In this blog post, we feature Dr. Ying Zhang. Ying is a Postdoctoral Research Associate in the Copos Lab at Northeastern University, jointly appointed in the Departments of Mathematics and Biology. She received her Ph.D. in Mathematics from Boston University, advised by Sam Isaacson. Her work focuses on developing numerical methods for partial differential equations, stochastic and mechanics-based multi-scale modeling of cellular and developmental processes in biology.
When did you first become interested in mathematics and biology?
My path to mathematics and biology was somewhat unexpected. I guess life is always full of surprises. I initially entered college as a pre-med student, dreaming of becoming a cardiovascular surgeon. While I enjoyed my bioscience courses, I gradually found myself drawn to differential equations and numerical analysis. A turning point came when I took Professor Sam Isaacson’s class — MA 579: Numerical Methods in the Biosciences — which opened up a whole new world. There was a path for me to combine all the things I loved. Eager to explore further, I took every math-bio course Professor Isaacson offered and had the opportunity to work on a research project with him. That experience solidified my interest and passion for mathematical biology. This led me to switch from pre-med to a math major. It was a bittersweet decision to let go of my dream of becoming a surgeon, but the joy I found in math biology made it clear I was on the right path. Professor Isaacson later became my Ph.D. advisor — a full-circle moment that continues to shape my academic journey.
Was the decision to do a Ph.D. an obvious and easy choice?
Doing a PhD was an obvious choice for me, yet not an entirely easy one. I knew I wanted to continue doing research in mathematical biology, but my academic path hadn’t been “designed” with that goal in mind from the beginning. Since I switched to a math major late in my sophomore year, I couldn’t take many advanced theoretical courses, which I thought were fundamental to be a competitive candidate. After speaking with several professors who encouraged me to apply, I gained enough confidence and gave it my best shot. I was committed to making it work. The bigger challenge, however, came from home. When I told my parents about my decision to pursue a Ph.D., they were shocked and strongly opposed it. They envisioned a more “practical” and “easier” path for me — earning a master’s degree and finding a stable industry job. From their perspective, a Ph.D. meant a difficult, uncertain life filled with long hours and little reward. It was hard to convince them otherwise, and, to be honest, I’m not sure I ever fully did. At some point, I chose to follow my passions, even if it meant going against their wishes. Looking back, I’m confident it was the right decision.
What are the main biological research questions that you are interested in?
I’m broadly interested in how microscopic changes ripple up to impact biological systems at larger scales — essentially, a biological version of the butterfly effect. This perspective drives my curiosity about multi-scale systems, particularly in the context of women’s health. I’m especially drawn to understanding how molecular-level dysfunctions can lead to complex phenomena like cancer metastasis. Answering these kinds of questions requires tools that can bridge different spatial and temporal scales — microscopic to macroscopic, stochastic to deterministic. During my Ph.D., I focused on developing numerical methods for particle-based stochastic reaction-diffusion systems, with applications to experimental studies of T cell receptor signaling. While these projects were rooted in chemical signaling and stochastic modeling, I became increasingly interested in how mechanics could offer a complementary lens on the same biological problems. This led me to shift focus during my postdoc toward mechanics-based models, using more deterministic approaches to study mesoscopic and macroscopic systems like collective cell migration and blood coagulation. Bringing together these diverse modeling frameworks has helped me chart a clearer path forward, and equipped me with the tools to better explore the complex, multi-scale dynamics that underlie health and disease.
What mathematical and computational tools do you find useful in your work?
In my day-to-day work, I regularly use a combination of MATLAB and C++. MATLAB is my go-to for data processing and figure generation, while C++ is essential for running computationally intensive simulations that would be too slow in MATLAB. For symbolic and algebraic work — like series expansions or asymptotic analysis — I often turn to Mathematica and Maple, which I find invaluable for checking and simplifying complex expressions. Depending on the project, I also occasionally use Python, R, and JMP, especially when specific packages or data analysis tools are more accessible in those environments. Ultimately, I like to stay flexible and choose the tool that best fits the task at hand, whether it’s numerical, symbolic, or statistical.
What makes you passionate about your work?
What excites me most about mathematical biology is its sheer breadth — there are so many fascinating, unanswered questions waiting to be explored. I’m especially drawn to the field’s highly interdisciplinary nature. It brings together theorists, modelers, and experimentalists, and I find that kind of collaboration incredibly stimulating. What’s even more rewarding is that it allows me to apply mathematical and computational tools directly to answer biological problems. There’s a deep sense of purpose in knowing that the work I do can contribute, even in a small way, to advancing our understanding of complex systems and potentially improving human health.
What do you like to do in your spare time outside of work?
Travel is a BIG part of my life — I love exploring new places whenever I get the chance. I’m especially drawn to spots with great outdoor activities and delicious local food. When I’m not traveling, I enjoy baking, cooking, and playing video games (mostly on my PS4). I also make time for meditation, which helps me clear my mind and recharge. A fun fact: I’m a certified Zumba instructor. I sometimes dance around with my energetic Corgi, Genie — she definitely keeps me on my toes.
Any advice for someone considering a career in mathematical biology?
As someone who’s made a few unexpected transitions in my career, I can say that mathematical biology has never let me down — it’s always full of surprises, especially during those in-between moments. It’s a field where you can find your niche and stay engaged for a lifetime, but it’s also incredibly flexible. You’re not locked into one path. If your interests evolve, you’re free to explore new directions, blend disciplines, and grow. Don’t be afraid of change. Transitions can feel daunting, but with courage and determination, each step becomes a valuable part of your journey. If I can navigate these shifts and find fulfilment in my journey, you absolutely can too!