Lithium acetate mediated paper-based assay for absorbance analysis of E. coli concentrations

Abstract

Paper-based assays have revolutionized POC diagnostics, offering significant values across diverse sectors due to their simplicity, cost-effectiveness, and portability. Detecting E. coli is critical for public health but faces challenges in traditional methods, prompting ongoing exploration of alternative approaches. To address the need for heightened sensitivity, this study introduces lithium acetate as a novel element in a paper-based E. coli detection assay, accompanying absorbance analysis using microplate readers. Utilization of lithium acetate as a lysis reagent and carrying out absorbance measurements in paper microtiter plates provide a significant stride in improving sensitivity and assay efficiency. The assay substantially reduced the analysis time to 4 hours with a lower quantification limit of 103 cfu/ml for detecting E. coli in pure cultures. The results suggest that the assay could determine 10 cfu/ml of E. coli in a contaminated milk sample with 4 hours of enrichment time. Thus, the study contributes towards improving E. coli detection with lower quantification limits and shorter analysis times. It is anticipated that the diagnostic methodology would circumvent the challenges in conventional E. coli detection methods, placing emphasis on absorbance analysis to achieve a streamlined, accurate, and rapid paper-based detection technique.