The Canadian Stroke Network has promoted such a unique multidisciplinary collaboration to develop new ways of delivering biomolecules and cells directly to the brain. Using this new technology, we have been able to stimulate endogenous stem cells to achieve tissue and functional repair of the brain after ischemic injury. The key design feature allows biomolecules to diffuse directly in brain tissue, thereby obviating the need to cross the blood-brain barrier. For this purpose, biomolecules are encapsulated in polymeric nanoparticles that are themselves distributed in an anti-inflammatory hydrogel comprised of hyaluronan and methyl cellulose. With a controlled release system, proteins and small molecules are delivered over a prolonged period of time to the neural stem cells that line the lateral ventricles. Compared to traditional avenues of delivery this biomaterials-based delivery strategy is less invasive and causes less tissue damage, ultimately resulting in better tissue and functional repair.
Likewise new strategies to enhance cell viability and tissue integration after their injection into brain tissue have been developed through application of this technology. Stem cell transplantation with injectable and bioresorbable hydrogels has resulted in improved brain repair relative to controls. Thus, the use of these innovative biomaterials for both biomolecule and cell delivery has a profound effect on tissue repair and behaviour, opening opportunities for safe and effective regenerative strategies in stroke treatment.
Acknowledgement: This work has been funded by the Canadian Stroke Network, NSERC, CIHR, Krembil Foundation and Stem Cell Network.