Self-assembled supramolecular nano vesicles for safe and highly efficient gene delivery to solid tumors.

The main obstacles for cationic polyplexes in gene delivery are in vivo instability and low solid-tumor accumulation. Safe vectors with high transfection efficiency and in vivo tumor accumulation are therefore highly desirable. In this study, the amphiphilic block copolymer poly(n-butyl methacrylate)-b-poly(N-acryloylmorpholine) was synthesized by reversible addition-fragmentation chain-transfer (RAFT) radical polymerization. The corresponding well-defined vesicles with narrow size distribution were tailored by finely regulating the packing parameter (ß) of copolymer (1/2 < ß < 1). Compared with traditional "gold-standard" polycation (polyethylenimine, 25 kDa), plasmid DNA condensing efficiency, DNase I degradation protection, and cellular uptake were improved by the supramolecular nano vesicles. In addition, the plasmid DNA transferring efficiency in 10% fetal bovine serum medium was enlarged five times to that of polyethylenimine in renal tubular epithelial and human hepatocellular carcinoma cell lines. This improved in vitro transfection was mainly attributed to the densely packed bilayer. This stealth polyplex showed high serum stability via entropic repulsion, which further protected the polyplex from being destroyed during sterilization. As indicated by the IVIS(®) Lumina II Imaging System (Caliper Life Sciences, Hopkinton, MA) 24 hours post-intravenous administration, intra-tumor accumulation of the stealth polyplex was clearly promoted. This study successfully circumvented the traditional dilemma of efficient gene transfection at a high nitrogen-from-polyethylenimine to phosphate-from-DNA ratio that is accompanied with site cytotoxicity and low stability. As such, these simply tailored noncytotoxic nano vesicles show significant potential for use in practical gene therapy.

Chemotherapy for gastric cancer by finely tailoring anti-Her2 anchored dual targeting immunomicelles.

Micelles with high in vivo serum stability and intratumor accumulation post intravenous (i.v.) injection are highly desired for promoting chemotherapy. Herein, we finely synthesized and tailored well-defined anti-Her2 antibody Fab fragment conjugated immunomicelles (FCIMs), which showed interesting dual targeting function. The thermosensitive poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide)(118) (PID(118)) shell with volume phase transition temperature (VPTT: 39 °C) and the anchored anti-Her2 Fab moiety contributed to the passive and active targeting, respectively. The doxorubicin (DOX) loading capacity of such FCIMs was successfully increased about 2 times by physically enhanced hydrophobicity of inner reservoir without structural deformation. The cellular uptake and intracellular accumulation of DOX by temperature regulated passive and antibody navigated active targeting was 4 times of Doxil. The cytotoxicity assay against Her2 overexpression gastric cancer cells (N87s) showed that the IC50 of the FCIMs was ≈ 9 times lower than that of Doxil under cooperatively targeting by Fab at T > VPTT. FCIMs showed high serum stability by increasing the corona PID(118) chain density (S(corona)/N(agg)). In vivo tissue distribution was evaluated in Balb/c nude mice bearing gastric cancer. As observed by the IVIS(®) imaging system, the intratumor accumulation of such finely tailored FCIMs system was obviously promoted 24 h post i.v. administration. Due to the high stability and super-targeting, the in vivo xenografted gastric tumor growth was significantly inhibited with relative tumor volume <2 which was much smaller than ≈ 5 of the control. Consequently, such finely tailored FCIMs with anti-Her2 active and temperature regulated passive dual tumor-targeting function show high potent in chemotherapy.