Tunable Resistive Pulse Sensing Nanoparticle Analyzer

What is the Tunable Resistive Pulse Sensing Nanoparticle Analyzer?

An analyzer that detects particles one by one as they pass through an adjustable elastomeric nanopore, using blockade of ionic current to measure size, concentration and, with voltage scaling, surface charge. It provides refractive-index-independent, high-resolution data in conductive electrolytes.

Overview

The instrument applies a voltage across a nanopore in a stretchable polyurethane membrane in electrolyte. Each particle passing the pore causes a transient current drop whose amplitude is proportional to its volume according to the Coulter principle, while pulse frequency at known pressure gives concentration. The pore can be stretched to tune its size, so a single membrane covers a range such as 40 to 10000 nm and the analyst can match the pore to the sample. Size measurement does not depend on refractive index, so it handles silica, polymer, lipid and mixed materials with equal accuracy, and resolves particles with small size differences. Particles must be conductive-medium compatible and pores may block in samples with aggregates or debris. Filtration, electrolyte matching and calibration with standards are used to keep pores clear.

How does it work?

Nanoparticle tracking analysis illuminates a dilute suspension with a laser sheet and records the scattered light of individual particles with a camera; software follows each track and derives a diffusion coefficient, converted to hydrodynamic diameter with the Stokes–Einstein equation, and counts particles per millilitre in a known volume. Resistive pulse sensing passes particles through a nanopore in an electrolyte; each particle transiently reduces ionic current in proportion to its volume, giving size and concentration. Field-flow fractionation separates particles in a thin channel by diffusion under a cross-flow before in-line light scattering detectors measure size and molar mass. Nano flow cytometers use hydrodynamic focusing and sensitive side-scatter and fluorescence detection to phenotype single particles. Sample dilution and calibration with reference beads are essential.

What are the key features?

• Tunable elastomeric nanopore covering 40 nm to 10 µm
• Coulter-principle sizing independent of refractive index
• Concentration from pulse rate at calibrated pressure
• Zeta potential estimation from voltage-dependent velocity
• Particle-by-particle resolution of close size populations
• Replaceable nanopore cartridges with size-matched options

What are the technical specifications?

A typical tunable resistive pulse sensing nanoparticle analyzer configuration offers size range of 40 nm–10 µm (pore dependent), measurement principle of Resistive pulse sensing (Coulter principle), concentration range of 10⁵–10¹¹ particles/mL, sample volume of 35–100 µL, applied voltage of 0.1–1.5 V and pressure control of 0–2 kPa, programmable. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Tunable Resistive Pulse Sensing Nanoparticle Analyzer is used in lipid nanoparticle and liposome sizing, extracellular vesicle counting, silica, latex and polymer particle QC, viral vector preparations and colloidal stability and surface charge studies. Across the wider Nanoparticle Analyzers class, laboratories also deploy it for liposome and lipid nanoparticle characterisation, extracellular vesicle and exosome research and viral vector and vaccine particle counting.

Which standards and certifications apply?

Relevant standards and methods include ISO 19430, ISO 13322-1, ISO 22412, ISO/TS 21362, ASTM E2834, ISO 21363 and GB/T 19627. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Nanoparticle measurements are very sensitive to sample preparation. Use particle-free, filtered diluents and clean glassware, and dilute to the instrument's optimum concentration window. Dust and bubbles produce false counts. Verify size and concentration with certified polystyrene or silica nanosphere standards at start-up and after changes of settings, and report camera level, detection threshold, temperature and number of tracks, because these parameters change results. Keep laser optics, flow cells and nanopores clean and stored as advised. Install in a stable, temperature-controlled room. Regulated work needs IQ/OQ/PQ, locked methods and audit trails.

How do I select the right Tunable Resistive Pulse Sensing Nanoparticle Analyzer?

Select resistive pulse sensing when size accuracy independent of optical properties and high resolution of mixed populations are the priority, in conductive electrolytes. Specify size range and pore sizes, sample matrix and filterability, sample volume, calibration particle availability, and whether surface charge is needed. Very dirty or aggregated samples may block pores.

How does it compare with other Nanoparticle Analyzers variants?

Decide what the measurement must deliver: concentration and size distribution of polydisperse samples, fluorescent subpopulation counts, high-resolution separation of mixtures, or single-particle phenotype. Nanoparticle tracking suits 30 to 1000 nm particles at 10⁷ to 10⁹ particles/mL. Resistive pulse sensing gives high-resolution, refractive-index-independent size for conductive dispersions. Field-flow fractionation coupled to multi-angle light scattering resolves mixtures and aggregates. Nano flow cytometry is preferred when labelling and marker analysis are needed. Check detection limit versus your smallest particle, required dynamic range, sample volume, and optical property dependence. Consider whether applicable guidance such as ISO 19430 and regulatory expectations for liposomes or vaccines apply, and who will operate and maintain the system.