By Jodi Frank
January 18, 2022
Across her academic career as an undergraduate student, Navreeta Singh has interned at three research laboratories, including the Air Force Research Laboratory, has co-authored two papers, and is now completing a year-long research project in a Princeton lab that involves characterizing the properties of microscopic-animal proteins.
Navreeta has a deep appreciation for the research opportunities that she has obtained as a Princeton University student over the last four years, and keeps forging ahead, her senior project enabling her to peer through some of the most sophisticated microscopes and imaging tools available at the university.
“Doing research has been an important part of my undergraduate experience,” says Navreeta, a fourth-year student in the Department of Mechanical and Aerospace Engineering. “It’s allowed me to start applying what I’ve been learning in my classes, and helped me grow a lot as a scientist and engineer.”
Growing up, Navreeta’s interest in engineering evolved from tinkering and constructing things from erector sets and pieces of wood. She built a Rube Goldberg machine and an automatic tuning device for her violin.
Then she came to Princeton and found her love of materials science and biomechanics, delving into the depths of the very small to study how individual molecules and atoms behave and interact with one another in a variety of biological and other materials.
Her senior project as a researcher in the Cohen Lab, headed by Assistant Professor Daniel Cohen, involves investigating tardigrade disordered proteins that enable microscopic animals, called “water bears,” to withstand extreme drought conditions. Such research could improve the ability to store stem cells, embryos, and even vaccines, without the use of refrigeration.
“Navreeta is a great collaborator in the lab, and her enthusiasm is contagious,” Prof. Cohen says. “She is a pleasure to work with and to teach.”
Water bears, or tardigrades, are eight-legged insect-related organisms that have pudgy-looking bodies. Not much bigger than a dust mite, they can be found in almost any environment that is wet or damp, from the depths of oceans, lakes, and swamps, to the inner reaches of moss and other vegetation. They are widely used in research because of their amazing ability to survive in harsh environments, such as acute drought, scorching heat, freezing temperatures, and even outer space.
When its habitat dries out, the water bear goes into a “tun state.” Its body shuts down into a dehydrated ball, with its metabolism rate declining to near nonexistence. It can remain in this state for years —decades even—reviving itself as soon as enough moisture returns.
Navreeta’s project includes working with hydrogels to emulate how tardigrade disordered proteins work to withstand drought. These proteins have been shown to form a fibrous, hydrogel structure when they're dehydrated. Other experiments include suspending the proteins in the hydrogels along with mammalian cells to see if the gels provide protection to the cells under arid conditions.
“Biological systems are beautiful and complex, and I enjoy applying principles of physics and mathematics to model and mimic them. I especially enjoy studying and imaging at the microscale, where we can elucidate details that explain large-scale phenomena,” Navreeta says. “But I honestly didn’t realize that I could combine physics with biology until I got to college. I hadn’t even heard of the field of biomechanics until I came to Princeton.”
That’s when she started working in Assistant Professor Andrej Košmrlj’s lab as an intern researching epithelial tissue, which lines nearly every part of the body, including the skin, blood vessels, intestines, and other organs. The epithelial cells that make up this tissue serve numerous purposes, including protecting the body against foreign objects and enabling better nutrient absorption.
Researchers are still learning about the diverse functions of epithelia, particularly in human development. In the development of an embryo, for example, the shape of epithelial tissue must change drastically, but it also has to hold some structure to function properly.
“We know that the mechanical properties of epithelial tissue are really complex, but we need to quantify them better,” Navreeta says. “We don’t understand, for example, how they react under a wide range of shearing frequencies.”
Navreeta studied epithelial tissue’s viscoelasticity, which has the combined characteristics of viscosity in liquids and elastic properties in solids. To study the viscoelastic properties of epithelial tissue, she used computer simulations involving meshing, the process of dividing an object into thousands or millions of smaller elements so one can see how atoms, molecules, or cells work in conjunction with one another under a variety of conditions and stresses. The more detailed a mesh is, the more accurate the model will be.
In her research, she combined thousands of cells to closely monitor the mechanical properties that a real tissue inside a body would have under mechanical stresses.
Navreeta has also studied vaccine development to combat syphilis as an intern at the University of Connecticut. Still prevalent around the globe, untreated syphilis can cause severe long-term health problems, including damage to the heart, brain, or other organs. It can also be spread from mother to child in the womb, causing birth defects and even death.
Last year, Navreeta had the opportunity to conduct research at the Air force Research Laboratory as an Air Armament Scholar. At the Florida-based lab, she conducted molecular dynamic simulations for explosive materials to study how pore shape at the molecular level affects explosion.
“It was a great opportunity. I had the chance to see some of the innovative technologies that the military is funding,” Navreeta says, adding that the experience increased her interest in defense and policy. As a result, she is pursuing the History and Practice of Diplomacy certificate at Princeton.
“I find that an interdisciplinary approach to academics, whether that’s between engineering and biology or technology and foreign policy opens up a lot of spaces for really interesting work,” she adds.
Outside of her classes and the lab, Navreeta enjoys playing the violin, which she has been doing since age 4. She is president of Princeton Music Outreach, a club that performs in nursing homes.
“There are so many connections you can make between music and science, but mostly I think it’s important to have something outside of work that you enjoy doing for its own sake.”