Kevin E. Healy
Departments of Bioengineering and Materials Science and Engineering
University of California at Berkeley
Skeletal fixation of prosthetic limbs requires communication of the implant with both hard and soft tissues, leading to distinct tissue implant interfacial problems associated with either fixation in bone, or soft tissue attachment in the transcutaneous region. In the former case, concepts gleaned from the fixation of dental and orthopaedic implants in bone can be converted to transcutaneous prosthetic limbs. For example, a general limitation in the performance of materials used in medical device is that they lack the ability to integrate with biological systems through either a molecular or cellular pathway. The inability to interact with biological systems has relegated biomaterials to a passive role dictated by the constituents of a particular environment, leading to unfavorable outcomes and device failure. The design and synthesis of biomaterials that circumvent their passive behavior in complex biological environments, and actively regulate the response of either proteins or mammalian cells is the focus of the work in my laboratory. A central theme in the design of materials that regulate tissue regeneration is that they do so through a combination of biomolecular recognition processes and device microarchitecture. In my research group we have designed and synthesized model biomimetic materials that can be used to test hypotheses regarding bone-materials interactions. We can control bone cell (e.g., osteoblast) behavior chemically, through specific ligand-receptor interactions, or by modifying the size of the cell to limit growth and promote differentiation. The implications of this work are that the chemistry of a material can be modified to alter the kinetics of bone formation surrounding around implants, increase the bone-material interfacial bond strength and, ultimately, increase initial implant stability of complex bone-contacting devices such as transcutaneous prosthetic limbs.