Glutardialdehyde induced fluorescence technique (GIFT): A new method for the imaging of platelet adhesion on biomaterials

is the adhesion and subsequent activation of platelets upon contact with bl ood. The development of new or modified materials necessitates adequate met hods for the detection and quantification of platelet/material interactions . These interactions are commonly investigated by means of scanning electro n microscopy (SEM), radioisotope and immunological techniques, or by quanti fication of released platelet contents. Given the lack of a simple, rapid, and inexpensive assay, we developed a novel method for the accurate assessm ent of platelet adhesion after contact with foreign surfaces, which enables quantitative measurements as well as imaging of the platelet shape change, and which omits conventional or immunological staining and time-consuming preparative steps. The glutardialdehyde induced fluorescence technique (GIF T) uses the epifluorescence of glutardialdehyde-fixed platelets detected by fluorescence microscopy and is suitable for opaque and transparent materia ls. Combined with computer-aided image analysis, numbers of adherent platel ets, platelet-covered surface, and average platelet spread area can be dete rmined as markers of surface thrombogenicity. To validate the technique, fo ur materials of different thrombogenicity [polypropylene (PP), poly(D,L-lac tide) (PDLLA), 2-hydroxymethyl-methacrylate-grafted PDLLA (PDLLA-HEMA), and heparin-coupled PDLLA-HEMA] were investigated by GIFT and SEM. We found co ncordant results with SEM and GIFT with the following ranking of thrombogen icity: PP > PDLLA > PDLLA-HEMA greater than or equal to PDLLA-HEMA-heparin. GIFT significantly discriminated between the investigated materials. The s urface modifications led to improved thromboresistance with reduced platele t adhesion and shape change. The main advantages of GIFT as compared with S EM are: no vacuum-drying or dehydration, less time-consuming procedure, fix ation and fluorescence "staining" in one step, and suitability for computer -aided image analysis allowing quantitative assessment of platelet adhesion as well as imaging of the platelet share change with high-contrast images. In conclusion, GIFT is a valid, rapid, and simple method for the quantitat ive determination of platelet/material interactions intended for the evalua tion of thrombogenicity of biomaterials surfaces. (C) 2000 John Wiley & Son s, Inc.