Preparation And Properties Of MPEG-b-PCL/PNVCL-b-PCL Mixed Micelles

Nano-micelles are a class of nanostructures that are self-assembled by amphiphilic block polymers.Nano-micelles are a class of nanocarriers with good application prospects.In this study,two micelles containing polyethylene glycol monomethyl ether MPEG were synthesized to study their properties in encapsulation and delivery of doxorubicin(DOX)and cytotoxicity.MPEG can effectively prevent the phagocytic immune system,in the micellar surface to make it functional,can protect the carrier from biological media in the immune attack and extend the cycle time in the system,enhance the dispersion,and increase the drug to reach the affected area probability.Thermo-sensitive materials can occur in the phase transition process,in the extended state,the drug can be encapsulated and released,when the collapse can be formed after the formation of core-shell composite micelles,to strengthen the stability,and slowly release of drugs.The composite micelles prepared in this paper are responsive to temperature,and the release rate can be regulated by the ratio of MPEG to PNVCL,and the biocompatibility is good and easy to enter into the cell.It is a carrier with good application prospect.The specific research is as follows:1.MPEG-b-PCL block polymer,was prepared by ring-opening polymerization of caprolactone(ε-Cl)with terminated hydroxyl groups of polyethylene glycol monomethyl ether(MPEG)as the catalyst and Sn(Oct)2)as catalyst.The polymer micelles(SM)with PCL as core and MPEG as shells were prepared,and the properties of micelles on the loading and release of drugs were studied.The results showed that the release rate at pH = 5.0 was faster than that at pH = 7.4 at 37 ℃.MTT experiments show that the micellar toxicity is small,endocytosis experiments show that micelles easily into the cell.2.In the presence of AIBN,PNVCL-OH was synthesized by free radical polymerization of NVCL with mercaptoethanol(HSCH 2 CH 2 OH)as chain transfer agent.The PNVCL-b-PCL block polymer was synthesized by ring-opening polymerization of caprolactone(ε-Cl)catalyzed by Sn(Oct)2.The(MSM)with PCL as the core and MPEG and PNVCL as the mixed shells were prepared.And the micelles were characterized and the effects of temperature sensitivity and drug loading and drug release under different conditions were studied.The results show that at pH = 7.4,the release rate of micelles at 25 ℃ is faster than that at 37 ℃,and the ratio of MPEG / PNVCL is changed,and the effect of control rate can be achieved.MTT experiments show that the complex micelles are less toxic.Endocytosis experiments show that it can easily enter the cells.3.Under the same conditions,the mixed micelles are slower than the traditional micelles,indicating that the mixed micelles have a good sustained release effect.