The Preliminary Study Of Chemical Modification Of Konjac Glucomannan And Its Application As Vaccine Vector

Konjac glucomannan(KGM), a kind of natural polymer polysaccharide, has good biocompatibility and biodegradability, and a good application prospect in the study of controlled release substrate. In this paper, the modified KGM were used to prepare two kinds of new nano material carriers by the ionic crosslinking method. In order to study the drug-loading ability and slow release property of the new nano material carriers, the representative antigen ovalbumin(OVA) was chosen as vaccine model. This work provides a theoretical basis for it as a vaccine vector in the future and the main research contents and results are as follows:(1) By hydrochloric acid catalytic degradation for two hours, the viscosity of KGM solution became the lowest and degradation product retained the basic structure of KGM. Then, the degradated KGM was modified with chloroacetic acid and 2,3- epoxypropyl trimethyl ammonium chloride, respectively. As a result, low molecular weight and well water-soluble carboxymethyl konjac glucomannan(CKGM) and quaternary ammonium konjac glucomannan(QKGM) were prepared and the degree of substitute(DS) was 1.08 and 0.14 respectively.(2) A new CKGM/QKGM complex nanoparticles were prepared by ionic gelation. In order to study the drug-loading ability and slow release property of the new nanomaterial carriers, the representative antigen ovalbumin(OVA) was chosen as vaccine model. The results indicated that nanoparticles were easy to prepare when the concentration of CKGM was between 0.5 mg/m L ~ 3.0 mg/m L, QKGM was between 1.0 mg/m L ~ 3.0 mg/mL. The best preparation process was as follows: CKGM concentration was 1.5mg/mL, QKGM concentration was 1.5mg/m L, OVA concentration was 2.5mg/m L, the pH value of OVA solution was 8.15, and the maximum encapsulation efficiency was 49.2%. Under optimal condition, CKGM/QKGM and CKGM/QKGM/OVA nano-carrier are all spherical and have a wide size distribution. The mean size of nanoparticles was 572.3nm and 717.1nm, respectively. The whole in vitro release process includes three phases: burst release, slow release, equilibrium release, and the preparation process has a great effect on the in vitro release properties. By reducing the concentration of CKGM or OVA, increasing the QKGM concentration or the pH value of OVA solution can effectively reduce the cumulative release rate of OVA; otherwise, the cumulative release rate of OVA can be increased.(3) QKGM and sodium tripolyphosphate(TPP) were used to form a new TPP/QKGM complex nanoparticles by electrostatic interaction. The preparation technology was optimized by using single-factor and orthogonal experiments by using ovalbumin(OVA) as the model vaccine. Moreover, the effect of preparation parameters on release properties in vitro were discussed. The results indicated that the concentration of QKGM had a great influence on the formation of nanoparticles. TPP/QKGM nano-carrier material was easy to prepare when the concentration of QKGM was between 0.5mg/m L ~ 3.0mg/m L, TPP was between 0.5mg/m L ~ 5.0mg/m L. The best fabrication process was as follows: TPP concentration is 0.5mg/mL, QKGM concentration is 1.0mg/mL, OVA concentration is 2.0mg/mL, pH value of OVA solution is 6.15 and the maximum encapsulation efficiency is 67.7%. Under optimal condition, TPP/QKGM and TPP/QKGM/OVA nano-carrier are all spherical and have a wider size distribution. The mean size of nanoparticles was 439.5nm and 706.5nm, respectively. The whole in vitro release process includes three phases: burst release, slow release, equilibrium release. And with respect to the OVA concentration and pH value, TPP and QKGM concentration have great influence on the in vitro release properties.