Tissue engineering (TE) is an emerging technique to develop biological substitutes forreplacing damaged tissues and organs. However, currently used biomaterials for making
TE scaffolds are considerably weaker than the native tissue and may not withstand
mechanical stimuli during culture needed in TE. Carbon nanomaterials (CNMs) are known
to enhance the stiffness of many engineering materials. In this research we explore the
use of carbon nanomaterials as reinforcements for tissue engineering scaffold
biomaterials. The candidate biomaterial used for this research is agarose, a hydrogel used in articular cartilage tissue engineering.
This research focuses on two broad aspects. The first deals with the application of
nanotechnology to tissue engineering in order to develop better scaffold materials and the second deals with the mechanical characterization and computational modeling of agarose and its nanocomposites as biphasic materials. This dissertation is divided into three parts. In part A, the effect of carbon nanofiber (CNF) concentration on the mechanical properties and biocompatibility of agarose is studied through mechanical testing and cell viability tests. We find that the mechanical properties of the agarose-nanocomposite improve with the addition of CNFs in a concentration dependent manner. Also, the agarose-CNF nanocomposites do not display any significant cytotoxicity. In part B, a variety of CNMs with different kinds of functionalizations are used to study the effect of type and functionalization of the CNMs on the mechanical properties and biocompatibility of agarose. The CNM type and functionalization that gives the best improvement in the mechanical properties of agarose without compromising its biocompatibility is found to be CNFs with COOH type of functionalization. These are selected for detailed mechanical testing and computational modeling in part C. Mechanical testing protocols are developed to model agarose and its nanocomposites as biphasic materials. Multistep unconfined compression stress-relaxation tests are used to develop constitutive equations for the solid phase and confined compression creep tests are used to develop constitutive equations for the fluid phase. The solid phase is modeled using the pseudo-elasticity theory coupled with compressible hyperelasticity to model the hysteretic stress-strain data obtained during the loading-unloading tests. The fluid phase is modeled using a strain-dependent permeability. The computational models developed closely agree with the experimental results.