Finding a medicine that can kill a cancer cell is only the beginning. It still has to reach that cell inside a person. The body may break it down or clear it away, and treatment can harm healthy tissue along the way. Paula Hammond builds tiny structures designed to protect medicines and help them reach a tumor.
I photographed Paula at the Massachusetts Institute of Technology in October 2023, inside the Chemical Engineering building where she had led the department for eight years. She was warm and easy to talk with. When she spoke about her students and colleagues, her affection for them was unmistakable.
Her work begins with something familiar: opposite electrical charges attract. Paula and her collaborators use that pull to assemble materials around particles far smaller than a single human cell. They add one ultrathin layer, then another with the opposite charge, gradually building a coating whose composition they can precisely control.
Each layer has a job. The outer coating can help protect the particle and encourage it to attach to particular cells. Other layers carry treatments or influence how they are released. The wrapping becomes part of the medicine.
This approach offers a way to tackle drug resistance. Some cancer cells produce proteins that pump chemotherapy drugs back out. Paula’s team has designed particles with a cancer drug at the core and small interfering RNA in the surrounding layers. The RNA reduces production of a protein involved in resistance, giving the chemotherapy a better chance to work.
Inside a living body, the difficulties multiply. Proteins collect on a particle’s surface. Immune cells may intercept it. Even reaching a tumor does not guarantee that the medicine will penetrate it or enter its cells. These approaches remain experimental, and every promising result in the laboratory brings questions about how they will behave in people.
I like the patience this kind of engineering requires. So much public attention goes to the discovery of a new molecule that it is easy to overlook what has to happen next. Paula studies the stubborn obstacles between a promising compound in a dish and a person it might help. Often the answer comes down to a tiny change on a surface, or the order of layers too thin to see.
She brings that same care to teaching and mentorship. In our conversation, she spoke about students finding their footing and young faculty finding their direction. She knew firsthand how much encouragement could matter. When she arrived at MIT as an undergraduate from Detroit, she had wondered if she belonged. Other students and professors helped her feel that she did.
She returned to MIT for her doctorate, joined the faculty in 1995, and in 2015 became the first woman and the first person of color to lead the Chemical Engineering department. She was named an Institute Professor in 2021. In January 2026, she became dean of the School of Engineering at the Massachusetts Institute of Technology, the first woman to hold that position.
Paula is a member of all three National Academies: the National Academy of Sciences, the National Academy of Engineering, and the National Academy of Medicine. Very few scientists ever receive that recognition across all three fields. Her work makes their connections tangible, turning the chemistry of materials into treatments that might one day save a patient’s life.
The work comes down to changes too small to see, tested and revised over years. For a patient, the difference could be a medicine that works where another has failed.
