(4eb) Mechanochemically-Responsive Active Living Matter in Complex Environments

Due to their out-of-equilibrium nature, active living systems have evolved to develop strategies to thrive in complex, structured environments such as biological tissue, bodily fluids, and soil. Yet, despite their importance in human health, biotechnology, and environmental applications, we still lack a mechanistic understanding of their dynamics in such environments—physiological studies mainly focus on genetic mechanisms in homogeneous conditions, and active matter physics often addresses abstract problems that fall short of real-life scenarios.

During my PhD and postdoc, I have taken the initial steps toward bridging the gap between these two disciplines by deciphering the coupling between activity—such as metabolism, motility, and growth—and the physicochemical properties of the environment. At the Max Planck Institute for Dynamics and Self-Organization, I developed a microscopy method to visualize the hydrodynamic and chemical fields generated by active droplets. This technique enabled me to elucidate collective behavior in active emulsions, from flow-induced phase separation to chemotactic self-caging.

Currently, as a postdoctoral researcher in Chemical and Biological Engineering at Princeton University under the supervision of Prof. Sujit Datta, I study how microbial activity reshapes their environments. My research has led to the discovery of a novel dispersal mechanism for microbial colonies in yield-stress media, where biogenic bubbles locally yield and restructure the granular matrix, facilitating long-distance colony entrainment. Additionally, I have demonstrated how bacterial communities self-organize to regulate metabolite transport into the colony.

Building on these accomplishments, I propose to establish a research program that bridges the gap between active matter physics and real-world applications, addressing key questions in human health, biotechnology, and environmental sciences. This represents a new frontier for chemical engineering: by engineering model environments that mimic the natural habitats of living systems and mapping the physical and chemical landscapes over time and space, I aim to study mechanochemically-responsive active living matter in complex environments. My initial research focus will include:

1. 1. Proliferation of microbial colonies in yield-stress environments. I aim to study the coupling between cell metabolism and the local rheology of a biomimetic model environment (transparent granular hydrogels) to uncover and elucidate the strategies adopted by nonmotile living systems to invade environments such as porous soil and colon crypts leading to genetic mixing and maximal colonization.

2. 2. Physical intelligence in synthetic active matter. I plan to construct shape-shifting active polymers using chemically-active droplets as building blocks. By exploring the interplay between the polymers' conformational dynamics, chemohydrodynamic interactions, and spatial memory, I aim to discover adaptive strategies for navigating complex, tortuous geometries which will inform the future design of micro-robots with physical intelligence.

3. 3. Self-organized bacterial communities. I aim to uncover the ecological implications of bacterial self-organization into structured multi-species communities. Motivated by the challenges of pulmonary bacterial infections, I will study how bacterial activity regulates the metabolite transport and alters the microstructure within their environment to achieve resilience against external stressors such as host immune system, antibiotics, and phages.

Teaching Interests

My training in mechanical engineering and physics has prepared me to teach a variety of engineering courses at both the undergraduate and graduate levels. I am particularly interested in teaching Fluid Mechanics, Thermodynamics, and Transport Phenomena. Additionally, I am enthusiastic about designing interdisciplinary elective courses that leverage my background in engineering, physics, and biology, such as Microfluidics, Soft Matter Physics and Engineering, and Biological Fluid Mechanics. During my PhD and postdoc training, I have had the privilege of mentoring 12 undergraduate and graduate students from diverse backgrounds. I am committed to continuing this mentorship in a diverse, equitable, and inclusive environment.

Selected publications: (Total 16, 8 first-author, 5 second-author, H-index 14)

B. V. Hokmabad, S. Saha, J. Agudo-Canalejo, R. Golestanian, C. C. Maass, Chemotactic self-caging in active emulsions, Proceedings of the National Academy of Sciences (USA) 119 (2022) e2122269119.

B. V. Hokmabad, R. Dey, M. Jalaal, D. Mohanty, M. Almukambetova, K. Baldwin, D. Lohse, C. C. Maass, Emergence of bimodal motility in active droplets. Physical Review X 11 (2021), 011043.

B. V. Hokmabad, K. Baldwin, C. Kreuger, C. Bahr and C. C. Maass. Topological Stabilization and Dynamics of Self-Propelling Nematic Shells. Physical Review Letters 123, (2019) 178003.

Dey, C. M. Buness, B. V. Hokmabad, C. Jin, & C. C. Maass. Oscillatory rheotaxis of artificial swimmers in microchannels. Nature Communications 13.1 (2022): 1-10.