Reversible Attachment of Retinal Implants and Drug Delivery Devices
Principal Investigator: Buddy Ratner
It is essential in biological implantation and drug delivery applications to have safe, effective, and stable adhesives between biological and engineered system surfaces. Such adhesives can be very useful in managing tears in the retina, complicated retinal detachments, as well as for attaching microelectronic devices to the retina. It is also essential that these adhesives are reversible, which will allow stable attachment during treatment, management of the eye conditions, and easy removal after treatment. Hydrogels, fibrin, sealants, and photocurable glues have been tested for the purpose of implanting microelectronic devices in the eye, with very limited success. The limited success has mostly been due to inflammation, toxicity, insuff
The inventors disclose the composition of thermoresponsive adhesives and a method for reversible attachment to biological tissues. Materials such as poly(dimethyl siloxane) (PDMs), polymide, or parylene C are coated with a thermoresponsive adhesive that allows them to be attached to a biological tissue. The thermoresponsive adhesive may include polymers such as alginate, hyaluronic acid, collagen, fibrin, chitin, agarose, cellulose, laminin, and polymerized N-isopropyl acrylamide (pNIPAM). These thermoresponsive adhesives possess the ability to attach to the biological tissue of interest at a critical temperature where strong adhesion occurs. For example, pNIPAM exhibits strong adhesion between 32oC and 38oC. pNIPAM-coated implants were effectively attached and detached from retinal surface by changing the temperature of the retinal tissue. The adhesives can be attached various types of eye tissue, such as the cornea or sclera, for repair of damaged tissue. The biodegradable nature of the adhesive allows attachment and repair of the eye tissue during treatment and easy removal afterwards. The adhesive can also be used for successful attachment of a microelectronic device such as a glaucoma shunt.
• The invention may be used to attach a microelectronic retinal prosthesis to the retina.
• It may be used as a means of repairing a plasma pNIPAM (ppNIPAM) coated punctum plug for temporary occlusion of the nasolacrimal duct for treating dry eye.
• ppNIPAM coated haptics inside the eye may also be used to repair intraocular lenses.
• Stem cells may also be attached to biological tissue using this method.
• Episcleral, ocular, or periocular implants may be attached using the thermoresponsive adhesives to deliver a chemotherapeutic-antineoplastic agent for the treatment of intraocular tumors.
• The adhesives used may include a wide range of commonly used polymeric materials that can be applied to biological tissue adhesion by simply changing the temperature of the tissue.
• The adhesives used show no toxicity and are highly biocompatible.
• pNIPAM coated retinal implants during tests showed very high stability. The implants were able to resist large forces in tests.
For more info, contact: Roï Eisenkot
- Wenqi Teng, Thomas J. Long, Qianru Zhang, Ke Yao, Tueng T. Shen, Buddy D. Ratner (Oct. 2014), A tough, precision-porous hydrogel scaffold: ophthalmologic applications., Biomaterials, 35, 8916 - 8926
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