Lectin-Functionalized Chitosan Nanoparticle-Based Biosensor for Point-of-Care Detection of Bacterial Infections

The WHO estimates an average of 10 million deaths per year due to the increasing number of infections and the predominance of drug resistance. To improve clinical outcomes and contain the spread of infections, the development of newer diagnostic tools is imperative to reduce the time and cost involved to reach the farthest population. The current study focuses on the development of a point-of-care technology that uses crystal violet entrapped, lectin functionalized chitosan nanoparticles to detect the presence of clinically relevant bacterial infections. Spherical nanoparticles of <200 nm in diameter make up the biosensing nanomaterial, showed specific clumping in the presence of bacteria to form visible aggregates as compared to a nonbacterial sample. Visible agglutination confirmed the presence of bacteria in the samples. The devices require just 100 μL of sample and were tested with various bacteria-spiked saline, simulated urine, artificial sputum, and simulated respiratory and wound swabs. The developed device did not require any sample preparation or sophisticated instruments while enabling rapid differentiation between bacterial and nonbacterial infections within 10 min. The in vitro results with bacteria-spiked simulated samples reveal 100% sensitivity and specificity with a limit of detection of 10⁵ cfu/mL. The nanomaterial developed was found to be stable for more than 90 days at accelerated conditions. The developed device can be a screening tool for home-based or clinical assessment and follow the treatment accordingly, reducing exposure to broad-spectrum antibiotics in the case of nonbacterial infections.