Fabrication And Application Of Sensitive Biosensor Based On Hydroxyapatite Nanowire/Reduced Graphene Oxide/Gold Nanoparticle Composite

Hydroxyapatite has good biological activity and biocompatibility,it is the ideal biomaterial in bone tissue engineering.At present,the application of hydroxyapatite in the field of biosensors has gradually become a topic of great concern due to its crucial role in the biological response to the size,shape and composition of the hydroxyapatite.In this study,hydroxyapatite microspheres and nanowires were synthesized by hydrothermal method without adding any organic phase and without any surfactant or template.The effect of reaction conditions on the growth morphology of hydroxyapatite was also explored.Graphene is a quasi-two-dimensional material with only one carbon atom layer thickness.It has the characteristics of large specific surface area,good chemical stability and excellent electrochemical performance.It is an ideal material for making biosensors and is widely used in electrochemistry.Gold nanoparticles?AuNPs?also known as colloidal gold,in addition to having a large specific surface area,specific surface area than the high activity of macroscopic quantum tunneling and other nano-materials shared nature,but also having good hydrophilic properties with a variety of biological macromolecules and maintaining its biological activity,which has been widely used in the preparation of sensors.By changing the pH value,the addition of graphene oxide,we can control the hydroxyapatite nanowires/reduced graphene oxide/nanocomposite materials with different morphologies and electrochemical properties.Our study shows that the adjustment of pH and the amount of graphene added before the hydrothermal reaction is crucial for the growth of hydroxyapatite crystals.Under the specific reaction conditions,there are mainly two typical topography products,namely microspheres and nanowires.The composite modified glassy carbon electrode prepared by hydrothermal reaction method was used to prepare the uricase biosensor and the anti-acid oxidase biosensor using the modified electrode as the working electrode.The experimental results show that the enzyme biosensor has excellent electrochemical performance with excellent performance.The specific experimental contents and research conclusions are summarized as follows:?1?Preparation of hydroxyapatite nanowire/redox graphene/nano-gold compositeIn this experiment,a simple hydrothermal method was used.Sodium phosphate dibasic was used as sodium source and calcium chloride was used as calcium source.The reaction was carried out in a simple aqueous solution at a ratio of Ca/P=5:3.Before the hydrothermal reaction,graphene oxide solution and colloidal gold were prepared by adjusting the amount of graphene oxide added at a nucleation temperature of 4°C,pH=4.5 and hydrothermal reaction temperature of 140°C to prepare a hydroxyapatite nanowire/oxidized Reduction of graphene/nano-gold composite.In this experiment,a simple hydrothermal method was used.Sodium phosphate dibasic was used as the sodium source and calcium chloride was used as the calcium source to react at a ratio of Ca/P=5:3 in pure aqueous solution.Before the hydrothermal reaction,a suitable amount of graphene oxide solution and colloidal gold were added.By adjusting the amount of graphene oxide,hydroxyapatite nanowires/redox graphene/nanocomposites were prepared under the conditions of 4?,pH=4.5 and hydrothermal temperature of 140?.?2?Uricase biosensors electrochemical detection of uric acidHydroxyapatite nanowires/redox graphene/nano-gold composite prepared by one-step hydrothermal method were used as electrode modification materials to prepare uricase biosensors,which made full use of the good conductivity and electrocatalytic activity of graphene decorated with gold nanoparticles and the excellent biocompatibility and large specific surface area of hydroxyapatite nanowires,enabling uric acid to be rapidly,sensitively and accurately performed detection.The experimental results show that the uricase biosensor has high sensitivity,low detection limit and large linear detection range(linear detection range of 1.95×10^-5-5.0×10^-3mol/L,the sensitivity of 1.5949×10^-2A/moL with a detection limit of3.9×10^-6mol L^-1?S/N=3?).?3?Ascorbate oxidase biosensor electrochemical detection of ascorbic acidHydroxyapatite nanowires/redox graphene/nano-gold composite prepared by one-step hydrothermal method were used as electrode modifying materials to prepare ascorbate oxidase biosensors which taken full advantage of the good conductivity and electrocatalytic activity of graphene and gold nanoparticles,the excellent biocompatibility and large specific surface area of hydroxyapatite nanowires.This allows it to detect ascorbate quickly,sensitively and accurately.The results showed that the ascorbate oxidase biosensor has high sensitivity,low detection limit and large linear detection range(sensitivity of 1.5949×10^-2A/mol,detection limit of 3.39×10^-6M?S/N=3?,the linear range of 3.90×10^-4-3.60×10^-2mol/L,the correlation coefficient of R²=0.9985)...