Radiolabeled Ag₂S quantum dots for the detection of breast cancer tumours

Breast cancer remains a major global health concern and is the most commonly diagnosed cancer among women. Early detection and effective treatment are essential for reducing mortality, highlighting the need for continued development of improved diagnostic and therapeutic agents. The integration of nanomaterials with radiopharmaceuticals represents a promising strategy for cancer imaging and targeted intervention. In this study, we introduce a novel radiolabelled nanocomposite for breast tumour imaging based on gallium-68 and Ag₂S quantum dots (QDs). Thioglycolic acid (TGA)-capped silver sulfide (Ag₂S) QDs were synthesized and characterized using high-resolution transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, photoluminescence spectroscopy, and UV-Vis spectroscopy. The nanoparticles were radiolabelled with high-purity ⁶⁸GaCl₃ through the TGA functional groups on the Ag₂S QD surface, followed by radiochemical purity and stability evaluation. In vivo biodistribution studies were performed in breast tumour -bearing mice following intravenous injection of ⁶⁸Ga@Ag₂S QDs, together with positron emission tomography (PET) imaging and ex vivo biodistribution analysis. This study demonstrates a feasible method for preparing radiolabelled Ag₂S QDs as a potential PET imaging agent for breast cancer detection. Owing to their rapid and high tumour uptake, ⁶⁸Ga@Ag₂S QDs may serve as promising candidates for further development as tumour-targeting PET nanoprobes.