(4bb) Engineering Active Materials

A grand challenge in soft materials lies in building reconfigurable systems which exhibit the robust, yet precise, self-organized multiscale structures found in living things. Basic physiological processes such as cell division and cell motility demonstrate the potential of soft materials to generate adaptable and responsive self-organized structures which need not remain fixed over time. However, engineering such self-organized dynamics into synthetic materials presents a significant hurdle. To develop rationally designed active materials, the underlying parameters which govern their collective behavior must be determined.

My research will exploit active cytoskeletal composites as a model experimental platform to identify the mechanisms which encode active self-organization. Reconstituted active cytoskeletal materials are uniquely suited because their structure, dynamics and material properties may be directly probed through optical microscopy and conventional rheological techniques.

My interdisciplinary research group will address the following aims:
1. Development of a modular optogenetic toolkit for active cytoskeletal composites.
Recent advances in bioengineering provide the means to precisely dictate, through the simple application of light, the active stresses and material crosslinking of cytoskeletal composites. These techniques offer immense potential to understand the role these interactions play in determining the evolving dynamics of active matter.

2. Characterization of active behavior.
The basic characterization of non-equilibrium active matter remains a significant challenge. The experimental accessibility of my system allows for the measurement of a wide variety of potential metrics in three dimensions.

3. Data-driven discovery of control parameters.
Achieving functional active matter requires robust mechanisms that control an active material's force-generating patterns. New data-driven methods (such as Sparse Identification of Nonlinear Dynamics) present the potential to capture, out of the many potential control parameters, those which most effectively determine self-organized configurations. However, these approaches require large, high-quality datasets which include all the potential parameters of the system behavior. The tractability of collecting the fields describing dynamics and structure through microscopy and the mechanical properties through rheology make it particularly suited to provide such data.

4. Implementation of control through external and internal mechanisms.
We will use control theory to identify spatiotemporal patterns of light-generated activity or crosslinking which direct the dynamics of active composites to a predetermined steady-state. Understanding how externally applied control will inform the design of active materials in which control mechanisms are encoded within the material.

Ultimately, it is my goal to have deterministic control of the spatial structure and temporal dynamics of active matter.

Research Experience:
Throughout my career, I have focused on the development of quantitative experimental frameworks to establish design principles for materials behavior and performance.

As a doctoral student, I built expertise in polyelectrolyte behavior and polymer science. My dissertation research extended the field of single-molecule mechanical behavior, demonstrating how excluded volume and electrostatic interactions can lead to similar mechanisms of polymer stiffening on long lengthscales. My experiments with hyaluronic acid showed the stiffening of moderately-charged polyelectrolytes, due to charge repulsion, does not follow the generally accepted theoretical frameworks. I then developed experiments that measured the excluded volume effects within branched polymers. To accomplish this, we employed a novel synthetic strategy to produce branched polymer architectures with precisely defined grafting density and chemical identity. The results established the magnetic tweezers as an effective probe of comb polymer mechanics. I have been able to leverage this training after my transition to the field of active matter because the detailed, molecular-scale interactions of these systems play an extremely important role, even on much larger lengthscales.

At the Brandeis MRSEC, I have focused on building a cytoskeletal composite network which can be driven into dynamically organized structures by molecular motors. The composite nature of my design allows the separation of mechanical properties from active properties because the passive components can be changed independently of the active components. The results show viscoelastic properties of a material can determine how active forces can arrange within a material and how they can be transmitted, leading to qualitative changes in the self-organized structures which emerge. We observe the coexistence of multiple organized states which exist only outside of equilibrium and control the balance between them, recapitulating the complex heterogeneous configurations of living things. By showing this behavior, we established a route to engineer the self-organized structures of active materials.

Publications:
J. P. Berezney, S. Fraden, Z. Dogic, in prep. (2021).
Innes-Gold, S. N., Berezney, J. P., & Saleh, O. A. (2020). Single-molecule stretching shows glycosylation sets tension in the hyaluronan-aggrecan bottlebrush. Biophysical Journal, 119(7), 1351-1358.
Chandrakar, P., Berezney, J., Lemma, B., Hishamunda, B., Berry, A., Wu, K. T., ... & Dogic, Z. (2018). Microtubule-based active fluids with improved lifetime, temporal stability and miscibility with passive soft materials. arXiv preprint arXiv:1811.05026.
Gagnon, D. A., Dessi, C., Berezney, J. P., Boros, R., Chen, D. T. N., Dogic, Z., & Blair, D. L. (2020). Shear-induced gelation of self-yielding active networks. Physical Review Letters, 125(17), 178003.
Stevens, M. J., Berezney, J. P., & Saleh, O. A. (2018). The effect of chain stiffness and salt on the elastic response of a polyelectrolyte. The Journal of chemical physics, 149(16), 163328.
Berezney, J. P., Marciel, A. B., Schroeder, C. M., & Saleh, O. A. (2017). Scale-dependent stiffness and internal tension of a model brush polymer. Physical review letters, 119(12), 127801.
Berezney, J. P., & Saleh, O. A. (2017). Electrostatic effects on the conformation and elasticity of hyaluronic acid, a moderately flexible polyelectrolyte. Macromolecules, 50(3), 1085-1089.
Berezney, J. P., & Saleh, O. A. (2014). Locked nucleic acid oligomers as handles for single molecule manipulation. Nucleic acids research, 42(19), e150-e150.

Awards:
CSP Fellowship, UCSB 2009-2011
Summer School Presentation Award, KAIST 2013
Poster Prized, UCSB MROP 2011
Travel Grants, ICMR 2012-2015
Travel Grants, UCSB MRL, 2009, 2010
Aaronsen prize, CMU, 2008

Teaching Interests:

As an interdisciplinary engineer, I am excited and qualified to teach core coursework in thermodynamics, fluid mechanics, transport phenomena, chemical kinetics, materials science, statistical mechanics, and dynamical systems. I also look forward to leveraging my research experience and interests to develop and teach electives in polymer science, soft matter physics, biomolecular engineering, rheology, and single molecule biophsyics. My teaching extends beyond the classroom and into the laboratory. Students and postdoctoral researchers in my research group will engage in an interdisciplinary approach towards soft and active matter that bridges chemical engineering, materials science, physics, chemistry, and biology.

Teaching experience:
Microfluidics, Brandeis MRSEC, instructor and organizer
Single Molecule Mechanics, JNN exchange instructor
Complex Fluids, UCSB (TA)
Biomolecular Mechanics, UCSB (TA)
Introduction to Materials Science, UCSB (TA)

Service:
I deeply value the richness of scientific communities, and I hope to contribute to their sustained growth and diversity. In my pursuit to recognize the contributions of diverse researchers in polymer physics and soft matter, I hosted and organized the Brandeis MRSEC Seminar Series, focusing on inviting speakers from underrepresented groups in science. I also played the role of non-faculty representative within the Brandeis MRSEC Executive Committee and headed the Trainee Committee to provide support, resources, and advocacy for graduate students and post-docs. This group cultivated a community of scholarship through a series of events which generated team-building and comradery within the organization. It also addressed important sites of development outside of typical avenues, providing access to training for those with less navigational capital within the science community.

At both Brandeis and UCSB, I supervised students at the undergraduate level, focusing on mentorship and supporting the students' continued engagement with the scientific method in their careers. Beyond the walls of the university, I have been an active participant in community engagement through discussions of science with the community, outreach efforts at local K-12 schools, virtual K-12 engagement through Skype-A-Scientist and, finally, as a science fair judge.