Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging

Abstract

Raluca Borlan,1,* Madalina Tudor,1,2,* Olga Soritau,3 Adrian Florea,4 Emoke Pall,5 Bogdan Pop,6,7 Dana Maniu,2 Simion Astilean,1,2 Monica Focsan1,2 1Nanobiophotonics and Laser Microspectroscopy Centre, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babes-Bolyai University, Cluj-Napoca, Cluj, Romania; 2Biomolecular Physics Department, Faculty of Physics, Babes-Bolyai University, Cluj-Napoca, Cluj, Romania; 3Department of Radiobiology and Tumor Biology, Oncology Institute Prof. Dr. Ion Chiricuta, Cluj-Napoca, Cluj, Romania; 4Department of Cell and Molecular Biology, Faculty of Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Cluj, Romania; 5Department of Infectious Diseases, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Cluj, Romania; 6Department of Pathology, Oncology Institute Prof. Dr. Ion Chiricuta, Cluj-Napoca, Cluj, Romania; 7Department of Pathology, University of Medicine and Pharmacy Iuliu Hatieganu, Cluj-Napoca, Cluj, Romania*These authors contributed equally to this workCorrespondence: Monica Focsan, Biomolecular Physics Department, Faculty of Physics, Babes-Bolyai University; Nanobiophotonics and Laser Microspectroscopy Centre, Interdisciplinary Research Institute on Bio-Nano-Sciences, Str. Treboniu Laurian 42, Cluj-Napoca, 400271, Romania, Email [email protected]: Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients.Methods: NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed.Results: Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach.Conclusion: Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation. Keywords: organic nanoparticles, dual-modal agents, NIR fluorescence imaging, NIR phototherapeutic agents, mild hyperthermia, melanoma

Keywords

• organic nanoparticles
• dual-modal agents
• nir fluorescence imaging
• nir phototherapeutic agents
• mild hyperthermia
• melanoma