title: Combination of on-chip field amplification and bovine serum albumin sweeping for ultrasensitive detection of green fluorescent protein.
abstract: We report a highly effective on-chip preconcentration method by combining field-amplified sample injection (FASI) and bovine serum albumin (BSA) sweeping for ultrasensitive detection of green fluorescent protein (GFP) on a simple cross-channel microchip device. With the formation of a stagnant sample/running buffer boundary by balancing the hydrodynamic flow and the electro-osmotic flow (EOF), GFP molecules can be continuously injected into the sample loading channel and stacked. We have also demonstrated that BSA is a very effective pseudo-stationary phase for sweeping concentration of proteins in comparison to the commonly used micelles. The combination of FASI and BSA sweeping yields a concentration factor of 3570 and a limit of detection of 8.4 pM for GFP. Using this method, we have separated GFP and GFP-insulin-like growth factor-I (GFP-IGF-I) fusion protein. The entire assay (GFP concentration, matrix elimination, and electrophoretic separation) can be completed within <5 min. Furthermore, we have successfully applied this method for the detection of GFP expression of E. coli cells and the GFP content in single E. coli cells.
authors.affiliation: Key Laboratory of Bioorganic Chemistry & Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, People's Republic of China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Pan
authors.forename: Meiping
authors.initials: M
authors.lastname: Zhao
authors.forename: Shaorong
authors.initials: S
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D046209:Electrophoresis, Microchip / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000032:analysis*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000032:analysis; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012710:Serum Albumin, Bovine; D007334:Insulin-Like Growth Factor I