Successive epoxy and carbodiimide cross-linking of dermal sheep collagen.
Cross-linking of dermal sheep collagen (N-DSC, T(S) = 46 degrees C, number of amine groups = 31 (n/1000)) with 1,4-butanediol diglycidyl ether (BDDGE) at pH 9.0 resulted in a material (BD90) with a high T(S)(69 degrees C), a decreased number of amine groups of 15 (n/1000) and a high resistance towards collagenase and pronase degradation. Reaction of DSC with BDDGE at pH 4.5 yielded a material (BD45) with a T(S) of 64 degrees C, hardly any reduction in amine groups and a lower stability towards enzymatic degradation as compared to BD90. The tensile strength of BD45 (9.2 MPa) was substantially improved as compared to N-DSC (2.4 MPa), whereas the elongation at break was reduced from 210 to 140%. BD90 had a tensile strength of 2.6 MPa and an elongation at break of only 93%. To improve the resistance to enzymes and to retain the favorable tensile properties, BD45 was post-treated with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of N-hydroxysuccinimide (NHS) to give BD45EN. Additional cross-linking via the formation of amide bonds took place as indicated by the T(S) of 81 degrees C and the residual number of amine groups of 19 (n/1000). BD45EN was stable during exposure to both collagenase and pronase solutions. The tensile properties (tensile strength 7.2 MPa, elongation at break 100%) were comparable to those of BD45 and glutaraldehyde treated controls (G-DSC). Acylation of the residual amine groups of BD45 with acetic acid N-hydroxysuccinimide ester (HAc-NHS) yielded BD45HAc with a large reduction in amine groups to 10 (n/1000) and a small reduction in T(S) to 62 degrees C. The stability towards enzymatic degradation was reduced, but the tensile properties were comparable to BD45.
Zeeman
R
R
Department of Chemical Technology, and Institute of Biomedical Technology, University of Twente, Enschede, The Netherlands.
Dijkstra
P J
PJ
van Wachem
P B
PB
van Luyn
M J
MJ
Hendriks
M
M
Cahalan
P T
PT
Feijen
J
J
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D002072:Butylene Glycols; D003094:Collagen / Q000737:chemistry*; D017364:Collagenases; D003432:Cross-Linking Reagents; D004355:Drug Stability; D005022:Ethyldimethylaminopropyl Carbodiimide; D066298:In Vitro Techniques; D008422:Materials Testing; D011402:Pronase; D012756:Sheep; D013718:Tensile Strength
D001672:Biocompatible Materials; D002072:Butylene Glycols; D003432:Cross-Linking Reagents; D003094:Collagen; C014376:1,4-bis(2,3-epoxypropoxy)butane; D017364:Collagenases; D011402:Pronase; D005022:Ethyldimethylaminopropyl Carbodiimide