Document Type

Honors Capstone Project

Date of Submission

Spring 5-1-2010

Capstone Advisor

Dr. Patrick T. Mather

Honors Reader

Dr. James Henderson

Capstone Major

Biomedical and Chemical Engineering

Capstone College

Engineering and Computer Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biological Engineering | Biomedical Engineering and Bioengineering

Abstract

One of the major challenges in tissue engineering today is inducing organization at the cellular level in vitro. Most biological tissues exhibit anisotropic behavior. They perform differently and have different mechanical properties in different directions. This environment is difficult to mimic with traditional cell culturing methods. The development of anisotropic cell substrates may have the potential to encourage the organization required at the cellular level to induce in vitro tissue formation, an exciting prospect for the advancement of the field of tissue engineering.

It is well known that liquid crystalline elastomers (LCEs) are highly organized polymers with temperature-dependent properties. Previous work has indicated that upon straining, mesogen chains within the material shift so that they are aligned in the direction of strain. This thesis addresses the hypothesis that this mesogen alignment results in the development of anisotropic modulus in LCEs. A newly developed procedure in rheology was developed to determine the degree of anisotropy experienced by LCEs fixed at 0, 50, and 100% strain. It was found that the LCEs did exhibit strain-induced anisotropic moduli. Furthermore, the degree of anisotropy, or the ratio of the longitudinal modulus to the transverse modulus, increased with increasing amounts of strain.

Based on the mechanical anisotropy seen in naturally occurring biological tissues, it was then hypothesized that strained samples would have an effect on cell alignment when used as a substrate in cell culture. No cell alignment was observed on any of the strained samples, but differential cell adhesion was observed. On unstrained samples, cells tended to adhere more readily around the edges, whereas cells on samples with 50% strain were more uniformly distributed, and very few adhered to the samples with 100% strain at all. Analysis of the reasons for these differences is beyond the scope of this thesis, but may be explored further in future work.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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