Rapid, Direct, Visualized and Antibody-Free Bacterial Detection with Extra Species Identification and Susceptibility Evaluation Capabilities

Bacterial antimicrobial resistance (AMR) driven by the abuse of antibiotics is a global highlight challenge, calling for a rapid, economical and generalizable bacterial detection technology. Here, in case of urinary tract infections (UTIs), a naked-eye, antibody-free and multi-functional bacterial assessment platform was designed, which consisted of concanavalin A modified gold nanoparticles (ConA-AuNPs), vancomycin modified gold nanoparticles (Van-AuNPs), and polymyxin B modified Prussian blue nanoparticles (PMB-PBNPs). Based on the fast agglutination of bacterial cells by concanavalin A, ConA-AuNPs could aggregate on various types of bacterial cells, which realize naked-eye detection within 30 min. Besides, due to the different affinity of vancomycin and polymyxin B to Gram-positive and Gram-negative bacteria, Van-AuNPs and PMB-PBNPs could bind to various species of bacteria selectively, then produce different colors within 2–6 h. Therefore, this colorimetric nanoplatform orderly realized the rapid detection, species identification (Gram-positive and Gram-negative), and susceptibility evaluation of bacteria, satisfying multiple needs from timely clinical diagnosis to accurate medication guidance. The feasibility was verified by clinical samples, which was consistent with the classical clinical test within only 1/48 of the process timing.