Antimicrobial Susceptibility Testing in a Rapid Single Test via an Egg-like Multivolume Microchamber-Based Microfluidic Platform.

Fast determination of antimicrobial agents' effectiveness (susceptibility/resistance pattern) is an essential diagnostic step for treating bacterial infections and stopping world-wide outbreaks. Here, we report an egg-like multivolume microchamber-based microfluidic (EL-MVM) platform, which is used to produce a wide range of gradient-based antibiotic concentrations quickly (∼10 min). The EL-MVM platform works based upon testing a bacterial suspension in multivolume microchambers (microchamber sizes that range from a volume of 12.56 to 153.86 nL). Antibiotic molecules from a stock solution diffuse into the microchambers of various volumes at the same loading rate, leading to different concentrations among the microchambers. Therefore, we can quickly and easily produce a robust antibiotic gradient-based concentration profile. The EL-MVM platform's diffusion (loading) pattern was investigated for different antibiotic drugs using both computational fluid dynamics simulations and experimental approaches. With an easy-to-follow protocol for sample loading and operation, the EL-MVM platform was also found to be of high precision with respect to predicting the susceptibility/resistance outcome (>97%; surpassing the FDA-approval criterion for technology-based antimicrobial susceptibility testing instruments). These features indicate that the EL-MVM is an effective, time-saving, and precise alternative to conventional antibiotic susceptibility testing platforms currently being used in clinical diagnostics and point-of-care settings.