Optical measurement of the mount of decrement in amyloid beta aggregations in the presence of silver nano particles

Amyloid aggregations are the major biomarkers of various chronic diseases. Currently, one of the most common tests for in-vitro quantification of amyloid fibrillation kinetics is Thioflavin T assay, which is based on the flurescence emission of Thioflavin T. Inspite of its helpfulness, still has some drawbacks, and hence, introducing other tests to confirm its results is indispensible. Herein, we used Z-scan method to find the nonlinear refractive indices of silver nano particles at various concentrations. According to the results, silver nano particles altered the order of the aggregations from 10-10 to 10-9 such way that the magnitude of the nonlinear refractive indices and the florescence intensities increased and decreased, respectively with increment in the concentrations. Having the maximum diminution in the fluorescence intensity and the and the largest magnitude of nonlinear refractive index, 0.24 μg/ml was recorded as the optimal concentration. Therefore, the results of Thioflavin T and Z-scan, aligned perfectly with each other in a way that the more the concentrations of the silver nano particles were, the more the magnitude of the nonlinear refractive indices, and the more decrement in the fluorescence intensities, and thus, silver nano particles can wipe out the aggregations, which is quantitatively measurable.