Résumé
Small interfering RNA (siRNA) has a promising future in the treatment of ocular diseases due to its high efficiency, specificity, and low toxicity in inhibiting the expression of target genes and proteins. However, due to the unique anatomical structure of the eye and various barriers, delivering nucleic acids to the retina remains a significant challenge. In this study, we rationally design PACD, an A-B-C type non-viral vector copolymer composed of a hydrophilic PEG block (A), a siRNA binding block (B) and a pH-responsive block (C). PACDs can self-assemble into nanosized polymeric micelles that compact siRNAs into polyplexes through simple mixing. By evaluating its pH-responsive activity, gene silencing efficiency in retinal cells, intraocular distribution, and anti-angiogenesis therapy in a mouse model of hypoxia-induced angiogenesis, we demonstrate the efficiency and safety of PACD in delivering siRNA in the retina. We are surprised to discover that, the PACD/siRNA polyplexes exhibit remarkable intracellular endosomal escape efficiency, excellent gene silencing, and inhibit retinal angiogenesis. Our study provides design guidance for developing efficient nonviral ocular nucleic acid delivery systems.
Résumé
OBJECTIVE: To prepare amphiphilic polycaprolactone-poly (arginine polymer) (PCL-R15)/siRNA Nanopexes, and two kinds of nanoparticles with different particle size were prepared by different process. After encapsulated siRNA with electrostatic interaction, both of two nanoplexes (NR60/siRNA and NR160/siRNA) were used to compare the effects in vitro cell levels. METHODS: The particle size and Zeta potential, siRNA loading and protection ability, cytotoxicity, cellular uptake mechanism and gene silencing efficiency of the two nanoplexes were investigated. RESULTS: The results show that the two nanoplexes have similar siRNA protection ability and cytotoxicity, but the difference between the two sizes is about 100 nm and the potential difference is about 20 mV. Moreover, NR160/siRNA complexes have higher cell uptake efficiency, more complex uptake pathways, and show greater gene silencing efficiency. CONCLUSION: These nanoplexes with different particle sizes can cause different transfection efficiency for siRNA delivery in cells.
Résumé
Rhodamine B (RhB) was used to decorate an amphipathic block polymers (β-CD-[P(AA-co-MMA)-b-PVP]4) in this study. First, after activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, rhodamine B was marked with hydroxyethyl methacrylate (HEMA) through ester exchange reaction. Second, the labeled amphipathic block polymers (β-CD-[P(AA-(HEMA-RhB)-MMA)-b-PVP]4) were synthesized after polymerization reaction of double bones between RhB-HEMA and other reactants. Finally, the structure of product was measured by FT-IR spectra and fluorospectro photometer (FLUORO). The critical micelle concentration of RhB-labeled and unlabeled amphipathic block polymers were 4.96×10-3, 5.09×10-3 mg·L-1, respectively, indicating no change of their micellization behavior. In vivo tissue distribution and whole-body fluorescent imaging were studied by vinpocetine (VP)-loaded polymeric micelles which were prepared through a solvent evaporation method. Compared to the result of in vivo tissue distribution and whole-body fluorescence imaging, a similar bio-distribution behavior of VP-loaded polymeric micelles was found. Those proved the successful fluorescence modification with a labeling yield of 4.13%. With in vivo fluorescence imaging technology, we established a fluorescence method for modification of amphipathic block polymers.
Résumé
Objectives: To investigate the effects of adhesion and proliferation of bone mesenchymal stem cells (BMSCs) in the surface of lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol PLGA-[ASP-PEG] tri-block polymer scaffolds, try to find a new biomaterial to induce seed cells in vitro for bone tissue engineering. Methods: Modified PLGA with polyethylene glycol (PEG) and asparagic acid (ASP) that has many ligands, and synthesis PLGA-[ASP-PEG] polymer material. BMSCs were cultured in PLGA-[ASP-PEG] polymer material and PLGA used as control group. Through precipitation method, MTT assay and total cellular protein detection to test the adhersion and proliferation of BMSCs. Scanning electron microscope is used to observe cells appearance. Results: BMSCs on the surface of PLGA-[ASP-PEG] polymer scaffolds are adherention to the culture flask, the number of cells is much higher than PLGA’s. The precipitation method suggest that adhesion and proliferation of BMSCs on the surface of PLGA-[ASP-PEG] is much higher than the control group(P