From Soapberries to RE-SELEX

Aimee Sanford

A career in medicine seemed like the obvious choice for Aimee Sanford. Her dream was to be a part of influencing and safeguarding public health. Then, the diagnoses came.

First, she and her brother were both diagnosed with autoimmune diseases in the same year. Then, her mother and father were both diagnosed with cancer within three years of each other.

There were no obvious environmental determinants for her family’s health concerns, but Aimee became committed to asking questions about why certain diseases develop and what factors lead to that development. Her personal experiences, combined with an increasingly complex understanding of human health, sparked a determination to pursue a career as a laboratory chemist.

As an undergraduate, Aimee pursued these questions at Emmanuel College in Boston. She joined the Gerdon Research in Analytical and Biomaterials (GRAB) Lab with Dr. Aren Gerdon where her work focused on building methods to study factors affecting bone and teeth formation. “Beyond growing an appreciation for the process of learning and acquiring new laboratory and problem-solving skills, I found this work especially interesting due to its underlying tie to public health,” says Aimee.

Following graduation in 2016, Aimee accepted an ORISE fellowship. The ORISE program connects the most talented and diverse college students, recent graduates, postdocs, and faculty to STEM internship and fellowship programs closely aligned with the interests of a variety of research facilities and federal agencies. Appropriate to her interest in public health, broadly defined, Aimee accepted a fellowship at the Centers for Disease Control and Prevention (CDC).

At the CDC, Aimee assisted in analytical method development to aid in outbreak response efforts related to chemical toxins present in soapberry fruits. Soapberry fruits can be used as a detergent or astringent and some healing traditions also use the plant as a home remedy for fever and other ailments. However, soapberry fruits contains amino acids that are toxic if ingested and have been linked to illnesses worldwide, including outbreaks of acute hypoglycemic encephalopathy in Asia. Aimee was energized by the tangible connection between her work and human health. “This work helped me gain an appreciation for the challenge of protecting against environmental toxins that are not compatible with established detection or treatment approaches,” she says. “This is further complicated by the rapid evolution of modern industrial practices, making food-borne contaminant detection even more crucial.” Food safety became a theme that would follow her when she made the decision to pursue graduate school.

Soapberry fruit

Currently, Aimee is a fifth year graduate scholar conducting research in the lab of Dr. Jennifer Heemstra. The Heemstra Group takes an interdisciplinary approach to harness the molecular recognition capabilities of nucleic acids for biological and environmental applications. The lab’s motto is “biomolecules can do amazing things.”

Jen Heemstra pictured in lab with recent alum Colin Swenson

“The biomolecules in our cells are like microscopic LEGO bricks,” explains Jen Heemstra. “They recognize each other and fit together in specific ways to build intricate, functional structures called biopolymers.”

Among the approaches that lab uses to explore these naturally occurring “building blocks”, is a promising class of detection methods called aptamer-based biosensors. However, it has proven technically challenging to directly select for biosensor activity when observing novel small molecule targets. Roughly, the Lego bricks are operating, but the language they’re speaking isn’t completely clear.

Aimee has developed a method to help circumvent these technical hurdles. This work titled “RE-SELEX: restriction enzyme-based evolution of structure-switching aptamer biosensors” was recently published in Chemical Science in their HOT Articles collection. Articles recommended by referees are debuted in this collection as “must reads” among the research published in a given year.

Excitingly, this method is highly tunable and can be used for virtually any small molecule target.

Aimee Sanford

The article describes Aimee’s use of the RE-SELEX method for the detection of kanamycin A. Kanamycin A is a diverse and powerful antibiotic used to treat a range of conditions in humans and animals. However, animal use has led this antibiotic to exist in the food supply at worrying concentrations. The ability to fine-tune methods to sense the presence of kanamycin A could lead to a better understanding of the potential drawbacks of overuse of kanamycin in the food supply and to improved food safety. 

Importantly, the method demonstrated in the article for sensing activity related to kanamycin A also has major potential for broader use. “Excitingly, this method is highly tunable and can be used for virtually any small molecule target,” says Aimee.

While Aimee’s paper is making waves today, this work wasn’t always “hot.” The project began development in the Heemstra Group over six years ago. “This is one of those projects that our group has dreamed about and worked on for many years, “ says Dr. Heemstra. “Aimee’s brilliant troubleshooting, innovative alternative approach, and fierce dedication are what brought RE-SELEX to reality.”

Aimee brings the same dedicated, innovative approach to building scientific community. During her time at Emory, she helped found one of the first student chapters of the International Chemical Biology Society (ICBS) in the United States in 2018. She has also serves as a dedicated peer mentor to researchers in the Heemstra Group. Graduate scholar Brea Manuel works closely with Aimee on projects using nucleic acids to enhance and inhibit enzyme function. “Aimee isn’t the type of mentor to just give you an answer,” says Brea. “But rather, she asks you questions that she’d ask herself when faced with a problem. This isn’t to be difficult. It’s to push her mentee to be the most independent scientist that they can be.”

Aimee isn’t the type of mentor to just give you an answer [. . . ] she asks you questions that she’d ask herself when faced with a problem.

Brea Manuel
Brea and Aimee pictured in lab

Today, Aimee is closer than ever to her career goal of understanding how environment impacts human health. “I am actively applying for industry jobs to continue growing as a leader, researcher, and innovator.“ In addition to her lab mates, cheering her on are cats Nuru and Sheeta and her partner, Bryan.

From RE-SELEX to her work as a peer mentor, Aimee will leave a legacy behind her at Emory. “Her knowledge and unconditional support are key reasons that I have become the independent scientist I am today,” says mentee Brea. “And like my mentor, Aimee, I am able to provide another mentee with this same support.”