Detecting molecules across different spatial scales remains a major challenge in biological samples, particularly in complex tissues such as brain, where linking molecular identification and nanoscale structural detail is essential for understanding function. Fluorescence microscopy provides selective labeling of specific molecules but cannot fully resolve many cellular and subcellular features, whereas electron microscopy reveals ultrastructure without molecular specificity. Bridging these modalities is difficult because commonly used fluorescent probes such as dyes and proteins cannot provide electron contrast. Quantum dots are particularly useful as they retain fluorescence while providing sufficient electron density for ultrastructural visualization. Here, we show that streptavidin-functionalized CdSe/CdS core/shell quantum dots can function as dual-modal probes for labeling γ-aminobutyric acid (GABA) neurons in brain tissue. The quantum dots produce bright and stable fluorescence signals for optical detection while their inorganic composition generates strong electron contrast in ultrathin sections examined by transmission electron microscopy. This work demonstrates that functionalized CdSe/CdS quantum dots can serve as stable dual-modal probes for fluorescence and electron microscopy in complex tissues, highlighting the potential of semiconductor nanocrystals for multifunctional imaging applications.
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Imaging of Brain Tissue Using CdSe/CdS Core/Shell Quantum Dots for Correlative Fluorescence and Electron Microscopy
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Received: 15 May 2026 | Revised: 05 Jul 2026 | Accepted: 25 Jul 2026 | Published: 14 Aug 2026
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