Explore this section to learn how ARCHIMEDES measures individual particles and cells with unprecedented resolution and accuracy.
Resonant Mass Measurement
Measuring a Particle
Mass and Size
Measuring Particle Density
What's the Music?

Measuring a Particle

Frequency ShiftTo measure a particle or cell, the resonant frequency is monitored as the particle passes through the microchannel resonator (right). The maximum excursion in the frequency occurs when the particle is at the tip of the resonator, and is proportional to the particle's buoyant mass, i.e., the mass of the particle over that of the fluid it displaces.

The frequency excursions for a large number of particles are measured one by one. From this information, Archimedes' Principle is used to build up the distribution of mass and size for the population.

Frequency to mass

SensorThe micrograph at right shows the path of the particles as they flow down the fluidic channel that introduces the sample, and enter the smaller fluidic channel that carries them through the microchannel resonator, and to then to the outlet channel.










The video below shows the view of the sensor channel inlet given by the integrated optical microscope. Individual 2 ┬Ám particles can be seen entering the sensor channel, and the excursion in resonant frequency is measured simultaneously. The histogram of particle size is updated in real time.

What's the music?