RESUMO
In a century when environmental pollution is a major issue, polymers issued from bio-based monomers have gained important interest, as they are expected to be environment-friendly, and biocompatible, with non-toxic degradation products. In parallel, hyperbranched polymers have emerged as an easily accessible alternative to dendrimers with numerous potential applications. Glycerol (Gly) is a natural, low-cost, trifunctional monomer, with a production expected to grow significantly, and thus an excellent candidate for the synthesis of hyperbranched polyesters for pharmaceutical and biomedical applications. In the present article, we review the synthesis, properties, and applications of glycerol polyesters of aliphatic dicarboxylic acids (from succinic to sebacic acids) as well as the copolymers of glycerol or hyperbranched polyglycerol with poly(lactic acid) and poly(ε-caprolactone). Emphasis was given to summarize the synthetic procedures (monomer molar ratio, used catalysts, temperatures, etc.,) and their effect on the molecular weight, solubility, and thermal and mechanical properties of the prepared hyperbranched polymers. Their applications in pharmaceutical technology as drug carries and in biomedical applications focusing on regenerative medicine are highlighted.
Assuntos
Materiais Biocompatíveis , Dendrímeros , Portadores de Fármacos , Glicerol , Poliésteres , Polímeros , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Dendrímeros/síntese química , Dendrímeros/química , Dendrímeros/uso terapêutico , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/uso terapêutico , Glicerol/síntese química , Glicerol/química , Glicerol/uso terapêutico , Humanos , Poliésteres/síntese química , Poliésteres/química , Poliésteres/uso terapêutico , Polímeros/síntese química , Polímeros/química , Polímeros/uso terapêutico , Medicina RegenerativaRESUMO
BACKGROUND: Aliphatic polyesters are widely used for biomedical, pharmaceutical and environmental applications due to their high biodegradability and cost-effective production. Recently, star and hyperbranched polyesters based on glycerol and ω-carboxy fatty diacids have gained considerable interest. Succinic acid and bio-based diacids similar to glycerol are regarded as safe materials according to the US Food and Drug Administration (FDA). Bioactive glass scaffolds utilized in bone tissue engineering are relatively brittle materials. However, their mechanical properties can be improved by using polymer coatings that can further control their degradation rate, tailor their biocompatibility and enhance their performance. The purpose of this study is to explore a new biopolyester poly(glycerol succinate) (PGSuc) reinforced with mesoporous bioactive nanoparticles (MSNs) as a novel coating material to produce hybrid scaffolds for bone tissue engineering. METHODS: Bioactive glass scaffolds were coated with neat PGSuc, PGSuc loaded with dexamethasone sodium phosphate (DexSP) and PGSuc loaded with DexSP-laden MSNs. The physicochemical, mechanical and biological properties of the scaffolds were also evaluated. RESULTS: Preliminary data are provided showing that polymer coatings with and without MSNs improved the physicochemical properties of the 1393 bioactive glass scaffolds and increased the ALP activity and alizarin red staining, suggesting osteogenic differentiation potential when cultured with adipose-derived mesenchymal stem cells. CONCLUSIONS: PGSuc with incorporated MSNs coated onto 1393 bioactive glass scaffolds could be promising candidates in bone tissue engineering applications.
RESUMO
The synthesis of four new analogues of marine nucleoside trachycladineâ A was accomplished by direct regio- and stereoselective Vorbrüggen glycosylations of 2,6-dichloropurine and 2-chloropurine with a d-ribose-derived chiron. Naturally occurring trachycladinesâ A and B and a series of analogues were examined for their cytotoxic activity against a number of cancer cell lines (glioblastoma, lung, and cervical cancer). Parent trachycladineâ A and two analogues (the diacetate of the 2,6-dichloropurine derivative and N-cyclopropyl trachycladineâ A) resulted in a significant decrease in cell viability, with the latter exhibiting a stronger effect. The same compounds enhanced the cytotoxic effect of docetaxel in lung cancer cell lines, whereas additional experiments revealed that their mode of action relies on mitotic catastrophe rather than DNA damage. Moreover, their activity as autophagic flux blockers was postulated.