Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

Many biomaterials being tested or used clinically are plastic-based with promising short-term results in animals and early clinical trials. Longer term results, however, can be sub-optimal to harmful. Biomaterials based on the extracellular matrix (ECM) are now being tested for stimulating regeneration but are they actually safer as believed, as there have been reported fatalities. My long-term goal is to understand how biomaterials and cells interact, to identify the "good" biomaterials that promote safe regeneration and avoid "bad" ones leading to problems. Extracellular vesicles (EVs) are key components in intercellular communication. They contain a wide range of cargo (mRNA, microRNA, proteins, signaling molecules and lipids) that modulate regeneration and have been proposed as cell-free therapeutic agents. However, there is no information on biomaterials-induced EV production and regeneration. I will test the hypothesis that EV are effectors for biomaterials-stimulated regeneration and that their pattern of expression and cargo will allow us to distinguish the good versus bad, or neutral biomaterials in terms of long-term outcomes. I will use the cornea as an experimental model as there is a long history of corneal implants made from a range of biomaterials with documented long-term clinical outcomes that can be used to aid in producing the EV “barcodes” (size, content, surface markers). I will begin with biomaterials in the form of implants that are designed as pro-regeneration scaffolds. We will fabricate implants made from methacrylates (poor regeneration) to blends of pHEMA/collagen (mediocre regeneration) to recombinant human collagen (excellent regeneration) and new materials based on mimetic analogs of collagen. Polyethylene glycol (PEG) hydrogels have been shown to be passive, and biocompatible by virtue of their inertness. A set of PEG-based scaffolds will be fabricated where we will add incremental amounts of collagen and collagen-like peptides until these scaffolds promote optimal growth of corneal and nerve cells, but not activate antigen presenting dendritic cells, in order to examine the changes in EV profile with increasing cell-friendliness. We will define EV expression based on their sub-type (microvesicles/microparticles/ectosomes; exosomes; or apoptotic bodies) and their protein and mRNA cargoes during cell-material interactions in vitro, by seeding cells onto materials as 2D constructs and compare their interactions as “implants” in 3D constructed corneal equivalents that we have characterized very well. These interactions will be observed in real time by confocal microscopy using two-photon confocal microscopy. In vitro results will be corelated with in vivo implantation. Our will be a barcode of EVs and contents that will point to biomaterials promoting successful regeneration versus those that give poor regeneration or an adverse reaction.