Cather Simpson Lecture Research Brief Inaugural David Breen

Cather Simpson Lecture Research Brief

Inaugural David Breen Lecture | Fourteen October twenty twenty-six | Twelve pm to One pm | AM one hundred three

The "Nespresso" of Diagnostics: Centrifugal Microfluidics for Point-of-Care Diagnostics; "Can we put the complicated work of a laboratory inside a small, easy-to-use machine?" "The Nespresso of Diagnostics" means making a medical test as easy to run as making coffee with a capsule machine.

A Nespresso machine works like this:

One. Put a coffee capsule into the machine.

Two. Press a button.

Three. The machine does the complicated work and gives you coffee.

Professor Simpson's idea is similar:

One. Put a tiny blood sample into a special cartridge, like the coffee capsule.

Two. Put the cartridge into a machine.

Three. The machine moves and mixes the sample with chemicals, then measures signs of disease.

"Centrifugal microfluidics" explains how it moves the blood: the cartridge spins, and the spinning pushes tiny amounts of liquid through small channels.

Connection to my research

My research on particle motion in cavity-channel flow connects to this lecture through geometry, confinement, particle transport and experimental validation. The useful link is understanding where material travels, how long it remains in a region, and whether it reaches a reactive surface. This brief connects those questions to published work and prepares a focused discussion about experiments and collaboration.

The lecture abstract reports simultaneous detection of an HBV surface antigen and two antibodies from a fingerstick sample in under thirty minutes. My mathematical and computational work examines particle trajectories, wall interactions, cavity retention and inertial effects. These could inform transport studies in diagnostics, but my current model is not yet a model of the Orbis cartridge.

Geometry is the common starting point: channels and chambers can promote transport, recirculation or retention. Laminar flow does not mean that inertia or mixing is absent. Recirculation may improve contact with reagents, while poorly exchanging regions may delay delivery or washing. Particle retention is also different from molecular capture, which requires diffusion and binding chemistry.

A particularly relevant paper co-authored by Simpson uses a moving one to two millimeter reactive bead in an oscillating chamber. Its scale and forcing differ from my small-particle cavity model. Applying my methods would require checking confinement, three-dimensional motion, rotating-frame forces and possible wall contact, rather than transferring predictions unchanged. Validation would connect fundamental flow physics to useful diagnostic design. Experimental setup to discuss

Published setup: laser-cut PMMA discs, an encoder-controlled motor, synchronized stroboscopic imaging, and a six hundred fifty nanometer laser with photodiode readout; CFD used Ansys Fluent. This is a model enzyme assay, not direct validation of the HBV test described in the invitation.

A proposed first experiment for my model: a transparent cavity-channel, controlled pump, dilute beads and a calibrated microscope/camera. Compare trajectories and residence times across flow rates and particle sizes, then discuss whether a rotating experiment is the appropriate next step.