Determination of mode of interactions between novel drugs and calf thymus DNA by using quartz crystal resonator

Quartz crystal resonator (QCR) was used to identify the mode of interactions between small DNA-binding molecules and calf thymus DNA (ctDNA) according to the alteration of the relative viscosity of the solution. The differential series resonant frequencies of a 10-MHz QCR mounted in a cell containing DNA and various DNA-binding molecules at different concentrations including DNA-intercalators: ethidium bromide (EB), planar platinum(II) quaterpyridine complex, [Pt(QP)](CF3SO3)2 (QP=2,2′:6′,2″:6″,2″′-quaterpyridine), ruthenium(II) quinonediimine complex of cyclam (cyclam=1,4,8,11-tetraazacyclotetradecane), [Ru(cyclam)(pqdi)]·(ClO4)2 (pqdi=9,10-phenanthroquinonediimine, pqdi) as well as groove binder, Hoechst 33342, separately were measured. Compared to traditional viscosity measurement method, the use of QCR has the benefits of automation, time saving, high sensitivity and stability, as well as easy operation and cleanup. Extreme viscous sample can also be conducted by QCR.