In vivo cell recruitment, cytokine release and chemiluminescence response at gold, and thiol functionalized surfaces

Hydroxylated and methylated surfaces were prepared by the self-assembled mo nolayer technique (SAM) of alkane thiols on gold. The surfaces were used to evaluate the influence of implant surface chemistry on protein deposition and inflammatory cell response. Implants were inserted subcutaneously in th e rat for 3 and 24 h. The surface chemical properties influenced the in vit ro rat plasma protein adsorption (ellipsometry/antibody) with few exception s (albumin not found and fibrinogen always found). The number of recruited cells and their distribution (DNA from implant versus from exudate) was inf luenced by the different chemistries at 24 h, but not at 3 h. HIS48+, ED1+, ED2+ and small numbers of CD5+ cells were present in the exudate at both t ime periods (flow cytometry), The cellular oxidative metabolism was low, al though cells on -OH surfaces responded with the highest phorbol ester-stimu lated chemiluminescence (CL)/DNA. The levels of cytokines IL-1 alpha, IL-1 beta and TNF alpha (ELISA) were not influenced by material surface chemistr y. Sham operated sites had a higher cytokine concentration/DNA compared wit h exudates from an implant milieu. The results of this study show that surf ace chemical functionalization modifies specific events in the inflammatory response around implants in soft tissues. (C) 1999 Elsevier Science Ltd. A ll rights reserved.