Design and Biodistribution of ۹۹mTc-Labeled Gold/Gold Sulfide Nanoconjugates: A Preclinical Evaluation in Balb/c Mice

Introduction: Gold/gold sulfide (GGS) nanoparticles exhibit strong near-infrared (NIR) absorption, high chemical stability, low cytotoxicity, and ease of surface functionalization, enabling deep tissue penetration and targeted cancer theranostics. This study aimed to develop and evaluate ۹۹mTc-labeled PEGylated GGS nanoconjugates for potential SPECT imaging applications.Material and Methods: GGS nanoparticles were synthesized by reacting HAuCl۴ with Na₂S and stabilized with polyvinylpyrrolidone (PVP). PEGylated GGS nanoparticles were radiolabeled with ۹۹mTc using SnCl۲, and radiochemical purity and stability were assessed via ITLC in RPMI and human serum up to ۲۴ h. Cytotoxicity and cellular uptake were evaluated in CT۲۶ colon carcinoma cells. Biodistribution was studied in BALB/c mice at ۱, ۴, and ۲۴h post-intravenous injection by gamma counting of excised organs.Results: ۹۹mTc-GGS-PVP nanoconjugates had an average diameter of ~۶۵.۹ nm, maintained strong NIR absorption post-labeling, and achieved high radiochemical purity (۹۷.۱ ± ۱.۱%) with stability >۸۵% in RPMI and >۸۲% in human serum at ۲۴h. Cytotoxicity was minimal, with ۷۸% cell viability at ۱۲۵ GGS. Cellular uptake increased from ۱.۹۸% at ۲h to ۱۰.۰% at ۲۴h. In vivo, the liver showed the highest uptake (۵۱.۴۴ ± ۷.۵۴ %ID/g at ۱h), decreasing to ۱۴.۱۹ ± ۶.۵۴ %ID/g at ۲۴h; spleen uptake was markedly lower (۱.۵۱ ± ۰.۸۱ %ID/g at ۱h, ۰.۷۶۵ ± ۰.۲۸ %ID/g at ۲۴h).Conclusion: The synthesized ۹۹mTc-GGS-PVP nanoparticles demonstrated high stability, low toxicity, favorable biodistribution, and preserved NIR absorption properties, making them promising candidates for dual-modality cancer theranostics. Their radiolabeling efficiency and biodistribution support their use as radiotracers for SPECT imaging and potential integration into combined diagnostic and therapeutic (theranostic) platforms.

کلیدواژه ها:

Nanoparticles ، Gold/Gold Sulfide ، Biodistribution ، Technetium Tc ۹۹m