Microfluidic assembly of uniform fluorescent microbeads fromquantum-dot-loaded fluorine-containing microemulsion

We report a facile strategy for fabricating fluorescent quantum dot (QD)-loaded microbeads by means of microfluidic technology. First, a functional fluorine-containingmicroemulsionwas synthesizedwith poly[(2-(N-ethylperfluorobutanesulfonamido)ethyl acrylate)-co-(methyl methacrylate)-co-(butyl acrylate)] (poly(FBMA-co-MMA-co-BA)) as the core and glycidyl methacrylate (GMA) as the shell via differential microemulsion polymerization. Then, CdTe QDs capped with N-acetyl-L-cysteine (NAC) were assembled into the poly(FBMA-co-MMA-co-BA-co-GMA) microemulsion particles through the reaction of the epoxy group on the shell of the microemulsion and the carboxyl group of the NAC ligand capped on the QDs. Finally, fluorescent microbeads were fabricated using the CdTe QD-loaded fluorine-containing microemulsion as the discontinuous phase and methylsilicone oil as the continuous phase by means of a simple microfluidic device. By changing flow rate of methylsilicone oil and hybrid microemulsion system, fluorescentmicrobeads with adjustable sizes ranging from 290 to 420 μm were achieved. Themorphology and fluorescent properties of the microbeads were thoroughly investigated using optical microscopy and fluorescence microscopy. Results showed that the fluorescent microbeads exhibited uniform size distribution and excellent fluorescence performance.