J. Funct. Biomater.2014, 5(3), 99-110; doi:10.3390/jfb5030099 - published 24 July 2014 Show/Hide Abstract
Abstract: The aim of this work was the preparation and characterization of a pro-prodrug able to simultaneously transport silybin, a drug possessing various pharmacological effects, and trans-ferulic acid, a known antioxidant. More specifically, l-phenylalanine-N-(4-hydroxy-3-methoxy-phenyl) prop-2-en-O-(2R,3R)-3,5,7-trihydroxy-2-((2R,3R)-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-2,3-dihydro-benzo-(1,4)-dioxin-6-yl)croman-4-one was synthesized by using the aminoacid l-phenylalanine (l-Phe) as carrier. Indeed, l-Phe is characterized by an intrinsic chemical reactivity due to the presence of an amino group, placed on the chiral center, and of a carboxylic group. The synthesis has been characterized first by adding silybin by means of carboxylic group and then, with the aim to confer antioxidant properties to this new carrier, by linking trans-ferulic acid to l-Phe via amino group. The so obtained derivative was then characterized by FT-IR, and 1H-NMR spectroscopies. Furthermore, its ability to inhibit lipid peroxidation induced by tert-butyl hydroperoxide in rat liver microsomes, was evaluated. The 1,1-diphenyl-2-picrylhydrazyl radical-scavenging effect, was also assessed. The release of silybin and trans-ferulic acid was determined in simulated gastric and intestinal fluids over the time. The results showed that the covalent bond between both (i) silybin; or (ii) trans-ferulic acid and the amino acid was degraded by enzymatic reactions. In addition, the pro-prodrug, showed strong antioxidant and scavenger activities. Due to these properties, this new pro-prodrug could be applied for the treatment of intestinal pathologies and it might improve the therapeutic potential of silybin which is strongly limited by its low solubility.
J. Funct. Biomater.2014, 5(2), 78-98; doi:10.3390/jfb5020078 - published 4 June 2014 Show/Hide Abstract
Abstract: In many machines and mechanical components, there is a need for new bearing technologies to reduce friction and wear, and provide precision control of motion when the load is varied. This can be provided by electronically controlled actuators and sensors on the surfaces, but then the system reliability can be an issue. In contrast, biomimetic surfaces can be created that adapt mechanically to variations in load. This work uses numerical methods to research the use of self-adapting surfaces for bearings that are based on the deformable nature of biological materials such as articular cartilage. These surfaces are designed to change their profiles to achieve a desired behavior, without any external control. The surfaces change their profile to control the film height and tilt of the bearing to a near constant value for different loads. If the surfaces are tilted, the grooved self-adapting surfaces will also react with a larger restoring moment than a conventional grooved surface. These surfaces could be beneficial to applications where electrical systems and controls are not feasible.
J. Funct. Biomater.2014, 5(2), 58-77; doi:10.3390/jfb5020058 - published 8 May 2014 Show/Hide Abstract
Abstract: Inhibition of smooth muscle cell (SMC) proliferation and preservation of a differentiated state are important aspects in the management, avoidance and progression of vascular diseases. An understanding of the interaction between SMCs and the biomaterial involved is essential for a successful implant. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human aortic SMCs. The nanowire surfaces were fabricated from polycaprolactone and were immobilized with collagen. The objective of this study is to reveal how SMCs interact with collagen immobilized nanostructures. The results indicate significantly higher cellular adhesion on nanostructured and collagen immobilized surfaces; however, SMCs on nanostructured surfaces exhibit a more elongated phenotype. The reduction of MTT was significantly lower on nanowire (NW) and collagen immobilized NW (colNW) surfaces, suggesting that SMCs on nanostructured surfaces may be differentiated and slowly dividing. Scanning electron microscopy results reveal that SMCs on nanostructured surfaces are more elongated and that cells are interacting with the nano-features on the surface. After providing differentiation cues, heavy chain myosin and calponin, specific to a contractile SMC phenotype, are upregulated on collagen immobilized surfaces. These results suggest that nanotopography affects cell adhesion, proliferation, as well as cell elongation, while collagen immobilized surfaces greatly affect cell differentiation.
J. Funct. Biomater.2014, 5(2), 43-57; doi:10.3390/jfb5020043 - published 8 May 2014 Show/Hide Abstract
Abstract: The effective and widely tested biocides: Benzalkonium chloride, bronopol, chitosan, chlorhexidine and irgasan were added in different concentrations to atelocollagen matrices. In order to assess how these antibacterial agents influence keratinocytes cell growth, cell viability and proliferation were determined by using MTT assay. Acquired data indicated a low toxicity by employing any of these chemical substances. Furthermore, cell viability and proliferation were comparatively similar to the samples where there were no biocides. It means that regardless of the agent, collagen-cell-attachment properties are not drastically affected by the incorporation of those biocides into the substrate. Therefore, these findings suggest that these atelocollagen substrates enhanced by the addition of one or more of these agents may render effectiveness against bacterial stains and biofilm formation, being the samples referred to herein as “antimicrobial substrates” a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.
J. Funct. Biomater.2014, 5(2), 29-42; doi:10.3390/jfb5020029 - published 31 March 2014 Show/Hide Abstract
Abstract: This study tested extracts from New Zealand seaweed Undaria pinnatifida containing fucoxanthin, in parallel with pure fucoxanthin, in nine human cancer cell lines, for anticancer activity. Growth inhibition effects of extracts from Undaria pinnatifida were found in all types of cancer cell lines in dose- and time- dependent manners. Cytotoxicity of fucoxanthin in three human non-cancer cell lines was also tested. Compared with pure fucoxanthin, our extracts containing low level of fucoxanthin were found to be more effective in inhibiting the growth of lung carcinoma, colon adenocarcinoma and neuroblastoma. Our results suggest that fucoxanthin is a functional biomaterial that may be used as a chemopreventive phytochemical or in combination chemotherapy. Furthermore, we show for the first time that some unknown compounds with potential selective anti-cancer effects may exist in extracts of New Zealand Undaria pinnatifida, and New Zealand Undaria pinnatifida could be used as a source for either functional biomaterial extraction or production of functional food.