Designing DNA nanostar hydrogels for sequence-specific degradation and antibody release.

DNA nanostar (DNAns) hydrogels are promising materials for in vivo applications, including tissue regeneration and drug and antibody delivery. However, a systematic and quantitative understanding of the design principles controlling their degradation is lacking. Here, we investigate hydrogels made of three-armed DNAns with varying flexible joints, arm lengths, and mesh sizes and use restriction enzymes (RE) to cut the DNAns structures while monitoring the gel's degradation. We discover that (i) removing flexible joints, (ii) increasing arm length, or (iii) relocating the RE site along a DNA linker markedly accelerates hydrogel degradation. In contrast, non-specific endonucleases, e.g. DNaseI, quickly degrade DNAns hydrogels regardless of design. Importantly, the release of antibodies from DNAns hydrogels can be modulated by the action of sequence-specific enzymes, confirming that design-dependent susceptibility to sequence-specific enzymatic degradation can be leveraged for responsive drug-delivery systems. These findings provide new design principles for engineering DNAns hydrogels with tailored material properties, sequence-specific enzymatic susceptibility, and controlled cargo release.