RESUMEN
Multicomponent interpenetrating polymer network (mIPN) hydrogels are promising tissue-engineering scaffolds that could closely resemble key characteristics of native tissues. The mechanical and biochemical properties of mIPNs can be finely controlled to mimic key features of target cellular microenvironments, regulating cell-matrix interactions. In this work, we fabricated hydrogels made of collagen type I (Col I), fibrin, hyaluronic acid (HA), and poly (ethylene glycol) diacrylate (PEGDA) using a network-by-network fabrication approach. With these mIPNs, we aimed to develop a biomaterial platform that supports the in vitro culture of human astrocytes and potentially serves to assess the effects of the abnormal deposition of fibrin in cortex tissue and simulate key aspects in the progression of neuroinflammation typically found in human pathologies such as Alzheimer's disease (AD), Parkinson's disease (PD), and tissue trauma. Our resulting hydrogels closely resembled the complex modulus of AD human brain cortex tissue (~7.35 kPa), promoting cell spreading while allowing for the modulation of fibrin and hyaluronic acid levels. The individual networks and their microarchitecture were evaluated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Human astrocytes were encapsulated in mIPNs, and negligible cytotoxicity was observed 24 h after the cell encapsulation.
RESUMEN
Objetivos. Evaluar y comparar las propiedades antioxidantes mediante ensayos in vitro de extractos acuosos de las algas roja Bryothamnion triquetrum y verde Halimeda opuntia y su relación con el contenido de polifenoles. Material y Métodos. Se utilizaron las técnicas in vitro: DPPH, Capacidad reductora, Inhibición de la peroxidación lipídica e inhibición de la hemólisis inducida por AAPH. Resultados. B. triquetrum: DPPH; CI50=1,15 ± 0,06, capacidad reductora a concentración; 128 mg/mL, DO=2,798, inhibición de la peroxidación lipídica; CI50=5,09± 0,25 e inhibición de la hemólisis con 12 mg/ mL; 35 %. H. opuntia: DPPH; CI50=12,34 ± 0,30 mg/mL, capacidad reductora; DO=0,800, inhibición de la peroxidación lipídica; CI50=1,25± 0,31 mg/mL e inhibición de la hemólisis; 82%. Conclusiones. Los resultados evidencian que B triquetrum resulto mucho más eficiente en los ensayos de DPPH y Capacidad reductora mientras H opuntia resulta más eficiente en Inhibición de la peroxidación lipídica e inhibición de la hemólisis. Se discuten algunos aspectos acerca de sus posibles mecanismos de acción
Objective. To evaluate and compare the antioxidant activity displayed by seaweed H. opuntia and B. triquetrum using different experimental in vitro antioxidant assessment models. Material and Methods. The following techniques are utilized: DPPH, Reducing power, inhibition of lipid peroxidation and inhibition of haemolysis. Results. B. triquetrum: DPPH; IC =1.15 ± 0.06, Reducing power (concentration 128 mg/mL), OD=2.798, inhibition of lipid peroxidation; IC 50 =5.09± 0.25 and inhibition of haemolysis; with 12 mg/mL; 35 %. H. opuntia: DPPH; IC 50 50 =12.34 ± 0.30 mg/mL, reducing power; OD=0.800, inhibition of lipid peroxidation; IC 50 =1.25± 0.31 mg/mL, inhibition of lipid peroxidation; C =1.25± 0.31 mg/mL and inhibition of haemolysis; 82%. 50 Conclusion. It was demonstrated that B.triquetrum extract was more effective than H. opuntia in reducing power and DPPH assays while H.opuntia was more effective in inhibition of lipid peroxidation in rat brain homogenates and the inhibition of red blood cell (RBC) haemolysis induced by AAPH. We discuss some aspects about their possible mechanisms of action
Asunto(s)
Animales , Ratas , Algas Marinas/citología , Algas Marinas/enzimología , Técnicas In Vitro/instrumentación , Técnicas In Vitro/métodos , Polifenoles/administración & dosificación , Hemólisis/genética , Estado Nutricional/genética , Estado Nutricional/fisiología , Artemia/anatomía & histología , Artemia/metabolismo , Algas Marinas/metabolismo , Algas Marinas/fisiología , Técnicas In Vitro/normas , Técnicas In Vitro/veterinaria , Polifenoles/farmacología , Hemólisis/fisiología , Estado Nutricional/etnología , Estado Nutricional/inmunología , Artemia/clasificación , Artemia/crecimiento & desarrolloRESUMEN
In this paper we have modified an existing material model introduced by Cantournet and co-workers to take into account softening and residual strain effects observed in polymeric materials reinforced with carbon nanotubes when subjected to loading and unloading cycles. In order to assess the accuracy of the modified material model, we have compared theoretical predictions with uniaxial extension experimental data obtained from reinforced polymeric material samples. It is shown that the proposed model follows experimental data well as its maximum errors attained are lower than 2.67%, 3.66%, 7.11% and 6.20% for brominated isobutylene and paramethylstyrene copolymer reinforced with multiwall carbon nanotubes (BIMSM-MWCNT), reinforced natural rubber (NR-MWCNT), polybutadiene-carbon black (PB-CB), and PC/ABS reinforced with single-wall carbon nanotubes (SWCNT), respectively.