Identifier

etd-07272012-151912

Degree

Master of Science in Biological and Agricultural Engineering (MSBAE)

Department

Biological and Agricultural Engineering

Document Type

Thesis

Abstract

Nano and micro particles have steadily grown in interest for synthetic bone composite structures. Nano and micro sized calcium phosphates especially are of interest because of the osteoinductive behavior of calcium phosphate. Engineered composites incorporating polymers and ceramics, such as poly l-lactic acid (PLLA)/β-TCP, for bone tissue regeneration have been well investigated for their proliferative and osteoinductive abilities. Limited research has been done to thoroughly investigate the effects of various sized β-TCP particles on human mesenchymal stem cell behavior. Foreign bodies are known to elicit an inflammatory and cytotoxic response and several nano-particles are known to elicit cytotoxic and pro-inflammatory responses of mesenchymal stem cells. In this study, the modulation of adult human adipose-derived mesenchymal stem cell (hASC) behavior exposed to β-TCP, as functions of particle size, content and composition in a polymeric-ceramic scaffold system was investigated. The objectives of this work include the development and characterization of monolithic 3-D polymeric-ceramic structures using a modified unidirectional fabrication technique to investigate the cytotoxic, pro-inflammatory and osteogenic potential of PLLA-β-TCP composite on adult human stem cells. Characterization of PLLA-β-TCP composites showed that increasing β-TCP content the compressive strength decreases. Viability of hASCs over a 7 day exposure study showed increasing cytotoxicity with respect to increasing particle concentration regardless of size, although acute (24hr) cytotoxicity was more influenced by size. qPCR was used to measure the pro-inflammatory (IL-6) expression as well as early osteogenic differentiation (hALP). Results suggest there is a modulation in stem cell behavior as a function of β-TCP particle size, concentration and composite system.

Date

2012

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Daniel Hayes

Included in

Engineering Commons

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