VRPI Thermoresponsive Reversibly Attachable Patch for Temporary Intervention in Ocular Trauma
Technical Report,15 Aug 2012,14 Aug 2015
University of Southern California Los Angeles United States
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Penetrating injuries to the eye can lead to decreased intraocular pressure IOP and potentially subsequent retinal detachmentand loss of vision, if not managed properly. The current standard of care in the civilian setting is to close sclerotomies and other perforations of the sclera are to place sutures which are uncomfortable and can lead to abrasion and infection from eye rubbing. In the theater of operations, the standard is to shield the eye and wait for transportation to a full service base hospital.Here we fabricate and test, both in vitro and in vivo, a sutureless reversibly adhesive wound closure for the eye. The enabling technology is a thermo-reversible adhesive poly n-isopropyl acrylamide, PNIPAM, which is adhesive to tissues at body temperature and non-adhesive at room temperature. Here we evaluated 1 PNIPAM sterilization stability, 2 PNIPAM thermalstability, 3 uniaxial adhesion strength to porcine sclera in vitro, and 4 in vitro IOP maintenance in a simulated eye model. Results were compared against cyanoacrylate glue, a common bioadhesive. Lastly, PNIPAM adhesive gel patches were tested in an in vivo rabbit model of scleral trauma. The primary endpoint for this study was that the PNIPAM hydrogel patch sustained a greater mean IOP vs. the mean IOP encountered using the current standard of care no intervention. The secondary outcome evaluated was the tissue response to the PNIPAM material. New Zealand rabbits underwent a surgical sclerotomy to create a full-thickness laceration 3mm in length through the eye. The treatment group n12 received thehydrogel patch and the control group n6 received no intervention. IOP measures were taken once every 12hrs for 4 days following the procedure.