A finger-actuated microfluidic biosensor for colorimetric detection of foodborne pathogens

• Published in: Food chemistry Vol. 381; p. 131801
• Main Authors: Qi, Wuzhen, Zheng, Lingyan, Hou, Yu, Duan, Hong, Wang, Lei, Wang, Siyuan, Liu, Yuanjie, Li, Yanbin, Liao, Ming, Lin, Jianhan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2022
• Subjects: Biosensing Techniques; Colorimetry; Foodborne pathogens; Gold; Gold@platinum nanocatalysts; Microfluidic biosensor; Microfluidics; Naked-eye detection; Salmonella; Smartphone App; Foodborne pathogens; Microfluidic biosensor; Gold@platinum nanocatalysts; Smartphone App; Naked-eye detection
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.131801

•A finger-actuated micropump was elaborately developed for accurate liquid injection.•A finger-actuated micromixer with chaotic structure was developed for efficient mixing.•Gold@platinum nanocatalysts were used to amplify biological signals.•The whole bacteria detection procedures were integrated onto a single microfluidic chip.•This microfluidic biosensor could detect Salmonella as low as 350 CFU/mL within 1 h. A microfluidic biosensor was developed for rapid detection of Salmonella using a finger-actuated micropump, a finger-actuated micromixer, gold@platinum nanocatalysts (Au@PtNCs) and a smartphone App. First, immune magnetic nanobeads (MNBs), bacterial sample and immune Au@PtNCs were successively finger-actuated pumped into microfluidic chip. Then, they were fully mixed using finger-actuated micromixer to form MNB-Salmonella-Au@PtNC complexes. After hydrogen peroxide-tetramethylbenzidine was pumped into chip and catalyzed by nanocatalysts on complexes, resulting in color change from colorless to blue, the image of catalysate was collected and finally analyzed by self-developed smartphone App or directly compared with Pantone color card in chip to determinebacterial concentration. Experimental results showed this biosensor could quantitatively detect Salmonella from 3.5 × 102 to 3.5 × 105 CFU/mL in 1 h with lower detection limit of 350 CFU/mL. This biosensor has successfully integrated loading, mixing, incubation, washing, separation and detection onto a chip and might pave a promising way for bacterial detection.