2017/12/01 by Sasikumar, Harish, Varma, Manoj M.
#Applied Physics (physics.app-ph) #Biological Physics (physics.bio-ph) #Biomolecules (q-bio.BM) #FOS: Biological sciences #FOS: Physical sciences
paper · doi:10.48550/arxiv.1712.00224
Optical molecular sensing techniques are often limited by the refractive index change associated with the probed interactions. In this work, we present a closed form analytical model to estimate the magnitude of optical refractive index change arising from protein-protein interactions. The model, based on the Maxwell Garnett effective medium theory and first order chemical kinetics serves as a general framework for estimating the detection limits of optical sensing of molecular interactions. The model is applicable to situations where one interacting species is immobilized to a surface, as commonly done, or to emerging techniques such as Back-Scattering Interferometry (BSI) where both interacting species are un-tethered. Our findings from this model point to the strong role of as yet unidentified factors in the origin of the BSI signal resulting in significant deviation from linear optical response.