Advances in Biomaterials The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Effect of Hydration on Physicochemical Properties of End-Capped PLGA Wed, 13 Aug 2014 11:51:47 +0000 The objective of this study was to assess the physicochemical effects of hydrating a hydrophobic end-capped poly(lactide-co-glycolide) (PLGA) polymer in the liquid and vapor state. PLGA RG503 polymer was incubated at 37°C in 0.5% polyvinyl alcohol (PVA) solution and at 90% RH. Samples were withdrawn at predetermined intervals and changes to polymer properties like glass transition temperature (Tg), moisture uptake, molecular weight change, and % acid number were determined using differential scanning calorimetry, Karl Fisher titrimetry, gel permeation chromatography, and acid base titrimetry, respectively. Study results showed that Tg was depressed instantaneously upon hydration, indicating that bulk water acted as a plasticizer of hydrophobic end-capped PLGA. Tg values decreased to levels below the incubation temperature when hydrated in 0.5% PVA solution but not in 90% RH. The drop in Tg exhibited a linear relationship () to the amount of water uptake by the polymer; higher moisture uptake was noted with liquid water. Removal of moisture from the polymer matrix resulted in recovery of Tg, only up to a period of 14 days. Presence of water in liquid or vapor form caused a reduction in molecular weight of the polymer and a corresponding increase in % acid number over the duration of the study. Susan D’Souza, Rossella Dorati, and Patrick P. DeLuca Copyright © 2014 Susan D’Souza et al. All rights reserved. Musculoskeletal Regenerative Engineering: Biomaterials, Structures, and Small Molecules Tue, 24 Jun 2014 10:14:29 +0000 Musculoskeletal tissues are critical to the normal functioning of an individual and following damage or degeneration they show extremely limited endogenous regenerative capacity. The future of regenerative medicine is the combination of advanced biomaterials, structures, and cues to re-engineer/guide stem cells to yield the desired organ cells and tissues. Tissue engineering strategies were ideally suited to repair damaged tissues; however, the substitution and regeneration of large tissue volumes and multi-level tissues such as complex organ systems integrated into a single phase require more than optimal combinations of biomaterials and biologics. We highlight bioinspired advancements leading to novel regenerative scaffolds especially for musculoskeletal tissue repair and regeneration. Tissue and organ regeneration relies on the spatial and temporal control of biophysical and biochemical cues, including soluble molecules, cell-cell contacts, cell-extracellular matrix contacts, and physical forces. Strategies that recapitulate the complexity of the local microenvironment of the tissue and the stem cell niche play a crucial role in regulating cell self-renewal and differentiation. Biomaterials and scaffolds based on biomimicry of the native tissue will enable convergence of the advances in materials science, the advances in stem cell science, and our understanding of developmental biology. Roshan James and Cato T. Laurencin Copyright © 2014 Roshan James and Cato T. Laurencin. All rights reserved. Plasma-Mediated Immobilization of Antibody with PEG as Spacer for Enhanced Endothelial Cell Adhesion and Proliferation Thu, 10 Apr 2014 14:15:34 +0000 Immobilization of anti-CD34 antibody is proven to be an effective strategy to accelerate reendothelialization and thereby lower the thrombosis of blood contacting grafts. To realize highly efficient immobilization of anti-CD34 antibody, an argon cold plasma-mediated graft process was developed with PEG as spacer arm in this study. In this process, the 316L stainless steel (316LSS) model substrate was first coated with ethylene vinyl acetate copolymer (EVA) followed by argon plasma treatment and PEG400 modification (EVA-PEG). The EVA-PEG was further ignited by argon plasma and then the anti-CD34 antibody was immobilized. XPS measurement indicated the successful immobilization of the EVA and the anti-CD34 antibody molecules. Compared with the anti-CD34 antibody anchored without PEG, the immobilized EVA-PEG-anti-CD34 antibody exhibited better capturing efficiency (increase about 1-fold) of specific antigen. Consequently, the endothelial cell attachment (before 12 h) and proliferation (1~4 days) were significantly improved. Further study showed that this EVA-PEG-anti-CD34 coating could reduce blood coagulation. Therefore, this cold plasma-mediated graft process with PEG spacer arm developed here is a promising strategy to immobilize antibody with higher bioactivity for rapid reendothelialization of the cardiovascular implants. Yuan Yuan, Jing Zhang, Min Yin, and Changsheng Liu Copyright © 2014 Yuan Yuan et al. All rights reserved.