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Developing new technologies that enable the repair or replacement of injured or diseased tissues is a major focus of regenerative medicine. This paper will discuss three ultrasound technologies under development in our laboratories to guide tissue regenera tion both in vitro and in vivo. A critical obstacle in tissue engineering is the need for rapid and effective tissue vascularization strategies. To address this challenge, we are developing acoustic patterning techniques for microvascular tissue engineerin g. Acoustic radiation forces associated with ultrasound standing wave fields provide a rapid, non -invasive approach to spatially pattern cells in three dimensions without affecting cell viability. Acoustic patterning of endothelial cells leads to the rapid formation of microvascular networks throughout the volumes of three -dimensional hydrogels, and the morphology of the resultant microvessel networks can be controlled by design of the ultrasound field. A second technology under development uses ultrasound to noninvasively control the microstructure of collagen fibers within engineered tissues. The microstructure of extracellular matrix proteins provides signals that direct cell functions critical to tissue regeneration. Thus, controlling collagen microfiber structure with ultrasound provides a noninvasive approach to regulate the mechanical properties of biomaterials and control cellular responses. The third technology employs therapeutic ultrasound to enhance the healing of chronic wounds. Recent studies de monstrate increased granulation tissue thickness and collagen deposition in murine dermal wounds exposed to pulsed ultrasound . In summary, ultrasound technologies offer noninvasive approaches to control cell behaviors and extracellular matrix organization and thus hold great promise to advance tissue regeneration in vitro and in vivo . Keywords: Ultrasound , tissue engineering, regenerative medicine, collagen, extracellular matrix, wound healing 1. |
