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Detection Limit for Optically Sensing Specific Protein Interactions in Free-solution

submitted on 01.12.2017, 06:32 and posted on 01.12.2017, 15:46 by Harish Sasikumar, Manoj M. Varma
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.



  • Analytical Chemistry

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Indian Institute of Science



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Declaration of Conflict of Interest

The authors declare no competing financial interest.