A Highly Sensitive Detection of Campylobacter spp. in Chicken Meat using Silica Nanoparticle Enhanced Dot Blot DNA Biosensor

Paper-based DNA biosensors are powerful tools in point-of-care diagnostics since they are affordable, portable, user-friendly, rapid and robust. However, their sensitivity is not always as high as required to enable DNA quantification. To improve the response of standard dot blots, we have applied a new enhancement strategy that increases the sensitivity of assays based on the use of biotinylated silica-nanoparticles (biotin-Si-NPs). After immobilization of a genomic Campylobacter DNA onto a paper membrane, and addition of a biotinylated-DNA detection probe, the hybridization was evidenced using streptavidin-conjugated to horseradish peroxidase (HRP) in the presence of luminol and H2O2. Replacement of the single biotin by the biotin-Si-NPs boosted in average a 30 fold the chemiluminescent read-out of the biosensor. The characterization of biotin-Si-NPs into a paper with immobilized DNA was done using a scanning electron microscope. A limit of detection of 3 pg/μL of DNA, similar to the available qPCR kits, is achieved but being cheaper, easier and avoiding the inhibition of DNA polymerase by molecules from the food matrices. We demonstrated that the new dot blot coupled to biotin-Si-NPs successfully detected Campylobacter from naturally contaminated chicken meat, without a need for PCR step. Hence, such enhanced dot blot paves the path to the development of a portable and multiplex paper based platform for point-of-care screening of chicken carcasses for Campylobacter.