Physical stimuli-responsive DNA hydrogels: design, fabrication strategies, and biomedical applications

Table 1 Stimuli-responsive DNA hydrogel responds to different stimuli according to compositions, such as polymers with other materials and cross-linkers, to show different features of the hydrogel

Types of physical stimuli	Cross-linkers	Name of polymers with other materials	Features of hydrogels	Refs.
Temperature	ssDNA	Polyacrylamide chains/acrylamide monomers/DNA	Unstable, gel dissolution	[41, 52, 59]
Temperature	DNA hybridization, metal ions	DNA, Collagen, hyaluronic acid, chitosan	Biocompatible, biodegradable, tunable mechanical properties	[35, 41, 52, 59]
Temperature	Sticky ends of Y scaffold and linker DNA	DNA	Transition of gel to sol	[38]
Temperature	Enzymatic ligated sticky arm of X-shaped DNA	DNA with AuNPs(nanoparticles) and DOX(drug)	Disassembly of hydrogel and release of AuNPs and DOX	[62]
Temperature	DNA duplex structure	PPO/DNA	Changes in strength can be observed	[63]
Temperature	Complementary ssDNA sequence	Polyacrylamide/DNA with NRs nanoparticles	Transition of gel to sol	[59, 65]
Light	Azobenzene functionalized ssDNA	Polyacrylamide/DNA	Changes volume	[52, 68]
Light	Glucosamine boric acid ester and trans-azobenzene intercalated units	Polyacrylamide/DNA	Cross-linked with low density, low in stiffness, photo-triggered transition is reversible, and finally transition of gel to sol	[69]
Light	Sticky ends of X-shaped DNA motifs	DNA with light-responsive artificial base cnvK	Transition of gel to sol	[70]
Magnetic field responsive	DNA duplex structure (Y scaffold + linker)	DNA with MNPs(nanoparticles)	Transition of gel to sol	[30]
Electrical responsive	Complementary DNA strands	Ferrocene, viologen, polyaniline, polypyrrole, and DNA	Changes in hydrogel properties such as swelling, contracting	[76, 77]

ISSN: 1477-3155