Synthesis And Property Study Of Biotinylated Poly(N-isopropylacrylamide)

At first, amidation and esterification of chemical modification methods were adopted in this paper, the hydroxyl biotin (Biotin-OH) and biotin initiator (Biotin-Cl) were prepared. At40℃,N-isopropylacrylamide monomers were initiated polymerization by atom transfer radical polymerization (ATRP) with catalytic system of CuCl/Me6TREN and solvent system of DMF:H2O=1:1(v/v), biotinylated poly(N-isopropylacrylamide)(Biotin-PNIPAM) was synthesized. On this basis, the polymer was reacted with europium chloride (EuCl3) and thiophene formyl a-trifluoro acetone (TTA) ligands, respectively. Biotin-PNIPAM/Eu(Ⅲ) and Biotin-PNIPAM/Eu(Ⅲ)-TTA complexe systems were synthesized. The products were investigated, and the results are showed as followed:The molecular weights of Biotin-PNIPAM polymers show good controllability, PDI value is in the range of1.06-1.11. As molecular weight increases(Mn=4240～9700), the properties of temperature response show a negative growth trend (LCST=35.6℃～33℃), and the LCSTs of Biotin-PNIPAM increase in different degree comparing with PNIPAM homopolymer. The Europium(Ⅲ) complexes also show sensitive temperature-responsive property. Comparing with Biotin-PNIPAM, their LCSTs increase appreciably. Polymer complexe systems also have excellent fluorescence performance. Comparing with EuCl3, fluorescent intensities of two complexes were optimized by89%and1407%, respectively. Polymer Biotin-PNIPAM and complexe Biotin-PNIPAM/Eu(Ⅲ) in organisms have good biological compatibility, they have application potentials in biological medicine field.