Solid-phase extraction of DNA by using a composite prepared from multiwalled carbon nanotubes, chitosan, Fe3O4 and a poly(ethylene glycol)-based deep eutectic solvent

Abstract

A magnetically responsive composite was prepared for improved solid-phase extraction of salmon sperm DNA sodium salt. It consists of chitosan-modified Fe3O4-magnetized multi-walled carbon nanotubes coated with a poly(ethylene glycol) based deep eutectic solvent. The sorbent was characterized by X-ray diffraction, vibrating sample magnetometry, Fourier transform infrared spectrometry, thermogravimetric analysis and transmission electron microscopy. The effects of the concentration of DNA, ionic strength, pH value, temperature and extraction time on extraction performance were optimized. Compared to plain Fe3O4, the new sorbent displays a superior DNA extraction capacity of 178 mg·g−1. It also displays favorable selectivity for DNA over bovine hemoglobin. Regeneration studies show that (a) 79% of DNA can be eluted from loaded sorbent by using 1 M NaCl, and that (b) the conformation of DNA remains unchanged as evidenced by CD spectra. The sorbent can be recycled six times without significant loss of extraction capacity. It was applied to the extraction of DNA from bovine whole blood prior to DNA quantitation by agarose gel electrophoresis. The results show this new sorbent to be a viable material for separation of DNA that excels by its low cost, high loading capacity and ease of regeneration.