In vitro blood reactivity to hydroxylated and non-hydroxylated polymer surfaces

Blood coagulation on biomaterials requires the combination of distinct activation processes

“…Fluorescence microscopy was used to determine the number of adherent leukocytes and thrombocytes. Supplementary to the DAPI staining reported previously [34], blood platelets were stained with FITC-conjugated antiCD41a (Becton Dickinson) overnight at 4 C. Samples were analyzed on a fluorescent microscope (Leica, DMIRE2), taking microphotographs of 20 predefined positions per sample. Adherent cell numbers were determined by computer-aided analysis (Image Tool, UTHSCSA, San Antonio, TX).…”

“…The complement system is a plasmatic immune defence system made up of over 20 different proteins usually being activated either by immunoglobulins or by specific surface structures found on bacteria and other pathogens. Certain biomaterial surface structures, such as hydroxyl groups, that resemble natural initiators are known to elicit activation of the complement system [34]. Cellular immune reactions are linked to leukocytes -mainly neutrophilic granulocytes and monocytes.…”

Are there sufficient standards for the in vitro hemocompatibility testing of biomaterials?

“…unfractionated heparin (UFH), low molecular weight heparin (LMWH) or pentasaccharide types (e.g. Fondaparinux) [58,59] are applied in varying concentrations (0.5 IU to 5 IU heparin per mL blood) [60][61][62][63][64]. For PRP based assays, concentrations of 0.105 -0.109 M and 0.129 M tri-sodium citrate are recommended by the British Committee for Standards in Haematology (BCSH) and International Society on Thrombosis and Haemostasis (ISTH) [65][66][67].…”

Intracellular signaling mechanisms associated with CD47 modified surfaces

“…Thus, developing an anti-inflammatory strategy to address this issue remains an unmet need in biomaterial science. To that end, numerous attempts have been made to enhance biocompatibility by functionalizing synthetic surfaces with bioactive or bioinert molecules [6-8]. Unfortunately, fewer efforts have been made to elucidate the intracellular signaling mechanisms that are initiated when cells come in contact with synthetic surfaces [9].…”