ratio,and encapsulated mRNA were evaluated.Overall prediction of SVEM(>97%)was comparably better than that of XGBoost/Bayesian optimization(>94%).Moreover,in actual experimental outcomes,SVEM prediction is close to the actual data as confirmed by the experimental PS(94-96 nm)is close to the predicted one(95-97 nm).The other parameters including PDI and EE were also close to the actual experimental data.
基金Science Foundation for Distinguished Young Scholars in Tianjin,Grant/Award Number:19JCJQJC61700National Natural Science Foundation of China,Grant/Award Numbers:52327802,52173078,51973152+1 种基金National Key R&D Program of China,Grant/Award Number:2022YFB3805702State Key Program of National Natural Science Foundation of China,Grant/Award Number:52130303。
文摘Low-temperature energy harvest,delivery,and utilization pose significant challenges for thermal management in extreme environments owing to heat loss during transport and difficulty in temperature control.Herein,we propose a light-driven photo-energy delivery device with a series of photo-responsive alkoxy-grafted azobenzene-based phase-change materials(a-g-Azo PCMs).These a-g-Azo PCMs store and release crystallization and isomerization enthalpies,reaching a high energy density of 380.76 J/g even at a low temperature of-63.92℃.On this basis,we fabricate a novel three-branch light-driven microfluidic control device for distributed energy recycling that achieves light absorption,energy storage,controlled movement,and selective release cyclically over a wide range of temperatures.The a-g-Azo PCMs move remote-controllably in the microfluidic device at an average velocity of 0.11-0.53 cm/s owing to the asymmetric thermal expansion effect controlled by the temperature difference.During movement,the optically triggered heat release of a-g-Azo PCMs achieves a temperature difference of 6.6℃ even at a low temperature of-40℃.These results provide a new technology for energy harvest,delivery,and utilization in low-temperature environments via a remote manipulator.
