In our previous studies, we have applied ethylene diamine (EDA) plasma-polymerization (or glow/discharge treatment) to create amino groups on the quartz crystals (with Ag electrodes) and immobilized antibodies on these crystals using glutaraldehyde (GA) (as crosslinker and spacer arm) to prepare immunosensors. Here, we report preparation of a QCM based nucleic acid sensor for investigation of hybridization, by following a very similar procedure for nucleic acid immobilization.