title: Bonding corneal tissue: applications of photoactivated diazopyruvoyl cross-linking agent.
abstract: Photoactivated bis-diazopyruvamide-N,N'-bis(3-diazopyruvoyl)-2,2'-(ethylenedioxy)bis-(ethylamine), (DPD)-was previously shown to bond materials containing type I collagen. However, tensile strength of bonded collagenous tissue ( approximately 78% water) was low compared with that of dehydrated collagenous gelatin ( approximately 14% water). Here we investigated the role of water in corneal tissue bond strength and in bonding corneal tissue to glass. Bonding corneal tissue to glass may be of value in surgically anchoring keratoprostheses to corneas to alleviate problems with extrusion. Bovine corneal samples were lyophilized for various times resulting in tissue hydrations of zero (no water content) to approximately 3.7 (normal water content). The lyophilized corneal tissue was bonded to solid gelatin sheets, to other corneal samples and to glass using 0.3M DPD in chloroform. Control runs used chloroform only. Samples were irradiated with 100 or 200 J of 320-500 nm light. Strong bonds formed with all three materials when corneal tissue hydration was </=1. No bonds or extremely weak bonds formed when tissue hydration levels were >1. No bonding occurred with chloroform alone. Formation of strong bonds only occurs with hydration levels </=1 because corneal collagen fibrils are tightly packed and close enough to cross-link with the 1.78 nm long DPD.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS, USA. gtimberl@kumc.edu
authors.forename: George T
authors.initials: GT
authors.lastname: Timberlake
authors.forename: Abraham L
authors.initials: AL
authors.lastname: Yousef
authors.forename: Stacy R
authors.initials: SR
authors.lastname: Chiles
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Moses
authors.forename: Richard S
authors.initials: RS
authors.lastname: Givens
mesh_terms: D000818:Animals; D002417:Cattle; D003315:Cornea / Q000737:chemistry* / Q000648:ultrastructure; D003432:Cross-Linking Reagents / Q000737:chemistry* / Q000528:radiation effects; D005021:Ethylamines / Q000138:chemical synthesis / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D008954:Models, Biological; D015394:Molecular Structure; D009596:Nitrophenols / Q000737:chemistry* / Q000528:radiation effects; D011773:Pyruvates / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D005021:Ethylamines; C483534:N,N'-bis(3-diazopyruvoyl)-2,2'-(ethylenedioxy)bis(ethylamine); D009596:Nitrophenols; D011773:Pyruvates; D014867:Water; C061076:4-nitrophenyl 3-diazopyruvate