Characterization of Nanoparticles

You can't comprehensively understand and appreciate the potential of nanoparticles unless you equip yourself with thorough knowledge of their preparation and uses. The characterization of nanoparticles is done using several different methods that have their origin in materials science.

Majority of the techniques used for characterization of nanoparticles are light-based, however, TRPS (Tunable Resistive Pulse Sensing), a non-optical nanoparticles' characterization method has also been developed. The latter enables simultaneous measurement of the surface charge, concentration and size of a large variety of nanoparticles. TRPS applies something known as Coultier principle that facilitates particle-by-particle measurement and quantification of the above-mentioned three important characteristics of nanoparticles, at high resolution.

Characterization of nanoparticles using conventional methods


The conventional approach for characterization of nanoparticles, in fact for any particle, involves:

  • The corresponding boiling point

  • The corresponding melting point

  • Solubility

  • The molecular composition or molecular structure

  • Water part and soil proportion

  • pH level

  • Vapour pressure

  • Octanol and water proportion

Parameters specifically involved in characterization of nanoparticles


The various parameters involved specifically in characterization of nanoparticles are:

  • Zeta potential

  • Aggregation

  • Porosity and surface area

  • Wettability

  • The interactive surface's size and shape

  • Hydrated surface analysis

  • Particle size distribution

  • Adsorption potential and

  • Solubility

You can use several different techniques for better understanding these parameters. Some of these techniques are:

  • DLS or Dynamic Light Scattering method

  • XPS or X-ray Photoelectron Spectroscopy

  • AFM or Atomic Force Microscopy

  • Electron Microscopy including SEM and TEM

  • NMR or Nuclear Magnetic Resonance

  • MALDI-TOF or Matrix-Assisted Laser Desorption / Ionisation Time-of-Flight Mass Spectrometry

  • NTA or Nanoparticle Tracking Analysis for the tracking of Brownian motion

  • FTIR or Fourier Transform Infrared Spectroscopy

  • Dual Polarisation Interferometry

  • XRD or Powder X-ray Diffraction

  • Ultraviolet visible spectroscopy

Different technologies used for characterization of nanoparticles

Various calibration and measurement technologies are in use for easy distribution and concentration of the manufactured nanoparticles varying from 1 nm to 100 nm in size, that employ certain practical techniques for this purpose.

A statistical analysis of the size and shape of the manufactured nanoparticles (like carbon nanotubes, titanium oxides and fullerenes) is done using these technologies. Furthermore, certain methods are employed for capturing the efficiency of the manufactured nanoparticles in air. Certain calibration technologies have also been developed for easy elimination of errors caused by the material and shape of the manufactured nanoparticles.

A statistical analysis of the size and shape of the manufactured nanoparticles (like carbon nanotubes, titanium oxides and fullerenes) is done using these technologies. Furthermore, certain methods are employed for capturing the efficiency of the manufactured nanoparticles in air. Certain calibration technologies have also been developed for easy elimination of errors caused by the material and shape of the manufactured nanoparticles.

More on non-optical nanoparticle characterization through TRPS

TRPS or Tunable Resistive Pulse Sensing method of nonoptical characterization of nanoparticles is a technique that enables high-throughput single particle measurements, as the bio molecular analytes and/or colloids are made to pass through (one at a time) a size-tunable nanopore.

The method makes use of the resistive pulse sensing principle that monitors the current flow through an aperture, combining it with the tunable nanopore technology, enabling the easy passage of particles (that need regulation) and ionic current by making appropriate adjustments to the pore size.

The particles passing through a pore get detected one-by-one, in the form of a transient change in current flow that's denoted as a blockade event. Its amplitude is denoted as blockade magnitude. Please note that since the blockade magnitude is proportionate to the particle size, calibrating it with a non-standard can return the accurate size of the particles.

Such nanopore-based detection method provides for comprehensive particle-by-particle assessment of the complex mixtures. The measurement accuracy can be significantly approved by optimizing the pore size to particle size by making adjustments to the pore's stretch.