Electrospinning Design Of Functional Nanostructures For Biosensors Applications

Electrospinning is a simple and effective strategy for fabricating nanofibrous structures and materials with large surface-to-volume ratios and desirable engineered properties.Thus,incorporating nanoscale building blocks（NBBs）like nanoparticles,graphene quantum dots,carbon nanotubes,and graphene into electrospun fibers has become one of the most attention-getting research topics in the field of biosensing.Generally speaking,there are two methods,pre-treatment and post-treatment,to introduce NBBs to nanofibers.In the pre-processing method,NBBs are introduced into the polymer matrix by adding appropriate precursors before the electrospinning process.This is a universal and effective method.What is more,NBBs are more stable because they are encapsulated within PMNFs by this means,which ensure their excellent reusability and long-term storage stability.In the post-processing,NBBs are introduced onto the PMNFs after the electrospinning process.This method can exploit the maximum capabilities of NBBs on the biological detection due to their exposed surface.In this thesis,we adopted the post-treatment methods.This thesis contains two segments.In the first part,we describe the preparation of nanoporous carbon nanofibers（CNFs）decorated with platinum nanoparticles（PtNPs）by electrospining polyacrylonitrile（PAN）nanofibers and subsequent carbonization and binding of PtNPs.The fabricated nanoprous CNF-PtNP hybrids were further utilized to modify glass carbon electrodes and used for the non-enzymatic amperometric biosensor for the highly sensitive detection of hydrogen peroxide（H₂O₂）.The morphologies of the fabricated nanoporous CNF-PtNP hybrids were observed by scanning electron microscopy,transmission electron microscopy and their structure was further investigated with Brunauer-Emmett-Teller（BET）surface area analysis,X-ray photoelectron spectroscopy,X-ray.diffraction,and Raman spectrum.The cyclic voltammetry experiments indicate that CNF-PtNP modified electrodes have high electrocatalytic activity toward H₂O₂ with a linear response range from 0.1 to 74.38 mM and a low detection limit of 1.9 μM（S/N=3）,besides,the chronoamperometry measurements illustrate that the fabricated biosensor has high sensitivity for detecting H₂O₂.In the second part,we describe the preparation of a novel polyacrylonitrile（PAN）nanofibrous membrane decorated with platinum nanoparticles（PtNPs）by electrospining method.In this procedure,3-aminopropyltriethoxysilane（APS）was electrospun as a precursor to introduce amine groups,and then adsorb PtNPs by in-situ precipitation.The fabricated PAN-PtNP hybrid membrane were further utilized to modify glass carbon electrodes and used for the non-enzymatic amperometric biosensor for highly sensitive detection of hydrogen peroxide（H₂O₂）.The morphologies of the fabricated PAN-PtNP hybrid membranes were observed by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and their structure was investigated by X-ray photoelectron spectroscopy（XPS）,ultraviolet-visiable spectrum and X-ray diffraction（XRD）.Due to exposed surface of PtNPs as well as the complexing effect between amine groups and PtNPs,the fabricated biosensor shows excellent biosensing performance with a linear response range from 5 μM to 53 mM and a low detection limit of 1.46 μM（S/N=3）,.The cyclic voltammetry experiments indicate that PAN-PtNP modified electrodes have high electrocatalytic activity toward H₂O₂ and the chronoamperometry measurements illustrate that the fabricated sensor has a high sensitivity for detecting H₂O₂.