Polyamide Polymer Microspheres Synthesis, Modification Of The Enzyme Interaction

Because some polymer microsphere, such as Poly(N-isopropylacrylamide) (PNIPAM) microgel possess some advantages, such as special temperature responsibility and biocompatibility, they can be used in many fields, such as the drug delivery, biochemical separations and biosensor. The rare earth and transition metal ions possess excellent light, electricity and magnetism properties. Their combination can obtained a kind of the biomedical polymer materials with the excellent properties. Therefore, based on the synthesis of P(NIPAM-co-St) copolymerized microspheres and PNIPAM-g-P(NIPAM-co-St) graft microspheres using NIP AM and styrene, this thesis investigated the changes in the structures and properties of the P(NIPAM-co-St) copolymerized microsphere before and after its interaction with the rare earth and transition metal ions. The interaction between PNIPAM-g-P(NIPAM-co-St) graft microspheres and biomelecules, such as horseradish peroxidase (HRP) was also investigated. The main results obtained are as follows:1. When the P(NIPAM-co-St) copolymerized microspheres and Tb(III) are formed the complex, Tb(III) mainly coordinates with O atoms in P(NIPAM-co-St), foming the P(NIPAM-co-St)-Tb(III) complex. The changes in the properties of P(NIPAM-co-St) before and after the formation of the P(NIPAM-co-St)-Tb(III) complex are asfollows:(1) The sizes of the P(NIPAM-co-St) copolymerized microspheres are uniform. The average size of microspheres is about 150 run. The average size of the P(NIPAM-co-St)-Tb(III) microspheres is about 160 nm. The change in the average size is small.(2) After forming the P(NIPAM-co-St)-Tb(III) complex, many Tb(III) ions are located on the surface of the microspheres. Thus, the positive charges on the surface of microspheres are increased.(3) After forming the P(NIPAM-co-St)-Tb(III) complex, the intensity of the fluoresnce peak of P(NIPAM-co-St) is decreased and the intensities of the fluoresnce peaks of Tb(III) are significantly increased. (4) After forming the P(NIPAM-co-St)-Tb(III) complex, the lower critical solution temperature (LCST) of P(NIPAM-co-St) is increased from 32 to 37℃.2. P(NIPAM-c0-St) can also form the complex with Mn(II). The change in the properties of P(NIPAM-co-St) before and after the P(NIPAM-co-St)-Mn(II) complex is similar to that for the P(NIPAM-co-St)-Tb(III) complex. However, the change is relatively small.3. The investigation results of the interaction of PNNS with some biomolecules and cell are as follows:(1) The adsorption of PNNS for ezymes has the selection. The adsorption ability of PNNS for HRP is larger than that for CAT. PNNS has no the adsorption ability for HB.(2) HRP can be adsorbed on the surface of PNNS. HRP and PNNS have a certain interaction. However, the interaction does not change the shape and size. After HRP is adsorbed on the surface of PNNS, the conformation of the peptide of HRP has a certain change. However, the structure of the heme group is almost not changed.(3) Basically, PNNS does not change the shape and size the cell. Thus, PNNS has the good cell compatibility.