IOP PUBLISHING BIOMEDICAL MATERIALS Biomed. Mater. 3 (2008) 034104 (8pp) doi:10.1088/1748-6041/3/3/034104 Biodegradable and radically polymerized elastomers with enhanced processing capabilities Jamie L Ifkovits 1 , Robert F Padera 2 and Jason A Burdick 1 1 Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA 2 Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA E-mail: burdick2@seas.upenn.edu Received 26 November 2007 Accepted for publication 13 February 2008 Published 8 August 2008 Online at stacks.iop.org/BMM/3/034104 Abstract The development of biodegradable materials with elastomeric properties is beneficial for a variety of applications, including for use in the engineering of soft tissues. Although others have developed biodegradable elastomers, they are restricted by their processing at high temperatures and under vacuum, which limits their fabrication into complex scaffolds. To overcome this, we have modified precursors to a tough biodegradable elastomer, poly(glycerol sebacate) (PGS) with acrylates to impart control over the crosslinking process and allow for more processing options. The acrylated-PGS (Acr-PGS) macromers are capable of crosslinking through free radical initiation mechanisms (e.g., redox and photo-initiated polymerizations). Alterations in the molecular weight and % acrylation of the Acr-PGS led to changes in formed network mechanical properties. In general, Young’s modulus increased with % acrylation and the % strain at break increased with molecular weight when the % acrylation was held constant. Based on the mechanical properties, one macromer was further investigated for in vitro and in vivo degradation and biocompatibility. A mild to moderate inflammatory response typical of implantable biodegradable polymers was observed, even when formed as an injectable system with redox initiation. Moreover, fibrous scaffolds of Acr-PGS and a carrier polymer, poly(ethylene oxide), were prepared via an electrospinning and photopolymerization technique and the fiber morphology was dependent on the ratio of these components. This system provides biodegradable polymers with tunable properties and enhanced processing capabilities towards the advancement of approaches in engineering soft tissues. (Some figures in this article are in colour only in the electronic version) 1. Introduction The well-known tissue engineering paradigm accounts for the importance of scaffolds, cells, and growth factors and combinations of these components for the successful design and integration of constructs into living systems to enhance tissue regeneration [1]. It is generally believed that cells either delivered or from surrounding tissues receive necessary cues from their microenvironment, which consists of both matrix (e.g., mechanics, chemistry) and soluble factors [2, 3]. With this in mind, the chemical and physical properties of scaffolds are of vital importance in controlling cellular behaviors (e.g., differentiation, matrix production) and in the overall success of the construct [2, 4–9]. Scaffolds may comprise natural enzymatically degradable biopolymers (e.g., hyaluronic acid) or synthetic polymers (e.g., polyurethanes), which are typically biodegradable, depending on the desired application and in vivo environment [10, 11]. One advantage to using synthetic polymers is the ability to tailor scaffold mechanical properties 1748-6041/08/034104+08$30.00 1 © 2008 IOP Publishing Ltd Printed in the UK