If you hold a blackberry, you’ll likely feel its bumps and grooves with your fingertips. When you pop it in your mouth, you may use your tongue to feel its bulbar structure. And if you’re like Bryan Shaw, a biochemist and biophysicist at Baylor University, you’ll notice that the fruit feels reminiscent of the structure of a very large molecule.
For Shaw, using his mouth to explore a blackberry at breakfast was a lightbulb moment. He saw an opportunity to create a new way for students with blindness to visualize complex molecular structures. Shaw’s son lost an eye to retinoblastoma when he was young. While spending time with him and a friend of his who is fully blind, Shaw noticed their tendency to explore their environment by putting foreign objects in their mouths. This prompted him to explore how his research team could promote STEM education for visually impaired students. Today, Shaw and his graduate student Katelyn Baumer published a paper in Science Advances reporting on the success of using tiny 3-D models to help students with blindness sense and visualize protein structures using their mouths.
“When you've lost your vision completely…you need to utilize every single sense you have, and the tongue is the finest tactile sensor you have,” Shaw says.
The team created tiny models ranging from the size of a peanut to that of a grain of rice. They made inexpensive models out of edible gummy bear gelatin that can be flavored to further enhance the sensory experience and can be packaged like candy. And they made other models of nonedible surgical resin. In this proof-of-concept study, the authors say these models have potential to be cheaply made, easily transported and safe to use—and in the case of the resin, safe to wash and reuse.
About 39 million individuals experience blindness and 285 million individuals are visually impaired worldwide, according to the World Health Organization. Students with visual impairments are often discouraged from partaking in chemistry and other sciences because they’re considered too dangerous or too visual for someone without eyesight.
“It's a virtue, historically, to keep blind kids out of chemistry—you're doing them a favor because chemistry so dangerous,” Shaw says. “This is a problem because chemistry is a central science. And if you keep kids out of chemistry, you keep them out of a deep understanding of many things.”
Hoby Wedler, a PhD chemist and entrepreneur not involved in the study who was born completely blind, says that new models are game-changing. Folded proteins are some of the most common and complex 3D images presented in STEM.
“Having access to those structures and being able to explore them and understand them would make protein chemistry a lot more approachable to me,” Wedler says. “Any tool that we can use to empower scientists and push back the frontiers of what we thought was impossible is great.”
Chemistry and biochemistry require an understanding of the shape and function of thousands of proteins and other complex molecules. The most common method for introducing blind students to these microscopic forms is to create large hand-held models.
“I teach biochemistry and there are 1,100 illustrations in the textbook. All of that imagery is inaccessible to a student if you're blind—you need a model,” Shaw says. “But you can't carry around a baseball-sized tactile model for every 3-D image in your book. You would need a pickup truck bigger than what they drive in Texas.”
Instead, the researchers sought to create something much more convenient. They pulled the crystalline structure of nine proteins from the Protein Data Bank, a repository of information about the 3-D shapes of complex biological molecules. For some models, they molded that edible gelatin into shapes the size of a peanut. To create even smaller replicas, they turned to a type of nontoxic resin commonly used in dental surgery. This nonedible material can be 3-D printed to make highly accurate models as small as a grain of rice.
The researchers blindfolded 281 college-age study participants, all of whom are sighted, and gave them each a protein model to feel in their mouth. They then offered the participants each of the nine protein models and asked the participants to feel them in their mouths and identify the original model. On average, participants could recall the models using their mouths with 85.6 percent accuracy. When asked to use their hands to identify proteins, the participants were accurate 84.8 percent of the time.
The researchers then asked a different group of sighted participants to study a computer model of a protein using their vision and pick that model out of a carousel of visual models of other proteins. They were able to correctly recall the protein 87.5 percent of the time.
When they ran a smaller-scale test with 31 students in elementary school, they logged similar results. The statistical similarities in how students could sense with their mouths compared with their hands and eyes aligns with some neuroscientists’ understanding that oral sensory perception is deeply rooted in the way humans experience their environment.
“It's something that's intuitive,” Shaw says. “We didn't have to train students how to do this. They just did it.”
The tongue is a complex structure consisting of densely packed muscles that can move fluidly and reach tight spaces, making it well suited for exploring the intricacies of tiny models.
When the tongue senses the composition of an object, it sends a signal to the somatosensory cortex in the brain to create a visual image. The authors say that resolution of the tongue is about half a millimeter, while that of fingertips is twice as large at one millimeter. When offered the smallest size models—those roughly the size of a grain of rice—about 40 percent of students had better recall using their mouths, compared with 30 percent who more accurately used their fingers.
“To me it's almost a little more primitive and a little more accurate than feeling things with my hands,” Wedler says. “When I feel things with my hands, I take them in, but they're not as embedded in my mind and in my being. When I feel things on my palate with my tongue, I am really making them a part of me.”
Wedler runs a company that helps individuals build what he calls “sensory literacy,” or fully utilizing taste, touch and smell to supplement eyesight. He says he feels he doesn’t need to work as hard to create mental images of objects when sensing with his mouth.
“As a blind chemist myself, I've struggled with understanding protein structure,” says Mona Minkara, a bioengineer at Northeastern University.
As a student, she created models of proteins using craft supplies like PlayDoh and pipe cleaners. In her current work as a computational chemist studying pulmonary surfactants, she says its critical to visualize the structure of the compounds she’s working with to understand their functions. Tools like braille and tactile models are helpful for understanding certain concepts, but these mini oral sensory models offer a solution that other assistive technology can’t compare with.
“Science really is observable by any of our senses,” Minkara says. “If this works as well as I envision it to work, this is breaking down a huge barrier. You don't need your eyes anymore to interact with the information. That's brilliant.”
Shaw says he hopes that products like these models will encourage children with visual impairments to feel confident becoming involved with STEM from a young age. The authors say that when using resin, the models each cost roughly ten cents to make. Shaw imagines if they’re one day approved for sale, they will be cheap and easy enough to produce that students—as early as third grade—could play with tubs of them, as they do with Legos.
“I hope this paper helps raise public awareness about these problems. It’s not that educators are mean, they just don't know what to do—they don't have the tools or the resources,” Shaw says. “The exclusion of blind kids in chemistry and STEM is going to be coming to an end.”