Used in biomedical imaging due to their strong optical properties and biocompatibility. The silica coating enhances stability and prevents aggregation in biological environments. Commonly applied in cancer detection and targeted drug delivery systems. Also utilized as contrast agents in microscopy techniques like dark-field imaging. Their surface can be easily modified with antibodies or therapeutic molecules for specific targeting. Applied in biosensors for rapid and sensitive detection of pathogens or biomarkers. Used in photothermal therapy, where they absorb near-infrared light to generate heat and destroy tumor cells. Industrial applications include catalysis and use in advanced coatings for optical devices.