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Main Authors: Michelotti, Francesco, Sepe, Elisabetta, Occhicone, Agostino, Danz, Norbert, Sinibaldi, Alberto
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.01862
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author Michelotti, Francesco
Sepe, Elisabetta
Occhicone, Agostino
Danz, Norbert
Sinibaldi, Alberto
author_facet Michelotti, Francesco
Sepe, Elisabetta
Occhicone, Agostino
Danz, Norbert
Sinibaldi, Alberto
contents Protein rotational kinetics are essential for understanding macromolecular behavior in crowded environments, yet measuring these dynamics at solid-liquid interfaces remains a significant challenge due to low signal strengths. Here, we experimentally demonstrate a label-based optical technique for measuring rotational diffusion kinetics using an all-dielectric multilayer stack that sustains both transverse electric and transverse magnetic polarized surface electromagnetic waves. We introduce the concept of Fluorescence Recovery after Orientational Photobleaching, a rotational analogue to the standard translatory fluorescence recovery after photobleaching technique, which utilizes anisotropic photobleaching via resonant transverse electric excitation followed by real-time monitoring of the orientational relaxation towards isotropy. Our ratiometric analysis of the transverse electric and magnetic polarized fluorescence components allows for a distance-independent estimation of the rotational friction coefficient. Applying this method to covalently bound neutravidin, we observe a rotational friction coefficient (about 5.8E-18 J s) significantly higher than in bulk solutions, highlighting the impact of surface anchoring and molecular crowding. The proposed approach provides a robust, high-sensitivity platform for resolving biomolecular dynamics in complex interfacial environments.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01862
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rotational Fluorescence Recovery after Orientational Photobleaching via surface electromagnetic waves on dielectric stacks
Michelotti, Francesco
Sepe, Elisabetta
Occhicone, Agostino
Danz, Norbert
Sinibaldi, Alberto
Optics
Biological Physics
Protein rotational kinetics are essential for understanding macromolecular behavior in crowded environments, yet measuring these dynamics at solid-liquid interfaces remains a significant challenge due to low signal strengths. Here, we experimentally demonstrate a label-based optical technique for measuring rotational diffusion kinetics using an all-dielectric multilayer stack that sustains both transverse electric and transverse magnetic polarized surface electromagnetic waves. We introduce the concept of Fluorescence Recovery after Orientational Photobleaching, a rotational analogue to the standard translatory fluorescence recovery after photobleaching technique, which utilizes anisotropic photobleaching via resonant transverse electric excitation followed by real-time monitoring of the orientational relaxation towards isotropy. Our ratiometric analysis of the transverse electric and magnetic polarized fluorescence components allows for a distance-independent estimation of the rotational friction coefficient. Applying this method to covalently bound neutravidin, we observe a rotational friction coefficient (about 5.8E-18 J s) significantly higher than in bulk solutions, highlighting the impact of surface anchoring and molecular crowding. The proposed approach provides a robust, high-sensitivity platform for resolving biomolecular dynamics in complex interfacial environments.
title Rotational Fluorescence Recovery after Orientational Photobleaching via surface electromagnetic waves on dielectric stacks
topic Optics
Biological Physics
url https://arxiv.org/abs/2604.01862