A Milliliter to Picoliter-level Centrifugal Microfluidic Concentrator for Fast Pathogen Detection and Antimicrobial Susceptibility Testing

Abstract The available pathogenic bacteria detection and antimicrobial susceptibility testing (AST) are still time-consuming and tedious because of the lengthy culture procedures. Various kinds of systems have promised a great reduction in AST time, however the high-efficiency and user-friendly bacteria enrichment is always a challenge to tackle. Here we introduce a centrifugation-based microfluidic concentrator for milliliter to picoliter bacteria suspension enrichment to achieve a fast and real-time pathogen detection and AST. The concentrator consists of a milliliter-level loading chamber and a picoliter-level enrichment channel. By centrifuging, all pathogen cells in chamber can be condensed into enrichment channel, achieving a milliliter to picoliter enrichment. Thus, the pathogen cells can be detected directly by microscopic observation. More importantly, the AST can be started from original sample without traditional pre-culture steps for the high enrichment efficiency. Since all the cells were confined at the picoliter-level channel tip, detectable growth of phenotype can be easily observed in a few hours, and the different inhibition mechanism on cells from different antibiotics can be clearly observed. The proposed concentrator shows a detection limit of 102 cell/mL with 0.5 h of enrichment for detection and another 3 h of micro-culture for AST.