Objective: The present study investigates viscoelastic properties of human autopsy brain tissue via nanoindentation to find feasible biomarkers for Alzheimer's Disease (AD) in ex vivo condition and to understand the mechanics of the human brain better, especially on the difference before and after progression of AD.Methods: Viscoelastic properties of paraformaldehyde-fixed, paraffin-embedded thin (8 μm) sectioned normal and AD affected human autopsy brain tissue samples are investigated via nanoindentation with a combined loading profile of a linear preloading and a sinusoidal loading at various loading frequencies from 0.01 -10 Hz. In 1,200 indentation tests for 10 human autopsy brain tissue samples from 10 different subjects (5 AD cases and 5 normal controls), viscoelastic properties such as Young's modulus, storage modulus, loss modulus, and loss factor of both gray and white matter brain tissues samples from normal and AD affected tissues were measured experimentally. Results:We found that the normal brain tissues have higher Young's modulus values than the AD affected brain tissues by 23.5 % and 27.9 % on average for gray and white matter, respectively, with statistically significant differences (p < 0.0001) between the normal and AD affected brain tissues. Additionally, the AD affected brain tissues have much higher loss factor than the normal brain tissues on lower loading frequencies.

His research interests are in the area of engineering design, and manufacturing process development for the polymer-based micro additive manufacturing process. Dr. Jariwala has participated and led several research projects from funded by NSF, the State of Georgia, and Industry sponsors on technology commercialization. At Georgia Tech, he is responsible for enhancing corporate support for design courses, managing design, and fabrication/prototyping facilities, coordinating the design competitions/expo and teaching design courses, with a strong focus on creating and enabling multidisciplinary educational experiences.