title: Physical and biological properties of a novel siloxane adhesive for soft tissue applications.
abstract: The aim of this study was to investigate the adhesive properties of an in-house aminopropyltrimethoxysilane-methylenebisacrylamide (APTMS-MBA) siloxane system and compare them with a commercially available adhesive, n-butyl cyanoacrylate (nBCA). The ability of the material to perform as a soft tissue adhesive was established by measuring the physical (bond strength, curing time) and biological (cytotoxicity) properties of the adhesives on cartilage. Complementary physical techniques, X-ray photoelectron spectroscopy, Raman and infrared imaging, enabled the mode of action of the adhesive to the cartilage surface to be determined. Adhesion strength to cartilage was measured using a simple butt joint test after storage in phosphate-buffered saline solution at 37 degrees C for periods up to 1 month. The adhesives were also characterised using two in vitro biological techniques. A live/dead stain assay enabled a measure of the viability of chondrocytes attached to the two adhesives to be made. A water-soluble tetrazolium assay was carried out using two different cell types, human dermal fibroblasts and ovine meniscal chondrocytes, in order to measure material cytotoxicity as a function of both supernatant concentration and time. IR imaging of the surface of cartilage treated with APTMS-MBA siloxane adhesive indicated that the adhesive penetrated the tissue surface marginally compared to nBCA which showed a greater depth of penetration. The curing time and adhesion strength values for APTMS-MBA siloxane and nBCA adhesives were measured to be 60 s/0.23 MPa and 38 min/0.62 MPa, respectively. These materials were found to be significantly stronger than either commercially available fibrin (0.02 MPa) or gelatin resorcinol formaldehyde (GRF) adhesives (0.1 MPa) (P < 0.01). Cell culture experiments revealed that APTMS-MBA siloxane adhesive induced 2% cell death compared to 95% for the nBCA adhesive, which extended to a depth of approximately 100-150 microm into the cartilage surface. The WST-1 assay demonstrated that APTMS-MBA siloxane was significantly less cytotoxic than nBCA adhesive as an undiluted conditioned supernatant (P < 0.001). These results suggest that the APTMS-MBA siloxane may be a useful adhesive for medical applications.
authors.affiliation: Smith & Nephew Research Centre, York Science Park, Heslington, York YO10 5DF, UK. darren.wilson@smith-nephew.com
authors.forename: D J
authors.initials: DJ
authors.lastname: Wilson
authors.forename: D H
authors.initials: DH
authors.lastname: Chenery
authors.forename: H K
authors.initials: HK
authors.lastname: Bowring
authors.forename: K
authors.initials: K
authors.lastname: Wilson
authors.forename: R
authors.initials: R
authors.lastname: Turner
authors.forename: J
authors.initials: J
authors.lastname: Maughan
authors.forename: P J
authors.initials: PJ
authors.lastname: West
authors.forename: C W G
authors.initials: CW
authors.lastname: Ansell
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000269:Adhesives / Q000737:chemistry*; D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002015:Bucrylate / Q000737:chemistry*; D002356:Cartilage / Q000187:drug effects / Q000378:metabolism; D002448:Cell Adhesion; D019902:Chondrocytes / Q000378:metabolism; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005557:Formaldehyde / Q000737:chemistry; D005780:Gelatin / Q000737:chemistry; D008956:Models, Chemical; D010710:Phosphates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011437:Propylamines / Q000737:chemistry*; D012118:Resorcinols / Q000737:chemistry; D012756:Sheep; D012821:Silanes / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D013997:Time Factors
chemical_list: D000178:Acrylamides; D000269:Adhesives; D001672:Biocompatible Materials; D017077:Culture Media, Conditioned; D010710:Phosphates; D011108:Polymers; D011437:Propylamines; D012118:Resorcinols; D012821:Silanes; D012833:Siloxanes; C503297:aminopropyltrimethoxysilane-methylenebisacrylamide; C477688:resorcinol-formaldehyde resin; C088294:3-aminopropyltrimethoxysilane; D005557:Formaldehyde; D002015:Bucrylate; D005780:Gelatin; C021221:N,N'-methylenebisacrylamide