Microfabrication and Characterization of Solid Surfaces Patterned with Enzymes or Antigen-Antibodies by Scanning Electrochemical Microscopy

The microfabrication and characterization of glass surfaces patterned with enzymes (diaphorase, horseradish peroxidase(HRP)) or antigen-antibodies (carcinoembryonic antigen (CEA), human chorionic gonadotropin (HCG) and human placental lactogen (HPL)) were studied using scanning electrochemical microscopy (SECM). Localized enzymes and antigen-antibody complexes with labeled enzymes were characterized on the basis of detection of catalytic current for ferrocenylmethanol by SECM. The SECM technique was extended to the enzyme-linked immunosorbent assay (ELISA). This method detects as low as ∼ 10⁴ CEA molecules in a single microspot. We also demonstrated a novel dual assay using microfabricated glass substrates with anti-HCG and anti-HPL microspots.