Nanomedicine & OPtical Microcavity analysis

Oxford HighQ is developing Optical Microcavity Analysis (OMCA) Instrumentation that can accurately report nanoparticle refractive index and nanoparticle diameter on a particle-by-particle basis.

Nanoparticles such as Mesoporous Silica (MSN) are trapped, optically tweezed in their native solutions, and the change in resonant wavelength of light within a micron-scale Fabry-Pérot open optical cavity is detected. This signal reports the composition of complex particles and opens up important applications in nanomedicine for providing a quantitative measurement of coating efficiency and of particle internal drug loading.

OMCA also has the potential to provide single nanoparticle sizing data similar to that obtained with SEM, but much faster and within native solutions, at a fraction of the SEM cost or complexity and with far less user training requirement.

In addition, OMCA offers rapid and consistent assessment of drug loading, be it a surface coating or internal loading, through measurement of refractive index, which can be achieved with 1% resolution.

The microcavities are plano-concave Fabry-Pérot resonators supporting well-characterised Gaussian modes of volume ~1 µm3. The mode is monitored via laser transmission relative to a reference cavity, mounted on the same chip to suppress noise. A nanoparticle entering the trap causes a red-shift and broadening of the mode that is dependent on the position of the nanoparticle within the confined field distribution.

Our first Optical Microcavity Analysis instrument for Nanomedicine applications is entering it’s final development stage and we are planning a full product launch during 2021. If you would like to receive updates including copies of our application and technical notes. please complete our contact request form


OMCA number distribution of polarizability (nm3) of PMMA (196nm) and
polystyrene nanoparticles (187nm) in water.

Oxford HighQ is a spinout from the University of Oxford’s Departments of Materials and Chemistry and is developing next-generation nanoparticle sensors. Our core technology of optical microcavities provides fundamental enhancement of signal strength that will offer a step change in fluid-based sensing across a wide range of applications and markets.

Mesoporous Silica Nanoparticles
with Camptothecin

OMCA number distribution of polarizability (nm3) of PMMA (196nm) and polystyrene nanoparticles (187nm) in water.

Find out more about our technology

Optical microcavity technology

Optical microcavities are micrometre-sized devices which confine light to a volume of space comparable with the optical wavelength.

Nanoparticle Characterisation

When a nanoparticle enters a microcavity it interacts with the light present by introducing a local change to the refractive index relative to the surrounding fluid.

Chemical Sensing

Our sensors are based on optical microresonators, which can amplify signals in any of the wide variety of optical methods commonly used in chemical sensing.


Oxford HighQ's world-class technologies are relevant to a wide range of industries.


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