Simple Preparation Of Two Fluorescent Conjugated Polymer Nanoparticles And Their Application In Biological Analysis

Conjugated polymer nanoparticles(CPNs),mainly composed of conjugated polymer,have emerged as a new class of nanomaterials in recent years.Owing to the combination merits of conjugated polymer and nanostructure material,including high fluorescence brightness,high optical stability,high emission rate,low cytotoxicity,easy synthesis and surface modification,the CPNs show great application prospects in the fields of fluorescence sensing,biological imaging and photodynamic therapy.In addition,CPNs also have unique electrical properties,showing a remarkable potential in the field of materials science.Therefore,to expand the application field of CPNs and deepen existing applications,it is of great significance to develop new synthetic methods for the rapid and easy preparation of CPNs.The aim of this paper is to develop novel facile synthetic methods for the preparation of conjugated polymer nanoparticles(CPNs),to rapidly prepare some CPNs that are easy to achieve mass production under milder conditions using low-cost polymer monomers,and to investigate the application of such CPNs in bioanalysis.The main contributions of this thesis are summarized as follows:(1)Simple preparation of fluorescent conjugated poly-o-phenylenediamine nanoparticles and its application for in vivo imaging of formaldehydeThe polymer nanomaterials,derived from poly-o-phenylenediamine and its derivatives,have become one of the research hotspots of electrochemistry and materials science in recent years.However,there is only few research concerning the optical properties of poly-o-phenylenediamine(PoPD)nanoparticles.Therefore,the simple preparation of fluorescent PoPD nanoparticles is of great significance for optical sensing and imaging applications.In this paper,poly-o-phenylenediamine nanoparticles with different structures were synthesized under the room temperature condition.Among them,the N-PoPDNPs nanomaterials,synthesized using HNO3 as the polymerization medium and H2O2 as the oxidant,have good sensing properties for formaldehyde(FA).Therefore,the N-PoPDNPs is employed as a typical example to explore the potential application in FA sensing and bioimaging.Thanks tothe selectivity for FA and two-photon characteristic,N-PoPDNPs exhibit some attractive advantages for FA imaging in living cells,such as deeper tissue penetration,higher signal-to-noise ratio and longer observation time.To our knowledge,there have been no reports of two-photon fluorescent nanoprobes for FA detection.Based on the above advantages,the N-PoPDNPsfluorescent probes reported in this paper have promising applications in the monitoring of FA in living cells.(2)One-Pot Synthesis of Conjugated Polymer Dots with Ultrasmall Size below 10 nm through Schiff-base Chemistry and Their Bioapplications in Monitoring Lysosomal p HDeveloping new strategies for facile synthesis of conjugated polymer dots(CPdots)derived from novel monomer species is highly desirable to improve their application.This paper describes a super-simple method,based on Schiff base condensation,for facilely fabricating ultrasmall CPdots under room temperature.This novel CPdots,prepared by reacting the o-benzoquinone with o-phenylenediamine catalyzed by hydrochloric acid,defined as OOPdots,show a variety of superior properties,such as uniform small size,red emission and high quantum yield.With abundant imine and amino groups on the surface,the OOPdots exhibit an excellent p H responsiveness via modulation of the self-assemble or dissociation.Further experiments indicate that the resulting OOPdots is a high-performance probe for labeling lysosomes in living cells and zebrafish.This work not only expands the application scope of OOPdots in the field of biological imaging,but also provides guidance for their rapid and large-scale preparation.