QCM-Based DNA biosensor for Salmonella typhimurium detection

This work demonstrated a QCM biosensor for the detection of Salmonella typhimurium using the specific DNA probe. A thiol DNA probe was immobilized onto quartz surface coated with gold through self-assembly via Au-S bonding formation. 6-mercapto-1-hexanol (MCH) was used as blocking reagent against non-specific DNA binding. Target DNA with 94 bp (single strand) was hybridized with its probe resulted in a decrease in the resonance frequency of the QCM biosensor. It was demonstrated that the QCM biosensor could recognize the target DNA sequence within 40-70 min. The frequency shift signal was distinguishable along with the increase of target concentration from 0.1 to 1.0 μM.