Chitosan oligosaccharide lactate (COL) chosen from different derivatives protects DNA against environmental stressors.

DNA is widely employed in biological science and materials science, driving a growing demand for its effective preservation. The conventional cryopreservation method is highly resource-intensive, requiring substantial storage space and continuous energy input. These limitations highlight the urgent need to develop cost-effective and efficient alternative strategies. In this study, we creatively extended the application of chitosan derivatives to the preservation of extracellular DNA, based on our previous work on chitosan-mediated nucleic acid enrichment and detection. Among different types of chitosan derivatives, chitosan oligosaccharide lactate (COL) was identified for its outstanding DNA-binding and re-release capabilities. Upon complexation with COL, DNA is effectively protected against major environmental stressors including enzymatic hydrolysis, oxidative damage, and ultraviolet irradiation, which were the major environmental stressors. This protective interaction significantly enhances the stability of DNA under non-cryogenic conditions, which in turn minimizes the losses in DNA concentration and integrity while preserving critical sequence information. Furthermore, the binding and release of COL with DNA could be achieved handily by pH adjustment. Moreover, COL could be readily available and amenable to large-scale production. Collectively, our findings provide a great potential method for realizing convenient and cost-effective DNA preservation at room temperature.