Compositions and methods for in situ-forming tissue constructs
Inventors
Myung, David • Hull, Sarah • Heilshorn, Sarah • Lindsay, Christopher • Madl, Christopher • LEE, Hyun Jong
Assignees
US Government Represented By Department Of Veterans Affairs • US Department of Veterans Affairs • Leland Stanford Junior University
Publication Number
US-12036314-B2
Publication Date
2024-07-16
Expiration Date
2039-06-27
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Abstract
Compositions and methods are provided for lamellar and defect reconstruction of corneal stromal tissue using biomaterials that form a defined gel structure in situ. Such gels can serve as cellular or acellular lamellar substitutes to reconstruct corneal stroma, facilitate matrix remodeling, and support multilayered re-epithelialization of wounded corneal stromal tissue, as well delivery vehicles for cells, biomolecules, and/or pharmaceutical agents to wound sites throughout the body.
Core Innovation
The invention provides compositions, kits, and methods for in-situ forming tissue constructs, specifically defined hydrogel structures, that can be cellularized to aid in wound healing and tissue regeneration. These constructs are particularly useful in the repair, regeneration, and reconstruction of lamellar or partial defects of wounded corneal tissue. The compositions are flowable biomaterials comprising biopolymers such as collagen, hyaluronic acid, or combinations thereof, modified to form hydrogels at the site of application via covalent crosslinking chemistry under ambient conditions without the need for external stimuli like light.
The core problem addressed is the limitation of existing corneal transplantation methods, including the shortage of donor tissue and the inability to effectively treat irregularly shaped or deep corneal stromal wounds with pre-formed grafts. Current approaches involving ex vivo formed constructs are often difficult to place within irregular ulcers and may lack sufficient mechanical stability. There is a clinical need for effective, minimally invasive, in-situ forming methodologies and compositions that can fill, stabilize, and regenerate deep corneal wounds, particularly in high-risk patients where penetrating surgery is undesirable.
Claims Coverage
The patent defines four main inventive features distributed across three independent claims, focusing on in-situ-forming corneal construct compositions and methods of treating wounded corneas.
In-situ-forming corneal construct composition with SPAAC crosslinking
A first composition comprising collagen functionalized with dibenzocyclooctyne (DBCO) or bicyclooctyne, and a second composition comprising collagen functionalized with azide linked through a polyethylene glycol spacer, both at collagen concentrations from 1.5 to 3 mg/mL and mixed in ratios from 1:3 to 3:1, that react by strain-promoted azide-alkyne cycloaddition (SPAAC) to form a defined gel structure in situ without external energy, encapsulating corneal stem cells, keratocytes, keratocyte precursors, keratinocytes, or keratinocyte precursors within the gel.
Encapsulation of keratocytes within the in-situ formed gel
The composition wherein keratocytes are encapsulated within the SPAAC crosslinked hydrogel, supporting cellularization of the corneal construct.
Method for treating or reconstructing wounded cornea using SPAAC-forming composition
A method comprising mixing the first composition (collagen functionalized with DBCO or bicyclooctyne) and the second composition (collagen functionalized with azide linked through PEG spacer) in ratios from 1:3 to 3:1, with collagen concentration from 1.5 to 3 mg/mL, containing cells such as corneal stem cells, keratocytes, or keratinocytes, applying the mixture to a surgically incised or wounded corneal area, wherein the compositions react in situ by SPAAC to form a defined gel structure without external energy source, thereby treating or reconstructing the cornea.
These claims collectively cover the in-situ forming corneal construct compositions based on biopolymer functionalization for SPAAC crosslinking with embedded regenerative cells, and their direct application methods to wounded corneal tissue enabling scaffold formation without external stimuli.
Stated Advantages
The in-situ formed gels are cytocompatible and support cell viability and phenotype, promoting stable keratinocyte morphology and multilayered re-epithelialization on wounded corneal tissue.
The hydrogels formed exhibit tunable mechanical properties through adjusting polymer functionalization ratios and concentrations, allowing stiffness adaptation for various applications.
The compositions form defined hydrogel structures under ambient conditions without external stimuli such as light or heat, reducing complexity and potential cytotoxicity associated with traditional crosslinking methods.
The injectable flowable biomaterial can conform to irregular wound geometries, enabling filling and stabilization of deep corneal ulcers and wounds not amenable to conventional graft placement.
Use of bio-orthogonal chemistries like SPAAC eliminates the need for catalysts or initiators, preventing toxicity and side reactions with surrounding biological tissues.
Documented Applications
Lamellar and defect reconstruction of corneal stromal tissue to treat surgically incised or wounded corneal areas by forming in-situ corneal stromal substitutes and scaffolds.
Facilitation of corneal matrix remodeling and supporting multilayered re-epithelialization for corneal wound healing.
Delivery vehicles for cells, biomolecules, and pharmaceutical agents to wound sites throughout the body.
Repair, regeneration, and/or reconstruction of skin, subcutaneous tissue, nerve, muscle, bone, cartilage, vitreous, tendon, ligament, fat, retinal, conjunctival, scleral, cardiac, adrenal, and other tissue types.
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