title: Improvement of antibody immobilization using hyperbranched polymer and protein A.
abstract: For the construction of a well-defined antibody surface, protein A was used as a binding material to immobilize antibodies onto gold-derivatized transducers. The traditional method tends to assemble protein A directly onto the gold-derivatized transducers. In this paper, we tried to indirectly bind protein A onto sensors through hyperbranched polymer (HBP) which was synthesized from p-phenylenediamine and trimesic acid. The three-dimensional structure of HBP and the characteristics including orientation control and biocompatibility of protein A led to highly efficient immunoreactions and enhanced detection system performance. With this strategy, cysteamine monolayer was first assembled onto Au electrodes associated with the piezoelectric quartz crystal; secondly, the cysteamine-modified gold electrode was further modified by the activated HBP; thirdly, protein A was immobilized onto the HBP film; and finally, antibodies were immobilized onto the surface of protein A film for detecting the corresponding antigen. The quartz crystal microbalance immunosensor thus fabricated was applied to detect hepatitis B surface antigen in solutions that ranged from 0.71 to 300 μg mL(-1). The detection limit was estimated to be 0.53 μg mL(-1). The immunosensor holds good selectivity, sensitivity, and repeatability.
authors.affiliation: College of Chemistry and Chemical Engineering, Hunan University of Arts and Science, Changde 415000, Hunan, China. sgyrab@yahoo.com.cn
authors.forename: Guangyu
authors.initials: G
authors.lastname: Shen
authors.forename: Chenbo
authors.initials: C
authors.lastname: Cai
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.forename: Jilin
authors.initials: J
authors.lastname: Lu
mesh_terms: D055910:Antibodies, Immobilized / Q000276:immunology*; D015374:Biosensing Techniques / Q000379:methods*; D003543:Cysteamine / Q000737:chemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D010655:Phenylenediamines / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013205:Staphylococcal Protein A / Q000737:chemistry*; D014233:Tricarboxylic Acids / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D006514:Hepatitis B Surface Antigens; D010655:Phenylenediamines; D011108:Polymers; D013205:Staphylococcal Protein A; D014233:Tricarboxylic Acids; D003543:Cysteamine; D006046:Gold; C069849:trimesic acid