Fabrication Of Poly(St-co-AAm) Photonic Crystal And Its Application For Glucose Detection

Photonic crystal is an artificial periodic dielectric structure with photonic band-gap.As a new kind of functional nano-materials,photonic crystal shows an extremely wide application prospect.Responsive photonic crystal is generated by combing photonic crystal and functional polymer.Because of its ability to respond rapidly to external stimuli,responsive photonic crystal be an ideal material for fabricating biochemical sensor.Polystyrene(polystyrene,PS)microspheres are a kind of widely used materials for fabricating photonic crystals,however,there are lots of disadvantages to photonic crystal when it merely take polystyrene as matrix material,such as high brittleness,sole function,and slowly-responsive,etc.In this paper,monodisperse functional poly(St-co-AAm)microspheres were prepared by emulsion polymerization method.Then,the crack-free 3D photonic crystals were fabricated with poly(St-co-AAm)microspheres by vertical deposition self-assembly.A pH-responsive photonic crystal was fabricated by functionalizing poly(St-co-AAm)nanocomposite,which can be used to detect glucose.The main work was carried out by the following two parts:(1)Poly(St-co-AAm)nanocomposite was prepared by emulsion polymerization method which take styrene as raw material and acrylamide as functional monomer.The chemical composition of the microspheres was verified and the optimal conditions of self-assembly recation were explored.The influences of initiators,emulsifiers quantity,functional monomer and agitation speed on the size of poly(St-co-AAm)nanocomposite were investigated.The poly(St-co-AAm)nanocomposite and photonic crystal were investigated by scanning electron microscopy(SEM)and optical fiber spectrometer.(2)The pH-responsive photonic crystal was fabricated by poly(St-co-AAm)microspheres.To develop a photonic crystal biosensor for glucose and glucose oxidase inhibitor sensing,photonic crystal was modified with glucose oxidase(GOD).In the presence of glucose,glucose oxidase hydrolyzes glucose to produce gluconic acid.The gluconic acid decreased reation pH,which leads to an blue-shift in the diffraction wavelength.The hydrolysis reaction of glucose would be suppressed when the glucose oxidase inhibitor is present in the reaction system,and the blue-shift of the diffraction wavelength would be decreased.Therefore,theconcentrations of glucose and glucose oxidase inhibitor can be sensitively evaluated by measuring the diffraction shifts.Due to the specificity of enzyme reaction,other structural analogues would have no effect on the detection,and it also shows good applicability in artificial tear testing.