16S rRNA Monitoring Point-of-Care Magnetic Focus Lateral Flow Sensor.

The detection and profiling of pathogenic bacteria is critical for human health, environmental, and food safety monitoring. Herein, we propose a highly sensitive colorimetric strategy for naked eye screening of 16S ribosomal RNA (16S rRNA) from pathogenic agents relevant to infections, human health, and food safety monitoring with a magnetic focus lateral flow sensor (mLFS) platform. The method developed was demonstrated in model 16S rRNA sequences of the pathogen O157:H7 to detect as low as 1 fM of targets, exhibiting a sensitivity improved by ∼5 × 10 times compared to the conventional GNP-based colorimetric lateral flow assay used for oligonucleotide testing. Based on the grayscale values, semi-quantitation of up to 1 pM of target sequences was possible in ∼45 min. The methodology could detect the target 16S rRNA from as low as 32 pg/mL of total RNA extracted from pathogens. Specificity was demonstrated with total RNA extracted from K-12 MG1655, (), and (). No signal was observed from as high as 320 pg/mL of total RNA from the nontarget bacteria. The recognition of target 16S rRNA from 32 pg/mL of total RNA in complex matrices was also demonstrated. The proposed mLFS method was then extended to monitoring and . Our approach highlights the possibility of extending this concept to screen specific nucleic acid sequences for the monitoring of infectious pathogens or microbiome implicated in a range of diseases including cancer.