“It’s probably the hardest thing I’ve ever done at MIT,” says Haley Nakamura, a second-year MEng student in the MIT Department of Electrical Engineering and Computer Science (EECS). She’s not reflecting on a class, final exam, or research paper. Nakamura is talking about the experience of being a teaching assistant (TA). “It’s really an art form, in that there is no formula for being a good teacher. It’s a skill, and something you have to continuously work at and adapt to different people.”

Nakamura, like approximately 16 percent of her EECS MEng peers, balances her own coursework with teaching responsibilities. The TA role is complex, nuanced, and at MIT, can involve much more planning and logistics than you might imagine. Nakamura works on a central computer science (CS) course, 6.3900 (Introduction to Machine Learning), which registers around 400-500 students per semester. For that enrollment, the course requires eight instructors at the lecturer/professor level; 15 TAs, between the undergraduate and graduate level; and about 50 lab assistants (LAs). Students are split across eight sections corresponding to each senior instructor, with a group of TAs and LAs for each section of 60-70 students.

To keep everyone moving forward at the same pace, coordination and organization are key. “A lot of the reason I got my initial TA-ship was because I was pretty organized,” Nakamura explains. “Everyone here at MIT can be so busy that it can be difficult to be on top of things, and students will be the first to point out logistical confusion and inconsistencies. If they’re worried about some quirk on the website, or wondering how their grades are being calculated, those things can prevent them from focusing on content.” 

Nakamura's organizational skills made her a good candidate to spot and deal with potential wrinkles before they derailed a course section. “When I joined the course, we wanted someone on the TA side to be more specifically responsible for underlying administrative tasks, so I became the first head TA for the course. Since then, we’ve built that role up more and more. There is now a head TA, a head undergraduate TA, and section leads working on internal documentation such as instructions for how to improve content and how to manage office hours.” The result of this administrative work is consistency across sections and semesters.

The other side of a TA-ship is, of course, teaching. “I was eager to engage with students in a meaningful way,” says Soroush Araei, a sixth-year graduate student who had already fulfilled the teaching requirement for his degree in electrical engineering, but who jumped at the chance to teach alongside his PhD advisor. “I enjoy teaching, and have always found that explaining concepts to others deepens my own understanding.” He was recently awarded the ​MIT School of Engineering’s 2025 Graduate Student Teaching and Mentoring Award, which honors “a graduate student in the School of Engineering who has demonstrated extraordinary teaching and mentoring as a teaching or research assistant.” Araei’s dedication comes at the price of sleep. “Juggling my own research with my TA duties was no small feat. I often found myself in the lab for long hours, helping students troubleshoot their circuits. While their design simulations looked perfect, the circuits they implemented on protoboards didn’t always perform as expected. I had to dive deep into the issues alongside the students, which often required considerable time and effort.”

The rewards for Araei’s work are often intrinsic. “Teaching has shown me that there are always deeper layers to understanding. There are concepts I thought I had mastered, but I realized gaps in my own knowledge when trying to explain them,” he says. Another challenge: the variety of background knowledge between students in a single class. “Some had never encountered transistors, while others had tape-out experience. Designing problem sets and selecting questions for office hours required careful planning to keep all students engaged.” For Araei, some of the best moments have come during office hours. “Witnessing the ‘aha’ moment on a student’s face when a complex concept finally clicked was incredibly rewarding.”

The pursuit of the “aha” moment is a common thread between TAs. “I still struggle with the feeling that you’re responsible for someone’s understanding in a given topic, and, if you’re not doing a good job, that could affect that person for the rest of their life,” says Nakamura. “But the flip side of that moment of confusion is when someone has the ‘aha!’ moment as you’re talking to them, when you’re able to explain something that wasn’t conveyed in the other materials. It was your help that broke through and gave understanding. And that reward really overruns the fear of causing confusion.”

Hope Dargan ’21, MEng ’23, a second-year PhD student in EECS, uses her role as a graduate instructor to try to reach students who may not fit into the stereotype of the scientist. She started her career at MIT planning to major in CS and become a software engineer, but a missionary trip to Sweden in 2016-17 (when refugees from the Syrian civil war were resettling in the region) sparked a broader interest in both the Middle East and in how groups of people contextualized their own narratives. When Dargan returned to MIT, she took on a history degree, writing her thesis on the experiences of queer Mormon women. Additionally, she taught for MEET (the Middle East Entrepreneurs of Tomorrow), an educational initiative for Israeli and Palestinian high school students. “I realized I loved teaching, and this experience set me on a trajectory to teaching as a career.” 

Dargan gained her teaching license as an undergrad through the MIT Scheller Teacher Education Program (STEP), then joined the MEng program, in which she designed an educational intervention for students who were struggling in class 6.101 (Fundamentals of Programming). The next step was a PhD. “Teaching is so context-dependent,” says Dargan, who was awarded the Goodwin Medal for her teaching efforts in 2023. “When I taught students for MEET, it was very different from when I was teaching eighth graders at Josiah Quincy Upper School for my teaching license, and very different now when I teach students in 6.101, versus when I teach the LGO [Leaders for Global Operations] students Python in the summers. Each student has their own unique perspective on what’s motivating them, how they learn, and what they connect to … So even if I’ve taught the material for five years (as I have for 6.101, because I was an LA, then a TA, and now an instructor), improving my teaching is always challenging. Getting better at adapting my teaching to the context of the students and their stories, which are ever-evolving, is always interesting.”

Although Dargan considers teaching one of her greatest passions, she is clear-eyed about the cost of the profession. “I think the things that we’re passionate about tell us a lot about ourselves, both our strengths and our weaknesses, and teaching has taught me a lot about my weaknesses,” she says. “Teaching is a tough career, because it tends to take people who care a lot and are perfectionists, and it can lead to a lot of burnout.”

Dargan's students have also expressed enthusiasm and gratitude for her work. “Hope is objectively the most helpful instructor I’ve ever had,” said one anonymous reviewer. Another wrote, “I never felt judged when I asked her questions, and she was great at guiding me through problems by asking motivating questions … I truly felt like she cared about me as a student and person.” Dargan herself is modest about her role, saying, “For me, the trade-off between teaching and research is that teaching has an immediate day-to-day impact, while research has this unknown potential for long-term impact.” 

With the responsibility to instruct an ever-growing percentage of the Institute’s students, the Department of Electrical Engineering and Computer Science relies heavily on dedicated and passionate students like Nakamura, Araei, and Dargan. As their caring and humane influence ripples outward through thousands of new electrical engineers and computer scientists, the day-to-day impact of their work is clear; but the long-term impact may be greater than any of them know.

Around the world, about 2 billion people suffer from iron deficiency, which can lead to anemia, impaired brain development in children, and increased infant mortality.

To combat that problem, MIT researchers have come up with a new way to fortify foods and beverages with iron, using small crystalline particles. These particles, known as metal-organic frameworks, could be sprinkled on food, added to staple foods such as bread, or incorporated into drinks like coffee and tea.

“We’re creating a solution that can be seamlessly added to staple foods across different regions,” says Ana Jaklenec, a principal investigator at MIT’s Koch Institute for Integrative Cancer Research. “What’s considered a staple in Senegal isn’t the same as in India or the U.S., so our goal was to develop something that doesn’t react with the food itself. That way, we don’t have to reformulate for every context — it can be incorporated into a wide range of foods and beverages without compromise.”

The particles designed in this study can also carry iodine, another critical nutrient. The particles could also be adapted to carry important minerals such as zinc, calcium, or magnesium.

“We are very excited about this new approach and what we believe is a novel application of metal-organic frameworks to potentially advance nutrition, particularly in the developing world,” says Robert Langer, the David H. Koch Institute Professor at MIT and a member of the Koch Institute.

Jaklenec and Langer are the senior authors of the study, which appears today in the journal Matter. MIT postdoc Xin Yang and Linzixuan (Rhoda) Zhang PhD ’24 are the lead authors of the paper.

Iron stabilization

Food fortification can be a successful way to combat nutrient deficiencies, but this approach is often challenging because many nutrients are fragile and break down during storage or cooking. When iron is added to foods, it can react with other molecules in the food, giving the food a metallic taste.

In previous work, Jaklenec’s lab has shown that encapsulating nutrients in polymers can protect them from breaking down or reacting with other molecules. In a small clinical trial, the researchers found that women who ate bread fortified with encapsulated iron were able to absorb the iron from the food.

However, one drawback to this approach is that the polymer adds a lot of bulk to the material, limiting the amount of iron or other nutrients that end up in the food.

“Encapsulating iron in polymers significantly improves its stability and reactivity, making it easier to add to food,” Jaklenec says. “But to be effective, it requires a substantial amount of polymer. That limits how much iron you can deliver in a typical serving, making it difficult to meet daily nutritional targets through fortified foods alone.”

To overcome that challenge, Yang came up with a new idea: Instead of encapsulating iron in a polymer, they could use iron itself as a building block for a crystalline particle known as a metal-organic framework, or MOF (pronounced “moff”).

MOFs consist of metal atoms joined by organic molecules called ligands to create a rigid, cage-like structure. Depending on the combination of metals and ligands chosen, they can be used for a wide variety of applications.

“We thought maybe we could synthesize a metal-organic framework with food-grade ligands and food-grade micronutrients,” Yang says. “Metal-organic frameworks have very high porosity, so they can load a lot of cargo. That’s why we thought we could leverage this platform to make a new metal-organic framework that could be used in the food industry.”

In this case, the researchers designed a MOF consisting of iron bound to a ligand called fumaric acid, which is often used as a food additive to enhance flavor or help preserve food.

This structure prevents iron from reacting with polyphenols — compounds commonly found in foods such as whole grains and nuts, as well as coffee and tea. When iron does react with those compounds, it forms a metal polyphenol complex that cannot be absorbed by the body.

The MOFs’ structure also allows them to remain stable until they reach an acidic environment, such as the stomach, where they break down and release their iron payload.

Double-fortified salts

The researchers also decided to include iodine in their MOF particle, which they call NuMOF. Iodized salt has been very successful at preventing iodine deficiency, and many efforts are now underway to create “double-fortified salts” that would also contain iron.

Delivering these nutrients together has proven difficult because iron and iodine can react with each other, making each one less likely to be absorbed by the body. In this study, the MIT team showed that once they formed their iron-containing MOF particles, they could load them with iodine, in a way that the iron and iodine do not react with each other.

In tests of the particles’ stability, the researchers found that the NuMOFs could withstand long-term storage, high heat and humidity, and boiling water.

Throughout these tests, the particles maintained their structure. When the researchers then fed the particles to mice, they found that both iron and iodine became available in the bloodstream within several hours of the NuMOF consumption.

The researchers are now working on launching a company that is developing coffee and other beverages fortified with iron and iodine. They also hope to continue working toward a double-fortified salt that could be consumed on its own or incorporated into staple food products.

The research was partially supported by J-WAFS Fellowships for Water and Food Solutions.

Other authors of the paper include Fangzheng Chen, Wenhao Gao, Zhiling Zheng, Tian Wang, Erika Yan Wang, Behnaz Eshaghi, and Sydney MacDonald.