Membrane labelling by fluorescent probes: Incorporation of TMA-DPH in erythrocyte membranes

A study of the labelling of isolated resealed erythrocyte membranes by TMA-DPH has been carried out. A quantitative study shows that saturation appears to take place when increasing the relative quantity of probe bulk concentration to membrane concentration; this is readily interpreted by a simple incorporation model with a limited number of sites in the membrane. A qualitative study shows that an increase in the labelling leads to an evolution of the probe fluorescence properties; the existence of different types of sites is involved in the interpretation but the system is too complex to allow it to be represented by a simple model. As a consequence of this study, care has to be taken in labelling biological material so as to avoid excessive probe incorporation.