(7k) Understanding Bacterial Biofilms for Improved Medical and Industrial Processes

Bacterial biofilms are a community of sessile bacteria which are ubiquitous in the natural environment, industrial settings, and in human hosts. These communities of bacteria form by attaching to a surface and creating a protective layer called the extracellular polymeric substance (EPS). Due to the EPS and other biofilm-specific resistance mechanisms, biofilms are very difficult to eradicate and can cause biofouling of industrial plant equipment, ship hauls, and pipe lines, to name a few. This biofouling can lead to weakened materials, contamination of products, and heat transfer problems. Additionally, these biofilms can form on medically implanted devices, lungs of patients, and hospital equipment. Biofilm infections cannot be readily treated with antibiotics alone since the resistance to antibiotics of the bacteria in a biofilm can increase a hundred-fold, requiring antibiotic concentrations above safe dosages. Although biofilm research has increased our understanding over the last few years, there is still much to learn about biofilms and many applications to be tested and utilized for biofilm mitigation.

The many problems and ubiquitous nature of biofilms create a unique niche for interdisciplinary research. My educational background is in chemical engineering and bioengineering; however, my postdoctoral position is in microbiology providing me a strong base for bridging the gap between the two disciplines. My interest in bacteria and biofilms started in my undergraduate career through the Center for Biofilm Engineering at Montana State University. While there I worked on the isolation and enrichment for magnetotactic bacteria for the development of a natural paramagnetic nanoparticle harvesting process. I also worked on a project to optimize micelle conformation from siderophores for the application of drug vesicles with Dr. Abigail Richards. I completed my doctoral work at the University of Iowa with Dr. Eric Nuxoll and worked with Pseudomonas aeruginosa biofilms for the development of an improved means of mitigating biofilms on medically implanted devices without invasive surgery. By using a polymer coating containing iron oxide nanoparticles on a medically implanted device, heat and antibiotics can be released directly to the surface where the biofilm is located using an alternating magnetic field, effectively killing the infection. This technology now has a patent pending. Currently I am a postdoctoral fellow at the University of Colorado Anschutz Medical Campus with Dr. Alexander Horswill. I am working with mutants of methicillin resistant Staphylococcus aureus, or MRSA, to determine the genes required for biofilm formation. Between my interdisciplinary research and traditional engineering background I plan to continue research with biofilms to determine natural inhibitor molecules in bacterial interactions and develop novel drug formulas from that information.

Successful Proposals

National Institutes of Health T32 Fellowship for Biocatalysis and Bioprocessing, 2012-2014, 2014-2015

Ballard and Seashore Dissertation Fellowship, 2017

Kammermeyer Graduate Fellowship, 2012-2013

Selected Publications

O’Toole A, Ricker EB, Nuxoll E. “Thermal mitigation of Pseudomonas aeruginosa biofilms.” Biofouling, 2015, Vol 31 (8), 665-675.

Ricker EB, Al-Jaafari H, Bader TM, Hundley BS, Nuxoll E. “Thermal Shock Susceptibility and Regrowth of Pseudomonas aeruginosa Biofilms.” International Journal of Hyperthermia, 2017, doi 10.1080/02656736.2017.1347964.

Ricker EB and Nuxoll E. “Synergistic Effects of Antibiotics and Heat on Pseudomonas aeruginosa Biofilms.” Biofouling, in revision.

Ricker EB, Coffel J, and Nuxoll E. “Wireless Heating of Pseudomonas aeruginosa Biofilms Using Iron Oxide Nanoparticle Coatings.” Advanced Healthcare Materials, in preparation.

Teaching Interests:

Teaching Experience

I have taught students from all different backgrounds through classes, tutoring, and mentoring. I have been a teaching assistant at the University of Iowa for chemical reactions engineering (a kinetics course), mass transfer and separation, and an introductory engineering course on engineering problem solving. For each of these courses I was responsible for creating discussion lectures, homework assignments and solutions, grading, and holding office hours in addition to my discussion time to work with the students. I learned to create lectures that introduced problem solving techniques and how to apply them to different situations. I encouraged class participation by asking students what they would suggest as the next step to keep them engaged and thinking critically. I found that the students who engaged more learned the material faster and that an environment with constant positive reinforcement fostered more students of different levels to contribute their opinions. I also achieved greater participations via projects in smaller groups which promoted discussion and demonstrated how the material learned in class could contribute to problems in the engineering world and day to day life. I was recognized for my teaching at the University of Iowa with the Osburn Teaching Award in 2016. I was also a teaching assistant at Montana State University for the introductory course for chemical and biological engineering. In this position, I set up experiments and worked with the students to further their knowledge gained from the experiments. In addition to teaching in a classroom setting I have enjoyed tutoring since 2010. Through my experiences tutoring I learned how to approach a problem from several different angles to help a student grasp the ideas and apply their analytical skills gained from one problem set to another. I also developed a more structured way of introducing ideas that can reach a broad range of students. Working with students outside of the classroom, such as mentoring students in the laboratory is a lot of fun and a great way to bring knowledge to a student in a different setting. I have mentored five undergraduates and one graduate student so far and have greatly enjoyed working with students in the laboratory setting. I was able to get each student to work in the laboratory effectively and encouraged the students to think critically about the experiments and how they could improve them.

Teaching Philosophy

Through my teaching experience I have developed a variety of presentation styles to develop analytical and critical thinking. Analytical approaches to engineering problems are numerous and can be fostered through a combination of interactive lectures and hands-on learning. Exciting and interactive lectures will encourage the students to participate and contribute ideas. Positive reinforcement for participation along with enthusiasm for a topic can make the difference between a forgotten topic and a memorable topic. This can be achieved through demonstrations, encouragement, and questions to the class throughout the lecture. Laboratory experiments and group projects encourage students to think critically about what they are doing while reinforcing the concepts learned in lectures. Projects can also be used to hone the students’ communication skills through presentations and writing. These projects can include problems that do not have a defined solution, challenging the students to think critically and apply their knowledge in a new way. In addition to the activities in a classroom, I plan on having students apply their knowledge and problem-solving skills to real world problems through Engineers Without Borders (EWB). I have been a part of several student and professional EWB projects and have grown as a person, intellectually and as a team member. I will either contribute to a current chapter or create an EWB chapter so that students can get field experience and internalize concepts by making them relevant. Through this experience the students will also form professional and personal contacts locally and all over the world. The analytical and critical thinking skills learned through lectures and hands on experiences will create another generation of productive and innovative engineers.