Current Lecture

Squishy Physics: The Mechanical Properties of Biological Tissues and their Connection to Neurodevelopmental Disorders

Abstract:

There is growing evidence that brain and neuronal development is linked to the bacterial health and diversity in our gut. However, we don't yet understand how the mechanics of the gut tissue might play a roll in this so-called "gut-brain axis." In the Sac State Biophysics and Soft Condensed Matter Group, we study the mechanics of soft materials such as biological cells and tissues, and are especially interested in how these relate to biological function and disease.

In this talk, I will describe some of the different tools and techniques we use to probe the physics of biological matter. I will share the results of a recent study, in which we investigated a species of fruit flies carrying a genetic mutation in the gene kismet, a gene orthologous to human neurodevelopment disorder risk genes. We found that flies carrying the genetic mutation performed worse in behavioral assays sensitive to neuronal development and functioning. The mutation also altered the composition and reduced the diversity of the symbiotic bacteria naturally inhabiting the gut of the flies. To understand how gut tissue mechanics might be implicated in these changes, we conducted high-precision force measurements on dissected fly gut tissue, and found that tissue from the mutant flies was mechanically different from the healthy flies both in terms of both the tissue's elasticity and strain stiffening behavior. Our findings suggest that the kismet gene contributes to the gut-brain axis, and also demonstate that intestinal tissue mechanics is a potentially novel and hitherto unappreciated element of the gut-brain communcation loop.

Bio:

Mikkel Herholdt Jensen received his B.S. in Physics and Mathematics from the University of Southern Denmark and his Ph.D. in Physics from Boston University, where he studied biopolymer mechanics and dynamics and their regulation by smooth muscle binding proteins. After completing his Ph.D. research, he held a 2-year postdoctoral appointment at the Harvard University School of Engineering and Applied Sciences, before joining the Department of Physics and Astronomy at Sacramento State in the Fall of 2015.

Together with fellow faculty member Eliza J. Morris, Mikkel runs the Biophysics and Soft Condensed Matter Group at Sac State. The experimental research group specializes in mechanical measurements of soft materials such as biological tissues and cells, foams, gels, food products, and plastics. He also collaborates with several researchers in the area, most recently the Parikh lab at UC Davis, with whom he was awarded funding by the National Science Foundation to investigate the dynamic behavior of experimental cell-mimetic systems starting in the Fall of 2024.

In addition to research in biological physics and soft condensed matter, Mikkel is also engaged in physics education research. He was awarded the College of Natural Sciences and Mathematics Outstanding Faculty Award for Teaching for the 2020/21 academic year, and is currently supported by a National Science Foundation award together with Physics Faculty Eliza J. Morris and Brianna Santangelo, and Bita Rivas from the College of Education to investigate the benefits of active learning pedagogies and student teamwork in introductory physics classrooms.

Lecture Information:

Date: Wednesday, October 2, 2024

5:45 - Reception in SQU 320

6:00 - Lecture in SQU 301

Parking is available without a permit in STUDENT spaces on the top (4th) floor PS2 from 5:00 PM - 8:00 PM.

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