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Freedman BR, Kuttler A, Beckmann N, Nam S, Kent D, Schuleit M, Ramazani F, Accart N, Rock A, Li J, Kurz M, Fisch A, Ullrich T, Hast MW, Tinguely Y, Weber E, Mooney DJ. Enhanced tendon healing by a tough hydrogel with an adhesive side and high drug-loading capacity. Nat Biomed Eng 2022; 6:1167-1179. [PMID: 34980903 PMCID: PMC9250555 DOI: 10.1038/s41551-021-00810-0] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 09/13/2021] [Indexed: 12/14/2022]
Abstract
Hydrogels that provide mechanical support and sustainably release therapeutics have been used to treat tendon injuries. However, most hydrogels are insufficiently tough, release drugs in bursts, and require cell infiltration or suturing to integrate with surrounding tissue. Here we report that a hydrogel serving as a high-capacity drug depot and combining a dissipative tough matrix on one side and a chitosan adhesive surface on the other side supports tendon gliding and strong adhesion (larger than 1,000 J m-2) to tendon on opposite surfaces of the hydrogel, as we show with porcine and human tendon preparations during cyclic-friction loadings. The hydrogel is biocompatible, strongly adheres to patellar, supraspinatus and Achilles tendons of live rats, boosted healing and reduced scar formation in a rat model of Achilles-tendon rupture, and sustainably released the corticosteroid triamcinolone acetonide in a rat model of patellar tendon injury, reducing inflammation, modulating chemokine secretion, recruiting tendon stem and progenitor cells, and promoting macrophage polarization to the M2 phenotype. Hydrogels with 'Janus' surfaces and sustained-drug-release functionality could be designed for a range of biomedical applications.
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Affiliation(s)
- Benjamin R Freedman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Andreas Kuttler
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Sungmin Nam
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Daniel Kent
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | | | | | - Nathalie Accart
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Anna Rock
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Jianyu Li
- Department of Mechanical Engineering, McGill University, Montreal, Quebec, Canada
| | - Markus Kurz
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Andreas Fisch
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Thomas Ullrich
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Michael W Hast
- Biedermann Lab for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Yann Tinguely
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Eckhard Weber
- Novartis Institutes for Biomedical Research, Basel, Switzerland.
| | - David J Mooney
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
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Multi-region finite element modelling of drug release from hydrogel based ophthalmic lenses. Math Biosci 2020; 331:108497. [PMID: 33098846 DOI: 10.1016/j.mbs.2020.108497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022]
Abstract
Understanding the way in which drug is released from drug carrying hydrogel based ophthalmic lenses aids in the development of efficient ophthalmic drug delivery. Various solute-polymer interactions affect solute diffusion within hydrogels as well as hydrogel-bulk partitioning. Additionally, surface modifications or coatings may add to resistance of mass transfer across the hydrogel interface. It is necessary to consider both interfacial resistances as well as the appropriate driving force when characterizing interface flux. Such a driving force is induced by a difference in concentration which deviates from equilibrium conditions. We present a Galerkin finite element approach for solute transport in hydrogels which accounts for diffusion within the gel, storage effects due to polymer-solute interaction, as well as partitioning and mass transfer resistance effects at the interface. The approach is formulated using a rotational symmetric model to account for realistic geometry. We show that although the resulting global system is not symmetric in the case of partitioning, it is similar to a symmetric negative semidefinite system. Thus, it has non-positive real eigenvalues and is coercive, ensuring the validity of the finite element formulation as well as the numerical stability of the implicit backward Euler time integration method employed. Two models demonstrating this approach are presented and verified with release experimental data. The first is the release of moxifloxacin from intraocular lenses (IOLs) plasma grafted with different polyacrylates. The second accounts for both loading as well as the release of diclofenac from disc shaped IOL material loaded for varied time periods and temperature.
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