Paper-based visual detection of Salmonella bacteria using isothermal DNA amplification and magnetic bead aggregation

ABSTRACT

Aims: The present study aimed to develop a new approach for detecting Salmonella species at picogram levels using magnetic bead (MB) aggregation through loop-mediated isothermal amplification (LAMP). Methodology and results: For the first time to our knowledge, Salmonella LAMP amplicons were analyzed using MB aggregation. LAMPs were conducted with a simple heat block, and the results were compared with those obtained with conventional LAMP-MB techniques. Furthermore, the volume and concentration of MB solutions were optimized. Our method detected Salmonella genomic DNA at a low picogram level (1 pg/µL). The specificity of this method was also examined using other bacterial species. Owing to specific Salmonella primers, the use of LAMPs approach was time effective; because these amplicons could be utilized after 20 min instead of the 1 h needed for conventional methods. Furthermore, LAMP-positive amplicons were rapidly detected within 5 min. Conclusion, significance and impact study The determination of DNA in biological samples is a recent keystone in genomic analysis techniques. Salmonella is a foodborne pathogen that causes many diseases and, in extreme cases, death. Accordingly, detecting Salmonella has become a vital issue for food safety and security. Combining DNA and MBs on paper helped us to develop a new method for label-free, non-immobilized, naked eye detection of Salmonella. The process is very specific owing to the use of exact primers and does not require heavy or expensive instrumentation. In the future, this method could be applied to biosensors as well as in biomedical and molecular diagnostic fields.