Ultrasensitive Detection of Mitochondrial DNA Mutation by Graphene Oxide/DNA Hydrogel Electrode

Abstract

6905wileyonlinelibrary.com of DNA. The bionic structure benefi ts the adsorption and hybridization of DNA. [ 3 ] The intermediate conductivity of electrode is sensitive to the change of conductivity introduced by trace DNA on the surface of electrode. On the contrary, this weak change is unobvious for the electrode with too high or low conductivity. As is well known, the conductivity of semiconductor silicon can be increased by adding certain impurities in minute quantities. Graphene oxide (GO) is a semiconductor and its conductivity can be improved by doping negatively charged molecules. [ 4 ] Therefore, the conductivity of hydrogel containing GO, water and natural biomolecules would be very sensitive to negatively charged molecules, such as DNA, and this hydrogel could be developed as novel DNA biosensor with high sensitivity.Fish sperm DNA is a natural DNA extracted from fi sh sperm and could form hydrogel with GO. [ 5 ] The GO/DNA hydrogel contains three components: GO, fi sh sperm DNA and water. Every component plays an important role in improving the sensitivity of DNA detection. GO is a semiconductor with intermediate conductivity compared with its reduced form (RGO) and most polymers, [ 6 ] which might produce a large conductivity change when trace DNA molecule was introduced. The hydrogel contains a large amount of fi sh sperm DNA molecules that could provide much higher biocompatibility than that of other chemical cross−linkers, which is advantageous for DNA hybridization in this bionic structure. The hydrogel also contains rich water that is similar to the natural environment for DNA hybridization, which is also benefi cial to improving the hybridization effi ciency of DNA. In addition, the hydrogel has a large specifi c surface and high diffusivity of small molecules [ 7 ] besides the biocompatibility. Therefore, it is a viable candidate for sensory and actuation applications. The sensitivity of biosensor is infl uenced by the conductivity of hydrogel which depends upon its thickness and component. [ 8 ] Conventionally, the hydrogel is simply coated onto the surface of classical electrodes, which makes the shape and thickness of hydrogel irregular and uncontrollable, respectively. One possible route is to form the hydrogel directly in a tube so that the shape would be fi xed and the thickness could be controlled as needed. The conductivity of hydrogel could be tuned by changing its component and thickness.Herein, we reported a hydrogel electrode prepared from GO and fi sh sperm DNA ( Scheme 1 ). The mixed solution of GO and Ultrasensitive detection of nucleic acid has attracted considerable attention recently in academic research and clinic diagnostics. Current approaches for DNA analysis involve complicated or expensive processes for labeling and often yield a high detection limit. In this study, a hydrogel electrode prepared from graphene oxide and fi sh sperm DNA is used for label−free mitochondrial DNA detection by impedimetric approach. The hydrogel has a bionic structure containing rich water ...

A hydrogel biosensor for high selective and sensitive detection of amyloid-beta oligomers

“…24,25 GO hydrogel was prepared based on our previous work except that no fish sperm DNA was added. 23 A total of 0.5 mL of 4.05 mg/mL GO was dropped into a 2 mL conicalbottom centrifuge tube, which was heated at 95°C for 1 h in a thermomixer and cooled down to room temperature to form GO hydrogel. Similarly, 4.05 mg/mL GO, 1.25 mM HAuCl 4 , and 1.2 mM NaBH 4 were thoroughly mixed in a centrifuge tube and then heated at 95°C for 1 h before cooling down to form GO/GNPs hydrogel.…”

“…The detection limit of our biosensor is lower than that of the other electrochemical or spectrometric methods for AβO detection based on PrP C probe (Table S2) due to the following possible reasons: first, EIS is a powerful electrochemical technology for the detection of small changes occurring at biosensor surfaces. Second, the bionic structure of the soft hydrogel with abundant water provides a friendly interface 23 In addition, the 3D porous structure of hydrogel has enormous space and allows rapid penetration of biomolecules into the electrode, which benefits the adsorption and binding of AβO.…”

“…22 In our previous studies, we have shown that GO hydrogel electrode is highly sensitive for DNA detection due to its bionic structure and tunable conductivity. 23 In this study, a novel GO/GNPs composite hydrogel biosensor for AβO detection was constructed. Our literature review shows that there is no study in which GO/ GNPs have been used as hydrogel biosensors for protein biomarker detection.…”

Molybdenum disulfide/graphene oxide nanocomposites show favorable lung targeting and enhanced drug loading/tumor-killing efficacy with improved biocompatibility

“…36,37 Lysine (Lys) and FA were purchased from Sangon Biotech (Shanghai, China). All MoS 2 samples were prepared from an original batch of the bulk materials.…”

Graphene Oxide for Biomedical Applications

“…The conductivity of this hydrogel can be tuned by varying the GO's properties. Moreover, this hydrogel electrode showed potential for the deduction of ovarian cancer cells DNA samples [29]. DNA immobiliized on GO glassy electrode nanocomposite was proposed for the detection of acrylamide (AA).…”