Construction of pH/reduction dual responsive MSN-HAgel containing HApt for tumor targeting carriers.

In this study, a pH/reduction dual responsive carrier containing 42nt-nucleic acid HApt based on mesoporous silica nanoparticles (MSNs) was designed. Two kinds of low molecular weight oligomeric hyaluronic acid (HA) were used to graft onto MSN for better drug encapsulation. Crosslinked MSN-HAgel and MSN-HAgel were prepared by crosslinking the HA chain through the sulfhydrylization of the carboxyl group on the HA side chain. An appropriate amount of sulfhydryl nucleic acid (HApt-SH) was added during the crosslinking reaction, which realized the targeting ability and apoptosis function to cancer cells overexpressing the HER2 receptor. Crosslinked HA had a good effect on decreasing the side effect of DOX that the drug leakage was less than 20% under a normal body environment. However, it could realize rapid and efficient drug release in a tumor environment. As to the release of HApt, it exhibited a good response to GSH. The cytotoxicity test showed that HApt contained in HAgel had a great targeting effect and significant cytotoxicity to SKBR3 cells. As a whole, this MSN-HAgel enabled the combination of gene therapy and chemotherapy, showing the synergistic effect of "1 + 1 > 2", providing a novel idea for cancer treatments.