Laurencin, Cato T.
Primary Appointment
University Professor and Chair, Biomedical Engineering
Contact Information
Box 800159
Telephone: 243-0252
Email: ctl3f@virginia.edu
Website: http://faculty.virginia.edu/laurencin/
Research Interests
Biomaterials, Polymer Synthesis, Tissue Engineering, Drug Delivery, Nanotechnology
Research Description
Bioreactor Related Research
There are currently two ongoing bioreactor-related research programs in our laboratory funded by the National Science Foundation (NSF) and National Aeronautics and Space Administration (NASA). A multidisciplinary approach is taken to design, fabricate and optimize three-dimensional (3-D) biodegradable poly (lactide-co-glycolide) (PLAGA) based scaffold in a dynamic flow environment in NASA rotating bioreactors for bone tissue engineering. Specifically, we exposed the 3-D scaffold to fluid and nutrient flux via placement in a dynamic flow environment in NASA rotating bioreactors and seek to gain a more fundamental understanding of the manner in which cells interact with these degradable polymeric scaffolds in a dynamic flow environment in NASA rotating bioreactors.
We also seek to develop a novel 3-D biodegradable polyphosphazene based scaffold in a dynamic flow environment in NASA rotating bioreactors suitable for bone tissue engineering. We will design, fabricate, characterize, and optimize 3-D polyphosphazene scaffolds for bone tissue engineering under a dynamic flow environment in NASA rotating bioreactors.
Our interdisciplinary projects address fundamental issues facing bone remodeling and formation, particularly regarding the effects of an in vitro dynamic flow environment in bioreactors on bone cell biology and bone formation in vivo. Results from these studies will serve as the foundation for future work aimed at exploring the effect of dynamic flow environment on bone healing and remodeling, and for optimizing bioreactor tissue engineering of bone.
Tissue Engineering of Bone
The goal of this work is to develop synthetic alternatives to orthopaedic tissues such as bone, ligament, and cartilage. Once implanted, the presence of cells and growth factors will initiate bone regeneration throughout the 3-D pore network. As regeneration continues, the matrix is slowly resorbed by the body. Upon complete degradation, the implant site is filled with newly regenerated bone and free of any residual polymer.
Using the biodegradable polymer poly (lactide-co-glycolide), we have developed a series of 3-dimensional porous structures based on microsphere technology. In combination with bone morphogenetic proteins and osteoblasts, these matrices will serve as scaffolds for bone regeneration.
Our research also focuses on the development and evaluation of polyphosphazene-ceramic composites that could be used as scaffolds for bone tissue engineering.
In studies examining cell growth on these matrices, we have utilized an osteoblast cell lines as well as bone cells isolated from rat calvaria to create a model system for cell growth on bioerodable materials. This image shows osteoblasts growing on the surface of our 3-D microsphere matrix. It is interesting to note that the cells are growing in a circumferential pattern due to the structure of the matrix.
Tissue Engineering of Ligament
The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, due to inherently poor healing potential and limited vascularization ACL ruptures do not heal and surgical replacement is often required. Our laboratory has produced a cell-seeded, degradable, three-dimensional (3-D) scaffold for ACL replacement and regeneration. Three-dimensional braiding techniques have been used to create a scaffold with optimized pore size for cell proliferation and tissue ingrowth, resistance to wear and rupture, and mechanical properties comparable to natural ACL. Presently, we are optimizing this structure to improve the biomechanical properties, adjust degradation time, and enhance the cell proliferation and tissue regeneration abilities of the implant. These changes will result in an implant that behaves more like natural ligament and enhances regeneration without rupturing after implantation.
Nanotechnology
Tissue engineering scaffolds fabricated from nanofibers are gaining importance due to their unique similarity to extracellular matrices, high porosity, and ease of fabrication. Also the nanofibers have an advantage of enormous surface area due to very high length to diameter ratio of the fibers. A very elegant process to make the nanofiber scaffolds is by subjecting the polymer solution or melts to very high potential difference. A variety of parameters such concentration, melt viscosity, potential difference etc. can be optimized to obtain desired diameter and morphology of the resultant nanofibers. Further these nanofibers can also be formed to three dimensional scaffolds that can be used as the scaffold for tissue engineering.
In our laboratory, we are investigating the different ways to fabricate two and three dimensional nanofibers from a variety of biodegradable and non biodegradable polymers that could be used for a various biomedical applications.
Drug Delivery
Funded by the National Materials Testing Bed Inc., Department of Defense, we are also studying the release of growth factors from nanofibers for skin regeneration in the case of burn victims and diabetic ulcer patients. In this work we are optimizing the various parameters associated with electrospinning for obtaining growth factor loaded nanofibers of consistent diameters for optimal release of growth factors for faster regeneration of the skin.
We have also developed a microsphere based drug delivery system for delivering radiosensitizers for the treatment of musculoskeletal tumors and rheumatoid arthritis.
p {font-weight:bold !important}