RESUMO
A novel type of cellular-uptake-shielding multifunctional envelope-type mesoporous silica nanoparticle (MEMSN) was designed for tumor-triggered targeting drug delivery to cancerous cells. ß-Cyclodextrin (ß-CD) was anchored on the surface of mesoporous silica nanoparticles via disulfide linking for glutathione-induced intracellular drug release. Then a peptide sequence containing Arg-Gly-Asp (RGD) motif and matrix metalloproteinase (MMP) substrate peptide Pro-Leu-Gly-Val-Arg (PLGVR) was introduced onto the surface of the nanoparticles via host-guest interaction. To protect the targeting ligand and prevent the nanoparticles from being uptaken by normal cells, the nanoparticles were further decorated with poly(aspartic acid) (PASP) to obtain MEMSN. In vitro study demonstrated that MEMSN was shielded against normal cells. After reaching the tumor cells, the targeting property could be switched on by removing the PASP protection layer via hydrolyzation of PLGVR at the MMP-rich tumor cells, which enabled the easy uptake of drug-loaded nanoparticles by tumor cells and subsequent glutathione-induced drug release intracellularly.
Assuntos
Portadores de Fármacos/química , Nanopartículas/química , Neoplasias/tratamento farmacológico , Dióxido de Silício/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacologia , Portadores de Fármacos/síntese química , Humanos , Microscopia Eletrônica de Transmissão , PorosidadeRESUMO
Amphiphilic triblock copolymers monomethoxyl poly(ethylene glycol) (mPEG)-b-poly(ε-caprolactone) (PCL)-b-poly(aminoethyl methacrylate)s (PAMAs) (mPECAs) were synthesized as gene delivery vectors. They exhibited lower cytotoxicity and higher transfection efficiency in COS-7 cells in presence of serum compared to 25 kDa bPEI. The influence of mPEG and PCL segments in mPECAs was evaluated by comparing with corresponding diblock copolymers. The studies showed the incorporation of the hydrophobic PCL segment in triblock copolymers affected the binding capability to pDNA and surface charges of complexes due to the formation of micelles increasing the local charges. The presence of mPEG segment in gene vector decreased the surface charges of the complexes and increased the stability of the complexes in serum because of the steric hindrance effect. It was also found that the combination of PEG and PCL segments into one macromolecule might lead to synergistic effect for better transfection efficiency in serum.
Assuntos
Técnicas de Transferência de Genes , Vetores Genéticos , Polímeros/química , Polímeros/síntese química , Animais , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Células COS , Chlorocebus aethiops , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/toxicidade , Etilaminas/química , Etilenoglicóis/química , Espectroscopia de Ressonância Magnética , Teste de Materiais , Metacrilatos/química , Micelas , Tamanho da Partícula , Poliésteres/química , Polietilenoglicóis/química , Polímeros/toxicidade , TransfecçãoRESUMO
In this study poly(aminoethyl methacrylate) (PAEMA), poly(3-amino-2-hydroxypropyl methacrylate) (PAHPMA), poly(2-(2-aminoethylamino)ethyl methacrylate) (PAEAEMA) and poly(3-(2-aminoethylamino) 2-hydroxypropyl methacrylate) (PAEAHPMA) were synthesized using atom transfer radical polymerization to evaluate the effect of hydroxyl groups on the relative properties of cationic polymeric gene vectors. The results of heparin displacement assays showed that PAHPMA possessed a stronger binding capacity than PAEMA. PAHPMA/DNA complexes and PAEAHPMA/DNA complexes had lower zeta potentials than those of PAEMA and PAEAEMA. MTT assay results indicated that PAHPMA and PAEAHPMA exhibited obviously lower cytotoxicities than PAEMA and PAEAEMA. Subsequently, in vitro gene transfection studies in 293T cells without serum showed that PAHPMA exhibited a lower transfection efficiency than PAEMA and PAEAHPMA/DNA complexes possessed a similar transfection efficiency to PAEAEMA/DNA complexes. Moreover, PAHPMA and PAEAHPMA retained similar transfection efficiencies in DMEM with 10% serum, but PAEMA and PAEAEMA showed slightly lower transfection efficiencies than in the absence of serum. The reason for these phenomena might be attributed to the introduction of hydroxyl groups into PAHPMA and PAEAHPMA, i.e. the existence of hydroxyl groups might increase the binding capacity to DNA and at the same time decrease the surface charge of the polymer/DNA complexes due to the formation of hydrogen bonds between the polymers and DNA. Therefore, a lower zeta potential and stronger binding ability may result in a lower gene transfection efficiency. This effect of hydroxyl groups decreased with increasing amino group density on the polymer.