Label-free microscale thermophoresis for the study of lactoferrin-drug interaction

In this study, a microscale thermophoretic (MST) method was developed to investigate lactoferrin-drug interaction using label-free system which depends on the intrinsic fluorescence of one interacting partner. The interaction between lactoferrin and the iron chelator deferiprone was first investigated to evaluate the excretion of deferiprone into mother milk during lactation. Furthermore, the interaction between lactoferrin and amphotericin B was investigated for possible explanation of the observed synergistic effect as antifungal effect. The experiments were performed on Monolith NT.115 LabelFree® (NanoTemper Technologies, Munich, Germany). Different concentrations of the intended drugs in the range of 0.007- 250 μM were titrated against 120 nM fixed concentration of lactoferrin which was dissolved in 0.1 M tris buffer at pH 7.4. The measurements were performed using standard capillaries at 20% excitation power and medium MST power. The results indicated a significant interaction between lactoferrin and deferiprone however, no significant interaction between lactoferrin and amphotericin B was observed. The data were analyzed using NT Analysis software which was provided by NanoTemper Technologies. The estimated binding constant for lactoferrin-deferiprone interaction was (8.9 x 10 -6 ± 1.6 SD) which is reported for the first time. This significant binding between lactoferrin and deferiprone may potentiates the drug secretion into mother milk. The technique shows fast and simple approach to study protein-drug interaction without complicated labelling procedures