title: Improved enzyme immobilization on an ionic-complementary peptide-modified electrode for biomolecular sensing.
abstract: An ionic-complementary peptide, EFK16-II, was used to modify a highly ordered pyrolytic graphite (HOPG) electrode surface. The nanofiber structure of the self-assembling peptide on the electrode surface was characterized by atomic force microscopy (AFM). Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) spectra showed that, upon addition of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), EFK16-II molecules tend to be cross-linked among themselves. Cross-linking of the peptide diminishes the number of carboxyl groups available for immobilizing a sensing enzyme, which is glucose oxidase (GOx) in the present case. A simple method based on premixing of the carbodiimide and GOx was developed; it inhibited peptide cross-linking and significantly improved enzyme immobilization. Biosensors constructed in this way showed increased overall signal intensity and a much higher sensitivity at 4.94 mA M(-1) cm(-2), a 6-fold increase compared to the previously reported peptide-modified electrodes. The results presented here demonstrate significant potential for ionic-complementary peptides for constructing electrochemical biosensors.
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Qian
authors.forename: Mushfique A
authors.initials: MA
authors.lastname: Khan
authors.forename: Susan
authors.initials: S
authors.lastname: Mikkelsen
authors.forename: P
authors.initials: P
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002234:Carbodiimides / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002234:Carbodiimides; D004800:Enzymes, Immobilized; D010455:Peptides; C009139:pyrolytic carbon; D002244:Carbon; D005949:Glucose Oxidase