Self-assembled vehicle construction via boronic acid coupling and host-guest interaction for serum-tolerant DNA transport and pH-responsive drug delivery.

By exploiting boronic acid coupling and host-guest chemistry, a pH-responsive drug/gene co-delivery nanoplatform is designed for cancer treatments with the excellently serum-tolerant transfection activity and the capability to load and release hydrophobic drugs in an acidity-accelerated manner. Via boronate linkage, γ-CD is allowed to spontaneously attach onto phenylboronic-acid-modified oligoethylenimine (PEI1.8K-PB2.9 ) at neutral condition. The formed vehicle/DNA nanoformulation is thus surrounded densely by γ-CD moieties to biomimic the carbohydrate-rich cell surface, providing a novel approach to overcome serum-susceptible drawbacks frequently associated with synthetic gene carriers. PEI1.8K-PB2.9 -γ-CD conjugates demonstrate significantly improved cell-biocompatibility and transfection activity over PEI1.8K-PB2.9 . Noticeably, serum-associated inhibition effect is negligible for PEI1.8K-PB2.9 -γ-CD-mediated transfection whereas marked transfection reduction occurs for PEI25K and PEI1.8K-PB2.9 upon serum exposure. Consequently, PEI1.8K-PB2.9 -γ-CDs afford much higher transfection efficiency, that is, 25-fold higher luciferase expression over PEI25K in presence of 30% serum. An anticancer drug of doxorubicin (DOX) is shown to be readily accommodated into the nanoformulation via host-guest chemistry and intracellularly co-delivered together with plasmid DNA. Due to the acidity-labile feature of boronate linkage, DOX/γ-CD inclusion complexes would be mostly detached from the nanoformulation triggered by acidity, leading to faster drug release. Furthermore, drug inclusion does not alter the serum-compatible transfection efficiency of PEI1.8K-PB2.9 -γ-CD.