Genetic detection in simulated-saliva using MPS coated QCM sensor without DNA isolation and amplification

Abstract

Early diagnosis plays a crucial role in curing the diseases. Especially, nowadays, PCR (Polymerase Chain Reaction) is used as a Gold Standart for genetically diagnosing illnesses. Alternative ways are being searched to be used instead of PCR because it takes more time to process, needs more investment, requires fully-armed laboratory condition which is available and accessible only in developed-countries. An alternative method which is able to make genetic detection in saliva would have relatively lower infection risks, and patient comfort would be much higher by the reason of invasive treatment is not processed.  e risk of transmission of contagious infections to medical offi cials or patients is lower with saliva compared to blood samples. QCM (Quartz Crystal Microbalance) which is a sensing device to be able to detect total mass-change on sensor surface with 0.5 ng/cm2 sensitivity by the alteration of resonance frequency has been used in this study. Sensor surface has been exposed to (3-Mercaptopropyl)trimethoxysilane (MPS) coating agent to increase the stability of sensor and provide a proper surface for suffi cient immobilization. Synthetic Probe DNA (pDNA) has been placed on the sensor surface to make it be able to detect target DNA (tDNA). After pDNA immobilization and blocking sensor surface with Bovine Serum Albumin (BSA), the surface has been exposed to negative control and 3 diff erent concentrations of tDNA at least 3 times for each concentration level. Results show that genetic material in simulated-saliva has been detected without the need of isolation, puri��������� cation and ampli��������� cation at 1.2 ng/cm2 (108 copies/mL) of sensitivity level.