DNA nanogel encapsulated by a lipid vesicle

DNA has been used as a new generic material due to its selectivity and intrinsic biocompatibility, to construct a variety of nano-architectures such as cubic, tetrahedral, and even complicated origami. Recently, a 3-D hydrogel matrix of DNA has been manufactured at macroscopic scale for biomedical applications as an extra-cellular matrix and a cell-free protein amplification platform. To explore DNA hydrogel in a microscopic level, we report a novel method to produce DNA nanogel enclosed by a lipid vesicle. Nano-sized DNA hydrogels have been simply prepared by mixing precursors with DOPC lipid components under repeated sonications, following by nanometer filtering. After peeling off outer lipids using a lipid-chaotropic reagent (Triton X-100), we observe uniform nanogels entirely composed of DNA. With increasing the amount of DOPC lipids, the size of DNA nanogel has decreased. Our theoretical model based on equilibrium thermodynamics predicts such trend consistent with experiments. It indicates that DOPC lipid molecules energetically interfere with crosslink mechanisms among DNA units. DNA nanogel of well-controlled size may be incorporated with functional multi-modules and further applied to novel and advanced technological tools for in vivo diagnostics or therapeutics in preventive medicines.