Pyridine derivatives as candidates for selective and sensitive fluorescent biosensors for lung cancer cell imaging and iron ions detection

A series of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile (APC) derivatives has been synthesized and their applicability for the role of fluorescent molecular sensors for chemical and biochemical applications has been evaluated. It has been found that the dimethylamino-substituted APC derivatives exhibit a very high solvatochromic effect, that makes them good candidates for application as chemosensors of polarity changes. The fluorescence intensity and emission wavelength of some of the derivatives turned out to be very sensitive to trace amounts of Hg2+, Hg22+, Sb3+ and Bi3+ ions, while other derivatives are selectively sensitive to the presence of Fe2+ and Fe3+ ions. Hence, these derivatives can be applied for the determination of those ions concentration in various media, such as waste water, food products or contaminated soils. Moreover, the applicability of the sensors studied for living lung cancer cells imaging was assessed. It has been found that all of the APC derivatives show good photostability under irradiation conditions used in fluorescence microscopy, while their response is not affected significantly by changes in temperature. Additionally, MTT assays indicated that these sensors were safe for the living cells. So, some of the derivatives studied may be applied for fluorescent staining of the living cells to enable their visualization by fluorescence microscopy.