Synthesis and Characterization of Fluorescent Spherical Polyelectrolyte Brushes

Fluorescent spherical polyelectrolyte brush (FSPB) with high content of luminescent quantum dots (QDs) embedded in core has been prepared and characterized. Fluorescent polystyrene core latex (MPL) was first synthesized and dispersed in aqueous solution by hybrid emulsion polymerization, poly(acrylic acid) (PAA) chains were then densely grafted onto nano-fluorescent PS beads via photo-emulsion polymerization. The obtained MSPB combines the advantages of fluorescence labeling with the characteristics of polyelectrolyte brushes. Transmission electron microscopy (TEM) shows QDs were introduced and mainly located in PS core, contributing to greater stability and biocompatibility of fluorophore. Photoluminescence studies prove that the encapsulation process does not affect fluorescence wavelength, hence FSPB has similar optical properties to isolated QDs. Like SPB without QDs embedded in core, the brush layer is also pH responded and ion strength sensitive and the length of PAA chains are controllable with AA dose. This kind of novel labeling nano-carrier is suitable for catalyst and protein immobilization, which is promising in the field of catalyst tracer and protein encoding.