Novel Fluorescent Probes for Amyloid Detection

Based on the notions of supramolecular nonenzymatic interaction of amyloid with known fluorescent probes (thioflavin T and Congo red) a search for the substances, which may be perspective as fluorescent probes selective to amyloid in the line of 4-N-aryl-3,5-dioxo-1-formyl-10-oxa-4-azatricyclo[5.2.11.7.02.6]dec-8-ene derivatives has been undertaken.

Dry crystals of the chosen substances having the structure of the molecular rotor similar to thioflavin T emitted light in the visible range of 421.0–435.5 nm, when excited by ultraviolet. Dissolution of the substances in 96° ethanol extinguishes fluorescence. Water-alcohol solutions of these substances (0.75%; water:ethanol 96°=1:1, pH>7) also did not emitted the light (beyond the sensitivity of photomultiplier FEU-39). Treating with alcohol solutions of the tested preparations the depersonalized deparaffinated, preliminarily stained with hematoxylin, human kidney sections with clinically and histologically proved kidney amyloidosis was not accompanied by a marked fluorescence. Staining of the sections of the same kidney with water-alcohol alkalized solution of these preparations after imbedding into the non-fluorescent transparent medium was accompanied by luminescence of all kidney structures in the visible range at a wavelength of 534 nm with a more intensive luminescence of amyloid deposits than cellular structures.

Conclusion. The result obtained opens good perspectives of using the tested substances as novel fluorophores for detecting amyloid.

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Sapozhnikov S.P., Karyshev P.B., Sheptukhina A.I., Nikolayeva O.V., Avruyskaya A.A., Mitrasov Y.N., Kozlov V.A. Novel Fluorescent Probes for Amyloid Detection. Sovremennye tehnologii v medicine 2017; 9(2): 91, https://doi.org/10.17691/stm2017.9.2.11