Noise force spectroscopy with Optical Tweezers

Abstract

In this work we will present a study of noise force spectroscopy using optical tweezers. In particular, we will study the fluctuations of two kinds of systems, a passive one, polystyrene spheres of known radius (bead), and a biological system like the red blood cells. Experimentally, we will directly optically trap the systems at rest and measure the force signal during 30s. Once we get the force signal, we will compute the power spectra which present a Lorentzian shape. By fitting the power spectrum to a Lorentzian, we will obtain the friction coefficient and the stiffness of both systems. The results are compatible with the theoretical predictions and the experimental values obtained by different techniques