Graphene- and Hyaluronic Acid-based Functional Materials for Stem Cell and Drug Delivery in Ischemic Tissue Regeneration

Abstract

Ischemic diseases, including hindlimb ischemia and renal ischemia-reperfusion (I/R) injury, cause severe tissue damage through oxidative stress from reactive oxygen species (ROS) and inflammation, impeding effective regeneration. This thesis aims at developing graphene- and hyaluronic acid (HA)-based functional biomaterials for cell and drug delivery systems to enhance ischemic tissue regeneration by mitigating ROS, improving cell survival, and enabling targeted therapeutic delivery. First, sonicated graphene oxide/alginate microgels (sGO/Alg) were developed to encapsulate mesenchymal stem cells (MSCs), protecting them from oxidative stress and enhancing paracrine-mediated angiogenesis. In a murine hindlimb ischemia model, these MSC-laden antioxidative microgels improved blood perfusion, reduced fibrosis, and promoted vascular regeneration. Second, a ROS-responsive graphene-HA nanomedicine (HA/rGO) was engineered for treatment of renal I/R injury. HA/rGO was designed to combine HA’s CD44-mediated targeting ability with the antioxidant capacity of graphene, thereby effectively reducing oxidative damage and pathological progression in injured kidneys. Finally, MSCs were modified with HA to specifically attenuate or prevent the progression of the acute kidney injury to chronic kidney disease following I/R-induced renal injury. HA conjugation on MSCs via maleimide-thiol chemistry preserved MSC stemness and paracrine function while enhancing kidney-specific accumulation and offering uses of a small amount of MSCs. In vivo studies in wild-type and Cd44⁻/⁻ mice demonstrated that HA-MSCs significantly attenuated fibrosis, tubular injury, and renin-angiotensin system dysregulation, with improved biodistribution and minimal off-target effects. These advanced delivery systems address key barriers in regenerative medicine, offering promising platforms for clinical translation in treating ischemic diseases and promoting tissue regeneration.