Amphiphilic molecules adsorbed at the interface could control the orientation of liquid crystals(LCs)while LCs in turn could influence the distributions of amphiphilic molecules.The studies on the interactions between...Amphiphilic molecules adsorbed at the interface could control the orientation of liquid crystals(LCs)while LCs in turn could influence the distributions of amphiphilic molecules.The studies on the interactions between liquid crystals and amphiphilic molecules at the interface are important for the development of molecular sensors.In this paper,we demonstrate that the development of smectic LC ordering from isotropic at the LC/water interface could induce local high-density distributions of amphiphilic phospholipids.Mixtures of liquid crystals and phospholipids in chloroform are first emulsified in water.By fluorescently labeling the phospholipids adsorbed at the interface,their distributions are visualized under fluorescent confocal microscope.Interestingly,local high-density distributions of phospholipids showing a high fluorescent intensity are observed on the surface of LC droplets.Investigations on the correlation between phospholipid density,surface tension and smectic LC ordering suggest that when domains of smectic LC layers nucleate and grow from isotropic at the LC/water interface as chloroform slowly evaporates at room temperature,phospholipids transition from liquid-expanded to liquid-condensed phases in response to the smectic ordering,which induces a higher surface tension at the interface.The results will provide an important insight into the interactions between liquid crystals and amphiphilic molecules at the interface.展开更多
Polymer flooding has been witnessed an effective technology for enhancing oil recovery from medium-to low-permeability reservoirs;however, direct visualization of polymer solution flow in such reservoir condition is s...Polymer flooding has been witnessed an effective technology for enhancing oil recovery from medium-to low-permeability reservoirs;however, direct visualization of polymer solution flow in such reservoir condition is still lacking. In this work, a three-dimensional (3D) core-on-a-chip device with a permeability of around 200 mD was prepared and employed to visualize the pore-scale flow and displacement of a self-adaptive polymer (SAP, 8.7 × 106 g·mol−1)−whose microscopic association structure and macroscopic viscosity can reversibly change in response to shear action−versus partially hydrolyzed polyacrylamide (HPAM), by recording their flow curves, monitoring dynamic transportation process via particle imaging velocimetry, and building 3D structure of remaining oil. The results show that, in single-phase flow, all polymer solutions exhibit flow thinning and then thickening regions as flow rate increases, but the transition between two regimes occurs at a small Weissenberg number (10−3−10−1) in this medium-permeable condition. In contrast to HPAM-1 with close weight-average molecular weight (Mw), the adaptive character not only extends SAP's shear-govern region, allowing SAP to propagate piece by piece and achieve higher accessible pore volume, but it also enhances the elastic resistibility of polymer in the extension-dominated regime, increasing the microscopic displacement efficiency. These two effects result in 1.5–3 times more oil recovery factor for SAP than for HPAM-1. Regarding ultra-high-Mw HPAM-2 (25 × 106 g·mol−1), plugging and chain degradation do occur, thus producing lower oil recovery than SAP. This work provides a direct approach for in-situ assessment of polymer-based displacing system under a more authentic condition of practical reservoirs.展开更多
Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is report...Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is reported.Microfluidic technology is utilized to emulsify the inner aqueous phase containing the shell polymer into monodisperse drops in the outer oil phase.As the cosolvent in the inner aqueous phase diffuses into the outer oil phase,the solubility of the shell polymer decreases,which eventually precipitates.Since the shell polymer,shellac,contains both hydrophilic and hydrophobic groups,it tends to wet both the inner aqueous phase and the outer oil phase,thus forming a solid shell at the periphery of the drop.We show that the diffusion rate of hydrophilic molecules encapsulated in the water core decreases as their molecular weight increases and the property of the microcapsules could further be modified by polyelectrolyte multilayer coating.These microcapsules are fabricated using FDA-approved polymer and non-toxic solvents and are of great use in drugs,cosmetics and foods.展开更多
Soft matter refers to a class of materials that can be easily deformed,either by small forces or by thermal energy.These materials generally have both solid-like and liquid-like behaviors.They are typically characteri...Soft matter refers to a class of materials that can be easily deformed,either by small forces or by thermal energy.These materials generally have both solid-like and liquid-like behaviors.They are typically characterized by some elastic coefficient whose value is many orders of magnitude less than most solids.The unit of an elastic constant is pressure or energy density.The energies that characterize materials can vary by a few orders of magnitude,from thermal energies to several electron volts,the latter of which characterize a strong covalent bond.However,the elastic coefficients of soft materials can be as much as ten orders of magnitude less than those of solids.This range must reflect a change in the length scale or the density term.Thus,the fundamental physics of soft matter always occurs at larger length scales,and it is the study of these larger length scales that gives the field its great fascination.展开更多
Microrobotic technologies provide a promising platform for minimally invasive and precise delivery in stem cell therapy.However,engineering multifunctionality into microscale systems remains a critical challenge.Here,...Microrobotic technologies provide a promising platform for minimally invasive and precise delivery in stem cell therapy.However,engineering multifunctionality into microscale systems remains a critical challenge.Here,we present a novel,all-inone Fe-alginate microgel microrobot capable of encapsulating single cells with high efficiency and multiple integrated functionalities.By leveraging bimagnetic FePt@Fe_(3)O_(4) nanoparticles(BMNPs)as both structural and functional crosslinking agents,these microgels enabled magnetically guided transport,stimulus-responsive cell release under light irradiation,and dual-mode T_(1)–T_(2) magnetic resonance imaging.Using a microfluidics-based encapsulation strategy,we achieved>90%encapsulation efficiency,eliminating the need for post-processing.The spherical and homogeneous structure of the microgels ensured excellent viability,proliferation,and function of encapsulated mesenchymal stem cells(MSCs)both in vitro and in vivo.In a murine model,the microrobots exhibited targeted navigation to deep tissue regions and controlled cell release.Our system represents a scalable,multifunctional microgel platform that addresses key translational bottlenecks in targeted and imageguided cell therapy.展开更多
Acoustofluidics,an interdisciplinary nexus of microfluidics and acoustics,is propelling the critical functionalities of manipulation,separation,and mixing within microscale environments.This integration leverages the ...Acoustofluidics,an interdisciplinary nexus of microfluidics and acoustics,is propelling the critical functionalities of manipulation,separation,and mixing within microscale environments.This integration leverages the accuracy of microfluidics with the manipulation capabilities of acoustics,thereby enhancing the vital sample processing steps and satisfying inquiries in experiments.To fulfill the requisites of practical application in clinical and research arenas,the evolution of acoustofluidics concentrates on accomplishing finer particle separation,instantaneous manipulation,and augmented integration capacity.Acoustofluidics has evolved into a sophisticated and versatile instrument for handling specimens and reactants,prompting a trend towards devices characterized by stable performance at elevated frequencies,programmable control,and seamless integration with auxiliary microfluidic systems.In this review,we present the latest advancements in the development of sophisticated acoustofluidic systems that enhance efficiency and enable precise modulation of performance across spatial and temporal scales,thereby extending their functionality and suitability for practical applications.展开更多
Understanding the complexity of biological systems requires a comprehensive analysis of their cell populations.Ideally,this should be done at the single cell level,because bulk analysis of the full population obscured...Understanding the complexity of biological systems requires a comprehensive analysis of their cell populations.Ideally,this should be done at the single cell level,because bulk analysis of the full population obscured many critical details due to artifacts introduced by averaging.However,this has been technically challenging due to the cumbersome procedure,low throughput,and high costs of performing analysis on a single-cell basis.Excitingly,technical improvements in single-cell RNA sequencing are making it economically practical to profile the transcriptomics of large populations of cells at the single-cell level,and have yielded numerous results that address important biological and medical questions.Further development of the technology and data analysis will significantly benefit the biomedical field by unraveling the function of individual cells in their microenvironments and modeling their transcriptional dynamics.展开更多
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.LY20B060027)National Natural Science Foundation of China(No.21878258)+2 种基金the Spanish Ministry of Economy MINECO for a Juan de la Cierva-Incorporacion Fellowship(No.IJCI-2014-22461)supported by the National Science Foundation(No.DMR1310266)the Harvard Materials Research Science and Engineering Center(No.DMR-1420570)。
文摘Amphiphilic molecules adsorbed at the interface could control the orientation of liquid crystals(LCs)while LCs in turn could influence the distributions of amphiphilic molecules.The studies on the interactions between liquid crystals and amphiphilic molecules at the interface are important for the development of molecular sensors.In this paper,we demonstrate that the development of smectic LC ordering from isotropic at the LC/water interface could induce local high-density distributions of amphiphilic phospholipids.Mixtures of liquid crystals and phospholipids in chloroform are first emulsified in water.By fluorescently labeling the phospholipids adsorbed at the interface,their distributions are visualized under fluorescent confocal microscope.Interestingly,local high-density distributions of phospholipids showing a high fluorescent intensity are observed on the surface of LC droplets.Investigations on the correlation between phospholipid density,surface tension and smectic LC ordering suggest that when domains of smectic LC layers nucleate and grow from isotropic at the LC/water interface as chloroform slowly evaporates at room temperature,phospholipids transition from liquid-expanded to liquid-condensed phases in response to the smectic ordering,which induces a higher surface tension at the interface.The results will provide an important insight into the interactions between liquid crystals and amphiphilic molecules at the interface.
基金financially supported by the National Natural Science Foundation of China(grant number U1762218).
文摘Polymer flooding has been witnessed an effective technology for enhancing oil recovery from medium-to low-permeability reservoirs;however, direct visualization of polymer solution flow in such reservoir condition is still lacking. In this work, a three-dimensional (3D) core-on-a-chip device with a permeability of around 200 mD was prepared and employed to visualize the pore-scale flow and displacement of a self-adaptive polymer (SAP, 8.7 × 106 g·mol−1)−whose microscopic association structure and macroscopic viscosity can reversibly change in response to shear action−versus partially hydrolyzed polyacrylamide (HPAM), by recording their flow curves, monitoring dynamic transportation process via particle imaging velocimetry, and building 3D structure of remaining oil. The results show that, in single-phase flow, all polymer solutions exhibit flow thinning and then thickening regions as flow rate increases, but the transition between two regimes occurs at a small Weissenberg number (10−3−10−1) in this medium-permeable condition. In contrast to HPAM-1 with close weight-average molecular weight (Mw), the adaptive character not only extends SAP's shear-govern region, allowing SAP to propagate piece by piece and achieve higher accessible pore volume, but it also enhances the elastic resistibility of polymer in the extension-dominated regime, increasing the microscopic displacement efficiency. These two effects result in 1.5–3 times more oil recovery factor for SAP than for HPAM-1. Regarding ultra-high-Mw HPAM-2 (25 × 106 g·mol−1), plugging and chain degradation do occur, thus producing lower oil recovery than SAP. This work provides a direct approach for in-situ assessment of polymer-based displacing system under a more authentic condition of practical reservoirs.
基金the Youth Founds of the State Key Laboratory of Fluid Power and Mechatronic Systems(Zhejiang University)“Thousand Talents Program” for Distinguished Young Scholars+2 种基金C.-X.Zhao acknowledges financial support from Australian Research Council through the award of a 2014 ARC Future Fellowship(No.FT140100726)supported by the National Science Foundation of U.S.A.(No.DMR-1310266)the Harvard Materials Research Science and Engineering Center(No.DMR-1420570)
文摘Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is reported.Microfluidic technology is utilized to emulsify the inner aqueous phase containing the shell polymer into monodisperse drops in the outer oil phase.As the cosolvent in the inner aqueous phase diffuses into the outer oil phase,the solubility of the shell polymer decreases,which eventually precipitates.Since the shell polymer,shellac,contains both hydrophilic and hydrophobic groups,it tends to wet both the inner aqueous phase and the outer oil phase,thus forming a solid shell at the periphery of the drop.We show that the diffusion rate of hydrophilic molecules encapsulated in the water core decreases as their molecular weight increases and the property of the microcapsules could further be modified by polyelectrolyte multilayer coating.These microcapsules are fabricated using FDA-approved polymer and non-toxic solvents and are of great use in drugs,cosmetics and foods.
文摘Soft matter refers to a class of materials that can be easily deformed,either by small forces or by thermal energy.These materials generally have both solid-like and liquid-like behaviors.They are typically characterized by some elastic coefficient whose value is many orders of magnitude less than most solids.The unit of an elastic constant is pressure or energy density.The energies that characterize materials can vary by a few orders of magnitude,from thermal energies to several electron volts,the latter of which characterize a strong covalent bond.However,the elastic coefficients of soft materials can be as much as ten orders of magnitude less than those of solids.This range must reflect a change in the length scale or the density term.Thus,the fundamental physics of soft matter always occurs at larger length scales,and it is the study of these larger length scales that gives the field its great fascination.
基金supported by the Key Laboratory of Pulsed Power Translational Medicine of Zhejiang Province,China(grant no.ZMY-KF-22003)the National Natural Science Foundation of China(grant nos.22177114 and 21778055).
文摘Microrobotic technologies provide a promising platform for minimally invasive and precise delivery in stem cell therapy.However,engineering multifunctionality into microscale systems remains a critical challenge.Here,we present a novel,all-inone Fe-alginate microgel microrobot capable of encapsulating single cells with high efficiency and multiple integrated functionalities.By leveraging bimagnetic FePt@Fe_(3)O_(4) nanoparticles(BMNPs)as both structural and functional crosslinking agents,these microgels enabled magnetically guided transport,stimulus-responsive cell release under light irradiation,and dual-mode T_(1)–T_(2) magnetic resonance imaging.Using a microfluidics-based encapsulation strategy,we achieved>90%encapsulation efficiency,eliminating the need for post-processing.The spherical and homogeneous structure of the microgels ensured excellent viability,proliferation,and function of encapsulated mesenchymal stem cells(MSCs)both in vitro and in vivo.In a murine model,the microrobots exhibited targeted navigation to deep tissue regions and controlled cell release.Our system represents a scalable,multifunctional microgel platform that addresses key translational bottlenecks in targeted and imageguided cell therapy.
基金supported by the National Natural Science Foundation of China(52025055,52322513,and 51975467)the Shaanxi University Youth Innovation Team.
文摘Acoustofluidics,an interdisciplinary nexus of microfluidics and acoustics,is propelling the critical functionalities of manipulation,separation,and mixing within microscale environments.This integration leverages the accuracy of microfluidics with the manipulation capabilities of acoustics,thereby enhancing the vital sample processing steps and satisfying inquiries in experiments.To fulfill the requisites of practical application in clinical and research arenas,the evolution of acoustofluidics concentrates on accomplishing finer particle separation,instantaneous manipulation,and augmented integration capacity.Acoustofluidics has evolved into a sophisticated and versatile instrument for handling specimens and reactants,prompting a trend towards devices characterized by stable performance at elevated frequencies,programmable control,and seamless integration with auxiliary microfluidic systems.In this review,we present the latest advancements in the development of sophisticated acoustofluidic systems that enhance efficiency and enable precise modulation of performance across spatial and temporal scales,thereby extending their functionality and suitability for practical applications.
基金This work was supported by the Harvard Materials Research Science and Engineering Center(NSF DMR-1420570)National Science Foundation(DMR-1708729)+1 种基金National Institutes of Health(P01HL120839)Harvard-Suzhou Industrial Park Research and engineering innovation initiative grant,and National Natural Science Foundation of China(81372496).
文摘Understanding the complexity of biological systems requires a comprehensive analysis of their cell populations.Ideally,this should be done at the single cell level,because bulk analysis of the full population obscured many critical details due to artifacts introduced by averaging.However,this has been technically challenging due to the cumbersome procedure,low throughput,and high costs of performing analysis on a single-cell basis.Excitingly,technical improvements in single-cell RNA sequencing are making it economically practical to profile the transcriptomics of large populations of cells at the single-cell level,and have yielded numerous results that address important biological and medical questions.Further development of the technology and data analysis will significantly benefit the biomedical field by unraveling the function of individual cells in their microenvironments and modeling their transcriptional dynamics.
