Photoluminescent hydrogel
Inventors
Assignees
New Jersey Institute of Technology
Publication Number
US-10653802-B2
Publication Date
2020-05-19
Expiration Date
2037-09-13
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Shown and described is a composition and a method to prepare a dopant-free photoluminescent hydrogel with synthetic polymers are disclosed. The hydrogel can be synthesized in one embodiment by incorporating an amino acid to a citric acid based polyester oligomer followed by multiple crosslinking group functionalization through a transesterification reaction using an enzyme such as Candida antarctica Lipase B (CALB) as a catalyst. The hydrogels are injectable, degradable, and their mechanical and photoluminescent properties are tunable. An in vivo study shows that the hydrogel emits strong fluorescence under visible light excitation and can completely degrade over time.
Core Innovation
The invention discloses a dopant-free photoluminescent hydrogel composed of synthetic polymers, specifically a citric acid and hexaethylene glycol based polyester oligomer with serine and ethyl thioglycolate, crosslinked using polyethylene glycol (PEG). The synthesis utilizes Candida antarctica Lipase B (CALB) as a catalyst for transesterification, allowing incorporation of amino acids into the polyester backbone and providing multiple crosslinking moieties. This hydrogel exhibits intrinsic photoluminescent properties without the need for external fluorescent dopants.
The problem addressed arises from conventional photoluminescent hydrogels that require doping or conjugation with organic dyes, fluorescent proteins, nanocrystals, or metal complexes, all of which pose limitations such as photobleaching, cytotoxicity, carcinogenesis, and adverse immune responses. Previous efforts using protein-based hydrogels had issues with low quantum efficiency, lack of tunability, potential immunogenicity, or reliance on toxic crosslinking agents, and newly developed synthetic biodegradable polymers lacked sufficient reactive moieties for hydrogel formation.
The invented hydrogel overcomes these drawbacks by achieving self-fluorescence and biodegradability through a biocompatible synthetic route, enabling in situ gelation, injectability, and optical traceability in vivo. Mechanical and photoluminescent properties can be tuned by varying formulation parameters such as pH, polymer concentration, and crosslinking agents. The hydrogel is shown to emit strong fluorescence under visible light excitation and degrades completely in vivo, making it suitable for applications requiring injectable, detectable, and biocompatible biomaterials.
Claims Coverage
There is one independent claim, which introduces several inventive features relating to the composition and synthesis of a biodegradable, dopant-free, photoluminescent hydrogel.
Dopant-free polyester-based biodegradable photoluminescent hydrogel
The hydrogel is defined as a citric acid and hexaethylene glycol based polyester oligomer-serine-ethyl thioglycolate-polyethylene glycol (CHPO-Ser-ET-PEG) hydrogel, synthesized from biocompatible monomers without the addition of exogenous fluorescent dopants.
Synthesis via florescent oligomer formation and enzymatic thiolation
The process includes: 1. Synthesizing a fluorescent oligomer by reacting amino acid serine, citric acid, and hexaethylene glycol to form a citric acid and hexaethylene glycol serine based polyester oligomer (CHPO-Ser), 2. Functionalizing the resulting oligomer using a transesterification reaction catalyzed by Candida antarctica Lipase B (CALB) to graft ethyl thioglycolate onto the backbone, introducing at least 5 to 7 thiol groups.
Formation of hydrogel using multi-arm PEG crosslinker
The hydrogel is formed by reacting the thiolated oligomer with a multiple arm polyethylene glycol (PEG) to crosslink and generate the hydrogel network.
Hydrogel emitting fluorescence under visible light with emissions up to 720 nm
The resulting hydrogel exhibits visible light-excited fluorescence, with emission detectable up to 720 nm, thereby enabling detection under visible light excitation.
The claim covers a specific composition and synthesis method of a biodegradable, photoluminescent, and injectable hydrogel based on a citric acid and hexaethylene glycol polyester oligomer modified with serine and thiol functionalities, enzymatically processed, and crosslinked with multi-arm PEG, yielding a material with intrinsic fluorescence and tailored degradability.
Stated Advantages
The hydrogel provides self-fluorescence and biodegradability without the drawbacks of photo-bleaching, toxicity, or immunogenicity seen in conventional doped hydrogels.
The material is injectable and moldable, allowing for minimally invasive administration and in situ gelation in irregular-shaped defects.
Mechanical and photoluminescent properties, as well as degradation rates and drug release profiles, are tunable by adjusting formulation parameters such as polymer concentration, pH, crosslinker type, and temperature.
Strong photoluminescence under visible light enables real-time, non-invasive in vivo imaging and tracking of implanted materials without extra fluorescent dye/labeling.
The hydrogel demonstrates superior biocompatibility in vitro and in vivo, promoting cell adhesion and proliferation without cytotoxicity or carcinogenic risks associated with traditional dopants.
Documented Applications
Implantable scaffolds for tissue engineering, providing an injectable and biodegradable scaffold with intrinsic photoluminescence for bioimaging and in vivo tracking.
Drug delivery devices, where the hydrogel acts as a vehicle for encapsulating and controllably releasing therapeutic molecules.
Fluorescent imaging probes for tracking material degradation and scaffold location using visible-wavelength fluorescence in living systems.
Interested in licensing this patent?