Highly sensitive RF detection and analysis of DNA solutions

We report the operation of a highly sensitive, tunable and stable RF interferometer, which is based on quadrature-hybrids. The interferometer is used to characterize and analyze DNA molecules, pBluescript (SK+) and pET21a, in ~1 nL DI water solutions. The obtained RF sensitivity at ~10 GHz is better than ~3×10^-15 mol/mL, which is close to the previously reported highest result. DNA molecular compositions are analyzed from RF measurements. The results suggest a new method for DNA solution examinations. We also show that partly damaged DNA molecules exhibit significant dielectric property changes. Additionally, DNA solution dynamics (i.e. relaxation time) is obtained through RF measurements between ~2.5 and ~10 GHz. Thus, the RF technique is promising for sensing and identification applications in biology and chemistry.