Construction And Evaluation Of The Composite Carriers Based On Polyvinyl Alcohol Hydrogel

As a water-soluble polymeric material, polyvinyl alcohol (PVA) has received much attentionin recent years. Due to its three-dimensional network structure, good elasticity, low toxicity andhigh swelling ratio, PVA hydrogel is considered to be an excellent drug carrier and tissueengineering scaffold material in biomedical field. However, there are still many problems to beresolved on its biomedical applications, such as poor biocompatibility, uncontrollable drugbehavior and insufficient mechanical strength and so on. As a result, the modification of PVAhydrogel becomes an inevitable trend. Among all the modification methods, the introduction offunctional materials into PVA hydrogel to form a composite gel is one of the research hotspots,which has greatly expanded the biomedical application of PVA hydrogel.Hollow mesoporous silica nanoparticles (HMSNs) have currently emerged as excellent drugcarriers because of their uniform particle size, tunable porous size, facile surface functionalization,good biocompatibility，high drug loading efficacy and some other characteristics. Meanwhile, thenanoscale feature of the nanofibrous microparticles (NMPs) or microspheres prepared throughthermally induced phase separation (TIPS) technique greatly mimics the structural feature ofcollagen fibers, which is the main component of the extracellular matrix (ECM). Therefore, NMPsare considered as a promising biomimetic tissue engineering scaffold. In order to expand theapplication of PVA hydrogel, the functional material HMSNs (inorganic) or NMPs (organic) wasincorporated into PVA hydrogel respectively to build two different composite systems. The maincontents are as follows:(1) Preparation and biocompatibility of the HMSNs/PVA composite hydrogel.HMSNs were prepared by using cetyl trimethyl ammonium bromide (CTAB), polystyrene(PS) as dual template and TEOS (TEOS) as silica source. The model drug hydrochloric aciddoxorubicin (DOX) was then loaded into HMSNs to form DOX-loaded HMSNs complex (calledas DMSNs). PVA hydrogel was prepared using a "freezing-thawing" physical crosslinking method.Thus, a new organic/inorganic HMSNs/PVA composite hydrogel was constructed, and themicrostructure, swelling ratio and biocompatibility properties of the resulting composite hydrogelwere evaluated. The results showed that HMSNs/PVA has a high swelling ratio and good bloodcompatibility. Moreover, the DMSNs/PVA composite exhibited a sustained and pH-responsive DOX release in vitro. In addition, MTT and CLSM results showed that the released DOX fromDMSNs/PVA strongly inhibited the growth of HeLa cells.(2) Preparation and biocompatibility of the NMPs/PVA composite gel scaffold.Poly(L-lactic acid)(PLLA) NMPs were prepared through TIPS technique, and the preparedNMPs were subsequently to construct a new type of biomimetic scaffold NMPs/PVA. Themicrostructure, swelling ratio and biocompatibility of the composite gel was also carried out. Theresults showed that the surface of NMPs/PVA was covered with NMPs, and three-dimensionalnetwork structure contains many pores which are conducive to the cell ingrowth. Furthermore,L929cells were selected as a model cell line to evaluate the cytotoxicity of NMPs/PVA. MTTassay and CLSM results showed that NMPs/PVA has non-toxic side effects on L929cells, and theintroduction of NMPs into PVA hydrogel can obviously improve the biocompatibility ofNMPs/PVA composite gel scaffold.In summary, the prepared drug delivery carrier HMSNs/PVA and biomimetic scaffoldNMPs/PVA hold considerable promise for the further biomedical applications.