Soft Tissue Scaffolds

Abstract

The effort to develop soft tissues is one of the most demanding and challenging applications in tissue engineering. Soft tissues such as myocardium, blood vessels, skeletal muscle, adipose tissue, and even cartilage often possess large volumes, have high cell densities, and can be mechanically active. 3‐D scaffolds that match the mechanical properties of the tissue that they are replacing are preferred for soft tissue engineering, because such materials might transmit mechanical forces to the developing tissue during in vitro or in vivo development. A well‐defined biodegradation rate is ideal so that host tissue can replace the scaffold and that stress can be transferred from the support scaffold to the new tissue over an appropriate time period. The scaffolds not only serve as a structural support, but also can play an important role in facilitating cell adhesion, growth, and vascularization throughout the scaffold both during in vitro cell culture and in vivo tissue regeneration. Currently used materials meeting these criteria are diverse and include entirely synthetic materials as well as those that are derived from natural sources, and formats that are continuous on a microscale (hydrogels) and those that have defined microporous architectures. Although natural materials have the inherent advantage of bioactivity, they also possess limitations when employed as soft tissue scaffolds that may be overcome with synthetics. Some limitations associated with natural materials include inducement of an immune response that can lead to rapid degradation as well as poor batch‐to‐batch consistencies. Synthetic polymers permit better control over chemical and physical properties leading to tunability in mechanical strength and degradation rate. Surface properties of synthetic materials can also be more easily modified for improved cell attachment or migration. Some disadvantages of synthetic tissue scaffolds consist of potential toxic degradation products and undesired inflammatory responses. In addition, fabrication methods can process materials into scaffolds of desired porosity, morphologies, and anisotropies. The focus of this article will provide a brief overview of the scaffold preparation, properties, and applications of soft tissue scaffolds.

Primary human dermal fibroblast interactions with open weave three-dimensional scaffolds prepared from synthetic human elastin

“…Synthetic polymers, such as poly(e-caprolactone) and poly(lactideco-glycolide) [16], have predictable and controllable physical properties, but tend to have poor biological activity and produce a range of cytotoxic degradation products [16,17]. A range of natural polymers, including fibrin [18,19], hyaluronic acid [20,21], fibrinogen [22] and collagen [23,24] have therefore been proposed as biologically superior dermal substitutes, with collagen showing the most potential [25][26][27][28].…”