RESUMO
L-Leucine (Leu) is a hydrophobic natural amino acid and can polymerize into poly-L-Leucine (PLeu) to be an excellent biocompatible material. In this paper, a hyperbranched copolymer polyethyleneimine-g-poly-L-leucine (PEI-g-PLeu) was synthesized by ring-opening polymerization with leucine NCA as monomer and PEI as initiator, which will be used as drug and gene co-delivery system for cancer therapy. To characterize the transfection efficiency in vitro, pGL3 as the reporter gene was loaded in PEI-g-PLeu to form complexes. Doxorubicin (DOX) with cis-aconitic anhydride linker (CAD) and calf thymus DNA (as model DNA) were co-loaded in PEI-g-PLeu to obtain PEI-g-PLeu/DNA/CAD nanoparticles to measure Zeta potentials and particle sizes. Lastly, CAD and modified Bc12-shRNA(as therapeutic gene) were co-loaded in PEI-g-PLeu to get PEI-g-PLeu/CAD/DNA complexes. Our finding revealed when PEI and PLeu with the molar ratio of 1:240, and PEI-g-PLeu and DNA with the mass ratio of 1:5, PEI-g-PLeu/CAD/DNA had negligible cytotoxicity with equivalent gene transfaction efficiency compared with PEI25k. As a result, PEI-g-PLeu/CAD/DNA was a promising drug and gene co-delivery system.
Assuntos
Materiais Biocompatíveis/síntese química , Sistemas de Liberação de Medicamentos , Técnicas de Transferência de Genes , Peptídeos/química , Polietilenoimina/química , Polímeros/síntese química , Animais , Materiais Biocompatíveis/química , Células Cultivadas , DNA/administração & dosagem , DNA/farmacocinética , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacocinética , Liberação Controlada de Fármacos , Interações Hidrofóbicas e Hidrofílicas , Iminas/química , Teste de Materiais , Camundongos , Tamanho da Partícula , Polietilenoimina/síntese química , Polietilenos/química , Polímeros/química , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/farmacocinética , TransfecçãoRESUMO
In this study, a pH-responsive detachable polyethylene glycol (PEG) shielding strategy was designed for gene delivery in cancer therapy. Polyethylenimine/DNA complex (PEI/DNA) was in situ shielded by aldehyde group-modified PEG derivatives. The aldehyde groups of PEG could react with the amino groups of PEI by Schiff base reaction. The Schiff base bond was stable in neutral pH but labile in slightly acidic pH, which made the PEG sheddable in tumors. PEG-coated nanoparticles (NPs) had distinct advantages compared to their mPEG counterpart, possessing decreased zeta potential, more compressed size, and enhanced stability. PEG/PEI/DNA NPs showed not only high tumor cell uptake and transfection efficiency in vitro but also efficient accumulation and gene expression in solid tumors in vivo. This pH-responsive detachable PEG shielding system has the potential to be applied to other polycationic nanoparticles that contain amino groups on their surfaces, which will have broad prospects in cancer therapy.