A microfluidic colorimetric biosensor for rapid detection of Escherichia coli O157:H7 using gold nanoparticle aggregation and smart phone imaging

• Published in: Biosensors & bioelectronics Vol. 124-125; pp. 143 - 149
• Main Authors: Zheng, Lingyan, Cai, Gaozhe, Wang, Siyuan, Liao, Ming, Li, Yanbin, Lin, Jianhan
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.01.2019
• Subjects: antibodies; Antibodies, Immobilized - chemistry; bacteria; Biosensing Techniques; biosensors; catalase; chickens; color; Colorimetric biosensor; Colorimetry; cross-linking reagents; detection limit; E. coli O157:H7; Escherichia coli Infections - diagnosis; Escherichia coli Infections - microbiology; Escherichia coli O157; Escherichia coli O157 - isolation & purification; Escherichia coli O157 - pathogenicity; Food Microbiology; Gold - chemistry; Gold nanoparticle aggregation; Humans; hydrogen peroxide; image analysis; magnetism; Metal Nanoparticles - chemistry; Microfluidic chip; Microfluidics - instrumentation; microparticles; mixing; mobile telephones; monitoring; nanogold; nanoparticles; organ-on-a-chip; polystyrenes; rapid methods; Smart phone imaging APP; Smartphone; Gold nanoparticle aggregation; Microfluidic chip; E. coli O157:H7; Smart phone imaging APP; Colorimetric biosensor
• DOI: 10.1016/j.bios.2018.10.006
• ISSN: 0956-5663; 1873-4235

We intended to develop a novel biosensor using gold nanoparticles (AuNPs) for indicating different concentrations of E. coli O157:H7 and smart phone imaging APP for monitoring color change of the AuNPs. The magnetic nanoparticles (MNPs) modified with the capture antibodies and the polystyrene microspheres (PSs) modified with the detection antibodies and the catalases were simultaneously used to react with the target bacteria in the first mixing channel of the microfluidic chip, and hydrogen peroxide was injected and catalyzed by the catalases on the MNP-bacteria-PS complexes. After the mixture of the AuNPs and the crosslinking agents were injected to react with the catalysate in the second mixing channel and incubated in the detection chamber, the aggregation of the AuNPs was triggered through the crosslinking agents, resulting in the color of the AuNPs changing from blue to red. Finally, the color was measured using the smart phone imaging APP to determine the amount of the bacteria. This biosensor exhibited a good specificity and sensitivity for detection of E. coli O157:H7 in chicken samples with a lower detection limit of 50 CFU/mL. •AuNP aggregation were successfully used for signal indication.•HSL-based smart phone imaging was effective to detect color change.•Microfluidic chip was successfully developed for on-chip bioreaction.•The detection limit of this biosensor was 50 CFU/mL for E coli O157:H7.•The mean recovery of E coli O157:H7 in the spiked chicken samples was ~96.8%.