An ATP-responsive linear DNA hydrogel

A single-stranded DNA with adenosine triphosphate (ATP) aptamer sequence and a single-stranded DNA with cohesive end were designed for the formation of linear DNA hydrogel. First, a double-stranded DNA monomer was formed by the hybridization of sticky ends. Then this monomer self-assembled to form a long linear DNA polymer and further form a DNA hydrogel by physically cross-linking. The formation of the hydrogel was characterized by rheological tests and the transition from the gel state to the solution state was observed by stress scanning. Using methylene blue (MB) as a marker, the responsive dynamics of the DNA hydrogel to ATP was characterized by UV absorption spectroscopy. Within 15 min after the addition of ATP, the absorbance of the DNA hydrogel at 664 nm rose rapidly and reached a plateau, indicating that the DNA hydrogel can respond quickly to ATP. Moreover, the absorbance of the DNA hydrogel at 664 nm has a good linear correlation with ATP concentration. For comparison, ATP, thymidine triphosphate (TTP), cytidine triphosphate (CTP) and guanosine triphosphate (GTP) were added to the DNA hydrogel, respectively. The UV absorption spectrum test showed that only the ATP-containing DNA hydrogel was depolymerized and MB was released, indicating that the DNA hydrogel has good stability and its response to ATP was specific.