Dual-Responsive Drug-Delivery System Based on PEG-Functionalized Pillararenes Containing Disulfide and Amido Bonds for Cancer Theranostics

The construction of a smart drug-delivery system based on amphiphilic pillararenes with multiple responsiveness properties has become an important way to improve the efficacy of tumor chemotherapy. Here, a new PEG-functionalized pillararene (EtP5-SS-PEG) containing disulfide and amido bonds was designed and synthesized, which has been used to construct a novel supramolecular nanocarrier through a host-guest interaction with a perylene diimide derivative (PDI-2NH4 ) and their supramolecular self-assembly. This nanocarrier showed good drug loading capability, and dual stimulus responsiveness to enzyme and GSH (glutathione). After loading of doxorubicin (DOX), the prepared nanodrugs displayed efficient DOX release and outstanding cancer theranostics ability.

Toward enzyme-responsive polymersome drug delivery

In drug delivery, enzyme-responsive drug carriers are becoming increasingly relevant because of the growing association of disease pathology with enzyme overexpression. Polymersomes are of interest to such applications because of their tunable properties. While polymersomes open up a wide range of chemical and physical properties to explore, they also present a challenge in developing generalized rules for the synthesis of novel systems. Motivated by this issue, in this perspective, we summarize the existing knowledge on enzyme-responsive polymersomes and outline the main design choices. Then, we propose heuristics to guide the design of novel systems. Finally, we discuss the potential of an integrated approach using computer simulations and experimental studies to streamline this design process and close the existing knowledge gaps.

Self-Assembly and Enzyme Responsiveness of Amphiphilic Linear-Dendritic Block Copolymers Based on Poly(N-vinylpyrrolidone) and Dendritic Phenylalanyl-lysine Dipeptides

In this study, we present the synthesis, self-assembly, and enzyme responsive nature of a unique class of well-defined amphiphilic linear-dendritic block copolymers (PNVP-b-dendr(Phe-Lys)n, n = 1-3) based on linear poly(N-vinylpyrrolidone) (PNVP) and dendritic phenylalanyl-lysine (Phe-Lys) dipeptides. The copolymers were prepared via a combination ofreversible addition-fragmentation chain transfer (RAFT) /xanthates (MADIX) polymerization of N-vinylpyrrolidone and stepwise peptide chemistry. The results of fluorescence spectroscopy, 1H NMR analyses, transmission electron microscopy (TEM), and particle size analysis demonstrated that the copolymers self-assemble in aqueous solution into micellar nanocontainers that can disassemble and release encapsulated anticancer drug doxorubicin or hydrophobic dye Nile red by trigger of a serine protease trypsin under physiological conditions. The disassembly of the formed micelles and release rates of the drug or dye can be adjusted by changing the generation of dendrons in PNVP-b-dendr(Phe-Lys)n. Furthermore, the cytocompatibility of the copolymers have been confirmed using human lung epithelial cells (BEAS-2B) and human liver cancer cells (SMMC-7721). Due to the fact of their enzyme responsive properties and good biocompatibility, the copolymers may have potential applicability in smart controlled release systems capable of site-specific response.