Developing data analysis methods for Nanofluidic Scattering Microscopy

Abstract

Nanofluidic Scattering Microscopy (NSM) is a label-free technique that allows the simultaneous measurement of molecular weight and size of single molecules and nanoparticles flowing through a nanochannel. Assuming free diffusion, the diffusivity coefficient derived from the trajectory of a particle can be utilized to determine its hydrodynamic radius via the Stokes-Einstein relation. However, non-specific atractive interactions between biological nanoparticles and the inner walls of the nanochannel, known as biofouling, immobilize the particle, invalidating the assumption of free diffusion and making impossible to accurately determine the particle size. This study introduces a computational method to detect biofouling in NSM, based on the statistical analysis of instantaneous kinetic energy in discrete Brownian motion. The method sets a probability threshold to either accept or reject the hypothesis of free diffusion, allowing for the exclusion of biofouled segments from diffusivity calculations, thereby enhancing the accuracy of hydrodynamic radius determination.