A reusable QCM biosensor with stable antifouling nano-coating for on-site reagent-free rapid detection of E. coli O157:H7 in food products

• Published in: Food control 2024-11, Vol.165, p.110695, Article 110695
• Main Authors: Forinová, Michala, Pilipenco, Alina, Lynn, N. Scott, Obořilová, Radka, Šimečková, Hana, Vrabcová, Markéta, Spasovová, Monika, Jack, Rachael, Horák, Petr, Houska, Milan, Skládal, Petr, Šedivák, Petr, Farka, Zdeněk, Vaisocherová-Lísalová, Hana
• Format: Article
• Language: English
• Subjects: Antifouling coating; biosensors; E. coli O157:H7 detection; Escherichia coli O157; food safety; liquids; milk; On-site analysis; QCM biosensor; quartz crystal microbalance; rapid methods; Reusability; sonication
• ISSN: 0956-7135; 1873-7129
• DOI: 10.1016/j.foodcont.2024.110695

Numerous biosensors have shown exceptional analytical performance under laboratory conditions, yet only a few are capable of on-site use with complex, non-model samples while exhibiting reliable analytical performance. Here, we present a new portable biosensor for the rapid (30 min) and accurate detection of bacterial agents in “real-world” food samples, which are originally in either solid or liquid form. The biosensor combines well-established quartz crystal microbalance (QCM) technology, with innovative terpolymer brush nano-coatings on the sensing surface to efficiently reduce non-specific fouling from food samples. Following reagent-free sample preparation, where solid food samples are homogenized, we validated the sensor's detection capabilities on native pathogenic Escherichia coli O157:H7 (E. coli O157:H7) in hamburgers, Czech dumplings, and milk. We achieved limits of detection (LOD), as low as 7.5 × 102 CFU/mL in milk, a value approaching fundamental QCM limits, using a simple direct detection assay format. The biosensor's exceptional reusability was demonstrated through 60 sequential hamburger sample injections, resulting in only a minor LOD shift toward the end of series. A 10-min sonication treatment during sample preparation significantly enhanced sensitivity for E. coli O157:H7 in hamburgers and dumplings, yielding LODs as low as 3.1 × 10³ CFU/mL and 2.6 × 10⁴ CFU/mL, respectively. For on-site analysis, we integrated the nano-coated sensing chip into a custom-built four-channel portable QCM biosensor with an optimized microfluidic system, which can be produced on a scale suitable for practical deployment. [Display omitted] •Portable reusable QCM biosensor for rapid detection of E. coli O157:H7 in food.•Stable bio-functional antifouling nanocoating combined with tailored microfluidics.•Biosensor reusable after 60 sequential injections of E. coli-free hamburger samples.•On-site rapid (