Study Of Biosensing Properties Based On Graphene Aerogel/Nanoparticle Hybrid

Graphene, a single-layer material comprising carbon atoms closely packed in a six-membered ring structure of a two-dimensional lattice, has attracted considerable interests since it was discovered in 2004. Graphene has been applied in bioelectronics and biomedical applications. Given its unique physical and chemical properties, such as large surface area, exceptional thermal stability, and ease of functionalization, graphene is an ideal matrix for electron transfer in optoelectronic devices, flexible electronics, and electrical biosensing. The use of metal nanoparticles(NPs) to decorate graphene to obtain graphene/metal nanocomposites has attracted considerable interest in the electrochemical sensing field because graphene-based metal nanocomposites display synergistic catalytic properties of both graphene and metal NPs. This method has been used extensively in fabricating biological functional interfaces and electrochemical sensors.To investigate this important aspect of graphene technology, we developed an improved hydrothermal procedure to fabricate graphene aerogel/gold NP(GA/GNs) hybrid and graphene aerogel/ platinum NP(GA/PNs) hybrid. Field-emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM), X- ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS) were used to characterize the GA/GNs and GA/PNs hybrids. These complexes were then studied for the electrochemical biosensor interfacial and electrochemical graphene / metal nanoparticle composite sensing properties. The electrochemical results show that the obtained GA/GNs and GA/PNs possess a large specific surface area, high porosity, good biocompatibility, and excellent electric conductivity.We first used a GA/PNs hybrids modified electrode to immobilize GOD for glucose detection. The electrochemical and electrocatalytic properties of the immobilized GOD were characterized by electrochemical methods. Our electrochemical biosensors exhibit excellent glucose sensing performance, with a remarkable sensitivity(257.60 ?A·mM-1·cm-2), an approximate linear detection range of glucose concentration(50 ?mol·L-1 to 450 ?mol·L-1), and a detection limit of 0.597 ?mol·L-1.We further developed an improved hydrothermal procedure to fabricate graphene aerogel/platinum NP(GA/PNs) hybrids. Due to the excellent catalytic properties of platinum nanoparticles, we realized a non-enzymatic detection of hydrogen peroxide(H2O2) and applied it to the detection of the cell. It exhibits excellent sensing performance to H2O2 with a remarkable sensitivity of 138.23 ?A·mM-1·cm-2, an approximate linear detection range of H2O2 concentration(1 ?mol·L-1 to 2785 ?mol·L-1), and a detection limit of 0.33 ?mol·L-1.Finally, GA/PNs hybrids were used to immobilize different enzyme, using different biological electrodes to achieve multi-index detection of uric acid and cholesterol. The detection of uric acid occurred in the linear range of 1 ?mol·L-1 to 1785 ?mol·L-1, sensitivity 66.69 ?A·mM-1·cm-2, and detection limit of 0.33 ?mol·L-1. The linear range of cholesterol detection, sensitivity and detection limit are 100 ?mol·L-1 to 700 ?mol·L-1, 7.07 ?A·mM-1·cm-2, and 33.3 ?mol·L-1, respectively.In conclusion, electrochemical detection results show that metal nanoparticles(NPs) to decorate graphene electrochemical biosensors exhibit excellent glucose, hydrogen peroxide(H2O2), uric acid and cholesterol sensing performance with wide linear ranges, high sensitivities, low sensing limits, rapid response times, good anti-interference properties, and repeatability. By integrating the advantages of conductors and aerogels, graphene aerogels/metal nanoparticles present a promising and advantageous interfacial platform for electrochemical biosensors, and have a good prospect in the fields of medical monitoring, clinical diagnosis, and biomedical devices.