Properties of Fiber Optic DNA Sensor Based on Fluorescence Quenching Using Lock-in Amplifier

摘要

To detect DNA concentration, a novel fiber optic biosensor based on fluorescence quenching was designed and constructed by using lock-in amplifier for signal measurement. A linear relationship between the relative phase delay ΔΦ of the sensing membrane and calf thymus DNA (ctDNA) concentration was observed in range from 2.0×10~(-9) to 4.0×10~(-7) M in the buffer of 5.0 mM Tris-HCl and 50.0 mM NaCl (pH 7.1), and the detection limit was 8.0×10~(-10) M. The biosensor has a response time of 65 s and shows good stability and repeatability.