Carboxyl-modified graphene oxide (GOÀCOOH) is shown to possess intrinsic peroxidase-like activity that can catalyze the reaction of peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue color reaction. A simple, cheap, and highly sensitive and selective colorimetric method for glucose detection has been developed and been used in buffer solution or diluted blood and fruit juice samples. Our work will facilitate the utilization of the intrinsic peroxidase activity of GOÀCOOH in medical diagnostics and biotechnology.As a novel one-atom-thick planar sheet of sp 2 -bonded carbon atoms, graphene has received much attention in recent years in materials science and biotechnology. [1][2][3][4][5][6][7][8][9][10][11] Significant progress has been made for the utilization of graphene in nanoelectronics, [1,3] nanocomposites, [4,5,7] biosensors, [8,9] and drug delivery. [10,11] Production of graphene sheets in bulk quantity and its modification with functional groups to improve water solubility have been recently reported. [6,11] All these achievements provide new insights into the application of this nanomaterial in medical diagnosis and biosensing. Here, we report that carboxyl-modified graphene oxide (GOÀCOOH) has peroxidase-like activity that can catalyze the reaction of peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to produce a blue color reaction. Kinetic studies indicate that GOÀCOOH has even higher catalytic activity to TMB than the natural enzyme, horseradish peroxidase (HRP). Like HRP, the catalytic reaction follows a ping-pong mechanism. Further studies indicate that the observed peroxidase-like activity is not related to the trace amount of metal catalyst in the sample but instead is caused by its own intrinsic property. This is evidenced by energy-dispersive X-ray (EDX) analysis.Peroxidase has great potential for practical application and can be used as a diagnostic kit for hydrogen peroxide (H 2 O 2 ) and glucose. For control of diabetes mellitus, it is important for minimizing diabetic complications to maintain blood glucose concentrations within the normal physiological range. [12] Up to now, a number of glucose sensors have been reported. [13][14][15][16][17][18][19][20][21] Among them, horseradish peroxidase (HRP) has been widely used to fabricate sensors for detection of the products of the glucose oxidase. [16][17][18][19][20][21] In comparison with HRP, GOÀCOOH is low-cost, easy to obtain, more stable to biodegradation, and less vulnerable to denaturation. These advantages indicate that GOÀCOOH can be useful in environmental monitoring and medical diagnostics. In this Communication, using GOÀCOOH peroxidase-like catalytic activity and glucose oxidase (GOx), a colorimetric method for glucose detection has been developed (Scheme 1). The results indicate that this method is simple, cheap, and highly sensitive and selective for glucose detection and has been used in buffer solution and diluted blood or fruit juice samples.GO...

A novel strategy to dissociate amyloid aggregation is presented, using localised heat generation from a clinically used amyloid staining dye, thioflavin-S (ThS)-modified graphene oxide (GO) under NIR laser irradiation. Compared to traditional chemotherapies, photothermal therapy shows reduced side effects and improved selectivity and safety.

Engineering carbon materials as the bifunctional catalysts for both electrocatalytic oxygen reduction/evolution reactions (ORR/OER) is highly promising for the large-scale commercialization of regenerative fuel cells and rechargeable metal-air batteries. Codoping carbons with heteroatoms can achieve unique electronic structures and show tailored electrocatalytic capabilities by rationally regulating their dopants. Sulfur is one of the most important dopants from both experimental and theoretical perspectives. In this work, a novel, highly efficient and environmentally benign method for sulfur incorporation into carbon framework has been developed facilely on the basis of graphene oxide-polydopamine (GD) hybrids to derive the N, S-codoped mesoporous carbon nanosheets. 16.7 at. % S can be conjugated to the GD hybrids associated with the S doping efficiency up to 6.1% after 800 o C pyrolysis, which is higher than most previous S doping approaches. The resultant N, Scodoped mesoporous carbon nanosheets exhibit superior performance with favorable kinetics and excellent durability as a bifunctional ORR and OER catalyst, which is much better than that of most reported metal-free doped carbon, even transition metal and noble metal catalysts. The high concentrations of multiple dopants, abundant porous architecture and good electron transfer ability are believed to significantly expedite the ORR and OER catalytic processes. In the light of physicochemical versatility and structural tunability of polydopamine (PDA), this work provides a universal platform towards further development of PDA-based carbon materials with heteroatom dopants as the highly efficient electrocatalysts.