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 procedure