Tunable resistive pulse sensing
Tunable Resistive Pulse Sensing (TRPS) is a single-particle technique used to measure the size, concentration and zeta potential of particles as they pass through a size-tunable nanopore.[1][2]
The technique adapts the principle of resistive pulse sensing, which monitors current flow through an aperture, combined with the use of tunable nanopore technology, allowing the passage of ionic current and particles to be regulated by adjusting the pore size.[3][4] The addition of the tunable nanopore allows for the measurement of a wider range of particle sizes and improves accuracy.[3][4]
Technique
Particles crossing a nanopore are detected one at a time as a transient change in the ionic current flow, which is denoted as a blockade event with its amplitude denoted as the blockade magnitude. As blockade magnitude is proportional to particle size, accurate particle sizing can be achieved after calibration with a known standard. This standard is composed of particles of a known size and concentration. For TRPS, carboxylated polystyrene particles are often used.
Nanopore-based detection allows particle-by-particle assessment of complex mixtures. By selecting an appropriately sized nanopore and adjusting its stretch, the nanopore size can be optimized for particle size and improve measurement accuracy.
Adjustments to nanopore stretch, in combination with a fine-control of pressure and voltage allow TRPS to determine sample concentration [5][6] and to accurately derive individual particle zeta potential[7] in addition to particle size information.
Applications
TRPS was developed by Izon Science Ltd, producer of commercially available nanopore-based particle characterization systems.[8] Izon Science Limited currently sell one TRPS device, known as the “Exoid”. Previous devices include the “qNano”, the “qNano Gold” and the “qViron”. These systems have been applied to measure a wide range of biological and synthetic particle types including viruses and nanoparticles. TRPS has been applied in both academic and industrial research fields, including:
- Drug delivery research (e.g. lipid nanoparticles and liposomes)
- Extracellular vesicles such as exosomes
- Virology and vaccine production
- Biomedical diagnostics
- Microfluidics
References
- ^ Dynamically resizable nanometre-scale apertures for molecular sensing"; Stephen J. Sowerby, Murray F. Broom, George B. Petersen; Sensors and Actuators B: Chemical Volume 123, Issue 1 (2007), pages 325-330
- ^ Vogel et al. (2011) "Quantitative Sizing of Nano/Microparticles with a Tunable Elastomeric Pore Sensor" Journal of Analytical Chemistry 83 (9), pp 3499–3506
- ^ a b Roberts et al. (2010) "Tunable Nano/Micropores for Particle Detection and Discrimination: Scanning Ion Occlusion Spectroscopy" Small - Volume 6, Issue 23, pp 2653–2658
- ^ a b Willmott et al. (2010) "Use of tunable nanopore blockade rates to investigate colloidal dispersions" J. Phys.: Condens. Matter 22, 45411
- ^ Willmott, G. R., Yu, S.S.C. and Vogel, R., “Pressure Dependence of Particle Transport Through Resizable Nanopores” Proceedings of ICONN, 128-131 (2010).
- ^ G. Seth Roberts, Sam Yu, Qinglu Zeng, Leslie C.L. Chan, Will Anderson, Aaron H. Colby, Mark W. Grinstaff, Steven Reid, Robert Vogel. “Tunable Pores for Measuring Concentrations of Synthetic and Biological Nanoparticle Dispersions” Biosensors and Bioelectronics, 31 pp. 17-25, (2012).
- ^ "A variable pressure method for characterising nanoparticle surface charge using pore sensors" Robert Vogel, Will Anderson, James Eldridge, Ben Glossop, and Geoff Willmott. Anal. Chem., Just Accepted Manuscript DOI: 10.1021/ac2030915 Publication Date (Web): February 27 (2012).
- ^ "IZON launch world's first commercial nanopore platform". PRLog. June 23, 2009.