North Carolina: 3D Printed Models Used as Tactile Teaching Tools in Introductory Biology Courses

North Carolina researchers worked together recently to create tactile teaching tools (TTT), outlining their work in the recently published ‘Building the lac operon: A guided-inquiry activity using 3D-printed models.’ By incorporating 3D printing, the scientists were on a mission to ‘level the playing field’ for visually impaired and otherwise disadvantaged students—as well as others who might not function well in visual learning environments.

As Makerspaces sprout up in learning institutions around the US, many teachers are using 3D printed models in class—offering innovative visual learning aids that allow for more comprehensive experiences in the classroom; however, in this study the researchers voiced concerns for blind and otherwise disabled or challenged students, motivating them to create 3D printed tactile teaching tools (TTT) for classroom use.

“TTTs are 3D models composed of multiple parts representing interacting components, such as proteins of a signaling pathway or monomers that compose a biological macromolecule,” explain the researchers. “These models are used for guided inquiry learning (GIL) activities that ask students to manipulate, assemble, or analyze structures in order to answer questions.”

Depending on the types of activities required in Process-Oriented Guided Inquiry Learning (POGIL), the TTTS are explored and defined, with questions becoming increasingly more challenging and complex; on the other hand, GIL activities use TTTs for added constructivist learning.

Students worked in small groups for the TTT/GIL activity learning about the structure of a group of genes known as the lac operon, often used to teach biology students the basics in gene regulation.

“The lac operon TTT utilizes magnets to simulate the binding of the LacI repressor to the operator and a vibration motor housed in the DNA model to indicate successful binding of the RNA polymerase to the relevant promoter sequences and initiation of transcription,” explained the researchers.

With the assistance of the TTT, the students can learn about each component and how they interact together in gene expression. They are then asked to predict outcomes for the interactions they have learned about.

“We hypothesized that the use of the lac operon TTT-GIL would result in increased student performance on assessments of related learning objectives in multiple educational settings, and that learning gains would be greater for students at a less resourced minority-serving institution (MSI) than at an R1 university,” said the research team.

Meant to be used at the introductory microbiology level, the authors state that the activities could also be used in general biology; however, the students should understand the ‘central dogma’ of molecular biology. The activity is around 75 minutes long, and is meant to result in students being able to diagram a bacterial operon, describe how the lac operon is regulated, and explain what happens when bacterium are ‘enabled to utilize two different sugars as growth substrates under catabolite repression control.’

3D-printed lac operon tactile teaching tool set. A. the yellow LacI repressor protein is shown binding to the operator site within the promoter. B. The allolactose (magnetic marble) is shown binding the LacI repressor, pulling it off of the operator sequence. With LacI unbound, the red/white RNA polymerase is able to bind to specific-10/-35 regions in the lac promoter as shown in C. Magnets are used to simulate interactions between components. The model utilizes a simple circuit with the battery contained within the RNA polymerase and a vibration motor contained in the gray DNA box. When the RNA polymerase binds to specific -10/-35 regions in the lac promoter, the circuit is completed, and the model begins to vibrate, representing transcriptional initiation.

The TTTs were 3D printed and then assembled and wired for classroom use, tested at both North Carolina State University (NCSU), an urban public R1 university, and the University of North Carolina – Pembroke (UNCP), a rural public minority-serving institution (MSI).

Institutional characteristics.

A total of 57 students were evaluated at NCSU during a 300-level introductory microbiology course. At UNCP, 29 students were evaluated during a 300-level introductory genetics course.

“Analysis of linked pre- and post-assessment scores demonstrated that the NCSU and UNCP interventions both resulted in statistically significant increases in performance on an individual level as well as increases in median assessment scores,” stated the researchers.

Characteristics of classrooms in which lac operon TTT-GIL activity was implemented and assessed.

The data that the researchers collected during this study reflected the effectiveness of using TTTs in the classroom, striving to learn abstract biological concepts.

“While 3D models have been utilized in the classroom in a variety of ways (Ramirez and Gordy, manuscript submitted), best practices for utilizing models in inclusive ways remain undefined. Based on these encouraging preliminary results, our group has expanded this approach to additional biological concepts covered in additional biological sciences undergraduate courses in a variety of classroom settings,” concluded the researchers.

“Future studies continuing to compare the effectiveness of TTTs for different student populations will help to establish TTT-GIL activities as a new tool for inclusive STEM teaching.”

3D printing in education is valuable in a wide range of age groups and grades, with new educational plans being developed, transformations occurring in countries like Brazil, 3D models being created for other educational applications like chemistry, and so much more.

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