We developed a new method utilizing rolling-circle-amplification reaction to produce DNA hydrogels possessing horseradish-peroxidase-like catalytic ability. DNA hydrogels make full use of the merits of DNA for its biocompatibility and programmability compared to other polymer materials. They possess the property of stability, obey the rule of precise base-pairing and function versatilely due to the artificial evolution of functional nucleic acid (FNA). There are two basic traditional methods to form DNA hydrogels, including DNA hydrogels that are composed of pure DNAs and DNA–polymer hybrids. The two methods also commit the weakness of high cost which hinders their practical applications. The reaction of rolling circle amplification (RCA) of short oligonucleotide template is an efficient isothermal amplification which provides a cost-effective method for hydrogel fabrication. When we incorporate one kind of FNA sequences, G quadruplex, into the products of RCA, the specific sequence-dependent molecular recognition, enables the horseradish peroxidase (HRP)-like catalytic activity with one-step preparation and high stability. Through rational design of the template sequences, the RCA products tend to form intermolecular G-quadruplex to crosslink the hydrogel. Encapsulated with hemin, the RCA hydrogel displays a high retention of hemin and an HRP-like catalytic ability that catalyzes ABTS2- (2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonate)) to ABTS●- with green color or 420 nm absorption. Of note, its catalytic ability can be retained under harsh preservation after a long-time storage. By encapsulation of glucose oxidase (GOx) during the RCA process, we fulfill a cascade enzymatic reaction which transformed the glucose signal into ABTS●- after the discovery of glucose by GOx, production of H2O2, and the further oxidation reaction of ABTS2- by hemin/G-quadruplex catalysis. In conclusion, the functionalized RCA hydrogel is prepared by one-step RCA method. G-quadruplex/hemin performs good catalytic ability in the hydrogel with high stability even at elevated temperatures and after long-term storage. Integrated with GOx, the hydrogel can form a complex system for glucose detection with superior sensitivity and stability. Due to the versatility of FNAs, this one-step RCA method can be broadened to fabricate more functionalized DNA hydrogels for practical applications.

One-step rolling circle amplification hydrogel with stable catalytic ability

256th National Meeting (2018)

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