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In recent years, several studies have validated the use of piezoelectric materials for in situ biological stimulation, opening new interesting insights for bio-electric therapies. In this work, we investigate the morphological properties of polyvinylidene fluoride (PVDF) in the form of microstructured films after temperature-driven phase transition. The work aims to investigate the correlations between morphology at micrometric (i.e., spherulite size) and sub-micrometric (i.e., phase crystallinity) scale and in vitro cell response to validate their use as bio-functional interfaces for cellular studies. Morphological analyses (SEM, AFM) enabled evidence of the peculiar spherulite-like structure and the dependence of surface properties (i.e., intra-/interdomain roughness) upon process conditions (i.e., temperature). Meanwhile, chemical (i.e., FTIR) and thermal (i.e., DSC) analyses highlighted an influence of casting temperature and polymer solution on apolar to polar phases transition, thus affecting in vitro cell response. Accordingly, in vitro tests confirmed the relationship between micro/sub-microstructural properties and hMSC response in terms of adhesion and viability, thus suggesting a promising use of PVDF films to model, in perspective, in vitro functionalities of cells under electrical stimuli upon mechanical solicitation.

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In recent years, mussel adhesive proteins have attracted much attention because they can form strong adhesive interface interactions with various substrates in a wet environment. Inspired by their catechol- and amine-based molecular structure, polydopamine (PDA), a dopamine derived synthetic eumelanin polymer, was recognized as a suitable bio-interface coating. PDA was successfully used to improve adhesion due to the availability of copious functional groups for covalently immobilizing biomolecules and anchoring reactive species and ions. Recently, it has been demonstrated that PDA and its derivatives can be successfully used for the surface modification of implants interfaces to modulate in vitro cellular responses in order to enhance the in vivo functionality of biomedical implants (i.e., prosthesis). Herein, we propose the development of multifunctional scaffolds based on polyε-caprolactone (PCL) electrospun fibers coated with PDA via electro fluid dynamic methods, by optimizing polymerization/oxidation reactions capable of driving PDA self-assembly, and, ultimately, investigating the effects on cell response. Morphological analyses have confirmed the possibility to obtain different surface topographies as a function of the coating process while in vitro studies proved the ability of PDA coating to interact with cells no compromising in vitro viability. In perspective, in vitro conductive properties of fibers will be further investigated in order to validate their promising use as bioconductive interfaces for tissue engineering applications.

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The pituitary is a central organ of the neuro-endocrine system in fish that plays critical roles in various physiological processes, including stress response and behavior. Although it is known that pituitary hormones can have a direct or indirect influence stimulating or suppressing the immune responses, whether there is a local immune response in the pituitary or what is the effect of the immune stimulus on the pituitary function in fish is unknown. With the aim to understand the interaction between the immune responses and the endocrine axes at the pituitary level, particularly the Hypothalamus-Pituitary-Interrenal (HPI) axis, pituitaries of rainbow trout (Oncorhynchus mykiss) were cultured in vitro, incubated with bacterin, or bacterin plus CRH, cortisol, human recombinant IL1ß, or spleen medium for 3 h, and then genes involved in pro-inflammation (il1ß, il8, tnfα1, ifnγ), anti-inflammation (tgfß1b, il10), immune modulation (mhcIIa, c3, mif) and stress response (crhbp, pomca, pomcb, gr1) were tested. Data showed that, incubation with bacterin alone and bacterin plus recombinant IL1ß or CRH, as well as medium from bacterin treated spleen caused significant up-regulation of pro-inflammatory genes il1ß and il8, while down-regulated the anti-inflammatory gene tgfß1b. Besides, recombinant IL1ß plus bacterin or alone caused raise of mhcIIa and tnfa, respectively. On the contrary, just a slight or even no alteration was recorded in the expression of stress response genes including crhbp, pomca, pomcb and gr1 in the in vitro cultured trout pituitary following this stimulation. These results suggest a local immune gene equipment in the pituitary of fish, and the potential for fish pituitary to develop both innate and adaptive immune responses, whereas that immune stimulation was not able to evoke a significant endocrine stress response in vitro.

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In this study, the characteristics of silk fibroin films obtained from regenerated aqueous silk fibroin solution of various races were evaluated. Three races based on original sources of silkworms were selected: Nangnoi-Sisaket 1 (NN), Nakhon Ratchasima 1 (K1), and Nakhon Ratchasima 2 (K8). The Tg and Td of silk fibroin films were around 147-156°C and 277-279°C, respectively. FTIR result revealed that all silk fibroin films had beta sheet conformation. K1 and K8 films were found to be more hydrophilic than NN film. From in vitro tests using L929 mouse fibroblast and rat bone marrow-derived stem cells (rMSCs), the cell attachment was slightly greater on K1 film than the other two films. The enhanced cell growth on K1 film might be related to its slightly high hydrophilicity and the higher content of serine. The result of osteogenic differentiation test showed that alkaline phosphatase and deposited mineral of rMSCs were higher on all silk fibroin films than on tissue culture plate. K1 film tended to promote osteogenic differentiation of rMSCs to a higher extent than NN and K8 films. K1 silk fibroin film exhibited a higher potential to support cell attachment, proliferation, and differentiation than other two films.

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Recalcitrance and contamination in Mahogany (Swietenia macrophylla King) and Spanish cedar (Cedrela odorata L.) stem tissues are the main causes of its ineffective in vitro propagation. The objectives of this research were: a) to evaluate sodium hypochlorite (NaOCl) and plant preservative mixture (PPM®) as surface disinfectants and/or added to the culture medium for the in vitro establishment of nodal explants taken from 10-year-old Mahogany and Spanish cedar plants, and b) to evaluate the in vitro response of such explants treated with N6-benzylaminopurine (BAP) (0, 2.2, 4.4, 8.8, 17.7 μM), silver nitrate (AgNO3) (0, 3 mg l-1), activated charcoal (0, 1 g l-1) and vented caps. All the experiments were arranged in a completely randomized design. The NaOCl at 15%, for 20 min, as a surface sterilization or PPM® at 2 ml l-1 into the culture medium, were the best treatments to reduce contamination for both species. For Mahogany explants, BAP at 17.7 μM resulted in higher percentages of bud breaks than Spanish cedar (64% and 25%, respectively). Leaves on elongated shoots dropped off by 20 days after starting the explants in culture and neither the activated charcoal nor the AgNO3 alone or combined prevented leaf abscission. The AgNO3 decreased contamination, but also increased leaf abscission. Bud breaks was two-fold higher for nodal explants established in vessels with vented caps than with normal caps. Mahogany nodal explants were easier to surface sterilize and more buds broke from BAP treated explants than Spanish cedar treated explants in the in vitro establishment.

La contaminación y la recalcitrancia de tejidos de tallo de Caoba (Swietenia macrophylla King) y Cedro español (Cedrela odorata L.) son las causas principales de su inefectiva micro-propagación. Los objetivos de la investigación fueron: a) evaluar el hipoclorito de sodio (NaClO) y una mezcal preservadora de plantas (PPM®) como desinfectantes superficiales y/o agregados al medio de cultivo para el establecimiento in vitro de explantes nodales de Caoba y Cedro español de 10 años de edad; b) evaluar la respuesta in vitro de tales explantes tratados con N6-benzylaminopurine (BAP) (0, 2.2, 4.4, 8.8, 17.7 μM), nitrato de plata (AgNO3) (0, 3 mg l-1), carbón activado (0, 1 g l-1) y tapas porosas. Los experimentos fueron establecidos bajo un diseño completamente al azar. La contaminación se redujo en ambas especies con NaOCl al 15% durante 20 min como desinfección superficial o con PPM® (2 ml l-1) agregado al medio de cultivo. El mayor porcentaje de brotación de explantes se obtuvo con BAP a 17.7 μM en caoba (64%) comparado con cedro (25%). Los brotes se defoliaron a los 20 días de cultivo y ni el carbón activado ni el AgNO3, solos o combinados evitaron la defoliación. El AgNO3 disminuyó la contaminación, pero incrementó la defoliación. La brotación fue dos veces mayor en los explantes nodales establecidos en recipientes con tapas porosas que cuando se utilizaron tapas normales. Los explantes nodales de Caoba respondieron mejor a la desinfección superficial y a los tratamientos de BAP comparados con los de Cedro español en el establecimiento in vitro.

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