Fluorescence-labeled hydrophilic nanoparticles via single-chain folding

Styrenic copolymers with fluorescent anthracene and crosslinkable groups are prepared from styrene (St)/methyl methacrylate (MMA)/1-(azidomethyl)-4-vinylbenzene copolymers (PS-N3), 9-((prop-2-ynyloxy)methyl) anthracene, and 3-(4-ethoxyphenyl)-3,4-dihydro-2H-benzo[e] [1,3] oxazine via click chemistry. The fluorescence-labeled nanoparticles are thus prepared via single-chain folding and intramolecular crosslinking in the ultradiluted solution of the polymers with anthracene and benzoxazine functionalities. MMA in the nanoparticles are then hydrolyzed into methacrylic acid, and the nanoparticles become partially hydrophilic. The dimension of the nanoparticles can be controlled in 5-20 nm. Such kind of nanoparticles exhibits excellent fluorescence performance at 412 nm when irradiated under the light of 367 nm.