Determination of the Concentration of Nucleic Acids Based on Light Scattering of a Complex Formed with Poly(Allylamine Hydrochloride)

Abstract

For the first time, poly(allylamine hydrochloride) (PAA) was used to determine nucleic acids with a light scattering technique. At pH 7.0, the light scattering intensity (LSI) of PAA is greatly enhanced by nucleic acid. The dynamic light scattering experiments prove that the enhanced LSI is caused by the formation of the big particles formed between DNA and PAA. Based on this, a new quantitative method for nucleic acid determination in aqueous solution has been developed. Under the optimum conditions, the enhanced LSI is proportional to the concentration of nucleic acid in the range of 0.01–6.0 µg/mL for herring sperm DNA, 0.02–6.0 µg/mL for calf thymus DNA and 0.02–8.0 µg/mL for yeast RNA if 3.0 × 10⁻⁵ mol/L PAA was employed. The detection limits are 5.6, 17.2, and 17.2 ng/mL, respectively. The concentration of nucleic acids in six synthetic samples were determined satisfactorily. At the same time, the light scattering technique has been successfully used to obtain the information on the effects of pH and ionic strength on the formation and the stability of the DNA/PAA complex, allowing the observation of the formation of the complexes between DNA and other polycations possible.

Keywords:

• Nucleic acids
• Poly(allylamine hydrochloride)
• Light scattering
• Interaction

Acknowledgment

This work was supported by the National Nature Science Foundation of China (Project No. 20275002).