FENAC provides a number of services for the analysis and characterisation of nanoparticles. These include:
A video introduction to FENAC
Microscopy Imaging
The facility has access to a wide range of imaging and microscopy techniques with sub-micrometer to sub-nanometer resolution.
Routinely we use:
Nanoparticle tracking analysis (NTA) provides real-time dynamic nanoparticle visualisation, and for specific samples with particular need, analysis can be done by coherent anti-Stokes Raman scattering (CARS) microscopy.
For biological applications, sub-nanometer resolution imaging of cells with associated nanoparticles can be performed using liquid-mode AFM, and we can prepare the samples for studying nanoparticles inside cells by TEM.
Ancillary data can also be collected, including chemical information on major elements, oxidation state and bond formation and type (EM-EDX and EELS), quantitative morphology information such as particle size distribution and shape factors, along with particle-particle force measurements.
Spectroscopy and Other Analysis
This general heading covers a wide range of methodologies and measurement parameters. ICP-MS and GFAAS will be used to measure metal concentrations of nanoparticles and dissolved metals down to nano-molar concentrations.
We routinely use dynamic light scattering (DLS) and zeta potential to determine size distribution and surface charge of nanoparticles in the samples of interest, and how these parameters change with e.g. temperature composition of the samples.
Fluorescence correlation spectroscopy is used to measure the size distribution and numbers of fluorescent nanoparticles at sub-nm resolution. Surface plasmon resonance, determined by UV-visible spectroscopy, is also used as an indication on nanoparticle size.
We have access to several X-ray diffraction (XRD) instruments to access crystal structure and mineralogical composition of nanoparticles in batch samples. XRD spectra can be used to calculate the crystallite size, e.g. the minimum possible size of the nanoparticles.
Our electron microscopes can also detect energy-dispersive X-ray diffraction, which is used to determine the elemental composition of individual nanoparticles, while x-ray photoelectron spectroscopy (XPS) is used alongside EM methods to measure surface chemistry.
We also use ICP-MS and GFAAS to determine the total metal concentrations in nanoparticle samples, 3D-EEM fluorescence to investigate interactions between nanoparticles and environmental and biological material, and ellipsometry to measure surface film formation and behaviour.
Access to small-angle neutron scattering facilities is available through a collaboration with the STFC ISIS Facility. FENAC can also provide scientific introductions to staff at the STFC Lasers for Science Facility and the Diamond Synchrotron.
Separation Methods
The facility use separation methods alongside the microscopic and spectroscopic techniques for nanoparticle characterisation.
Symmetric and asymmetric flow field-flow fractionator (FlFFF), with on-line uv, fluorescence and multi-angle light scattering detection can be used to separate nanoparticles and other sample components in complex samples, and to determine their continuous size distribution.
Split-flow thin cell (SPLITT) fractionation, dialysis and various ultrafiltration devices (UF), including cross flow ultrafiltration (CFUF), are also used for size fractionation.