389 research outputs found
Detection Limit for Optically Sensing Specific Protein Interactions in Free-solution
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.Comment: 7 Page Manuscript + 14 Page Supplementary Informatio
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