A film-based integrated chip for gene amplification and electrochemical detection of pathogens causing foodborne illnesses

Abstract

Given the increased interest in public hygiene due to outbreaks of food poisoning, increased emphasis has been placed on developing novel monitoring systems for point-of-care testing (POCT) to evaluate pathogens causing foodborne illnesses. Here, we demonstrate a pathogen evaluation system utilizing simple film-based microfluidics, featuring simultaneous gene amplification, solution mixing, and electrochemical detection. To minimize and integrate the various functionalities into a single chip, patterned polyimide and polyester films were mainly used on a polycarbonate housing chip, allowing simple fabrication and alignment, in contrast to conventional polymerase chain reaction, which requires a complex biosensing system at a bench-top scale. The individual integrated sensing chip could be manually fabricated in 10 min. Using the developed film-based integrated biosensing chip, the genes from the pathogens causing foodborne illnesses were simultaneously amplified based on multiple designed microfluidic chambers and Hoechst 33258, which intercalates into double-stranded DNA, to generate the electrochemical signal. The target pathogen gene was accurately analyzed by square wave voltammetry (SWV) within the 25 s, while the gel electrophoresis required about 30 min. Based on the developed integrated biosensing chip, the 1.0 × 10¹ and 1.0 × 10² colony-forming unit (CFU) of Staphylococcus aureus and Escherichia coli were sensitively detected with high reproducibility in the 25 s. On the basis of the significant features of the film-based molecular analysis platform, we expect that the developed sensor could be applied to the screening of various pathogens as a POCT device.

Keywords: Electrochemical DNA analysis; Film-based polymerase chain reaction; Point-of-care testing.