Submicron polyacrolein particles in situ embedded with upconversion nanoparticles for bioassay.

We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb(3+) and Er(3+) based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay.