A cost-effective and field-deployable sensing system for chip-integrated detection of bacteria with the naked eye

To tailor the broadly applied polymerase chain reaction (PCR) technology to point-of-care settings, an intuitive, time-saving, and cost-effective method to determine the DNA amplification results has significant practical potential. Herein we present an economical and field-deployable sensing system that enables naked-eye readout of PCR results. The proposed system is powered by an amplification enhancer to greatly enhance the positive-to-background ratio and a palm-sized readout device to assist on-site applications. High specificity, as well as single-copy sensitivity, was achieved in detecting Salmonella enterica and other bacterial pathogens. Using the proposed system, we identified the pathogenic bacterial strains in artificially contaminated food samples easily, quickly, and reliably. Also crucial for point-of-care testing, this naked-eye readout system applies to microfluidic platforms with the sample volumes scaled down to 1 μL. The time savings, portability, and cost-effectiveness of the established sensing system make it transformative for on-chip bacteria detection in point-of-care and field settings, especially in resource-limited areas.