Preparation Of Functional Fluorescent Polymer Nanoparticles Via Miniemulsion Polymerization

The preparation process of fluorescent polymer nanoparticles via one-step miniemulsion polymerization method is simple.The prepared nanoparticles are expected to exhibit good biocompatibility,excellent water dispersibility and be functionalized easily.Based on this,we prepared fluorescent polymer nanoparticles by miniemulsion polymerization,and then modified the nanoparticles to obtain a ratiometric fluorescent nano-probe for detection of hypochlorite acid.Nanoparticles were prepared with new stabilizers instead of common stabilizers and their stabilization mechanism was studied.A new type of photoswitchable fluorescent polymer nanoparticles was prepared without stabilizer and its application was studied.The specific contents are as follows:(1)The emergence of novel lysosome-targetable and ratiometric fluorescent probes for visualizing intracellular hypochlorous acid(HCl O)is useful for exploring HCl O-associated diseases.Thus,Combining miniemulsion polymerization and surface modification technology,a ratio fluorescent nanoprobe was synthesized for lysosomal HCl O imaging in living cells.The unique nanostructure can not only effectively separate the HCl O sensing unit(on the surface of nanoparticles)and aggregation induced emission(AIE)-based reference fluorogen(in the core of nanoparticles)to prevent severe ACQ phenomenon,but also possess high water solubility,well-resolved fluorescence signals,good biocompatibility and excellent photostability,etc.Significantly,thanks to the positive charge and good cell-membrane permeability of nanoparticles,the as-prepared PNRFN can selectively accumulate in lysosomes,and it can be further successfully used to tracking exogenous/endogenous HCl O in lysosomes.(2)In miniemulsion polymerization,stabilizer plays a key role in stabilizing the dispersion of two mutually insoluble phases(i.e.,water?oil).Recent studies have shown that water-soluble fluorescent dyes can be used as miniemulsion stabilizers to avoid a series of deficiencies in traditional stabilizers.Combining the principle of fluorescence resonance energy transfer(FRET)with 4-(1,2,2-triphenylethyl)phenylundecene-10-enoate(TPE-Aly)was employed as aggregation induced emission(AIE)dye and donor,Eosin Y as the acceptor and stabilizer,styrene as the monomer,and novel fluorescent polymer nanoparticles with dual fluorescence emission characteristics were synthesized by one-step miniemulsion polymerization.The aggregation behavior of the stabilizers on the oil / water of miniemulsion drop surface were studied.The structure and proportion of the donor-acceptor were optimized by FRET efficiency,and the size distribution and particle size of the nanoparticles were optimized.The degree of dye aggregation on the surface of the nanoparticles was calculated.Various stability tests show that Eosin Y can be used as an excellent stabilizer for miniemulsion polymerization and has broad application prospects in the field of functional materials research.(3)Based on the FRET principle,the green fluorescent dye2-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino)ethyl methacrylate(NBDME)as the donor and energy-matched photoswitchable molecule2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-indolin]-1'-yl)ethyl methacrylate(SPMA)as the acceptor were covalently incorporated into polymeric nanoparticles via surfactant-free miniemulsion polymerization with 11-methacrylamidoundecanoic acts as a comonomer and stabilizer at the same time.This preparation method mentioned is not only advantageous for enhancing the stability of nanoparticle structure,but also can effectively avoid dye leakage that may occur during the long-term use process.The as-prepared photoswitchable fluorescent polymeric nanoparticles(PFPNs)exhibit approximate particle diameter of 80 nm,with narrow size distribution(PDI),fast photo-responsiveness,excellent photostability,favorable photoreversibility and good long-term stability etc.The PFPNs are successfully applied to rewritable fluorescence patterning.