Apr 30
Jean Dreyfus Lectureship: Tim Swager, Massachusetts Institute of Technology
Thu, April 30, 2026
• 7:30pm
- 8:30pm (1h) • Olin 141
John D. MacArthur Professor of Chemistry, MIT Department of Chemistry
Refreshments will be served beginning at 7:00pm.
Optical Biosensors from Complex Dynamic Oil Droplets in Water
This lecture will focus on the design of systems that make use of colloidal materials to create sensors. In one theme, we make use of the reconfiguration of complex liquid emulsions (droplets) and related materials can be triggered chemically, biochemically, or with magnetic fields. Complex liquid droplets behave as optical lens systems and small changes in surface tensions can change focal lengths or cause systems to switch between optically transmissive or scattering states. Central to this scheme is that the fluids in the droplets have different densities and hence are aligned by the earth’s gravity. The induced optical changes can be triggered with chemical, photochemical, or biochemical stimuli and thereby create new generations of sensors. Demonstrations of these methods for the detection pathogenic bacteria will be presented for applications in food safety. Droplets that turn on light in a direction or alternatively reflect light in response to trace pathogenic bacterial will be described. I will also describe methods by which droplets can be used to create complex magnetic objects that reflect light on demand.
**Sponsored by the 2025 Jean Dreyfus Lectureship for Undergraduate Institutions program
from Chemistry