Poly-N-isopropylacrylamide (pNIPAM): a reversible bioadhesive for sclerotomy closure. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Lima, Luiz; Morales, Yael; Cabral, Thiago
• Is Part Of: International journal of retina and vitreous. Volume 2:Issue 1(2016)
• Page Start: 1
• Page End: 7
• Publication Date: 2016-12
• Subjects: Pars plana vitrectomy -- pNIPAM -- Retina -- Thermosensitive glue; Retina -- Diseases -- Periodicals; Retina -- Periodicals; Ophthalmology -- Periodicals; 617.735
• DOI: 10.1186/s40942-016-0048-5
• Languages: English
• ISSNs: 2056-9920

Abstract

Abstract Purpose To determine the safety and efficacy of poly-N -isopropylacrylamide, a thermoresponsive adhesive, for sutureless sclerotomy closure in rabbits. Methods Eight rabbits were randomized into three groups: short-term acute, mid-term chronic, and long-term chronic studies. A corresponding control group in which the scleral wounds were sutured by 6–0 vicryl sutures was assigned for each study group. A 20-gauge sclerotomy was performed following a core vitrectomy and 0.1 mL of 50 % liquid poly-N -isopropylacrylamide was applied to the scleral wounds. Before the polymer application, the scleral surface was raised above 32 °C using a halogen bulb lamp. Follow-up exams included color external and fundus photography, fundus fluorescein angiography, optical coherence tomography, and electroretinography. After the last follow-up assessment, the rabbits were sacrificed and histopathological studies on the scleral incision sites were performed. Results Scleral wound healing was observed in the long-term chronic study rabbits. Histological studies were able to identify poly-N -isopropylacrylamide polymer at the sclerotomy site in the mid-term chronic study rabbits. Besides iatrogenic cataracts due to mechanical instrument touch in 2 rabbits, no other ocular abnormalities were identified in any of the eyes in the perioperative setting or during the follow-up period. Cornea, retina, and vitreous remained unaffected, and no abnormal inflammatory reaction or endophthalmitis was noticed in the 3 study groups. Filtering blebs indicative of leakage through the sclerotomies were not observed during the follow-up period. Conclusion Poly-N -isopropylacrylamide may provide effective in vitro scleral adhesion above 32 °C. Clinical studies are required to evaluate its utility in patients undergoing pars plana vitrectomy.