Construction And Properties Of Liposome-Coated Stimulus-Responsive Nanogels

Liposomes,as an effective drug delivery system,have attracted much attention in the treatment of cancer.However,the optimal structure design of liposomes to inhibit premature release of anticancer drugs during blood circulation and improve drug release rate inside tumor cells is still a dilemma for liposomes applied to antitumor drug delivery.Based on the above problems,two kinds of lipogels drug delivery systerms were synthesized and evaluate their effect in the treatment of tumor in this paper.The main contents and conclusions were described as follows:(1)We developed a liposomes-templated in situ polymerization process to prepare liposomes-camouflaged redox-responsive nanogels platform(denoted ‘R-lipogels’)for intracellular doxorubicin delivery.The obtained R-lipogels were characterized for their size,morphology and structure,loading and release profiles,stability,cellular uptake and in vitro cytotoxicity.The results indicated that drug-loaded R-lipogels with controlled size and high stability not only can achieve a very high DOX-loading capacity(12.9%)and encapsulation efficiency(97.3%)by ammonium sulfate gradient method and very low premature leakage at physiological condition,but also can quickly release DOX in the reducing microenvironment of tumor cells,resulting in effective growth inhibition of tumor cells.In a sum,the strategy provided here provides a facile approach to develop liposomes-nanogels hybrid system with combined beneficial features of stealthy liposomes and responsive nanogels,achieving high stability,high drug loading and controlled release,which potentially resolved the dilemma between systemic stability and intracellular rapid drug release and thus offered a promising nanomedicine platform for cancer therapy.(2)Based on the first part of the study,we constructed a pH and redox dual sensitive lipogels by the templated in situ polymerization process.The lipogels containing the pH sensitive liposome shell and redox sensitive nanogel core.The results of in vitro drug release studies showed that pH and redox dual sensitive lipogels could respond quickly to environmental stimuli.In vitro cell experiments revealed that DOX was able to completely release the drug through disulfide cleavage and enlargement of the liposome membrane pores at high GSH concentrations and at low pH in the cell and killed tumor cells efficiently.These results indicated that lipogels system have a great potential in drug delivery and lays a foundation for the study of nanocarrier.