title: Particle-by-particle quantification of protein adsorption onto poly(ethylene glycol) grafted surfaces.
abstract: The use and advantage of flow cytometry as a particle-by-particle, low sampling volume, high-throughput screening technique for quantitatively examining the non-specific adsorption of proteins onto surfaces is presented. The adsorption of three proteins: bovine serum albumin (BSA), immunoglobulin gamma (IgG) and protein G, incubated at room temperature for 2 h onto organosilica particles modified with poly(ethylene glycol) (PEG) of increasing MW (2000, 3400, 6000, 10,000 and 20,000 g mol(-1)) and grafted amounts (0.14-1.4 mg m(-2)) was investigated as a model system. Each protein exhibited Langmuir-like, high affinity monolayer limited adsorption on unmodified particles with the proteins reaching surface saturation at 1.8, 4.0 and 2.5 mg m(-2) for BSA, IgG and protein G, respectively. Protein adsorption on PEG-modified surfaces was found to decrease with increasing amounts of grafted polymer. PEG grafting amounts >0.6 mg m(-2) effectively prevented the adsorption of the larger two proteins (BSA and IgG) while a PEG grafting amount >1.3 mg m(-2) was required to prevent the adsorption of the smaller protein G.
authors.affiliation: Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD, Australia.
authors.forename: Annie
authors.initials: A
authors.lastname: Chen
authors.forename: Darby
authors.initials: D
authors.lastname: Kozak
authors.forename: Bronwyn J
authors.initials: BJ
authors.lastname: Battersby
authors.forename: Matt
authors.initials: M
authors.lastname: Trau
mesh_terms: D000327:Adsorption; D007074:Immunoglobulin G / Q000737:chemistry*; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013499:Surface Properties
chemical_list: C029152:G-substrate; D007074:Immunoglobulin G; D009419:Nerve Tissue Proteins; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols