Preparation Of Multiple Response Polymers And Studies Of Their Immobilized Enzymes

Stimulated response polymer,also known as smart materials,has aroused widespread concern of scientists in recent decades of natural science research.Although these materials are macroscopic polymers,they can respond differently to small changes in external environmental conditions and assemble a variety of different reactive groups into the same one by the self-assembly effect of the polymer.Nowadays,as people demand changes in materials,more and more intelligent materials are designed and applied with industrial and clinical.At present,these smart materials have a very good application prospects in the affinity separation;immunoassay;enzyme load recovery and drug delivery and other biomedical and nano-technology fields.These facts illustrate that stimulating responsive polymer play an increasingly important role in our daily life and have broad prospects for research in stimulating responsive polymers.The reactive groups on the polymer chain determine the stimulus responsebehavior of the polymer,and the addition of one or more responsive groups to a polymer chain via various polymerization means yields a single responsiveness or multiple response of the polymer.Common irritation is:pH,temperature,ionic strength,light,redox,and interaction with the host and guest.By changing these external stimuli,not only can controll the polymer more precisely,but also the amount of each reactive group in the polymer chain can be controlled so that the polymer can be adapted to the demand multi-application environment.Based on the above theory and atomic transfer radical polymerization(ATRP),ring-opening polymerization(ROP),click chemistry and other methods,two new multi-stimulated response polymers were designed and prepared,and their physical and chemical properties were studied in detail,self-assembly form and application.The content of this paper is as follows:(1)Synthesis of core-shell interchangeable polymer and its size and number-tunable self-assemblyMulti-responsive smart materials have been attracting great interest within the scientific community for many years.Here we report a novel triple-stimuli-responsive block polymer sensitive to pH,temperature and light.The AB2C type polymer PDEAEMA-PNIPAAm2-PMAA formed with the host polymer?-CD-PNIPAAm-PDEAEMA and the guest polymer Azo-PNIPAAm-PMAA through host-guest interaction.Both host and guest parts are synthesized by atom transfer radical polymerization(ATRP)of NIPAAm,DEAEMA and MAA.By changing the conditions of the self-assembly environment,three distinct types of micelles with a core-shell structure can be obtained.Furthermore,the self-assembly the size of the micelles and of the core-shell structure when physico-chemical cues are applied to the system.Like the king of monkey in china,the AB2C polymer can change between the whole multi-responsive polymer(PDEAEMA-PNIPAAm2-PMAA)and two different small responsive polymers(?-CD-PNIPAAm-PDEAEMA and Azo-PNIPAAm-PMAA)by different light irradiation.The two different small responsive polymers can form four small different core-shell structure micelles in different pH and temperature.So it's possible to control the structure,size and number of the micelles by changing the conditions of the environment.(2)Synthesis and characterization of the multi-responsive material PCL-hv-PNIPAAm@PCL-PMAAA novel type of stimuli-responsive support material was formed by synthesized by Poly(caprolactone)-Poly(methacrylic acid)(PCL-PMAA)and Poly(caprolactone)-hv-poly(N-Isopropyl acrylamide)(PCL-hv-PNIPAAm).PCL-PMAA obtained from PCL-PtBMA which synthesized by atom transfer radical polymerization(ATRP)and ring opening polymerization(ROP)of tert-butyl methacrylate(tBMA)and?-Caprolactone(CL)by simple hydrolysis with trifluoroacetic acid.?-cyclodextrin(?-CD)and azobenzene(Azo)were employed as the starting groups,respectively,to synthesize ?-CD-PNIPAAm and Azo-PCL.Then the PCL-hv-PNIPAAm was obtained by host-guest interaction between ?-CD-PNIPAAm(host polymer)and Azo-PCL(guest polymer).Both PCL-PMAA and PCL-hv-PNIPAAm formed the microspheres by self-assembly.The morphology of the self-assembled structures was confirmed by NMR,TEM,GPC,DLS and so on.(3)The study of immobilized enzyme on the multi-responsive material PCL-hv-PNIPAAm@PCL-PMAAThe multi-responsive material PCL-hv-PNIPAAm@PCL-PMAA can form microspheres in aqueous solution.These microspheres were,then,used for the immobilization of pectinase by electrostatic interaction.The optimal immobilization reaction parameters were 10 U/mL for pectinaseat 25 ? for 4 h at pH 6.Compared with free pectinase,the immobilized enzyme was found to exhibit better tolerance to variations in pH and temperature,as well as improved storage stabilities.Furthermore,the relative activity of the immobilized pectinase was controlled at about 13%when the temperature was above LCST of PNIPAAm.The relative activity of the enzyme was further controlled by different light irradiation.There is about 15%influence on the relative activity of immobilized pectinase.This new material for enzyme support display good environmental adaptability was able to precisely tune and tailor the activity of an immobilized enzyme.This paves the way to its application as a biocatalyst,for example,in food industries.