Fig 1: Alkali-treatment of Ti increases adhesion of blood cells.(a) Schematic drawing depicting the experimental procedure, timeline and naming of the experimental conditions. (b–g) Immunofluorescent micrographs of native (b–d) and alkali-treated (e–g) Ti surfaces, either exposed to blood (b,e), blood and subsequently seeded fibroblasts (c,f) or fibroblasts only (d,g), shown here 24 h after seeding fibroblasts. Samples were stained for cell nuclei (DAPI, blue), F-actin (green) and platelet integrin aIIb (CD41, red). One field of view of each condition (using the same magnification) from donor 4 is presented as XY (top) and XZ side view maximum intensity projections (middle) and as surface rendered 3D representations (bottom). Alkali-treatment of Ti was observed to increase platelet and leukocyte adhesion to the surfaces, resulting in formation of a more homogenous and dense blood clot with increased thickness (as shown in XZ side views) compared to native Ti. (h,i) Quantification of cellular components on native and alkali-treated Ti exposed to blood (white bars), blood & fibroblasts (grey bars) or fibroblasts (dark grey bars), 24 h after fibroblast seeding. Total cell volumes per field of view were quantified using F-actin staining (h). Platelet-specific cell volume contribution was estimated from CD41, platelet integrin aIIb stained volume (i). Reported values in boxplots represent mean (middle square), median (central line), 25th to 75th percentile (box) and standard deviation (whisker) of 7 fields of view of duplicate Ti surfaces per condition repeated for 5 donors. Statistically significant differences between conditions are indicated by (*) for p < 0.05, by (**) for p < 0.01 and by (***) for p < 0.001. Significantly increased amount of cellular components, as well as platelets were found on alkali-treated Ti compared to native Ti when exposed to blood.