Smart Hydrogels Based on Self-Assembly of One Short Single-Stranded DNA for Functional Surface Patterning

As smart soft materials with programmable functions and excellent biocompatibility, DNA hydrogels have great potential in a variety of application fields, such as in the fabrication of soft biosensing devices. However, most DNA hydrogels are formed by self-assembly of multibranched DNA structures or with the assistance of enzymatic processes or chemical modifications, which significantly increases the complexity of material designing and the cost of construction. Herein, we report on the construction of responsive DNA hydrogel based on the self-assembly of one short single-stranded DNA (ssDNA), and the self-assembly can also occur within a polymeric matrix to construct interpenetrating network (IPN) hydrogel. Mechanism investigation reveals that the self-assembly between the short ssDNA strands leads to the formation of long linear DNA structures and looped structures, and the entanglement between these DNA assemblies at high concentrations results in the formation of three-dimensional hydrogel networks. By programming the sequence of the ssDNA strand, pH-responsive DNA hydrogel or catalytic DNA hydrogel can be constructed. Furthermore, the interpenetration of the catalytic DNA networks within a polyacrylamide hydrogel matrix leads to the formation an IPN hydrogel with higher structure stability and with excellent catalytic activity on the polymerization of aniline into conductive polyaniline (PANI). The successful construction of conductive PNAI patterns templated by the IPN hydrogel films is further achieved, which may hold potential in soft electronic and biosensing applications.