ANYL 141

Polymer swelling can be achieved by introducing target analytes to swellable polymer particles containing functional groups that selectively interact with the target analyte. For example, polymers with swelling properties like poly (N-Isopropylacrylamide) can be copolymerized with chelating ligand moiety like bipyridine which complexes with metal ions. The polymer can be labeled with two fluorescent molecules referred to as donor and acceptor. Introduction of metal ions that complex with the ligand causes a change in the particle size which can be monitored by fluorescence resonance energy transfer (FRET). A change in the particle size causes a change in the ratio of the fluorescence intensities of the two fluorophores. A novel design of Copper (II) ion sensor based on lightly cross-linked poly (N-Isopropylacrylamide-co-N-((4-methyl-2, 2-bipyridine-4-yl) methyl)-N-propylacrylamide) and poly (N-Isopropylacrylamide-co-tert-butoxycarbonyl methyl-(3-vinyl-phenyl) amino)-acetic acid tert-butyl ester) polymers were prepared by dispersion polymerization in acetonitrile. The polymers were labeled with 2-Naphthylmethacrylate and 9-vinylanthracene fluorophores. Particle stabilization was achieved by poly (styrene-co-acrylonitrile) and N, N'-methylene-bis-acrylamide was used as crosslinker. On hydrolysis of the ester group and suspending the polymer particles in pH 6 buffer, the particles exhibited FRET property with various concentrations of Copper (II) ions when excited at the excitation wavelength of the donor.