Preparation and Properties of Amphiphilic Polymer Nanospheres Containing Aza-crown ether

An amphiphilic polymer containing adenine and aza-crown ethers, poly-{[N,N-bis(2-ethoxy)-1,10-diaza-18-crown-6][5-methylene-(1-adenine)]sophthaloyl ester} (PCASE), was synthesized. The SEM morphology observed indicates that the amphiphilic PCASE polymer self-organized into diameters of about 140 similar to 210 nm nanospheres in dilute aqueous solution after recognized with 5-fluorouracil spontaneously. The sizes of PCASE/5-flu nanospheres in dilute aqueous solution determined by dynamic light scattering (DLS) are mainly dispersed at 120 similar to 230 nm. The molecule recognition based on hydrogen bond between adenine of polymer and 5-fluorouracil substrate in PCASE/5-flu nanospheres was studied. After recognition the C(2)=O stretching vibration at 1724 cm(-1) of 5-fluorouracil subtract shifted to 1718 cm(-1), the NH2 stretching vibration at 3324 cm(-1) disappeared, and a new peak at 3432 cm(-1) arised, indicating the formation of hydrogen bonds between 5-fluorouracil and adenine in polymer PCASE. The study on variable temperature FTIR show that the peak 1718 cm(-1) shifted back to the position at 1724 cm(-1), and the new peak 3432 cm(-1) disappeared finally, indicating that the H-bond was broken.