Adhesion of human leukocytes to biomaterials: An in vitro study using alkanethiolate monolayers with different chemically functionalized surfaces

Abstract

The adhesion of human leukocytes to self-assembled monolayers of well-defined surface chemistry was investigated in vitro. Polymorphonuclear (PMN) and mononuclear leukocytes were isolated from human blood by centrifugation techniques. The effect on adhesion of cell activation produced by pre-incubation of leukocytes with phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA) was also studied. Gold substrates were modified by treatment with alkanethiols with three different terminal chemical groups: COOH, OH, and CH(3). After incubation with the two subpopulations of leukocytes, the monolayers were washed, treated with fixative, stained with a Giemsa method, and observed by light microscopy to quantify the number of attached leukocytes. Comparative quantification of the density of leukocyte adhesion to the three types of self-assembled monolayers was determined. The hydrophobic surface expressing CH(3) was found to be the one that induced the highest adhesion density of leukocytes, both of PMN and mononuclear cells. In vitro activation of both mononuclear and PMN leukocytes further increased cell adhesion to the chemically defined monolayers that were used. This enhancement was higher for PHA-activated than for PMA-stimulated mononuclear cells, whereas PMA treatment of neutrophils resulted in a higher rate of adhesion of these cells than PHA stimulation.

Adsorbed fibrinogen leads to improved bone regeneration and correlates with differences in the systemic immune response

“…The inflammatory response to implantable devices is greatly influenced by the material surface chemistry, as demonstrated previously by others [5] and us [6][7][8][9]. Using self-assembled monolayers (SAMs) we demonstrated that methyl-terminated SAMs cause early inflammatory cell recruitment in vivo [8], more polymorphonuclear leukocytes (PMNs) than mononuclear cells [9] and the formation of thicker fibrous capsules around implanted materials [6].…”

Species and Density of Implant Surface Chemistry Affect the Extent of Foreign Body Reactions

“…In those reports, -OH bearing surfaces were found to possess poor biocompatibility. 67,70,[72][73][74][75] A possible explanation for this phenomenon could be the activation of complement proteins, particularly C3b [Tang 1997]. C3b covalently links with the nucleophilic -OH group activating the alternative pathway in the complement system [McNally 1994;Hirata 2003].…”

Cell-Adhesive and Cell-Repulsive Zwitterionic Oligopeptides for Micropatterning and Rapid Electrochemical Detachment of Cells

“…In previous studies, alkanethiol SAM-coated surfaces have been shown to cause local acute inflammatory reactions and adhesion of leukocytes in vivo. 17,18 It is possible that alkanethiol molecules transferred with the cells induce the inflammatory reaction, which would compromise the biocompatibility of this approach. Furthermore, chemical agents used to couple RGD peptides to the carboxyterminals of alkanethiol SAMs could also be a source of toxic contaminants.…”