title: A protein A-based orientation-controlled immobilization strategy for antibodies using nanometer-sized gold particles and plasma-polymerized film.
abstract: A novel protein A (PA)-based strategy for the orientation-controlled immobilization of antibodies using nanometer-sized gold (Nano-gold) particles and an amine-terminated plasma-polymerized film (PPF) has been proposed. A quartz crystal microbalance was fabricated, accordingly, coupling with haptoglobin (HP) antibody followed by HP immunoassay, as a model test system. The crystal was modified with plasma-polymerized n-butyl amine film to deposit Nano-gold particles and PA, on which HP antibodies were immobilized. The surface topology of the as-prepared crystal was characterized by use of scanning electron microscopy. In contrast to the traditional flat gold surface, the assembled Nano-gold particle monolayer could allow PA molecules bound with higher bioactivity and loading amount (density), achieving better antibody-binding capabilities. Results indicate that immunosensors prepared using the developed PPF-Nano-gold-PA binding procedure exhibit increased analytical performance compared with those produced using the direct PA binding procedure and the PPF-based glutaraldehyde cross-linking procedure. A HP serum concentration as low as 0.41 nM can be determined by this new system. Regenerated simply by rinsing in the acid buffer, the proposed sensor can achieve up to 11 assay cycles without significant loss of sensitivity.
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Yanli
authors.initials: Y
authors.lastname: Liu
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Yang
authors.forename: Ting
authors.initials: T
authors.lastname: Deng
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D000818:Animals; D000906:Antibodies; D015374:Biosensing Techniques / Q000379:methods* / Q000592:standards; D006046:Gold; D006242:Haptoglobins / Q000032:analysis / Q000276:immunology; D006801:Humans; D036103:Nanotechnology; D010316:Particle Size; D011108:Polymers; D012680:Sensitivity and Specificity; D013205:Staphylococcal Protein A; D013499:Surface Properties
chemical_list: D000906:Antibodies; D006242:Haptoglobins; D011108:Polymers; D013205:Staphylococcal Protein A; D006046:Gold