Interactions between hemin-binding DNA aptamers and hemin-graphene nanosheets: Reduced affinity but unperturbed catalytic activity

Author: 
Date created: 
2019-03-12
Identifier: 
etd20120
Keywords: 
Functionalized graphene
Hemin-graphene nanosheets
Hemin-binding aptamers
G-quadruplex DNA
Peroxidase-like activity
Abstract: 

Hemin-graphene nanosheets (H-GNs) were reported to exhibit peroxidase-like activity, salt-induced aggregation, and the ability to discriminate single-stranded and double-stranded DNA colorimetrically. In the meantime, hemin-binding DNA aptamers were isolated by in vitro selection, which bind hemin tightly and exhibit enhanced peroxidase activity. In this research, it was demonstrated that H-GNs can in fact discriminate hemin-binding DNA aptamers not only from nonspecific strands but also among different hemin-binding DNA sequences. As such, H-GNs can be used for the determination of the binding affinities of various hemin-binding DNA aptamers. Particularly, the H-GN/DNA interaction was examined by exploiting the peroxidase-like activity of the hypothesized H-GN/aptamer ternary complex. The binding of the aptamer to H-GNs was validated by the conformity of data obtained from kinetic assays to the specific ligand binding model. Although the binding affinity of the aptamer to H-GNs was weaker and the catalytic activity of the resulting complex is lower than that of hemin/aptamer complex in solution, the catalytic activity of the H-GN/aptamer complex is much higher compared to that of the “parent” H-GNs.

Document type: 
Thesis
Rights: 
This thesis may be printed or downloaded for non-commercial research and scholarly purposes. Copyright remains with the author.
File(s): 
Supervisor(s): 
Hua-Zhong Yu
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) M.Sc.
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