Determination of nucleic acids with a near infrared cyanine dye using resonance light scattering technique

A new method for the determination of nucleic acids has been developed based on the enhancement effect of resonance light scattering (RLS) with a cationic near infrared (NIR) cyanine dye. Under the optimal conditions, the enhanced RLS intensity at 823 nm is proportional to the concentration of nucleic acids in the range of 0-400 ng mL−1 for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA), 0-600 ng mL−1 for snake ovum RNA (SO RNA). The detection limits are 3.5 ng mL−1, 3.4 ng mL−1 and 2.9 ng mL−1 for CT DNA, FS DNA and SO RNA, respectively. Owing to performing in near infrared region, this method not only has high sensitivity endowed by RLS technique but also avoids possible spectral interference from background. It has been applied to the determination of nucleic acids in synthetic and real samples and satisfactory results were obtained.