Electrochemical biosensor system
Fabricating the Screen-printed carbon electrodes (SPCE) biosensor for pathogens detection:
The field of electrochemical biosensor has grown rapidly in recent years. Electrochemical sensors of detecting virus infection and bacterial contamination have also been developed. In our lab, a disposable amperometric immunosensor strip was fabricated for the rapid detection of Dengue virus and E. coli O157:H7. Screen printed carbon electrodes (SPCE) were framed by commercial silver and carbon ink, and then electrochemically characterized by coupling them with HRP-conjugated antibody. Hydrogen peroxide and ferrocenedicarboxylic acid (FeDC) were used as the HRP substrate and mediator, respectively. Response current (RC) of the immunosensor strips could be significantly amplified by 13-nm Au nanoparticles (AuNPs) immobilized on the working electrode. Our results show that the combined effects of AuNPs and FeDC enhanced RC approximately 13 folds. Our studies point out that the SPCE modified with AuNPs has potential as further applications to incorporate into an integrated system for rapid pathogen detection.
Piezoelectric biosensor system
Using oligonucleotide-functionalized Au nanoparticles to rapidly detect foodborne pathogens on quartz crystal microbalance biosensor
A circulating-flow piezoelectric biosensor, based on an Au nanoparticle amplification and verification method, was used for real-time detection of a foodborne pathogen, Escherichia coli O157:H7. A synthesized thiolated probe (Probe 1; 30-mer) specific to E. coli O157:H7 eaeA gene was immobilized onto the piezoelectric biosensor surface. Hybridization was induced by exposing the immobilized probe to the E. coli O157:H7 eaeA gene fragment (104-bp) amplified by PCR, resulting in a mass change and a consequent frequency shift of the piezoelectric biosensor. A second thiolated probe (Probe 2), complementary to the target sequence, was conjugated to the Au nanoparticles and used as a “mass enhancer” and “sequence verifier” to amplify the frequency change of the piezoelectric biosensor. The PCR products amplified from concentrations of 1.2 × 102 CFU/ml of E. coli O157:H7 were detectable by the piezoelectric biosensor. A linear correlation was found when the E. coli O157:H7 detected from 102 to 106 CFU/ml. The piezoelectric biosensor was able to detect targets from real food samples.
Selected publications related to this topic
Lin YH, Chen SH, Chuang YC, Lin YR, Chang CA, Shen TY, Lin CS*. 2008. Amperometric immunosensor for the detection of Escherichia coli O157:H7 foodborne pathogen by Au nanoparticles-modified disposable screen printed carbon electrodes. Biosensors and Bioelectronics. 23: 1832-1837.
Chen SH, Wu VCH, Lin CS*. 2008. Detection of the Escherichia coli O157:H7 sequence using Au nanoparticles for signal amplification and sequence verification on a circulating-flow quartz crystal microbalance DNA sensing system. Journal of Microbiological Methods. (In press)
Peng SL, Tsay YW, Lin CS, Tang CY. 2008. Designing DNA Fingerprints of Viral Genomes by RFLP Using Unique Sequences. Bioinformatics (In press).
Wu VCH, Chen SH, Lin CS*. 2007. Real-time detection of Escherichia coli O157:H7 sequences using a circulating-flow system of quartz crystal microbalance. Biosensors and Bioelectronics 22:2967-2975.
Sun YL and Lin CS*. 2003. Establishment and application of a fluorescent PCR-RFLP method for identifying of porcine, caprine, and bovine meats. Journal of Agricultural Food and Chemistry. 51:1771-1776.
Lin CS, Yang PC, Sun YL. Method for meat identification using mitochondrial 12S rRNA of cattle, goat, or pig specific primers. IPA-ROC I 268959.
Chen SH, Lin CS, Chen GT, Lin YH, Shen TY. Composite modified electrode trip. (Pending IPA-ROC: 0096124501)
Chen SH, Lin CS, Chen GT, Lin YH, Shen TY. Composite modified electrode trip. (Pending CN: 200710127590.4)