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CUE 2006

Chemical & Biological Engineering: Polymer Hydrogels Offer a New Approach to Cell Replacement Therapy

A clear, polymer hydrogel that protects and controls the growth of transplanted neural cells may offer hope to patients with Parkinson's disease, a neurodegenerative illness that leads to impairments in motor function and eventually death.

A polymer carrying neural stem cells would be injected into the area of a patient's brain where dopaminergic neurons have been lost, and activated with ultraviolet light in a procedure known as photo-polymerization.  Using light-activated chemistry, the process gives three-dimensional structure to the gel when it is in place, allowing it to support and control cell proliferation and differentiation through the use of growth factors, and later to biodegrade when it is no longer needed.

Not only would the hydrogel act as a carrier of the transplanted cells and a guide for the delivery of growth factor therapy, but it would also protect the cells being introduced, improving their survival rate and the patient's chances of recovery. The vast majority of cells in traditional neural replacement therapy typically die off within a week. 

"The protectant qualities of the hydrogel may make it a more robust therapy than a simple transplant," says CU Assistant Professor Melissa Mahoney.

Mahoney and her team of nine undergraduate and graduate students are trying to determine how a hydrogel's properties, such as porosity, strength, and biodegradability, affect the growth of neural cells. Their approach involves photo-encapsulating neural cells from rats in experimental hydrogels and observing them with a confocal microscope to determine cell survival and structural change over time.

Eventually, the research team hopes to develop a specific type of polymer hydrogel appropriate for further clinical study. That could take place in collaboration with scientists at the University of Colorado at Denver and Health Sciences Center within the next year.

Mahoney is one of several faculty in the chemical and biological engineering department using photo-polymerization to create synthetic materials that aid in healing the body, but the only one focusing on brain tissue.

"As a graduate student, I worked on drug delivery to the brain. I was fascinated by it because it's a really complex, massive organ," she says.

Mahoney joined the CU-Boulder faculty in January 2005 after doing post-doctoral research in neural biology at Duke University and the Woods Hole Marine Biological Laboratory. Funded primarily by the National Institutes of Health, Mah-oney's research has applications ranging from treatment of Parkinson's to other disorders of the central nervous system, such as brain injuries and Alzheimer's disease.

Last fall, she received national attention for her work from Technology Review, which selected Mahoney as one of the top 35 young innovators in technology, business, and the arts. The honorees were selected by a prestigious panel of judges and described as "having the potential to profoundly impact the world."

For Parkinson's patients and others with central nervous system disorders, that may be just around the corner.

For more information, visit www.colorado.edu/che/research/Faculty/mahoney
Department web site: www.colorado.edu/che