Squishy Physics

ATTENTION: Due to the ongoing Coronavirus Disease 2019 (COVID-19) outbreak, in line with the safety policies of Harvard University (https://www.harvard.edu/coronavirus), Squishy Physics seminars are postponed to a date to be defined. Harvard is closely monitoring the situation, and seminars will restart as soon as it will be safe to do so.


Next seminar: DATE TBD in Pierce Hall 209 at 6:00 PM

Neuron Biomechanics in Controlled Environments.

Cristian Staii

Department of Physics and Astronomy, Tufts University


Abstract: Neurons are the primary working units of the nervous system. A single neuron is a very specialized cell that develops two types of processes during growth: axons and dendrites. In the developing brain these processes grow and make connections with other neurons thus wiring up the nervous system. Despite recent advances, the fundamental mechanisms that underlie the formation of functional connections between neurons are still poorly understood. In the first part of my talk I will present detailed experimental and theoretical analysis of neuronal growth in response to external geometrical and mechanical cues. The experimental results demonstrate that axons display strong directional alignment on micro-patterned surfaces, and that the degree of alignment is completely determined by the surface geometry. Theoretically, neuronal growth is described by a general stochastic model, based on a simple automatic controller with a closed-loop feedback system. In the second part of my talk I will present combined atomic force microscopy and fluorescence measurements, which demonstrate that changes in external temperature affect both the elastic modulus and the cell volume in the case of cortical neurons. We find a power law relationship between cell elastic modulus and volume, and propose a simple model, based on elastic properties of biopolymer networks, that predicts the observed relationship. In addition, we track individual components of the cytoskeleton (microtubules and actin) and connect the observed variations in elastic modulus and volume with temperature-induced changes in the cytoskeletal dynamics.



Squishy Physics & Pizza Seminar Series

When: Wednesday Evenings - Pizza served at 5:55 PM, talks start at 6 pm till...

Where: Room 209, Pierce Hall, 29 Oxford St, on the Harvard Campus. Directions and parking instructions are here.

What: These talks are informal, with emphasis on new results and ideas, rather than polished presentations. The Squishy audience members typically include soft matter scientists, physicists, engineers, chemists, and biologists.  The goal is to stimulate discussion with the audience.  Talks are typically about 45 minutes long, with lots of questions along the way.

Pizza: Only the finest! 

How to join the weekly Squishy Physics mailing list: please visit the Signup Page.


Parking: Metered parking is available on Oxford Street.  Speakers, please contact Matthew Zahnzinger to obtain a parking permit.  

Squishy Physics is sponsored by the Cabot Corporation, Dean Cherry Murray and the Weitz Research Group.

If you have comments or suggestions or would like to give a talk, please contact Stefano Aime or Perry Ellis.

Here is the upcoming schedule