Research
Theoretical Biophysics
Specialization
Biophysics lies at the intersection of two disciplines with vastly different approaches and nomenclatures; however, it is also an area ripe with opportunities for collaborative projects and unsaturated avenues of research. I am focused on one such avenue: exploring how mechanical stress and feedback play into the development of multicellular organisms. A full understanding of biological growth requires elucidation of how cells use mechanical stress fields to harmonize their activities.
Experimental investigations of the mechanical aspects of biological development are restricted by limitations in current technology. This is especially true in terms of evaluating the stress fields that permeate developed tissues and developing embryos. I overcome these limitations through dynamic system modeling: representing embryonic tissues as a mechanically active media and then using the model to perform experiments. Working with experimental collaborators provides meaningful insight, and the spirit of this joint approach is applicable to almost all stages of biological growth and development. I am currently applying my skills to the question of what kinds of mechanical feedbacks and stress fields are at play during the embryonic development of the common fruit fly.
The Common Fruit Fly
The common fruit fly (Drosophila melanogaster) is the best understood organism, both genetically and embryologically, making it an ideal system for exploring intercellular coordination via mechanical stress feedback. My work primarily focuses on two genetically coded regional cellular movements known as ventral furrow formation (VFF) and cephalic furrow formation (CFF). These are the two initiating morphogenetic movements of gastrulation, a critical process whereby an embryo reorganizes from being single layered structure to a multilayered one. VFF moves a large strip of cells on the underside of the embryo inwards through a spontaneous generation of curvature, creating the embryo’s middle layer. CFF, on the other hand, slowly deepens as cells roll over a cleft to form a deep, transitory structure whose function is unknown.
Although genetically driven, these are inherently mechanical processes that require the coordination of individual cellular shape changes. Many cellular components and processes are shared across species. Understanding how the cells of the fruit fly harmonize their activity sheds light on how the cells of all organisms might communicate via mechanical stress. Through an interdisciplinary collaboration (developmental biology, mechanical engineering, and physics), we have used live and fixed embryos imaging to inform development of multiple models that capture mechanical aspects of VFF and CFF.
Future Direction
The understanding of mechanical feedback during biological development is still fragmented; I intend to continue working to fill this knowledge gap. This will include continued work with my collaborators on the development and refinement of a three-dimensional model of the fruit fly embryo; however, dynamic system modeling can be applied to a wide variety of biological processes. I am also interested in exploring how mechanical stress affects embryogenesis in other organisms (zebrafish or sea urchins) and how cells around an incision coordinate wound healing efforts through mechanical feedback.
I will continue working with collaborators within the realm of granular materials. My work with collaborators in this area has mostly focused on exploring aspects of the flow rate enhancement peak that can be achieved through proper placement of an obstacle within the hopper through modeling. I have also forayed into some experimental work attempting to observe this flow rate enhancement in a physical, three-dimensional system.
Publications
The mechanics of cephalic furrow formation in the Drosophila embryo
Redowan A. Niloy, , Jeffrey H. Thomas, Jerzy Blawzdziewicz
Biophysical Journal, 2023 | Elsevier via CellPress (full text).
A Markov chain Monte Carlo model of mechanical-feedback-driven progressive apical constrictions captures the fluctuating collective cell dynamics in the Drosophila embryo
Guo-Jie Jason Gao, , Jeffrey H. Thomas, Jerzy Blawzdziewicz
Frontiers in Physics, 28, 2022 | Frontiers in Physics (full text).
Mechanical Feedback and Robustness of Apical Constrictions in Drosophila Embryo Ventral Furrow Formation
, Guo-Jie Jason Gao, Mahsa Servati, Dylan Schneider, Presley K. McNeely, Jeffrey H. Thomas, Jerzy Blawzdziewicz
PLOS Computational Biology, 17(7), 2021 | PLOS Computational Biology (full text).
Enhanced flow rate by the convergence of Tetris particles when discharged from a hopper with an obstacle
Guo-Jie Jason Gao, Fu-Ling Yang, , Jerzy Blawzdziewicz
Physical Review E, 103(6), 2021 | Physical Review E or arXiv.org (full text).
Coordination of Ventral Furrow Formation During Drosophila Gastrulation Through Mechanical Stress Feedback
Ph.D. Dissertation, Texas Tech University, 2019 | Texas Tech University DSpace Repository (full text).
Understanding the Local Flow Rate Peak of a Hopper Discharging Discs through an Obstacle Using a Tetris-like Model
Guo-Jie J. Gao, Jerzy Blawzdziewicz, , Shigenobu Ogata
Granular Matter, 21(25), 2019 | SpringerLink or arXiv.org (full text).
Embryo as an active granular fluid: stress-coordinated cellular constriction chains
Guo-Jie Jason Gao, , Jeffrey H. Thomas, Jerzy Blawzdziewicz
J. Phys. Condens. Matter, 28(41), 2016 | IOP Science or arXiv.org (full text).