Light-Free Iridium–Luciferase Conjugates Enable Carbon-Centered Radical Proximity Labeling and Deep-Tissue Microenvironment Mapping

02 June 2025, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Carbon-centered radicals offer unmatched nanometer-scale precision for proximity labeling, yet existing light-driven platforms such as μMap are limited by shallow tissue penetration and phototoxicity. We present the first fully light-free, dualluciferase BRET system that redefines in vivo proximity proteomics. A bespoke Ir(III) photocatalyst-[Ir(dF(CF₃)ppy)₂(bpy-N₃-maleimide)]PF₆ is site-specifically tethered to both EGFR-targeting antibodies and luciferases (NanoLuc or RLuc8.6-535), placing the catalyst and donor within 10 nm for on-demand single-electron transfer. This architecture generates high-efficiency carbon radicals deep within tissue (>3 mm) without any external light source, eliminating phototoxicity while preserving nanometer spatial resolution. By leveraging NanoLuc’s intense emission and RLuc8.6-535’s spectral isolation, we achieve unprecedented signal-to-noise ratios and proteome coverage—unlocking a truly in vivo-compatible route for spatially resolved microenvironment mapping.

Keywords

Carbon-centered radicals
Proximity Labeling
Deep live tissue labeling

Supplementary materials

Title
Description
Actions
Title
Supplementary data-chemrexiv
Description
This file include all figures.
Actions

Supplementary weblinks

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.