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Fluorescent dyes that emit in the near-infrared (NIR) region gained increasing attention in medical imaging and fluorescence guided surgery. [1,2] Optical imaging allows the surgeons to visualize the normal and diseased tissues in real-time.[2] Particularly interesting in this respect is NIR fluorescent coatings on medical devices such as implants, catheters and stents etc., which are extensively used in various treatments and surgical procedures. However, most of the existing coating materials are composed of either indocyanine green (ICG) or other visible/blue light active fluorophores. ICG-based coatings suffer from limited brightness and poor photostability whereas blue/visible light active coatings are not compatible with well-established laparoscopic systems. [3] Here, we introduce new NIR coating material composed of cyanine dye salts and a biocompatible polymer. [4] The dye is encapsulated into the polymer coating with help of bulky counterions, which, according to our studies on polymeric nanoparticles, [5] prevents dye leakage and minimizes self-quenching. A series of dyes based on cyanine 7.5 family were synthesized and tested. In comparison to ICG-based coatings, our new NIR coatings exhibit superior brightness and photostability Moreover, these coating materials showed good adhesion properties and useful to coat medical devices, including metallic fiducials and catheters. Such coated medical devices show high fluorescence brightness and exceptional stability in air and buffer medium for at least 150 days. Moreover, our coatings are biocompatible and thus, appear promising for biomedical use. We have demonstrated the various possible medical applications of the NIR coated devices (fiducials and catheters) in ex-vivo and in-vivo porcine models. Funding: This work was supported by “NICE” grant of SATT Conectus, Alsace. References: [1] A. H. Ashoka, et. al. J Phys Chem Lett, 2019, 10, 2414. [2] S. Hernot et. al. Lancet Oncol, 2019, 20, e354. [3] Y. Choi et. al. Surg Endosc 2011, 25, 2372. [4] European patent application filed. [5] Reisch, et al., Nature Commun., 2014, 5, 4089.
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