Newly developed QCM-DNA biosensor for SNP detection in small DNA fragments: A wine authenticity case study

We propose a QCM-DNA biosensor for single nucleotide polymorphism (SNP) detection in samples of differing complexity. An optimized protocol is presented, focusing on parameters affecting probe immobilization and hybridization efficiency. Our results led to the implementation of thiolated probe reduction with TCEP, followed by immobilization in PBS buffer containing MgCl2. The biosensor exhibited an enhanced specificity at 37 °C, achieving detection of single mismatches using synthetic targets. Using real samples, we applied the biosensor in a wine authenticity assessment context. The addition of dithiothreitol improved stability and reproducibility when testing wine DNA samples. The QCM-DNA biosensor was able to specifically detect complementary DNA in leaf and wine DNA samples, distinguishing between samples with two heterozygous mismatches. The biosensor solely depends on DNA extraction, basic instrumentation, and reagents, without requiring PCR or signal amplification strategies. Our findings show the biosensor potential for applications in wine authenticity assessment and other fields requiring complex analysis in undemanding settings.