title: Poly-N-isopropylacrylamide (pNIPAM): a reversible bioadhesive for sclerotomy closure.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Doheny Eye Institute, University of California Los Angeles (UCLA), Los Angeles, CA USA ; Federal University of Sao Paulo (UNIFESP), Rua Botucatu, 821, Vila Clementino, Sao Paulo, São Paulo 04023-062 Brazil.
authors.forename: Luiz H
authors.initials: LH
authors.lastname: Lima
authors.affiliation: Doheny Eye Institute, University of California Los Angeles (UCLA), Los Angeles, CA USA.
authors.forename: Yael
authors.initials: Y
authors.lastname: Morales
authors.affiliation: Federal University of Sao Paulo (UNIFESP), Rua Botucatu, 821, Vila Clementino, Sao Paulo, São Paulo 04023-062 Brazil.
authors.forename: Thiago
authors.initials: T
authors.lastname: Cabral
keywords: Pars plana vitrectomy; Retina; Thermosensitive glue; pNIPAM