title: Single Cell Transfection through Precise Microinjection with Quantitatively Controlled Injection Volumes.
abstract: Cell transfection is a technique wherein foreign genetic molecules are delivered into cells. To elucidate distinct responses during cell genetic modification, methods to achieve transfection at the single-cell level are of great value. Herein, we developed an automated micropipette-based quantitative microinjection technology that can deliver precise amounts of materials into cells. The developed microinjection system achieved precise single-cell microinjection by pre-patterning cells in an array and controlling the amount of substance delivered based on injection pressure and time. The precision of the proposed injection technique was examined by comparing the fluorescence intensities of fluorescent dye droplets with a standard concentration and water droplets with a known injection amount of the dye in oil. Injection of synthetic modified mRNA (modRNA) encoding green fluorescence proteins or a cocktail of plasmids encoding green and red fluorescence proteins into human foreskin fibroblast cells demonstrated that the resulting green fluorescence intensity or green/red fluorescence intensity ratio were well correlated with the amount of genetic material injected into the cells. Single-cell transfection via the developed microinjection technique will be of particular use in cases where cell transfection is challenging and genetically modified of selected cells are desired.
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Yu Ting
authors.initials: YT
authors.lastname: Chow
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Shuxun
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Biomedical Science, City University of Hong Kong, Hong Kong, China.
authors.forename: Chichi
authors.initials: C
authors.lastname: Liu
authors.affiliation: Stem Cell and Regenerative Medicine Consortium, Department of Physiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, China.
authors.forename: Chi-Wing
authors.initials: CW
authors.lastname: Kong
authors.affiliation: Stem Cell and Regenerative Medicine Consortium, Department of Physiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, China.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Li
authors.affiliation: Department of Biomedical Science, City University of Hong Kong, Hong Kong, China.
authors.forename: Shuk Han
authors.initials: SH
authors.lastname: Cheng
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Sun
mesh_terms: D057205:Automation, Laboratory / Q000379:methods; D002478:Cells, Cultured; D005347:Fibroblasts / Q000737:chemistry; D005456:Fluorescent Dyes / Q000032:analysis; D006801:Humans; D006874:Hydrostatic Pressure; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008845:Microinjections / Q000379:methods*; D010957:Plasmids / Q000032:analysis; D059010:Single-Cell Analysis / Q000379:methods*; D013997:Time Factors; D014162:Transfection / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D008164:Luminescent Proteins