Technology

Our measurements are carried out on the Tunable Resistive Pulse Sensing platform TRPS. We offer complimentary characterisation techniques upon request.

How it works
Here we describe tunable resistive pulse sensing (TRPS) the pore can be stretched in real time to suit the sample. The brief set up and theory for TRPS technologies is as follows: a stable ionic current is established by two electrodes, separated by a pore; as particles/analytes translocate the pore they temporarily occlude ions, leading to a transient decrease in current known as a “blockade event”. By monitoring changes in blockade width, blockade magnitude (Δip) and blockade frequency (events/min), it is possible to elucidate the zeta potential, size, and concentration of colloidal dispersions in situ.

Sample requirements
Compatible with any buffer
Size range 50 nm upto 10 mm
Capable of being run with upto 20% ethanol mixtures

Applications

  • Nanomedicines: the focus of this week’s conference. Nanoparticle-based drug’s activity is know to be dependent on physical characteristics (size, shape and zeta potential) as well as its chemical ones (encapsulated drug or surface protein). Relying purely on DLS for characterisation jeopardises the whole the discovery and clinical testing process, as this technique doesn’t provide accurate enough information about particles physical properties. Furthermore, there is a growing requirement for accurate assessment of particle concentration, rather than estimate based on weight, that only TRPS can provide.
  •  Virus: TRPS can provide total virus particle count, which is a proxy for infectivity. It also allows accurate stability studies, as viral particle aggregation can be quantified. It can also be used for vaccine formulation purposes (simultaneous measurement of active ingredient and adjuvants). NTA is biggest competition on this market.
  • Bacteria: similarly to viruses, accurate count and purity study. Can also measures OMVs, which are vesicles excreted from bacteria, just like exosomes are produced by cells. Flow cytometry is used extensively for these, but it doesn’t provide size/aggregation and OMV measurement.
  • Lipids/polymer/inorganic/magnetic/metallic particles: reliable, number based measurement, true polydispersity, aggregation study, zeta when possible (shape element if we can pull qualitative info). NTA, DLS and DCS compete with TRPS.
  • Exosomes: Accurate size, size distribution, concentration and, if required, zeta potential, measurement. TRPS is approved by the ISEV for the physical characterisation of EVs, which is compulsory for publication. NTA is not as accurate, especially for concentration (log scale accuracy only). We can add qEV isolation to the service.