Andor Technology has revealed that its electron multiplying CCD camera, in combination with an imaging spectrograph and a sheath flow cuvette, is being used in metal nanoparticle analysis.
Researchers at the La Jolla Bioengineering Institute in California have been able to analyse individual metal nanoparticles at rates of 100 per second or faster using the technology.
This new capability will remove current bottlenecks associated with characterising single nanoparticles, potentially leading to the development of brighter and more uniform tags for use in biomolecular detection and cancer therapeutics.
Exploiting the unique structure-dependent optical properties of metal nanoparticles depends on controlling particle size and shape, and this is limited not only by synthetic and assembly approaches, but also on the ability to efficiently measure nanoparticle optical properties.
Ensemble (or bulk) characterisation techniques are simple and fast, but do not directly reveal information about sample heterogeneity.
Single nanoparticle analysis techniques based on microscopic imaging reveal heterogeneity, but are slow and labour intensive.
The approach developed by the team at La Jolla provides multiparameter optical measurements of thousands of individual nanoparticles in just a few minutes.
An Andor Newton electron multiplying CCD (EMCCD) camera was used to collect Raman scattering spectra since it offers a combination of high detection efficiency, low noise, and faster spectral acquisition rates, without any loss of data quality.
In this case, the EMCCD is used to capture spectral data from individual surface-enhanced resonant Raman (SERRS) nanoparticle tags with signal integration times of only 300us.
The researchers are using this technique to guide the development of brighter and more uniform SERRS tags, which have much narrower spectral features compared with fluorescence labels.
This should enable more highly multiplexed measurements of cells and molecules than is currently possible with fluorescence flow cytometry.
