Preparation And Property Study Of Nano-hydrogels With Good Biocompatibility

Nano-hydrogels are typically defined as nano-particles have physically or chemically crosslinked three-dimensional polymer network.As materials with high resemblance with biological soft tissues,and the nanogels had perfect biocompatibility.pH-sensitive nanogels were prepared by in situ cross-linking.There were many advantages,including cheap materials,simple synthesis method,that are widely used in the biomedical area such as drug delivery.(1)Firstly,we optimized the experimental route,and prepared oxidized alginate(OSA)with satisfactory water solubility.The optimal experimental condition was determined by changing different molar ratios of reactants and analyzing the products through UV spectrum.Whereafter,the resulting OSA was characterized by IR,Raman,~1H-NMR and XRD.The results show that the OSA under optimal reaction condition has highest oxidized degree.Besides,the double carboxyl groups were oxidized to double aldehyde groups which can replace glutaral or glyoxal as the cross linker in the in-situ crosslinking for the preparation of nanogels.(2)The experimental route of hydroxypropylation of chitosan was optimized.We prepared hydroxypropyl chitosan(HPCS)with superb water solubility successfully while saving time and raw materials.We determined the optimal conditions for hydroxypropylation of chitosan through single factor experiment.Therewith,IR,Raman,~1H-NMR,XRD were used to analyze the products,which shows the HPCS prepared under the optimal condition has higher grafting yield.(3)Without any crosslinker,emulsifier and surfactant,we successfully prepared pH-sensitive nanogels through in-situ crosslinking reaction.By exploring the influence of nanoparticle size,the nanogels with homogeneous size and favorable dispersity were produced.We analyzed the final products with IR,TEM,AFM,XRD,Zeta-potential,size distribution,rheological property and turbidimeter,etc.The results show that under optimal condition,the nanogels has a relatively narrow distribution of particle size at around 48 nm.Meanwhile,there is pH-sensitivity during pH 4-6,which may provide a helpful foundation of drug loading and vivo release for the next research.This synthetic route has amount of benefits,such as easy to synthesis,environmentally friendly,lower cost,toilless to industrialization.Thus,it is a technique with broad prospects.The innovations in this paper:Without any crosslinker,emulsifier and surfactant,HPCS and OSA reacted to nano-hydrogels through in-situ crosslinking method.Favorable dispersity,narrow size distribution and pH-sensitivity which between pH=4-6 are the advantages of our nanogels.