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Nanocapillary Electrokinetic System for Particle Tracking / Counting and Microscopy

Technology Overview

Tracking the motion of single nanoparticles in liquid solution is a gateway to high accuracy particle counting as well as understanding and monitoring physical, chemical, and biological processes at the nanoscale. This technology has recently been demonstrated to carry out high-speed tracking of nanoparticles and macromolecules using elastic light scattering.

The weak scattering or single small viruses (26 nm) was successfully detected. For the first time, their fast thermal diffusion was tracked at a frame rate of more than 2 kHz (see Figure 1). As a step forward towards clinical applications, single urinary vesicles as small as 35 nm were also tracked by elastic light scattering (the first successful attempt of detecting biological vesicles that are narrower 70 nm in freely diffusing suspension). These vesicles have a low-refractive index (n <1.4), as confirmed by comparing their thermal diffusion and light scattering cross section.

This particle-tracking system embeds a silica-based single-mode optical fiber with a hollow-core (nanometer scale) to suppress the free-diffusion or single nanoparticles and direct them into the detection volume. When light is coupled to the nanoparticle-filled optical fiber and detection is performed with a microscope lens at a right angle to the guided illuminating light, the untethered motion of nanoparticles can be imaged and tracked in a quasi-1D geometry for an unlimited unlimited duration with negligible disturbance (Figure 1). For details see ACS Nano, 9 (12), 12349–12357, Open Access.

Figure 1: a. Schematic representation of our single nanoparticle / virus tracking setup. b. CCMV virus that we have tracked. c. The nanofluidic access or single-mode optical fiber. d. Quasi-1D tracking or a single CCMV virus.


1. Biomolecular research
2. Biomedical diagnostics
3. Colloid chemistry
4. Environment pollution
5. Chemical identification


This invention is a user-friendly, plug-and-play add-on device for conventional optical microscope or method to tackle biologically relevant questions based on single nanoparticle detection. The name of this device is 'nanoCET' (nano Capillary Electrophoretic Tracking) and encompasses a cartridge and a stage. Keeping the needs of the biomedical research into account, the nanoCET cartridge will be disposable and cost-effective, and can be detachable from the nanoCET stage. The nanoCET stage is an add-on to the conventional microscope, which can be rented, leased, and purchased as a one-time investment. Interested parties can perform test experiments in the inventor's lab with the resident existing setups.

Keywords: particle count, nanoparticle, microparticle, particle tracking, flow cytometry, microparticle analysis, airborne particles, water analysis, vesicles, exosomes, colloids, liquid chromatography, microscopy, hollow fiber

Key benefits

  • Platform capable of detecting, tracking, counting, and measuring single nanoparticles, vesicles, and biomolecules
  • It uses a unique (patented) step-index hollow core fiber to propagate light without distorting the particle image (unlike other structured hollow core fibers).
  • This method does not involve any nanofabrication processes or fluorescent labels
  • Consisting of a plug and play cartridge along with a nanofluidic optical platform, the system does not require any modification of existing microscopy setup
  • The platform will enable measurements at single nanoparticle level, electrophoretic separation, and studying diffusion and aggregation dynamics

Luris reference number


Patent status

Patent rights are already granted in the UK and being acquired in the EU and in the USA.