Development of a new fluorescent nanosensor based on metal –organic frameworks (MOF) for determination of lamotrigine in exhaled breath condensate

Abstract

In the present study, a fluorimetric method based on metal –organic framework (MOF) was designed to determine the concentration of lamotrigine in the exhaled breath condensate. The used MOF consists of Tb3+ ions as the metal moiety and dimethylformamide and 1,10-phenanthroline as the organic moiety.Aim: The development of a new method based on MOF for lamotrigine determination in exhaled breath condensate is one of the objectives of this research. Methods: MOF was synthesized from a solution containing terbium with phenanthroline and dimethylformamide, then a certain volume of MOF solution was added to the sample of lamotrigine and after the time required for drug-MOF interaction, the fluorescence intensity at wavelength of 545 nm was measured and the difference between the fluorescence intensity in the presence and absence of lamotrigine was recorded as a analytical signal. The effect of important factors such as pH, reaction time, concentration of MOF was investigated and finally by plotting the calibration curve, the characteristics of the analytical method such as accuracy, precision and repeatability were investigated and the method was used to determine drug concentration in biological samples. Discussion: This MOF has poor fluorescence in the basic media. This weak fluorescence is due to the energy transfer from nitrogen atoms of dimethylformamide and phenanthroline to oxygen atoms of dimethylformamide. The fluorescence of this framework increases in an acidic media due to the protonation of nitrogen atoms and the consequent inhibition of energy transfer. Lamotrigine adding to the above system reduces the fluorescence intensity. The probable reason for this quenching is the competition of lamotrigine with protons and thus the re-establishment of energy transfer.Results: The linear range is between 0.05 to 0.2 μg/ml and the detection limit is 11 ng / ml.