This unique technique achieves rapid, simple and quantitative diagnostics for the AST based on Brownian motion of functionalized particles combining with immunoassays. As bacteria bind to the particles, Brownian motion will decline due to the increase of equivalent particle diameter. This instrument features rapid (<3 h), less wasteful (<3 μL), low-cost and low initial concentration (10^5 cfu/mL).

We proposed a technique combining optical diffusometry and bead-based immunoassays to achieve rapid antimicrobial susceptibility testing (AST). Both Gram-positive and Gram-negative bacteria can be successfully captured by the vancomycin-modified particles. This technique currently features rapid AST (<3 h), high sensitivity, low sample volume (<3 μL), and low initial concentration of bacteria (~10^5 CFU/mL).

This technique can be applied in the aquaculture industry to detect the number of bacteria in fish farms. It can also be used in the food industry to detect whether the number of bacteria exceeds tolerance or not. In medical treatments, effective antibiotic control and reduction of waste of medical resources can be achieved. In addition, novel research applications can be explored in the academic field.