Positive Charged Polymer as a Probe for DNA Determination by Resonance Light Scattering

Abstract

Electrostatic interactions of calf thymus DNA (ct-DNA) with a positive charged polymer were investigated based on measurements of enhanced resonance light scattering (RLS) signals, and were proved by scanning electron microscopy (SEM). The optimal pH value was 7.0 in a phosphate-buffered saline solution (PBS) and the maximum RLS peak located at 344.8 nm. The RLS signal enhancement (DeltaI(RLS)) could be linearly correlated with the concentration of ct-DNA in the range of 0.0900 to 2.70 microg mL(-1), and the detection limit (S/N = 3) was 17.0 ng mL(-1). The binding ratio and the binding constant between DNA and polymer were also provided.