Supramolecular Hydrogel Inspired from DNA Structures Mimics Peroxidase Activity

Abstract

We herein report that hydrogels can be prepared from guanosine and boronic acids in the presence of K+ and Pb2+ ions. These supramolecular hydrogels are formed via G-quartet like self-assembly of guanosine and its boronate esters. The potential of this hydrogel construct in mimicking enzyme-like activity has been demonstrated for the first time. We have observed that the self-assembled structure present in K+ stabilized hydrogel binds to iron­(III)-hemin and shows peroxidase activity, catalyzing oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Furthermore, the conformation of the G-quartet assemblies in the hydrogel can be altered by varying the stabilizing cations K+ and Pb2+. This conformational switching has been used to devise a molecular logic gate for sensing of toxic Pb2+ ions.

Applications of guanine quartets in nanotechnology and chemical biology

“…Dash and colleagues reported on the design of catalytic Gquartetbased hydrogels formed by boronateesterfunctionalized guanosines that act as logic gates. K + and Pb 2+ are the on and off inputs, respectively, and the product of the oxidation of 3,3′,5,5′tetramethylbenzidine is the output, thanks to its characteristic absorbance signal at 652 nm that pro vides a convenient readout of the efficiency of the opera tion 89 . Pei and colleagues exploited a similar approach to design bioelectronics nanodevices (i.e.…”

Drawing with Iron on a Gel Containing a Supramolecular Siderophore

“…The basis for these gels is usually the G 4 ⋅K + quartet (Figure ), a H‐bonded macrocycle templated by K + that stacks to give nanofibers. Guanosine hydrogels, described a century ago, are finding many new and diverse applications in just the past few years . Since it is not involved in the G‐quartet, the nucleoside's sugar can be modified to give gels with unique properties.…”

“…Since it is not involved in the G‐quartet, the nucleoside's sugar can be modified to give gels with unique properties. Reaction of the 2′,3′‐diol with boron species gives functional guanosine‐borate gels . The 5′‐OH provides another modification site.…”

Drawing with Iron on a Gel Containing a Supramolecular Siderophore

“…[6] Theb asis for these gels is usually the G 4 ·K + quartet (Figure 1), aH -bonded macrocycle templated by K + that stacks to give nanofibers.G uanosine hydrogels,d escribed ac entury ago, [7] are finding many new and diverse applications in just the past few years. [8][9][10][11][12][13] Since it is not involved in the G-quartet, the nucleosidessugar can be modified to give gels with unique properties.R eaction of the 2',3'-diol with boron species gives functional guanosine-borate gels. [9][10][11][12][13][14] The 5'-OH provides another modification site.L ehn used a5 'hydrazide that reacts with aldehydes to give responsive gels, [15] and we made a5 '-hydrazine that forms G 4 -gels for covalent trapping of toxic a,b-unsaturated carbonyls and remediation of anionic dyes from water.…”

“…[8][9][10][11][12][13] Since it is not involved in the G-quartet, the nucleosidessugar can be modified to give gels with unique properties.R eaction of the 2',3'-diol with boron species gives functional guanosine-borate gels. [9][10][11][12][13][14] The 5'-OH provides another modification site.L ehn used a5 'hydrazide that reacts with aldehydes to give responsive gels, [15] and we made a5 '-hydrazine that forms G 4 -gels for covalent trapping of toxic a,b-unsaturated carbonyls and remediation of anionic dyes from water. [16] To create ap H-switchable hydrogel for "water-in-water" separation of cationic dyes and metal ions,w ee valuated guanosine-5'-carboxylic acid (2)asagelator.Carboxylic acids are pH-responsive groups in many supramolecular gels.…”