The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems.Many techniques have been developed to measure the ligand-receptor binding k...The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems.Many techniques have been developed to measure the ligand-receptor binding kinetics at the single-cell level.However,few techniques can measure the physiologically relevant shear binding affinity over a single cell in the clinical environment.Here,we develop a new optical technique,termed single-cell rotational adhesion frequency assay(scRAFA),that mimics in vivo cell adhesion to achieve label-free determination of both homogeneous and heterogeneous binding kinetics of targeted cells at the subcellular level.Moreover,the scRAFA is also applicable to analyze the binding affinities on a single cell in native human biofluids.With its superior performance and general applicability,scRAFA is expected to find applications in study of the spatial organization of cell surface receptors and diagnosis of infectious diseases.展开更多
Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and nanotechnology.Optothermal tweezers exhibit superior manipulation capability at low optical intensity.However,our...Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and nanotechnology.Optothermal tweezers exhibit superior manipulation capability at low optical intensity.However,our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal tweezers.Herein,we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers,which enables us to rationally design the tweezers for optimum performance in targeted applications.Specifically,we have revealed that the non-uniform temperature distribution induces water polarization and charge separation,which creates the thermoelectric field dominating the optothermal trapping.We further design experiments to systematically verify our atomistic simulations.Guided by our new model,we develop new types of optothermal tweezers of high performance using low-concentrated electrolytes.Moreover,we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge,which has been challenging for conventional optical tweezers.With the atomistic understanding that enables the performance optimization and function expansion,optothermal tweezers will further their impacts.展开更多
基金Y.L.,H.D.,J.L.and Y.Z.acknowledge the financial support of National Institute of General Medical Sciences of the National Institutes of Health.(DP2GM128446)National Science Foundation(ECCS-2001650)X.L.,M.Y.acknowledge the financial support of National Natural Science Foundation of China(No.11874397).
文摘The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems.Many techniques have been developed to measure the ligand-receptor binding kinetics at the single-cell level.However,few techniques can measure the physiologically relevant shear binding affinity over a single cell in the clinical environment.Here,we develop a new optical technique,termed single-cell rotational adhesion frequency assay(scRAFA),that mimics in vivo cell adhesion to achieve label-free determination of both homogeneous and heterogeneous binding kinetics of targeted cells at the subcellular level.Moreover,the scRAFA is also applicable to analyze the binding affinities on a single cell in native human biofluids.With its superior performance and general applicability,scRAFA is expected to find applications in study of the spatial organization of cell surface receptors and diagnosis of infectious diseases.
基金the National Science Foundation(No.NSF-CMMI-1761743)the National Aeronautics and Space Administration Early Career Faculty Award(No.80NSSC17K0520)+2 种基金the National Institute of General Medical Sciences of the National Institutes of Health(No.DP2GM128446)L.H.L.acknowledges financial support from the National Natural Science Foundation of China(No.62075111)the State Key Laboratory of Precision Measurement Technology and Instruments.The authors are grateful to Prof.Brian A.Korgel and Dr.Taizhi Jiang for providing Si particles.They also thank Yaoran Liu,Jingang Li,Kan Yao and Zhihan Chen for useful discussions。
文摘Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and nanotechnology.Optothermal tweezers exhibit superior manipulation capability at low optical intensity.However,our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal tweezers.Herein,we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers,which enables us to rationally design the tweezers for optimum performance in targeted applications.Specifically,we have revealed that the non-uniform temperature distribution induces water polarization and charge separation,which creates the thermoelectric field dominating the optothermal trapping.We further design experiments to systematically verify our atomistic simulations.Guided by our new model,we develop new types of optothermal tweezers of high performance using low-concentrated electrolytes.Moreover,we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge,which has been challenging for conventional optical tweezers.With the atomistic understanding that enables the performance optimization and function expansion,optothermal tweezers will further their impacts.
