Methacrylate Oligomers with Pendant Isocyanate Groups as Tissue Adhesives

Abstract

Oligomers containing pendant isocyanate groups and residual double bonds were synthesized from m-isopropenyldimethylbenzylisocyanate, [TMI], and/or 2-isocyanatoethylmethacrylate, [IEM], and methacrylate or vinyl monomers. The compounds were characterized by physico-chemical means. Most of the oligomers are liquids at room temperature, stable in air, have a MW range from 1400 to 2600 and an isocyanate content from 5% to 18%. The compounds, especially those with TMI or IEM and TMI and methacrylate constituents dissolved in suitable solvents yielded stronger, more permanent bonds to glutaraldehyde treated bone than other tissue adhesives. Thermocycling in water for one week between 5°C and 55°C did not decrease adhesion indicating that exposure to water or thermal shock produced no deterioration of the bond. No correlation between bonding efficiency and -NCO content or increase in molecular weight could be established. Tensile adhesion of human dentin joined to composite restorative resins by means of the oligomers was similar to that of the best dental bonding agents. Vinyl monomers containing oligomers are preferable to bond dentin to dental composites. The oligomeric compositions are also excellent soft tissue adhesives. For example, they provide a strong bond between collagenous substrates such as calfskin and cured denture base resins. Subject to their biocompatibility the formulations could find many applications in medicine, dentistry or veterinary science.