DETERMINATION OF THE PROTEIN LAYER THICKNESS

Detection of biomarkers in picomolar or subpicomolar concentrations for revealing marker proteins at the early stage of neurodegenerative diseases is an urgent problem. One of the stages of its solution is determination of the marker's protein layer thickness adhering to the surface of magnetized nanoparticles. In this work, we present an algorithm for determining the protein layer thickness on the surface of magnetized polydisperse nanoparticles having logarithmically normal size distribution of the magnetic core, as well as the results of the analysis of the error in the determination of the thickness of this layer. The analysis is based on an analytical solution of the equation of diffusion of nanoparticles. With the aid of this solution, in the computational experiment the concentration profiles along the length of the measuring channel have been imitated at the given values of the "measurement" duration, protein layer thickness on the nanoparticles surface, and of the relative accidental error of "measurements." It is shown that at the protein layer thickness above 10 nm the proposed technique allows one to determine this thickness with a relative error 5-10 times lower than the error of measuring their concentration.