Date of Last Revision

2017-04-27 10:13:43


Biomedical Engineering - Biomechanics

Degree Name

Bachelor of Science

Date of Expected Graduation

Spring 2017


Many instruments are used to find elastic properties of biological samples using methods such as tensile and bending tests, but using the atomic force microscope (AFM) is considered a non-destructive method because it can provide repeated local stiffness information without damaging the sample. It additionally allows the sample to be tested in an aqueous environment, which is optimal for soft materials such as hydrogels. The nanoindentation is performed via cantilever, measuring the deflection of the cantilever during the contact of the sample using a laser. Compared to hard samples, testing soft materials can present more challenges when working with the AFM, creating the need for a refined technique.[1] This study will explore ways to improve the accuracy and feasibility of testing hydrogels, which are significant in biomaterials research as they offer the ability to be altered mechanically and chemically to fit the needs of cells.[2] The technique for testing the hydrogels will be refined through a process moving from dry to wet samples, attempting to repeatedly and successfully obtain topography and elastic properties through high resolution topography scans and force curves.


  1. Radmacher, M., Tillamnn, R.W., Fritz, M., and Gaub, H.E. (1992), From molecules to cells: imaging soft samples with the atomic force microscope. Science. 257: 1900-1905
  2. Flake, M. M., Nguyen, P. K., Scott, R. A., Vandiver, L. R., Willits, R. K., and Elbert, D. L. Poly(ethylene glycol) microparticles produced by precipitation polymerization in aqueous solution. Biomacromolecules 12 (844-850). 2011.

Research Sponsor

Dr. Rebecca Willits

First Reader

Dr. Rouzbeh Amini

Second Reader

Dr. James Keszenheimer



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.