Self-assembly of PbS hollow sphere quantum dots via gas–bubble technique for early cancer diagnosis

Quantum dots (QDs) with their unique optical properties have attracted widespread interest in cancer diagnosis and therapy. Due to their ability to absorb and emit light very efficiently, lead sulfide (PbS) hollow spheres with nanometer-to-micrometer dimensions having tailored structural, optical, and surface properties represent an important class of QDs that are potentially useful for early cancer detection. In this study, PbS hollow sphere QDs have been successfully synthesized using a template-free and green method. The formation of hollow structures was explained by a gas–liquid interface aggregation mechanism, in which the formation of SO2 gas bubbles plays a key role. The synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDX), photoluminescence (PL) and Fourier transform infrared spectroscopy (FTIR). The results demonstrate that the PbS hollow spheres possess good optical quality with strong luminescence properties, which indicate their capabilities for the simultaneous detection of multiple cancer biomarkers in blood assays and cancer tissue biopsies.