Quantum Dot Applications in Biomedical Imaging

Quantum dots are semiconductor nanocrystals distinguished by size-dependent emission wavelengths, high brightness and exceptional photostability. Their broad absorption spectra coupled with narrow, tunable emission peaks enable simultaneous excitation of multiple probes for multiplexed imaging. In biomedical contexts, quantum dots have been tailored for in vitro cellular labelling, in situ hybridisation of nucleic acids, and in vivo deep-tissue visualisation. Surface engineering and bioconjugation strategies impart water solubility, biocompatibility and target specificity, allowing functionalisation with peptides, antibodies or carbohydrates. Advances in cadmium-free formulations and glyco-quantum dots mitigate toxicity concerns and enhance clearance profiles. Near-infrared emitting variants exploit optical windows in biological tissue to achieve centimetre-scale penetration with reduced autofluorescence, while superbright probes improve signal-to-noise ratios at low doses. Single-particle tracking of quantum dots has elucidated intracellular transport mechanisms and nanoparticle–cell interactions, informing design of optimised imaging agents. Emerging platforms couple quantum dot fluorescence with photoacoustic or electrochemical readouts, broadening diagnostic capabilities. Collectively, these developments point to a versatile suite of probes for high-resolution, quantitative imaging in basic research, diagnostic pathology and image-guided surgery.

Research from Nature Portfolio

Recent studies have introduced superbright short-wave infrared quantum dots that combine chemical synthesis with ultrafast laser processing to yield contrast agents operating in the second near-infrared window. These probes exhibit an approximate eighty-fold enhancement in quantum yield, enabling low-dose, deep-tissue in vivo imaging at reduced excitation intensities. Complementary work on single-particle tracking harnesses live-cell imaging of quantum dots to quantify intracellular diffusion, clustering and vesicular release. Multidimensional analysis of brightness and trajectory parameters has revealed how zwitterionic surface chemistries promote uniform cytosolic behaviour and reliable imaging metrics. In parallel, a new generation of compact quantum dots has been engineered for fluorescence in situ hybridisation of mRNA, overcoming size constraints and photophysical limitations of organic dyes. These probes deliver robust transcript quantification, enhanced photostability and multiplexed detection of distinct mRNA species within single cells.

Research from all publishers

A green synthesis pathway has been devised for Cd-free glyco-CuInS₂ quantum dots bearing thiol-linked monosaccharides. These water-soluble probes display dual emission in the visible and near-infrared ranges, strong membrane targeting and uniform penetration into three-dimensional tumour spheroids, with successful translation to in vivo imaging. Another study has reviewed the rapid growth of near-infrared emitting quantum dots for biosensing and bioimaging applications, highlighting their reduced tissue autofluorescence, improved penetration depth and diverse uses from photoelectrochemical sensors to fluorescence-guided surgery. In a complementary approach, fluorescent quantum dots have been functionalised as biosensors for cancer-related microRNA monitoring. By exploiting the fluorescence capacity of quantum dots and the aberrant expression of microRNAs in tumour cells, these platforms achieve sensitive, real-time tracking of molecular markers to inform early prognosis and therapeutic response.

Quantum Dot Applications in Biomedical Imaging publication trend

The graph below shows the total number of articles in quantum dot applications in biomedical imaging across all publications each year (not limited to Nature Index journals).

Technical terms

Quantum dot: A semiconductor nanocrystal with size-tunable optical properties used as a fluorescent probe.

Quantum yield: The ratio of photons emitted to photons absorbed, indicating fluorescence efficiency.

Near-infrared window (NIR-II): The tissue-transparent wavelength range from approximately 1,000 to 1,700 nm, used for deep-tissue imaging.

Förster resonance energy transfer (FRET): A distance-dependent energy transfer mechanism between a donor and an acceptor fluorophore.

Photostability: The ability of a fluorescent probe to resist photobleaching under prolonged illumination.

Surface passivation: The process of coating a nanocrystal surface to prevent nonradiative recombination and improve biocompatibility.

References

1. Green synthesis of glyco-CuInS2 QDs with visible/NIR dual emission for 3D multicellular tumor spheroid and in vivo imaging. Journal of Nanobiotechnology (2023).
2. Near infrared quantum dots for biosensing and bioimaging. TrAC Trends in Analytical Chemistry (2024).
3. Ultrafast photochemistry produces superbright short-wave infrared dots for low-dose in vivo imaging. Nature Communications (2020).
4. Single quantum dot tracking reveals the impact of nanoparticle surface on intracellular state. Nature Communications (2018).
5. Quantum Dots for Cancer-Related miRNA Monitoring. ACS Sensors (2022).
6. Enhanced mRNA FISH with compact quantum dots. Nature Communications (2018).