Fluorescent Silicon Nanoparticles for Biological Applications

Fluorescent silicon nanoparticles, commonly known as silicon quantum dots (SiQDs), represent a burgeoning class of zero-dimensional nanomaterials distinguished by their tunable photoluminescence, high photostability and inherently low toxicity. Owing to quantum confinement effects, SiQDs exhibit size- and surface-dependent emission across the visible spectrum, enabling tailored probes for in vitro and in vivo imaging. Advances in synthesis—ranging from hydrothermal routes to microwave-assisted pyrolysis—have yielded water-soluble, biocompatible constructs with quantum yields rival­ling those of traditional cadmium-based quantum dots. Surface functionalisation with hydrophilic ligands or biomolecular moieties confers colloidal stability and target specificity, while maintaining robust fluorescence. In parallel, the development of ratiometric and multi-emission schemes has enhanced quantitative sensing of ions, pH and biomolecules within live cells. The intersection of superior optical performance and benign silicon chemistry has catalysed applications in cellular labelling, drug delivery tracking, biosensing and theranostics. As a result, fluorescent silicon nanoparticles occupy a unique niche, offering a sustainable and versatile platform for imaging, diagnostics and real-time monitoring of biological processes.

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Fluorescent Silicon Nanoparticles for Biological Applications publication trend

The graph below shows the total number of articles in fluorescent silicon nanoparticles for biological applications across all publications each year (not limited to Nature Index journals).

Technical terms

Silicon quantum dot (SiQD): A nanoscale silicon particle (typically 2–10 nm) exhibiting size-dependent electronic and optical properties due to quantum confinement.

Photoluminescence: The process by which a material absorbs photons and then re-emits them as light, commonly used to report nanoparticle emission characteristics.

Quantum yield: The ratio of emitted to absorbed photons, indicating the efficiency of fluorescence in a nanoparticle system.

Surface functionalisation: Chemical modification of nanoparticle surfaces to confer water solubility, biocompatibility and target specificity.

Ratiometric fluorescence: A sensing approach that measures the ratio of two emission intensities, providing self-calibrated read-outs less sensitive to environmental fluctuations.

References

1. Recent Advances in Silicon Quantum Dot-Based Fluorescent Biosensors. Biosensors (2023).
2. One-Step Hydrothermal Synthesis of Yellow and Green Emitting Silicon Quantum Dots with Synergistic Effect. Nanomaterials (2019).
3. Imitation-mussel fluorescent silicon quantum dots for selective labeling and imaging of bacteria and biofilms. Frontiers in Bioengineering and Biotechnology (2022).