Prerna Sharma is fascinated with the science of all things Squishy

Harini Barath

SEEMA Stem, SEEMA Magazine, SEEMA Network, SEEMA woman of science. SEEMA woman magazine. Prerna Sharma for SEEMA. SEEMA Indian Institute of Science.

In 2015, Forbes India featured Prerna Sharma in 30 Under 30, a national list of young achievers. Sharma, who was only 29 at the time, was a faculty at Physics Department of the Indian Institute of Science in Bangalore, India. She works in the area of soft matter physics—the science of all things squishy—a field at the intersection of physics, chemistry and biology. In particular, Sharma’s lab works on bio-inspired physics as well as biophysics. They use biological organisms to sometimes answer questions in physics and sometimes answer questions about the organisms themselves.

One theme of her lab is the study of self assembly. An oft-quoted example to illustrate the idea of self assembly is to think of a computer. We know it is assembled from a variety of components that are put together in a specific manner. Imagine that instead, the components are simply thrown in together and shaken up, and a functional computer emerges from the mix! Collectives of nanoparticles and microorganisms are seen to display such self assembly. They spontaneously self-organize into patterns and collective behaviors emerge. For example, in the right conditions, the complex bacterial ribosome with about 55 different protein molecules among others, will self-assemble in a test tube. To understand phenomena such as these, Sharma examines self assembly using rod-shaped viruses that form highly ordered monolayers.

In another direction the lab pursues, they work with a simple algae, which has a single eyespot with which it senses its environment looking for light. “I know how a single algae detects light. Now, if I have 100 of them, are they going to detect light better or worse than that single cell?” asks Sharma. The algae also has two cilia—little hairlike structures that help the algae move. These can be removed from the algae and reactivated independently. Sharma studies their mechanics to understand the collective behaviour of a carpet of cilia within which cilia move together. The same cilia is sitting on our lungs, so this approach can be used as a model to understand their function and behavior.

Physics was a field Sharma grew into. She openly admits that she struggled to grasp the nuances of the subject as a fresh undergraduate at Delhi’s St. Stephen’s college. Over three years, however, she worked to master it. After briefly considering other career options, she went on to enroll for a PhD on the back of stellar test results that earned her a spot at one of India’s premier research institute, the Tata Institute of Fundamental Research. She worked with polystyrene beads to understand how colloids stick to glass. Sharma borrowed an idea from a neighboring field of rheology bringing a fresh insight into the process of adhesion. Adhesion has relevance in biology too, it is how, for instance, blood cells stick to our veins.

Starting young as a faculty came with its share of challenges. Often mistaken for an undergraduate herself, Sharma had to learn how to manage large, sometimes restless, classrooms. She takes pride in being a patient mentor who gives students the time they need to learn and figure things out for themselves in the lab.

Tai chi helps her cope with the ups and downs of the job. She learnt the value of physical fitness the hard way, she says, and now encourages her students to pursue interests outside work to strike a good balance.

Sharma believes that this is an exciting time for the field of soft matter physics. Access to cutting edge technology is making it possible to experimentally realize many ideas in ways that were not possible before. She looks forward to discovering more insights into collective behaviors in the microscopic world.