Synthesis of Silicon Quantum Dots for Bioimaging Applications and Their Impact on Public Health

Quantum dots (QDs), nanostructures inside semiconductors, exhibit distinct optical and catalytic properties due to quantum confinement, with precise size and emission control. Considering the toxicity concerns, Si QDs are promising substitutes for cadmium-based QDs in optoelectronics and deep-tissue imaging. QD attributes can be tailored using colloidal and hydrothermal method. Hydrosilylation and surface modification improve Si QD biocompatibility and stability for biological imaging. Core-multishell QDs, having multiple material layers around a core, are stable and tunable, making them suitable for LEDs, solar cells, and bio-imaging. For bio-imaging, dye-functionalized Si QDs are good light-harvesting probes, while metal-functionalized ones such as Sc–Si QDs are potentially useful for in vivo imaging with low cytotoxicity. Sulfhydryl-Si QDs are excellent bioimaging probes due to their long-lasting photoluminescence. QDs can also detect early-stage pancreatic cancer by targeting specific cell surface proteins and outperforming fluorescent labels for ovarian cancer diagnosis. Si QD cytotoxicity depends on size, coating, and cell type, requiring thorough evaluation. Synthesizing high-quality QDs with durable properties remains challenging, for microwave-assisted and colloidal methods. Additionally, toxicity concerns leads research into non-toxic materials and coatings. Bismuth- and gadolinium-co doped carbon QDs (Bi, Gd-CQDs) offer many fluorescence hues for imaging, while perovskite and metal–organic framework QDs (MOF QDs) improve optoelectronics and environmental sensing. QDs have many scientific applications, and more research on them can improve their efficacy, safety, and beyond. This chapter gives insight into Si QDs and their applications.