Recently, the team of Professor Lin Jianhan of the School of Information and Electrical Engineering of China Agricultural University published the latest research results in the famous journal biosensor and Bioelectronics (Biosensors and Bioelectronics) in the sensor field, entitled “A biosensor for detection of Salmonella typhimurium based on finger pressing mixing and nuclear pore membrane separation.”
This study skillfully combines the interdisciplinary knowledge of engineering technology, biotechnology and nanomaterials, and uses the technologies of nuclear pore membrane separation and simulated enzyme catalysis to develop a new finger-pressed microfluidic chip without external power, which not only saves the cost of bacterial detection, but also simplifies the complex bacterial detection process. This low-cost, easy-to-operate, highly sensitive and fast biosensor has the potential for field detection and can provide novel ideas for rapid screening of foodborne pathogenic bacteria.
In this study, on the microfluidic chip, through finger pressing operation, combined with nuclear pore membrane filtration, the sensitive detection of foodborne pathogens was realized in a short time.
First of all, the finger pressure mixer was used to mix the bacterial samples and immune gold and platinum particles (mimic enzyme), and the specific labeling of the target bacteria was realized.
Then, the bacterial-mimetic enzyme complex was filtered by nuclear pore membrane to separate the bacterial-mimetic enzyme complex from the excess mimetic enzyme.
Then, the intercepted bacterial-mimic enzyme complex was used to catalyze the mixed solution of hydrogen peroxide and tetramethylbenzidine, resulting in obvious color changes on the surface of the nuclear pore membrane.
Finally, the smartphone is used to take pictures and image processing, so as to calculate and analyze the number of target bacteria. Through a simple finger-pressing microfluidic chip, the biosensor can complete the steps of sample mixing, bacterial separation, background cleaning, catalytic coloration and so on.
Schematic diagram of sensitive detection of foodborne pathogenic bacteria