Fabrication And Application Of Liquid Crystal Photonic Crystal Microspheres

In the field of clinical medical detection,in order to reduce the volume of samples,the cost and speed of detection,the technology of multiplex biomolecular detection has a strong demand for application.Among them,multiplex detection based on microspheres has more advantages and has been widely used in high-throughput detection of proteins,nucleic acids and other fields.However,the traditional double antibody sandwich method needs to use the labeled antibody,which is quite expensive.Compared with traditional label detection methods,label-free detection has many advantages,such as lower detection cost,simpler operation steps and shorter detection time.Liquid crystal material is one of the new materials for label-free detection in real time.Due to its spiral periodic orderly internal structure,cholesteric liquid crystal(CLC)microspheres can be used as structural color-coding microspheres.It can be used to detect biomolecules by the changes of the pattern on the surface of microspheres before and after the attachment of biomolecules,thus label-free real-time detection can be achieved.Moreover,due to the smooth surface and high sphericity,liquid ccrystal microsphere can also be used as whispering gallery mode microcavity,which has a wide application prospect in the microlaser field.In this thesis,structural color-coding liquid crystal microspheres which can be applied to multiplex label-free biomolecular detection was fabricated by combining the photonic crystal structural color coding technology and microfluidics.The feasibility of applying the liquid crystal photonic crystal microspheres in biomolecular detection and microlaser were also researched.This kind of liquid crystal photonic crystal microspheres have a wide application prospect in the detection of tumor markers,early diagnosis of autoimmune diseases and genetic diagnosis of inherited diseases.The research content of this paper can be divided into the following three parts:(1)Fabrication of liquid crystal photonic crystal microspheres.Microspheres with-red,orange,yellow,green,blue-five kinds of structural color were prepared by microfluidic method,monodispersed and with the diameter of 100 ?m.The influence of the different chiral dopant concentration on the structural color liquid crystal photonic crystal microspheres,and the effect of the different preparation methods on the monodispersity of microspheres were studied.And the effect of different external microfluidic channel flow velocity on the size of microspheres was explored.(2)Biomolecular detection based on the change of optical patterns on the surface of liquid crystal microspheres.The optical properties of liquid crystal microspheres were studied.The influence of different concentrations of SDS(surfactant sodium dodecyl sulfate),PVA(poly(vinyl alcohol))and biomolecules on the optical pattern on the surface of the liquid crystal photonic crystal microspheres were studied.(3)The WGM spectra of liquid crystal photonic crystal microspheres.The optical properties of microspheres of liquid crystal photonic crystals with and without different types and concentrations of laser-grade fluorescent dyes,and their response to laser were investigated.The feasibility of using the fluorescent dye-doped liquid crystal microspheres as WGM microcavity for microlasing was studied.