Cranberry Proanthocyanidins-PANI Nanocomposite for the Detection of Bacteria Associated with Urinary Tract Infections

Consumption of cranberries is associated with the putative effects of preventing urinary tract infections (UTIs). Cranberry proanthocyanidins (PAC) contain unusual double A-type linkages, which are associated with strong interactions with surface virulence factors found on UTI-causing bacteria such as extra-intestinal pathogenic Escherichia coli (ExPEC), depicting in bacterial agglutination processes. In this work, we demonstrated the efficacy of cranberry PAC (200 μg/mL) to agglutinate ExPEC (5.0 × 10⁸ CFU/mL) in vitro as a selective interaction for the design of functionalized biosensors for potential detection of UTIs. We fabricated functionalized screen-printed electrodes (SPEs) by modifying with PAC-polyaniline (PANI) nanocomposites and tested the effectiveness of the PAC-PANI/SPE biosensor for detecting the presence of ExPEC in aqueous suspensions. Results indicated that the PAC-PANI/SPE was highly sensitive (limit of quantification of 1 CFU/mL of ExPEC), and its response was linear over the concentration range of 1-70,000 CFU/mL, suggesting cranberry PAC-functionalized biosensors are an innovative alternative for the detection and diagnosis of ExPEC-associated UTIs. The biosensor was also highly selective, reproducible, and stable.