New star-shaped carriers composed of β-cyclodextrin cores and disulfide-linked poly(glycidyl methacrylate) derivative arms with plentiful flanking secondary amine and hydroxyl groups for highly efficient gene delivery

Series of new β-cyclodextrin-cored starlike carriers for gene delivery

The development of safe and effective β-cyclodextrin (β-CD)-cored cationic star gene carriers has attracted considerable attention. In this work, a series of star-shaped hemocompatible CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors composed of β-CD cores and piperazine (PP)-, N-(aminoethyl)piperazine (AEPP)-, or N-(3-aminopropyl)-2-pyrrolidinone (APP)-functionalized poly(glycidyl methacrylate) arms were successfully proposed and compared for highly efficient gene delivery. Such star carriers possess plentiful secondary amine, tertiary amine, and nonionic hydroxyl groups. CD-PGPP, CD-PGAEPP, and CD-PGAPP were effective in condensing plasmid DNA into nanoparticles, whose sizes were 100-200 nm and positive ζ potentials were 25-40 mV at nitrogen/phosphate (N/P) ratios of 10 and above. CD-PGPP, CD-PGAEPP, and CD-PGAPP showed significantly lower cytotoxicity than control poly(ethylenimine) (PEI; ∼25 kDa). At most N/P ratios, CD-PGAPP exhibited better gene transfection performance than CD-PGPP and CD-PGAEPP particularly in HepG2 cells. More importantly, in comparison with PEI, all of the CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors did not cause undesirable hemolysis.

Star-shaped cyclodextrin-poly(l-lysine) derivative co-delivering docetaxel and MMP-9 siRNA plasmid in cancer therapy

A new cyclodextrin derivative (CD-PLLD) consisting of a β-cyclodextrin core and poly(l-lysine) dendron arms was prepared by the click conjugation of per-6-azido-b-cyclodextrin with propargyl focal point poly(l-lysine) dendron of third generation, and then used for docetaxel (DOC) and the best siRNA plasmid targeting MMP-9 (pMR3) co-delivery. Different from commonly used amphiphilic copolymers with cationic character, the as obtained cyclodextrin derivative may be used directly for the combinatorial delivery of nucleic acid and lipophilic anticancer drugs without a complicated micellization process. It was found that CD-PLLD/pMR3 nanocomplex showed a good gene transfection efficiency in vitro, and could mediate the reduce of MMP-9 protein in HNE-1 cells. For co-delivery analysis, the obtained CD-PLLD/DOC/pMR3 complexes could induce a more significant apoptosis than DOC or pMR3 used only, and decreased invasive capacity of HNE-1 cells. Moreover, the star-shaped copolymer exhibited better blood compatibility and lower cytotoxicity compared to PEI-25k in the hemolysis and MTT assays, which should be encouraged in nasopharyngeal cancer therapy.

Bioreducible POSS-cored star-shaped polycation for efficient gene delivery

The bioreducible star-shaped gene vector (POSS-(SS-PDMAEMA)8) with well-defined structure and relatively narrow molecular weight distribution was synthesized via atom transfer radical polymerization (ATRP) of (2-dimethylamino)ethyl methacrylate (DMAEMA) from a polyhedral oligomeric silsesquioxane (POSS) macroinitiator. POSS-(SS-PDMAEMA)8 was composed of a biocompatible POSS core and eight disulfide-linked PDMAEMA arms, wherein the PDMAEMA chain length could be adjusted by controlling polymerization time. POSS-(SS-PDMAEMA)8 can effectively bind pDNA into uniform nanocomplexes with appropriate particle size and zeta potential. The incorporation of disulfide bridges gave the POSS-(SS-PDMAEMA)8 material facile bioreducibility. In comparison with POSS-(PDMAEMA)8 without disulfide linkage, POSS-(SS-PDMAEMA)8 exhibited much lower cytotoxicity and substantially higher transfection efficiency. The present work would provide useful information for the design of new POSS-based drug/gene carriers.

A well-defined coil–comb polycationic brush with “star polymers” as side chains for gene delivery

The well-defined polycationic brush with super-high grafting density of PDMAEMA showed higher transfection capability than the single star polymer and PEI25K.