Electrospinning Nanocomposites:Preparation And Application In Electrochemical Sensors

Glucose is a major component of carbohydrate in animals and plants,and its quantitative determination is of great importance in clinical chemistry,biochemistry and food analysis.Therefore,the construction of high-performance sensor to achieve rapid,sensitive detection of glucose has become the focus of the current study.Due to the small size effect and the large specific surface area of nanomaterials,it shows great superiority in the construction of sensor.Based on the three-dimensional nitrogen-doped carbon nanotubes with large specific surface area,excellent conductivity and biocompatibility,there is a great advantage in building sensors.TiO₂ nanomaterial is stable,non-toxic,cheap,high catalytic activity and has a large specific surface area and strong hydrophilic properties,which is suitable for the development of electrode materials.Copper oxide nanomaterials have excellent catalytic activity,stability,and easily involved in electrocatalytic small molecule reactions,which stimulate our interest in nonenzymatic detection.Based on the characteristics of the above materials,we build the sensor with the three kinds of materials: NCNT@CNFs,HNF-TiO₂ and CuO/TiO₂.the major work is as follows:?1?Three-dimensional?3D?nitrogen-doped carbon nanotubes@carbon nanofiber composites?NCNT@CNFs?were prepared by electrospinning and chemical vapor deposition?CVD?.The composites were characterized by SEM,TEM,XPS,Raman,UV-vis and EIS techniques.GOD is directly loaded on the composite to construct a glucose sensor,a glucose biosensor with remarkable sensitivity?24.8mAM-1 cm-2?,a low detection limit?6 ?M,S/N=3?,and a wide linear range?0.1mM-12.5 mM,R=0.9992?can be simply constructed.The biosensor exhibited good storage stability,high reproducibility,satisfactory anti-interference ability,and strong applicability to real samples.The N-doping combining with abundant defective sites and the favorable 3D network structure could effectively avoid enzyme leakage,maintain the bioactivity of the enzyme,and facilitate electron transfer,which resulted in excellent electrocatalytic performance.?2?The NCNT@CNFs were fixed with hemin to construct H₂O₂ biosensors.The novel biomimetic H₂O₂ biosensor has a rapid redox response with a low detection limit?0.03 ?M,S/N=3?and a wide linear range?0.08-137.2 ?M,R=0.998?.The biosensor exhibited high reproducibility,good storage stability,and satisfactoryanti-interference ability.The large surface area of the NCNT@CNFs and the biocompatible microenvironment greatly increase the surface coverage of the hemin,and its network structure ensures efficient mass transfer of the redox species.?3?A free-standing TiO₂ hollow nanofibers?HNF-TiO₂?were successfully prepared by sol-gel and low-temperature calcination method using electrospun nanofibers as templates.HNF-TiO₂ was characterized by SEM,TEM,XRD,FT-IR,UV-vis,XPS and EIS.And it was further explored for glucose oxidase?GOD?immobilization and biosensing.The biosensors show good sensing performances both in O₂-free and O₂-containing conditions with good sensitivity,satisfactory selectivity,long-term stability and sound reliability.This porous and nanotubular HNF-TiO₂ provides a well-defined hierarchical nanostructure for GOD loading,and the fine TiO₂ nanocrystals facilitate direct electron transfer from GOD to the electrode,also the strong interaction between GOD and HNF-TiO₂ greatly enhances the stability of the biosensor.?4?A novel CuO nanoparticle-loaded TiO₂ hollow nanofiber film?CuO/TiO₂?was prepared by a simple and scalable electrospun nanofiber film template-assisted sol-gel method.The loading of CuO nanoparticles in CuO/TiO₂ composites and the preparation of TiO₂ hollow nanofibers were carried out in one step.The composites were characterized by SEM,TEM,XRD,XPS,UV-vis and EIS.In application to glucose detection,CuO/TiO₂ showed high electrocatalytic activity towards the oxidation of glucose in alkaline media.Under optimal experimental conditions,the sensor exhibited a wide linear range?0.02-19.26 mM,R=0.996?.Additionally,the sensor showed high sensentivity,acceptable reproducibility and excellent selectivity.Its excellent sensing properties are attributed to the large specific surface area of CuO/TiO₂,the narrow pore size distribution,and the good dispersibility of CuO nanoparticles.