How to detect fluorescence in nanoparticles
As the Product Manager for NanoSight Pro, I’ve studied nanoparticles extensively, and I’ve seen how fluorescence detection has become a game-changer for nano- and bioparticle analysis. As an extension of traditional light scattering techniques, fluorescence can support your research and provide even deeper insights.
NanoSight Pro leverages these advantages to offer detailed insights into nanoparticle size, concentration, and identity—information that’s invaluable in fields ranging from biophysics to nanomedicine. Read on to find out how.
What is fluorescence?
Certain molecules, called fluorophores, have the remarkable ability to produce fluorescence. How? Imagine a football being kicked into the air. When the ball is struck, it absorbs the energy of the kick and rises high into the air. However, it quickly loses that energy and falls back to the ground. Similarly, fluorophores can be brought to a high-energy state when they interact with an excitation source, for example specific laser wavelength.
These molecules absorb the light as they gain energy. But, just like the football, they can’t hold onto that energy for long. Almost immediately, they release the extra energy by emitting light. This emitted light is what we call fluorescence. The light released has a longer wavelength and is often a different color than the light absorbed.
The power of fluorescence detection
Detecting fluorescence from nano- and bioparticles can significantly enhance our ability to analyze their subpopulations. By attaching fluorophores to nanoparticles, we can label and track them using nanoparticle tracking analysis (NTA) – just like a GPS system can monitor the position of objects.
Existing techniques like Dynamic Light Scattering use lasers to illuminate nanoparticles and small biologics – but aren’t able to identify specific particles. However, fluorescence detection tools like the NanoSight Pro from Malvern Panalytical apply specific laser wavelengths and fluorescence filters to detect and analyze fluorescently tagged particles of interest, unlocking new possibilities in your research.
How NanoSight Pro measures fluorescence
NanoSight Pro and its NS Xplorer software employ NTA by combining laser illumination with a high-sensitivity camera to visualize nanoparticles that scatter the laser light and emit fluorescence. When run in fluorescence mode, here’s how it works:
- Light from a laser excites the particles at a wavelength that matches the fluorophore’s absorption peak.
- As the fluorophores emit light, a long-pass filter allows only the fluorescence signal to reach the camera, blocking any scattered light.
- The software tracks the movement of each fluorescent particle over time, analyzing their Brownian motion and reporting high-resolution size distribution
- By counting the number of fluorescent particles within a known volume, NanoSight Pro determines particle concentration.
What’s more, it does all this in under 5 minutes.
This capability opens up exciting possibilities, enabling you to analyze specific particles, understand biologics, optimize drug formulations, and even develop diagnostic tools.
Benefits for extracellular vesicle research
Fluorescence detection can help to advance research of the tiny biologics we know as extracellular vesicles (EVs). Detecting and analyzing EVs is challenging due to their small size and the complexity of biological samples.
By labeling their surface biomarkers with fluorescent dyes or antibodies, NanoSight Pro can help you selectively visualize and track these vesicles within your sample.
Understanding their characteristics provides insights into disease mechanisms and holds the potential to revolutionize how we diagnose and treat diseases.
Applications in drug delivery
In drug delivery applications, nanoparticles can be loaded with therapeutic agents and tagged with fluorophores for targeted analysis. The NanoSight Pro’s fluorescence mode empowers formulation developers to evaluate the success of purification strategies, assess surface modifications, and confirm the payload of drug delivery vectors. Within minutes, it can provide detailed insights into specific LNP characteristics while simultaneously reporting on size, polydispersity, concentration, or titer.
This direct and visual validation offers researchers an added layer of confidence in their data and formulations, ensuring they are ready for the next step: in vivo assessment.
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