Enhanced albumin affinity of silicone rubber.
The authors have developed a method to increase the albumin affinity of silicone rubber-containing medical devices. A vinyl-methyl silicone co-monomer was hydroxylated via an oxymercuration-demercuration reaction and then film-coated on a silicone rubber sheet. C16 acylation of the -OH coated sheet was carried out by an esterification reaction catalyzed by 4-DMAP. FTIR spectroscopy confirmed the presence of -OH groups following the hydroxylation reaction, and (CH2)n groups following the acylation reaction. 125I-labeled albumin binding studies indicated graded enhancements, according to reagent concentration, with maximal 2.7X and 2.5X increases for 20% -OH coated and 20% -OH/C16 acylated surfaces, respectively. Incubation with a protein denaturant, sodium dodecyl sulfate (SDS), removed 73% of adsorbed albumin from unmodified controls, with only 25 and 34% removal from 20% -OH coated and 20% -OH/C16 acylated surfaces, respectively. These results suggest that -OH and C16 modified surfaces not only preferentially adsorb albumin, but also retain it in a more stable configuration; this is an unexpected finding for -OH modified surfaces. Based on similar albumin affinities for biocompatible C18 alkylated and C16 acylated polyether polyurethanes, the authors expect significant improvements in thromboresistance and complement-activating potential for this modified silicone rubber.
Tsai
C C
CC
Department of Surgery, University of Texas Southwestern Medical Center, Dallas 75235.
Frautschi
J R
JR
Eberhart
R C
RC
D000215:Acylation; D000327:Adsorption; D000818:Animals; D002417:Cattle; D006900:Hydroxylation; D008855:Microscopy, Electron, Scanning; D011145:Polyvinyls; D012710:Serum Albumin, Bovine; D012826:Silicone Elastomers; D012828:Silicones; D012833:Siloxanes
D011145:Polyvinyls; D012826:Silicone Elastomers; D012828:Silicones; D012833:Siloxanes; C034183:vinyl polysiloxane; D012710:Serum Albumin, Bovine