Lanthanide-encoded Poly(styrene-co-methacrylic Acid) Microspheres: Synthesis and Characterization

Lanthanide-encoded polystyrene-co-methacrylic acid (P(S-MAA)) microspheres with narrow size distributions were synthesized by two-stage dispersion polymerization. I examined how the amounts of methacrylic acid (MAA) and lanthanide (Ln) salts affect the composition of the particles formed in the reaction. Also, I performed a systematic study of Ln ion release into different aqueous solutions. In normal buffers, these particles were stable against ion leakage, even upon prolonged storage and stirring. When strong chelating agent ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were present in buffer, the loss of Ln ions increased to 15 % after 8 weeks. A preliminary kinetic study of Ln ion incorporation was performed to help understand the particle formation mechanism.MAS