We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific singl...We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific single-stranded oligonucleotides colorimetrically.By exploiting the tendency of the H-GNS to aggregate under high ionic strength and their inherent catalytic activities,excess H-GNS were removed and the amount of H-GNs remaining in the supernatant was quantified.Subsequently,the binding affinity of hemin-binding DNA aptamers to the H-GNS was determined upon titration with the DNA.With the conformity of the experimental data to the Langmuir adsorption isotherm,hemin is hypothesized to be sandwiched between the G-quadruplex DNA and graphene forming a ternary complex as a result of the specific bind-ing of the aptamer with the H-GNS.The binding affinity of the aptamer is not as strong as that of hemin/G-quadruplex in solution,which is attributed to electronic effects imparted by the graphene surface.The catalytic activity of the resulting complex,however,was confirmed to be higher than that of H-GNs alone.展开更多
基金the financial supports of Natural Sciences and Engineering Research Council(NSERC)of Canada and National Natural Science Foundation of China(no.21775095)。
文摘We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific single-stranded oligonucleotides colorimetrically.By exploiting the tendency of the H-GNS to aggregate under high ionic strength and their inherent catalytic activities,excess H-GNS were removed and the amount of H-GNs remaining in the supernatant was quantified.Subsequently,the binding affinity of hemin-binding DNA aptamers to the H-GNS was determined upon titration with the DNA.With the conformity of the experimental data to the Langmuir adsorption isotherm,hemin is hypothesized to be sandwiched between the G-quadruplex DNA and graphene forming a ternary complex as a result of the specific bind-ing of the aptamer with the H-GNS.The binding affinity of the aptamer is not as strong as that of hemin/G-quadruplex in solution,which is attributed to electronic effects imparted by the graphene surface.The catalytic activity of the resulting complex,however,was confirmed to be higher than that of H-GNs alone.
