When Paula Hammond first arrived on MIT’s campus as a first-year scholar within the early Eighties, she wasn’t certain if she belonged. In reality, as she informed an MIT viewers yesterday, she felt like “an imposter.”
Nevertheless, that feeling didn’t final lengthy, as Hammond started to seek out help amongst her fellow college students and MIT’s school. “Group was actually necessary for me, to really feel that I belonged, to really feel that I had a spot right here, and I discovered individuals who had been prepared to embrace me and help me,” she stated.
Hammond, a world-renowned chemical engineer who has spent most of her tutorial profession at MIT, made her remarks in the course of the 2023-24 James R. Killian Jr. School Achievement Award lecture.
Established in 1971 to honor MIT’s tenth president, James Killian, the Killian Award acknowledges extraordinary skilled achievements by an MIT school member. Hammond was chosen for this 12 months’s award “not just for her great skilled achievements and contributions, but additionally for her real heat and humanity, her thoughtfulness and efficient management, and her empathy and ethics,” in keeping with the award quotation.
“Professor Hammond is a pioneer in nanotechnology analysis. With a program that extends from fundamental science to translational analysis in drugs and power, she has launched new approaches for the design and improvement of complicated drug supply techniques for most cancers remedy and noninvasive imaging,” stated Mary Fuller, chair of MIT’s school and a professor of literature, who introduced the award. “As her colleagues, we’re delighted to have a good time her profession right this moment.”
In January, Hammond started serving as MIT’s vice provost for school. Earlier than that, she chaired the Division of Chemical Engineering for eight years, and he or she was named an Institute Professor in 2021.
A flexible method
Hammond, who grew up in Detroit, credit her mother and father with instilling a love of science. Her father was considered one of only a few Black PhDs in biochemistry on the time, whereas her mom earned a grasp’s diploma in nursing from Howard College and based the nursing faculty at Wayne County Group Faculty. “That offered an enormous quantity of alternative for ladies within the space of Detroit, together with girls of coloration,” Hammond famous.
After incomes her bachelor’s diploma from MIT in 1984, Hammond labored as an engineer earlier than returning to the Institute as a graduate scholar, incomes her PhD in 1993. After a two-year postdoc at Harvard College, she returned to hitch the MIT school in 1995.
On the coronary heart of Hammond’s analysis is a method she developed to create skinny movies that may primarily “shrink-wrap” nanoparticles. By tuning the chemical composition of those movies, the particles may be personalized to ship medication or nucleic acids and to focus on particular cells within the physique, together with most cancers cells.
To make these movies, Hammond begins by layering positively charged polymers onto a negatively charged floor. Then, extra layers may be added, alternating positively and negatively charged polymers. Every of those layers could comprise medication or different helpful molecules, similar to DNA or RNA. A few of these movies comprise tons of of layers, others only one, making them helpful for a variety of purposes.
“What’s good in regards to the layer-by-layer course of is I can select a gaggle of degradable polymers which might be properly biocompatible, and I can alternate them with our drug supplies. Because of this I can construct up skinny movie layers that comprise totally different medication at totally different factors inside the movie,” Hammond stated. “Then, when the movie degrades, it may launch these medication in reverse order. That is enabling us to create complicated, multidrug movies, utilizing a easy water-based method.”
Hammond described how these layer-by-layer movies can be utilized to advertise bone progress, in an software that might assist individuals born with congenital bone defects or individuals who expertise traumatic accidents.
For that use, her lab has created movies with layers of two proteins. One among these, BMP-2, is a protein that interacts with grownup stem cells and induces them to distinguish into bone cells, producing new bone. The second is a progress issue known as VEGF, which stimulates the expansion of recent blood vessels that assist bone to regenerate. These layers are utilized to a really skinny tissue scaffold that may be implanted on the harm website.
Hammond and her college students designed the coating so that when implanted, it could launch VEGF early, over every week or so, and proceed releasing BMP-2 for as much as 40 days. In a research of mice, they discovered that this tissue scaffold stimulated the expansion of recent bone that was practically indistinguishable from pure bone.
Concentrating on most cancers
As a member of MIT’s Koch Institute for Integrative Most cancers Analysis, Hammond has additionally developed layer-by-layer coatings that may enhance the efficiency of nanoparticles used for most cancers drug supply, similar to liposomes or nanoparticles constituted of a polymer known as PLGA.
“We have now a broad vary of drug carriers that we are able to wrap this manner. I consider them like a gobstopper, the place there are all these totally different layers of sweet and so they dissolve one after the other,” Hammond stated.
Utilizing this strategy, Hammond has created particles that may ship a one-two punch to most cancers cells. First, the particles launch a dose of a nucleic acid similar to quick interfering RNA (siRNA), which may flip off a cancerous gene, or microRNA, which may activate tumor suppressor genes. Then, the particles launch a chemotherapy drug similar to cisplatin, to which the cells are actually extra weak.
The particles additionally embrace a negatively charged outer “stealth layer” that protects them from being damaged down within the bloodstream earlier than they will attain their targets. This outer layer may also be modified to assist the particles get taken up by most cancers cells, by incorporating molecules that bind to proteins which might be ample on tumor cells.
In more moderen work, Hammond has begun creating nanoparticles that may goal ovarian most cancers and assist stop recurrence of the illness after chemotherapy. In about 70 p.c of ovarian most cancers sufferers, the primary spherical of remedy is very efficient, however tumors recur in about 85 p.c of these circumstances, and these new tumors are often extremely drug resistant.
By altering the kind of coating utilized to drug-delivering nanoparticles, Hammond has discovered that the particles may be designed to both get inside tumor cells or stick with their surfaces. Utilizing particles that stick with the cells, she has designed a remedy that might assist to jumpstart a affected person’s immune response to any recurrent tumor cells.
“With ovarian most cancers, only a few immune cells exist in that area, and since they don’t have a variety of immune cells current, it’s very tough to rev up an immune response,” she stated. “Nevertheless, if we are able to ship a molecule to neighboring cells, these few which might be current, and get them revved up, then we would be capable to do one thing.”
To that finish, she designed nanoparticles that ship IL-12, a cytokine that stimulates close by T cells to spring into motion and start attacking tumor cells. In a research of mice, she discovered that this remedy induced a long-term reminiscence T-cell response that prevented recurrence of ovarian most cancers.
Hammond closed her lecture by describing the influence that the Institute has had on her all through her profession.
“It’s been a transformative expertise,” she stated. “I actually consider this place as particular as a result of it brings individuals collectively and allows us to do issues collectively that we couldn’t do alone. And it’s that help we get from our associates, our colleagues, and our college students that basically makes issues attainable.”
