Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Anamika Prasad

Abstract

Motivation: Long term tissue survivability ex-vivo can greatly facilitate research on the influence of external stimulus (loading, radiation, microgravity) on the tissue, including mechanisms of disease transmission and subsequent drug discoveries. Bioreactors (used to culture living tissue ex-vivo) can be a valuable tool to study cell activity during physiological processes by mimicking their in-vivo native 3D environment.
Objective Statement: We have developed a compact, 3D printed bioreactor equipped with both continuous flow-perfusion and dynamic mechanical-loading stimulations, capable of maintaining ex-vivo viability of swine cancellous bone cores over a long period. Qualitative study of the cultured cores (in terms of material composition and mechanical properties) has also been carried out.
Materials and Method: Trabecular cores of 10mm diameter and 10mm height extracted from the femoral head of freshly sacrificed swine were cultured in the bioreactor. External stimulations of flow perfusion (15mL/h) and mechanical loading (35N at 0.22Hz for 1hour daily) were imparted to the cultured samples. Periodic analysis of tissue viability, mechanical stiffness and compositional make-up were carried out via Confocal Fluorescent Microscopy, Nanoindentation and Raman Spectroscopy respectively. To find the optimized flow rate for stimulation, effect of media perfusion was compared between 15mL/h, 35 mL/h and 60 mL/h flow rates. Ongoing work involves analyzing the effect of different loading signals to extract the optimized mechanical loading parameters.
Result: Tissue survivability could be achieved up to 35 days of culture. Matrix composition could be best retained via combination of continuous flow perfusion and periodic mechanical loading. Increasing the perfusion rate to 60mL/h yielded best results in prolonging tissue survivability and in maintaining bone quality.
Conclusion: We have characterized compositional and cell viability changes under exvivo storage of swine cancellous bone, with primary focus on development of the tissue culture platform and optimization of stimulation parameters. The 3D printed platform, equipped with both flow-perfusion and mechanical loading is capable of successfully culturing cancellous tissue up to 35 days.

Library of Congress Subject Headings

Bioreactors.
Tissue culture.
Three-dimensional printing.

Format

application/pdf

Number of Pages

74

Publisher

South Dakota State University

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Rights Statement

In Copyright