Decoding the sticky chemistry of frog tongues

Photo credit: Functional Morphology and Biomechanics lab, University of Kiel.

The next generation of high-tech adhesives could take some design cues from the tongues of frogs, according to new research led by the Oregon State University College of Engineering.

Findings were published Nov. 26 in the journal Biointerphases.

Frogs use their highly specialized tongues to capture prey, with a force that can exceed their own body weight. This is possible, in part, because the frog’s tongue is covered with a sticky mucus that functions as a pressure-sensitive adhesive.

“This mucus is able to generate large adhesive forces in response to the high strain of retraction,” said the study’s corresponding author, Joe Baio, assistant professor of bioengineering. “The goal of this study was to determine the chemical structure of the surface of this mucus after a tongue strike, which had not been done previously.”

Mucus is an aqueous, gel-like secretion containing proteins called mucins that naturally form linear polymeric chains that typically have disordered or “random coil” secondary and tertiary structures.

Fibril formation in frog tongue mucus enables it to function as a pressure-sensitive adhesive.

Recent studies of frog tongue mucus resulted in visual observation of fibrils — multiple protein chains twisted like fibers around a central axis — between the frog’s tongue and the target surface.

“This fibril formation indicates an induced change in the chemical structure of the mucus during tongue retraction,” Baio said. “And it is these fibrils that allow the mucus to generate strain-responsive adhesive forces by acting as molecular shock absorbers for the tongue.”

Collaborators at the Zoological Institute of the University of Kiel, Germany, collected mucus samples from three adult horned frogs. The scientists induced the frogs to strike glass microscopy slides by placing a slide about 2 inches in front of each frog and holding up a cricket immediately behind the slide.

Highly detailed near edge X-ray absorption fine structure microscopy images of the layers of mucus left behind on the slide were collected on the National Institute of Standards and Technology beamline at the National Synchrotron Light Source.

OSU researchers then characterized the surface chemistry of the mucus, which, they concluded, confirms the formation of fibrils in response to tongue retraction, supporting previous classifications of the frog sticky-tongue mechanism as a pressure-sensitive adhesive.

The study was supported by funding from the National Science Foundation, the U.S. Department of Energy and the Aarhus University Research Foundation.

Researchers from the University of Aarhus, Denmark, University of Kiel, Germany, and the National Institute of Standards and Technology were among the collaborators.

Johnson Interns Poster Session

The 2018 Johnson Interns Poster Session will take place on Monday, Nov. 26, from 6 to 7 p.m. on the second floor of the Learning Innovation Center. The following posters will be presented by the students named below. (Mentors and affiliated institutions are identified in parentheses after the poster title.)

Pete and Rosalie Johnson established the Pete and Rosalie Johnson Undergraduate Internship Program to support undergraduates in the School of Chemical, Biological, and Environmental Engineering. The Johnson Internship is available to any CBEE student who has successfully completed the first year CBEE courses CBEE 101 (or equivalent COE intro engineering course) and CBEE 102.

  • Emi Ampo (BioE), “Perfusate Tonicity and its Effects on Osmotic Damage in a Porcine Renal Model” (Higgins/OSU)
  • Solomon Baez (BioE), “Perfusate Tonicity and its Effects on Cryoprotectant Delivery in a Porcine Renal Model” (Higgins/OSU)
  • Renuka Bhatt (ChE), “Sustainable Solar Thermal Energy” (AuYeung/OSU)
  • Anne Chhing (BioE), “Quantifying Fluid Dynamics of Fetal Heart Defects by using Computational Methods on ADINA” (Rugonyi /OHSU)
  • Kacy Childress (ChE), “Effect of Roadside Tree Lines on Outdoor Concentrations of Traffic-Derived Particulate Matter” (Linda George/PSU)
  • Cameron Chun (BioE), “Algorithmic Computational Modeling of Congenital Chicken Embryo Hearts With Ventricular Defects” (Rugonyi/OHSU)
  • Andrew Gates (ChE), “Thin Film Transistors Via Dip Coating” (Chang/OSU)
  • Marisela Gonzalez Crawford (EnvE), “Interactions between Haematococcus Extracellular Polymeric Substances  and Gold Nanoparticles” (Nason/OSU)
  • Tucker Holstun (ChE), “Lithium Ion Battery Cathodes with Enhanced Capacity and Cycling Stability Via a Novel Sol-Gel Coating” (Feng/OSU)
  • Alekos Hovekamp (ChE), “UiO-66 Synthesis Conditions and Growth on Silica Nanofibers” (Chang/OSU)
  • Riley Humbert (ChE), “Role of Carbon Supports for Pd/Au Nanoparticle-Based Catalysts” (Jaio/PSU)
  • Melanie Huynh (BioE), “Using Machine-Learning to Model Adsorption of Nano-Porous Materials” (Simon/OSU)
  • Sophia Jones (ChE), “Thinner Films: Synthesis and characterization of nano-structured compounds” (Dave Johnson/UO)
  • Kyra Kadhim (BioE), “Modeling the Mechanical Properties of a Human Spinal Disc” (Rochefort/OSU)
  • Zavi Kaul (ChE), “Testing the Reliability of a Spinal Disc Emulator ” (Rochefort/OSU)
  • Mira Khare (ChE), “Deciphering the genetic code using ConvNets” (Simon/OSU)
  • Lauren Lippman (ChE), “Inactivation of Microorganisms Using UV Radiation and a Microfluidic Reactor” (Navab/OSU)
  • Francine Mendoza (ChE), “Finite element analysis to investigate the cause of venous collapse after stent placement” (Rugonyi/OHSU)
  • Rachel O’Brien (BioE), “Expression of “Click Chemistry” Immobilized β-glucosidase Mutants by Genetic Code Expansion for Bioactive Coatings” (Schilke/OSU)
  • Kian Patel (ChE), “Lyophilization of Phenylalanine Dehydrogenase” (Fu/OSU)
  • Rachel Polaski (BioE), “Paper Microfluidic Device for Phenylketonuria Therapy” (Fu/OSU)
  • Heidi Reed (ChE), “Ammonia Inhibition of Anaerobic Digestion of Municipal and Gresham Sludge with FOG Addition” (Radniecki/OSU)
  • AJ Rise (BioE), “Facet Analysis of Pt-implanted γ-Al2O3” (Arnadottir/OSU)
  • Rees Rosene (BioE), “Bone Morphogenic Proteins: Implications for Cellular Regeneration.” (Giers/OSU)
  • Elizabeth Rupp (BioE), “Form Follows Function: the Toxicological Effects of Shape, Size, and Surface Stabilization” (Harper/OSU)
  • Katherine Trese (BioE), “Platelet presence maintains activity of contact pathway members in coagulation ” (McCarty/OHSU)

Kelsey Stoerzinger: Living in a materials world

Kelsey Stoerzinger joined the faculty this fall as an assistant professor of chemical engineering.

Kelsey Stoerzinger is motivated in her work by a desire to help solve the world’s energy problems. But she says it was her own natural curiosity that first led her to an academic career in engineering.

“I’m really fascinated by understanding how things work,” said Stoerzinger, who came to Oregon State this fall as an assistant professor and Callahan Faculty Scholar in Chemical Engineering. “I love digging super deep into problems. The general engineering mindset first took root for me when I was trying to understand how materials work — how they behave and deform. I like understanding how materials work the way they do, how they behave, and how they drive chemistry.”

Stoerzinger’s research focuses on electrochemistry and catalysis. Broadly speaking, her work is concerned with energy storage and conversion, and the many ways that water is used in these processes. In the simplest cases, water is used as a coolant. A lot of processes also generate wastewater, which requires engineers to design processes for treatment and recycling. And, in many reactions, water is either a product or a reactant.

A big part of Stoerzinger’s research involves looking at how to make reactions more efficient using catalysis or electrocatalysis. These processes use a type of material, called a catalyst, which is not itself consumed by the reaction. Rather, a catalyst acts as a sort of broker for the reaction — utilizing the unique chemical properties at its surface to enable a reaction to proceed more efficiently or more rapidly. Catalysts can also be used to determine the selectivity of the reaction, or what products are produced.

“I do a lot of work understanding the details of why catalysts work the way they do, fundamental studies to elaborate reaction mechanisms,” Stoerzinger said. “But the goal is to move from having an understanding about, for example, what is the rate-limiting step of a particular reaction, to figuring out how we can design around that. So the research is both to understand how these materials work and also to design and develop new materials and processes.”

Historically, Stoerzinger’s work has been concentrated in the area of electrolysis; that is, splitting water molecules into hydrogen and oxygen. Energy is stored in the bonds of hydrogen and oxygen and released when the two are combined to make water. One way to get energy out of hydrogen is with fuel cells, another of Stoerzinger’s interests, and another area where catalysts play a key role.

After completing her undergraduate work in materials science and engineering at Northwestern University, Stoerzinger earned her Master of Philosophy degree in physics at Cambridge University, where she was a Churchill Scholar. From there, she went to the Massachusetts Institute of Technology to earn her doctorate with a graduate research fellowship from the National Science Foundation.

From there, she was awarded a two-year postdoctoral fellowship at Pacific Northwest National Laboratory (PNNL), where she was able to pursue her own research interests full-time. At PNNL, Stoerzinger focused on photoelectrochemistry. Her work involved developing new materials to convert energy from captured photons (as from sunlight) directly into chemical fuel.

“Instead of having a photovoltaic solar cell powering an electrolyzer, you are combining these two processes into one,” she said. “You can make a single material that can do all of that, which is pretty amazing. This enables you to reduce the overall footprint and eliminate a lot of waste.”

At Oregon State, Stoerzinger is interested in looking at different types of reactions, including nitrate reduction for cleaning up groundwater, and methane oxidation for fuel cells. She’s also looking at ways to reuse some wastewater streams and exploring more abundant sources of water for electrolysis.

“Right now when we use electrolysis to make hydrogen, it requires extremely clean water, and that’s a big limitation,” she said. “If we are thinking in terms of a hydrogen fuel economy, it’s going to require more water than we currently consume for drinking. This could potentially be a huge tax on our existing resources.”

In addition to her research, Stoerzinger says she has a real passion for teaching.

“Teaching is just a transformative way to touch so many people and to really shape their careers,” she said. “I remember many teachers throughout my graduate and undergraduate education who have shaped me as a person. They have made me the scientist that I am, and they will continue to influence the things that I do in my career. Being part of that transformation in someone else’s education is just awesome.”



CBEE teaching fellowship projects announced

Seven teams of faculty from the School of Chemical, Biological, and Environmental Engineering have been selected to spearhead innovative teaching fellowship projects this academic year. These projects, part of the school’s “Revolution in CBEE” initiative, aim to support and advance the initiative’s two main goals: inclusivity and meaningful professional learning.

The Revolution in CBEE is supported by a five-year, $2 million grant, awarded by the National Science Foundation’s “Revolutionizing Engineering Departments” (RED) program in 2015, “to enact groundbreaking, scalable and sustainable changes in undergraduate education.” CBEE’s RED grant proposal pledged to “make bold and deliberate changes to the educational environment and practices.” These projects are an instrumental part of that effort. Each project was awarded a modest stipend internally to help defray incidental costs associated with its implementation.

Below are brief descriptions of the seven projects (team lead identified in parentheses):

Writing in the CBEE Curriculum (Elain Fu, Christine Kelly)

This project aims to develop a resource specific to CBEE disciplinary knowledge, for both students and instructors, that will help to create consistent expectations across courses regarding the format and quality of student writing. Currently, students move through classes with inconsistency in writing instruction, scoring, and feedback. The team envisions the creation of a CBEE writing handbook that both instructors and students will use. This resource will allow instructors to emphasize their focus, while communicating to students the breadth of material that constitutes good writing.

Vertical Integration of Cross-Disciplinary Coursework and Advanced Computation (Kate Schilke)

This project aims to integrate advanced computational methods into coursework by developing MATLAB problems and projects for CBEE sophomore and junior core courses. These problems and projects will incorporate meaningful context and broad disciplinary representation. Some of the material will include statistics content as well. The goal is to enable faculty to adopt the problems in their course with minimal effort, regardless of their familiarity with MATLAB.

Balancing Student Assessment and Inclusivity in a Critical Introductory Course (Phil Harding)

This project aims to help transition what in the past might have been considered a “weeder” course into a precise and efficient tool for helping to determine whether individual students’ needs are best served by advancing within their engineering program. Toward that end, more information and better tools are required, to balance the need for accurate student assessment with the need for inclusivity in engineering programs. The project will collect, analyze, and share data from a critical introductory course over two consecutive fall terms. It is predicted that collecting, sharing, and discussing this data with students will increase participation, awareness, and student performance.

Professional Competency Development in Bioengineering Graduate Students through Embedded Co-Curricular Activities across Core Curriculum (Morgan Giers)

This project aims to define specific professional competencies desired by bioengineering graduate students and future employers, such as grant writing, knowledge of intellectual property, or budget calculation. This is to be accomplished through surveying students, alumni, and employers in the bioengineering industrial advisory board. The project also aims to embed co-curricular activities that advance professional competencies in the bioengineering core curriculum courses.

Improving the Instructional Practices of Senior-Level ENVE Courses: ENVE 456 (Stacey Harper)

This project aims to revamp the Sustainable Water Resources Development course taught each spring by Stacy Harper. The goal is to make the class more interactive using a problem-solution, team-based approach. Partnering with Devlin Montfort (and others), she intends to evaluate the developed teaching materials, ensure inclusive teaming during course activities, and determine assessment criteria and a strategy for targeted improvement of the classroom experience.

Inclusive Teaming (Nick AuYeung)

This project aims to develop strategies for fostering inclusivity in teamwork and collaboration across a range of engineering courses. Last year, this project team explored literature on inclusive and effective teaming strategies, and several members who taught CBEE courses tried new team formation, support, and assessment practices in their classrooms and discussed those with the group. This year, they will continue to develop content and teaching tools that support four main areas: team formation; functional teaming curricula (e.g., conflict management and effective communication); modules to engage students in the examination of complex structures, systems, and ideologies that sustain discrimination and the unequal distribution of power and resources in the practice of engineering; and assessment instruments to measure student teaming competencies

Process Simulation Curriculum Integration (Nick AuYeung, Natasha Mallette)

This project aims to integrate process simulation into foundational classes, using the Aspen software suite. For this project, team leaders, along with two highly accomplished students with at least senior standing, will work to create meaningful Aspen modules that instructors can use in their classes (typically twice per term) to reinforce conceptual understanding introduced in class through a visual process simulation, and to give students familiarity with the software. Modules will consist of written instructions and short video supplements to show software tips.

Madison Webb joins CBEE advising team

Madison Webb joined the School of Chemical, Biological, and Environmental Engineering this fall as the school’s newest undergraduate academic advisor. Webb joins Lindsay Wills and head advisor Kimberly Compton, as part of the school’s newly configured, dynamic, and proactive advising team, dedicated to student success.

A native of Beaverton, Webb is a proud “Beaver Believer,” and an Oregon State alum herself. After graduating in 2013 with a Bachelor of Arts degree in history, Webb started working on campus with international students in the INTO partnership. She worked her way up from entry level, joining the ranks of the university’s professional faculty in 2016 as an undergraduate progression advisor.

The job of an advisor involves not only understanding complicated institutional policies and processes, but also being able to communicate them to students, in order to motivate them and keep them on track toward graduation. Webb says her experience has given her the ability to explain policies and processes to students in a variety of different ways.

“People have different learning styles,” she said. “I try to focus on that, and also the nuances of how our students got to where they are. They come from multiple different paths and backgrounds, and having additional layers of understanding helps us to be more effective in helping them.”

Webb says she derives great personal satisfaction from being able to watch students grow.

“We get to watch them as they go through these big life changes, making big decisions that can affect their entire futures,” she said. “Our role is to be a support network for them, giving them the correct information and letting them see the path they need to take to reach the finish line.”

In addition to her work advising students, Webb has become a student again herself. She is currently working on a Master of Science degree in educational leadership and policy from Portland State University, with an emphasis in higher education. A former competitive gymnast, Webb is also a coach and co-owner of PEAK Elite Gymnastics Academy, in Corvallis.