Electrochemical Investigation of TLR4/MD-2-Immobilized Polyaniline and Hollow Polyaniline Nanofibers: Toward Real-Time Triaging of Gram-Negative Bacteria Responsible for Delayed Wound Healing

Detecting gram −ve bacterial colonies is crucial in address-ing the clinical challenges associated with chronic wounds and delayed healing. These bacteria can exacerbate wound conditions, hindering natural healing and potentially leading to infections. The electrochemical sensing platform presented in this study serves as a valuable tool for healthcare professionals to make timely and targeted treatment decisions. Toward this, we developed a cost-effective electrochemical sensing platform leveraging the TLR4/MD-2 complex to detect gram −ve bacterial colonies. Our biosensors were meticulously fashioned using polyaniline (PANi) and hollow PANi (HPANi) nanofibers. Notably, the HPANi-based sensors, owing to their distinctive hollow structure, facilitated amplified responses under comparable experimental conditions compared with PANi-based counterparts. The designed sensing platform demonstrated exceptional accuracy in identifying Escherichia coli (gram −ve), showcasing a theoretical detection limit of 0.215 CFU/mL for PANi and a remarkably improved 0.14 CFU/mL for HPANi. These sensors displayed outstanding selectivity for gram −ve bacteria, even amidst gram +ve bacteria and fungi. Moreover, our platform demonstrated remarkable sensitivity, yielding 3.04 ((ΔR/R)/CFU/mL)/cm² for the HPANi-based sensor, surpassing the performance of the PANi-based sensor at 1.98 ((ΔR/R)/CFU/mL)/cm².