title: Electrochemical detection of hepatitis B surface antigen using colloidal gold nanoparticles modified by a sol-gel network interface.
abstract: BACKGROUND
  A novel potentiometric immunosensor for the detection of hepatitis B surface antigen has been developed by self-assembling gold nanoparticles to a thiol-containing sol-gel network.
  
  
  METHODS
  A cleaned gold electrode was first immersed in a hydrolyzed (3-mercaptopropyl) trimethoxysilane sol-gel solution to assemble a three-dimensional silica gel, and then gold nanoparticles were absorbed onto the thiol groups of the sol-gel network. Finally, hepatitis B surface antibody was assembled onto the surface of the gold nanoparticles. The self-assembling procedure was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Detection is based on the change in potentiometric response before and after the antigen-antibody reaction.
  
  
  RESULTS
  Tests relating to the detection of hepatitis B surface antigen demonstrate that the potentiometric immunosensor exhibited a rapid potentiometric response (<4 min), with high sensitivity, good reproducibility, and long-term stability. The linear range was from 4 to 960 ng.mL(-1) with a detection limit of 1.9 ng.mL(-1) (S/N = 3) and the lifetime was 1 month.
  
  
  CONCLUSIONS
  Analytical results of several specimens using the developed technique showed satisfactory agreement with those from an ELISA method. This method shows promise for detecting HBsAg in clinical specimens.
authors.affiliation: Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P.R. China.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Xia
authors.initials: X
authors.lastname: Zhong
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Dai
mesh_terms: D002138:Calibration; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D005782:Gels / Q000737:chemistry; D017979:Gold Colloid / Q000737:chemistry*; D006514:Hepatitis B Surface Antigens / Q000032:analysis* / Q000737:chemistry; D007118:Immunoassay; D049329:Nanostructures / Q000737:chemistry*; D011199:Potentiometry; D015203:Reproducibility of Results
chemical_list: D005782:Gels; D017979:Gold Colloid; D006514:Hepatitis B Surface Antigens