Communication—DNA Quadruplex Hydrogel Beads Showing Peroxidase Activity

Abstract

Biodegradable, intelligent, and self-healing hydrogel beads showing peroxidase activity has been prepared by adding hemin to "DNA quadruplex hydrogel" beads prepared by assembling dG 4 -PEG-dG 4 triblock copolymers through G quadruplex formation between the dG 4 portion. Efficient binding of hemin to parallel G-quadruplexes in hydrogels was confirmed by observing hyperchromicity of hemin absorbance. The enzymatic activity of resulting hemin peroxidase was visualized both with fluorogenic and chromogenic substrates. These observations serve as the first direct evidence of the presence of G-quadruplexes in DNA quadruplex hydrogels utilizing G-quadruplexes.

Application of DNA Quadruplex Hydrogels Prepared from Polyethylene Glycol-Oligodeoxynucleotide Conjugates to Cell Culture Media

“…Not only regular duplexes [4], but also four-stranded structures called “G-quadruplex” and “i-motif” are often used to construct DNA hydrogels due to their attractive features: metal ion or pH responsiveness [14,15,16,17,18,19,20,21,22,23,24]. We have recently developed a new class of hydrogels utilizing such DNA quadruplexes as cross-linking points of the 3D polymer network [25,26,27]. Polyethylene glycol-oligodeoxynucleotide (PEG-ODN) conjugates bearing merely four deoxyguanosine residues (dG4) for G-quadruplexes or five deoxycytidine residues (dC5) for i-motifs at the ends of linear or four-way branched PEG, were prepared as macromonomers by applying high-efficiency liquid phase (HELP) synthesis of oligonucleotides developed by Bonora et al with a few modifications [28].…”