BME Summer Seminar Series

Wednesday, August 3^rd, 2022

9:30-10:30AM EST

Via Zoom Meeting – link below*

Evaluation links:

Donghyun Yim: https://purdue.ca1.qualtrics.com/jfe/form/SV_9MGUg3h2ttyv0ma

Seul Ah Lee: https://purdue.ca1.qualtrics.com/jfe/form/SV_1AhGIPCOkyDtoPA

Computational Modeling of Axonal Cytoskeletal Structure Driving Neurite Outgrowth

Donghyun Yim (T. Kim, advisor)

Abstract: Introduction: The neuron elongates forward in length to reach other neurons located far away from it and thus form the neural network, which is often referred to as neurite outgrowth. Four cytoskeletal elements are known to be engaged in neurite outgrowth: microtubule filaments, cross-linkers, dynein motors, and actin cortex. Dynein motors walk toward the minus end of microtubules, whereas their bodies are fixed at the plus end of microtubule counterparts, which results in the microtubule sliding. By contrast, cross-linkers either between microtubule pairs or microtubule-actin connections work as transient springs and therefore suppress the neurite elongation. Previous computational studies showed that molecular interplays between these components can lead to outgrowth. However, systematic understanding of mechanism driving the neurite outgrowth still lacks.

Methods: To this end, an agent-based model, which comprises essential cytoskeletal elements and reflects their mechanical properties and interactions, was constructed. The microtubule filament was simplified into serially connected segments with bending allowed as a whole. Both cross-linker and motor were equipped with two hinged arms and their dynamic behaviors were assumed to occur in a force-dependent manner, based on findings of previous single-molecule studies.

Results: We explored a wide parametric space consisting of several parameters. Our broad parametric studies showed that higher concentration of microtubules is beneficial to accelerate the neurite outgrowth, whereas dense population of cross-linkers suppresses the neurite outgrowth. The analytic study was also extended into probing how the average length and stiffness of microtubule filaments affect elongation rate. In addition, we investigated how interactions between microtubules and surrounding actin cortex change the neurite outgrowth.

Discussion: Overall, we developed the agent-based cytoskeletal model to describe neurite growth. We are putting computational effort to enhance the model by incorporating microtubule dynamics into the model.

Development of Vision and Eye Care Devices in Soft Contact Lenses

Seul Ah Lee (C. Lee, advisor)

Abstract: Much research has been done on smart contact lenses, especially as a minimally invasive

diagnostic platform and a drug delivery system. The eyes provide rich physiological and broad

diagnostic information, making contact lens sensors a promising disease diagnostic tool. A smart

contact lens, one such contact lens sensor, can quantify the concentrations of various biomolecules

and electrolytes in ocular fluids and physical biomarkers of the eye, such as intraocular pressure

(IOP). Continuous and non- or minimally invasive contact lens sensors can be directly utilized in

a clinical or point-of-care setting. However, smart contact lenses lack practicality for patient use

due to the field being relatively new and underdeveloped. Here, we introduce the incorporation of

contact lens sensors and their fabrication, sensitivity, power source, and readout mechanisms. The

incorporation is to monitor glaucoma and conditions associated with eye health, such as dry eye

syndrome and inflammation. The resulting soft contact lens sensors fit seamlessly across different

corneal curvatures and thicknesses in human eyes. The lens can also wirelessly capture the

intraocular pressure by utilizing the principle of the capacitor and mechanical deformation of the

microfluidic channel under ambulatory conditions. Also, we will discuss the colorimetric ocular

electrolyte tear fluid sensor to detect the color change of dry eye disease and inflammation. We

assessed the in vitro biocompatibility, ex vivo functionality, and in vivo safety of the soft contact

lens sensor.

*Join Zoom Meeting

https://purdue-edu.zoom.us/j/92168739019?pwd=cnBOaFBxN3FWVVVTWC8wWWhaekdIdz09

Meeting ID: 921 6873 9019

Passcode: biomedical

Liz Rowen

She/Her

Graduate Program Assistant
Weldon School of Biomedical Engineering

Martin C. Jischke Hall of Biomedical Engineering
206 S. Martin Jischke Drive
West Lafayette, IN 47907-2032

o: 765-494-1197