Article

Enhancing in vivo circulation and siRNA delivery with biodegradable polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol) copolymers

Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Marburg, Germany.
Biomaterials (Impact Factor: 8.31). 06/2012; 33(27):6551-8. DOI: 10.1016/j.biomaterials.2012.05.055
Source: PubMed

ABSTRACT The purpose of this study was to enhance the in vivo blood circulation time and siRNA delivery efficiency of biodegradable copolymers polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol) (hy-PEI-g-PCL-b-PEG) by introducing high graft densities of PCL-PEG chains. SYBR(®) Gold and heparin assays indicated improved stability of siRNA/copolymer-complexes with a graft density of 5. At N/P 1, only 40% siRNA condensation was achieved with non-grafted polymer, but 95% siRNA was condensed with copolymer PEI25k-(PCL570-PEG5k)(5). Intracellular uptake studies with confocal laser scanning microscopy and flow cytometry showed that the cellular uptake was increased with graft density, and copolymer PEI25k-(PCL570-PEG5k)(5) was able to deliver siRNA much more efficiently into the cytosol than into the nucleus. The in vitro knockdown effect of siRNA/hyPEI-g-PCL-b-PEG was also significantly improved with increasing graft density, and the most potent copolymer PEI25k-(PCL570-PEG5k)(5) knocked down 84.43% of the GAPDH expression. Complexes of both the copolymers with graft density 3 and 5 circulated much longer than unmodified PEI25 kDa and free siRNA, leading to a longer elimination half-life, a slower clearance and a three- or fourfold increase of the AUC compared to free siRNA, respectively. We demonstrated that the graft density of the amphiphilic chains can enhance the siRNA delivery efficiency and blood circulation, which highlights the development of safe and efficient non-viral polymeric siRNA nanocarriers that are especially stable and provide longer circulation in vivo.

0 Followers
 · 
110 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nucleic acid carriers need to possess multifunctionality for overcoming biological barriers, such as the stable encapsulation of nucleic acids in extracellular milieu, internalization by target cells, controlled intracellular distribution, and release of nucleic acids at the target site of action. To fulfill these stepwise functionalities, "bioresponsive" polymers that can alter their structure responding to site-specific biological signals are highly useful. Notably, pH, redox potential, and enzymatic activities vary along with microenvironments in the body, and thus, the responsiveness to these signals enables to construct nucleic acid carriers with programmed functionalities. This chapter describes the design of bioresponsive polymers that respond to various biological microenvironments for smart nucleic acids delivery.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We have synthesized poly(ε-caprolactone-co-tert-butyl glycidyl ether) (CL-co-BGE) statistical copolymers using 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis [tris(dimethylamino)phophoranylidenamino]-2Λ5,4Λ5-catenadi(phosphazene) (t-BuP4) as the catalyst. The hydrolysis of the resulting polymers yields amphiphilic poly(ε-caprolactone-co-glycidol) (CL-co-GD) copolymers. By use of the quartz crystal microbalance with dissipation (QCM-D), we have investigated the enzymatic degradation of the copolymers. It is shown that the degradation rate increases with the content of hydrophilic (GD) units. (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) (MTT) assay experiments demonstrate that the CL-co-GD copolymers have low cytotoxicity.
    Journal of Polymer Science Part A Polymer Chemistry 01/2015; 53(7):846-853. DOI:10.1002/pola.27515 · 3.54 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Novel light-responsive nanoparticles based on an amphiphile with a single photolabile linker between its hydrophilic head and hydrophobic tail was developed for small interfering RNA (siRNA) delivery. Upon UV exposure, cleavage of the linkage resulted in rapid shell detachment of the nanoparticles, which facilitated siRNA release and enhanced gene silencing efficiency.
    RSC Advances 01/2014; 4(4):1961. DOI:10.1039/c3ra44866e · 3.71 Impact Factor