The art of chemistry, and the chemistry of art

"Art."

This was not the answer that Shoshana Williams, PhD ‘25, expected when she asked her class of chemistry undergraduate students to share their interests. It was her first day teaching an introductory summer course at the Asian University for Women in Bangladesh. With her planned curriculum dismantled within the first few minutes, Shoshana set to work revising her lesson plans to make the course more engaging for her art-savvy students. 

“I went back to my notes I was planning to present on chemistry in medicine and human health and thought about how I might highlight the ways that chemistry influences art instead,” said Williams. “When I arrived in Bangladesh, it was just after a holiday, and many of my students still had celebratory henna art, called mehndi, on their hands. They wanted to show me and to tell me about it. This was a common cultural practice that all my students were familiar with. And so I said, okay. We can figure out the chemistry of henna.”

For most, improvising an entirely new curriculum and connecting fields as disparate as art and chemistry might have been too much. But for Shoshana, who is a chemistry PhD student and part of the Chemistry/Biology Interface training program at Sarafan ChEM-H, moving between different fields is within her normal routine. As part of this interdisciplinary program at Stanford, she designs and makes antimicrobial polymers that evade the tricks bacteria use to become antibiotic-resistant. Her project combines chemistry and biology to create new antibiotics that are not only resistance-proof but also affordable and scalable for use in disadvantaged countries.   

“I think that from the very beginning of the project, using cost as a design constraint was important and really meaningful,” said Shoshana. 

The chemistry of henna

Shoshana’s passion for helping others goes far beyond her science. She is also a dedicated teacher and advocate for women’s education. In 2021, she learned of an opportunity to remotely lead a scientific proposal writing class for advanced students at the Asian University of Women. This institution provides higher education to women from over 20 nations, including a large population of refugees from Afghanistan who were denied the right to education in their home country under Taliban rule. 

“I was sad to see that loss of access to education,” said Williams. “I think that learning can be really empowering, and I enjoy sharing that with others. I wanted to do something to be of service.” 

For the next 18 months, Williams guided her students as they developed original research proposals and personal statements for their graduate school applications. Shortly after, the university had an opening for a summer introductory chemistry instructor and asked if she wanted the position. Despite being in the middle of her PhD research using chemistry to make new antibiotics, Shoshana jumped at the opportunity. Suddenly, she found herself in Bangladesh learning the chemistry of henna. 

The dye used in henna is extracted from the leaves of the henna shrub. The dye chemically reacts with keratin, a protein present in hair, skin, and nails, which is how it stains the skin—a reaction that is aided by a mild acid, such as lemon juice.

“A lot of my students had mothers and grandmothers who would squeeze lemon juice on their hands when they put on the henna paste,” Williams said. “It was really cool to be able to say, ‘Look, that’s not superstitious, they’re providing the reagents for a chemical reaction.’ My students were excited to see something that they were passionate about, presented as an area of academic interest.”

When first applied, henna paste is orange but then darkens over time into a deep brown—another chemical reaction. 

“You can monitor the color on your skin and figure out the kinetics of this oxidation reaction, using nothing more advanced than your eyes,” said Williams. “It’s adaptable to low-resource settings because you don’t need a lab for it. You can just do this with your skin and your eyes.”

Upon returning to Stanford, Williams published this student activity in the Journal of Chemical Education. 

Building cultural and scientific connections

Reflecting on her time in Bangladesh, Williams shared that her favorite part of the experience was the people.

“It was a good opportunity to see a new part of the world, to learn from my students, and to build relationships and friendships. They were really tremendous students.”

Shoshana, who hopes to become a professor after her postdoctoral training, is also grateful to have a PhD mentor, Eric Appel, professor of materials science and engineering, who encouraged her to follow her teaching interests and take a summer away from the research lab to further develop those skills and passions. 

Wherever Williams ends up next, she will surely provide the same encouragement and inspiration to her students, as well as a gift for bringing people together through universal human experiences—in this case, molecules and art.  

“Chemistry is deeply involved in our everyday lives,” she said. “And you can look for it in any activity, passion, or interest.” 

Eric Appel is an associate professor of materials science and engineering and, by courtesy, professor of bioengineering and pediatrics - endocrinology. He is also a senior fellow at the Woods Institute for the Environment, a faculty fellow at Sarafan ChEM-H, and a member of Bio-X, the Wu Tsai Neurosciences Institute and Human Performance Alliance, the Stanford Cancer Institute, the Maternal and Child Health Research Institute (MCHRI), and the Cardiovascular Institute