(13b) DNA Hybridization Monitoring Using the QCM-D and EIS

Detection of specific DNA/RNA sequences is important in numerous applications including clinical diagnosis such as genetic disorders and pathogen detection. The detection of mismatched base pairs in DNA plays a crucial role in the diagnosis of genetic-related diseases and conditions, especially for early stage treatment. The Quartz Crystal Microbalance with Dissipation (QCM-D) sensor combined with electrochemical impedance spectroscopy (EIS) was used to monitor DNA hybridization and mismatched base pair detection. The QCM-D technique measures the adsorbed mass change while EIS gives additional electrochemical signal change. The gold surface was modified with single stranded DNA (ssDNA) using thiol or biotin-avidin conjugate. Optimal DNA immobilization conditions such as probe density and immobilization methods were determine by monitoring hybridization efficiency. DNA hybridization with perfect match and single mismatched pair was distinguished using QCM-D and EIS data. Combining QCM-D and EIS for DNA hybridization detection is a promising technique to detect DNA sequence or single nucleotide polymorphism.