title: Catch and release cell sorting: electrochemical desorption of T-cells from antibody-modified microelectrodes.
abstract: The development of integrated microsystems capable of interrogation, characterization and sorting of mammalian cells is highly significant for further advancement of point-of-care diagnostics and drug discovery fields. The present study sought to design a novel strategy for releasing antibody-bound cells through electrochemical disruption of the underlying antibody (Ab) layer. A microsystem for selective capture and release of cells consisted of an array of individually addressable gold microelectrodes fabricated on a glass substrate. Poly(ethylene glycol) (PEG) hydrogel photolithography was employed to make the glass regions non-fouling, thus, ensuring selective localization of proteins and cells on the microelectrodes. The gold surfaces were decorated with anti-CD4 Ab molecules using standard alkanethiol self-assembly and carbodiimide coupling approaches. The Ab-functionalized electrodes selectively captured model T-lymphocytes (Molt-3 cells) expressing CD4 antigen while minimal cell adhesion was observed on PEG hydrogel-modified glass substrates. Importantly, application of a reductive potential (-1.2V vs. Ag/AgCl reference electrode) resulted in release of surface-bound T-cells from the electrode surface. Cyclic voltammetry and fluorescence microscopy were employed to verify that the detachment of captured T-cells was indeed due to the electrochemical disruption of the underlying alkanethiol-Ab layer. In the future, the cell sorting approach described here may be combined with microfluidic delivery to enable Ab-mediated capture of T-lymphocytes or other cell types followed by release of select cells for downstream gene expression studies or re-cultivation.
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, 451 East Health Sciences Street #2619, Davis, CA 95616, United States.
authors.forename: He
authors.initials: H
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.forename: Alexander
authors.initials: A
authors.lastname: Revzin
mesh_terms: D000327:Adsorption; D000906:Antibodies / Q000737:chemistry / Q000276:immunology*; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D045744:Cell Line, Tumor; D002469:Cell Separation / Q000379:methods*; D004563:Electrochemistry; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D016130:Immunophenotyping / Q000379:methods; D007938:Leukemia / Q000473:pathology; D008839:Microelectrodes; D008856:Microscopy, Fluorescence; D011092:Polyethylene Glycols / Q000737:chemistry; D013379:Substrate Specificity; D013499:Surface Properties; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D015704:CD4 Antigens; D020100:Hydrogels; D011092:Polyethylene Glycols; D006046:Gold