A newly developed hydrogel allows for a new method of cell transplantation. Created by researchers at the University of Toronto, the injectable gel-like biomaterial can not only successfully mimic the properties of human tissue but also offers protection for stem cells as they integrate into tissue after being transplanted. This expedites healing and recovery for stroke victims and has even been shown to partially reverse blindness in some cases. The method is currently being used to develop new forms of regenerative therapy for repairing nerve damage, as well as drug development and delivery.
Stem cells can be easily grown in petri dishes. However, when left on their own inside the human body, they often fail to integrate into the new tissue and die quickly. The hydrogel provides a layer of protection by encasing the stem cells, allowing them to survive and integrate properly. According to engineering professor and principal researcher Molly Shoichet, this allows stem cell therapy to become more realistically viable.
Hydrogel is engineered from only two components: methylcellulose, which is what forms the gel and holds the cells together, and hyaluronan, which is what keeps the cells alive. It is capable of evenly distributing both cell types in the syringe and possesses “shear-thinning” properties that allows it to be injected via a fine gauge needle. According to results from tests conducted on blind mice, approximately 10 to 15 percent of vision was regained.
In a similar study featuring rodent models of stroke injuries, Shoichet and her team noticed that the mice’s motor coordination significantly improved after transplantation via hydrogels. The researchers are hoping that the hydrogel could potentially be used in different body sites.
The team first attempted to use the hydrogel for transplantation in 2015, injecting healthy photoreceptor cells (which are responsible for vision) into damaged retinas. However, while a moderate level of vision repair was achieved, it ultimately failed to meet their expectations because photoreceptors are intricately linked with retinal pigmented epithelium (RPE) cells. In conditions such as age-related macular degeneration, the deterioration of the RPE subsequently results in deterioration of the photoreceptors. In traditional transplant cases, these cells are typically injected separately to replace dead cells.
“What other groups have typically done is either inject photoreceptors in a saline solution, which often results in cells clustering together, or surgically implant a layer of RPE cells usually grown on a polymer film,” said Shoichet.
Recently, AmacaThera, one of the companies utilizing hydrogel, has received approval to perform human trials for a new post-surgical pain anesthetic. This aims to combat the onslaught of opioid addiction from anesthetic drugs.
Shoichet recently received this year’s Gerhard Herzberg Canada Gold Medal for her work on the hydrogel material. It is the highest science prize awarded in the country and recognizes “sustained excellence” and “overall influence” of research in the natural sciences or engineering, and includes a $1 million grant. Shoichet’s work has also been awarded by the likes of the Canada Council Killam Prize for Engineering, and she has also been named a L’Oréal-UNESCO For Women in Science Laureate. Shoichet recently served as Ontario’s first chief scientist and was a former officer of the Order of Canada.
To learn more about the Gerhard Herzberg Canada Gold Medal award, visit the Natural Sciences and Engineering Research Council of Canada’s (NSERC’s) website.
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