Development of elastic biomaterials as high performance candidates for tissue engineering applications

Tropoelastin is an extracellular matrix protein, which polymerises to form elastin in the body. Due to its distinctive structural, mechanical and biological properties, tropoelastin provides a versatile building block for manufacturing biomaterials applicable to tissue engineering. Silk fibroin is a fibrous protein that has been widely used in biomedical applications because of its strength and durability. Hybrid protein polymers comprised of recombinant human tropoelastin and silk fibroin have favourable characteristics as implantable scaffolds in terms of mechanical and biological properties. In this thesis, a new class of elastic biomaterials based on tropoelastin and silk protein mixtures was developed. Tropoelastin and silk proteins were mixed and stabilised using a novel methodology and the fabrication, characterisation and potential applications of two different materials, a biocompatible film and a highly twisted yarn were explored. The fabricated tropoelastin-silk films were considered for potential corneal replacement applications. They performed similarly to the natural cornea in terms of optical clarity, refractive index, glucose permeability and mechanical properties. They showed a remarkable combination of physical properties encompassing flexibility, elasticity and suturability. Furthermore, the films supported both corneal epithelial and endothelial cell growth and function indicating that this new biomaterial may be suitable for corneal tissue regeneration. The fabricated tropoelastin-silk yarns were continuous, uniform, well twisted and strong. The yarns were easy to handle and could be used to fabricate woven meshes. The meshes supported cell growth and proliferation in vitro and were well-tolerated on in vivo implantation. The compatibility of the tropoelastin-silk yarns with textile technology processing methodologies makes them applicable for the manufacturing of a range of 3D materials suitable for tissue engineering applications

Inhibitive S. aureus Infection to HUVECs Induced by Trehalose and Glucose-functionalized Gold Nanoparticles

Microbial adhesion to host cells represents the initial step in the infection process. Several methods have been explored to inhibit microbial adhesion including the use of glycopolymers based on mannose, galactose, sialic acid and glucose. These sugar receptors are however abundant in the body and they are not unique to bacteria. Trehalose in con-trast is a unique disaccharide that wildly expressed by mi-crobes. The role of trehalose in bacteria has widely been in-vestigated but this carbohydrate has not yet been explored as anti-adhesive. Herein, gold nanoparticles (AuNPs) coated with trehalose-based polymers have been prepared and compared to AuNPs coated with glucose-functionalized were developed to inhibit. Acting as anti-adhesive, trehalose-functionalized nanoparticles particularly decreased the infec-tion of HUVEC cells by S. aureus, while outperforming the control nanoparticles. Microscopy revealed that trehalose coated nanoparticle bind strongly to S. aureus compared to the controls. As a conclusion, nanoparticles based on treha-lose could be suitable to inhibit S. aureus infection

Optically robust, highly permeable and elastic protein films that support dual cornea cell types

Damaged corneas can lead to blindness. Due to the worldwide shortage of donor corneas there is a tremendous unmet demand for a robust corneal replacement that supports growth of the major corneal cell types. Commercial artificial corneas comprise plastic polymers that do not adequately support diverse cell growth. We present a new class of protein elastomer-dominated synthetic corneas with attractive performance that intimately couple biologically active tropoelastin to mechanically robust and durable protein silk. Fabricated films substantially replicate the natural cornea physically and by interacting with both key cells types used in cornea repair. Performance encompasses optical clarity at high transmittance, compatible refractive index, substantial glucose permeability, compliant mechanical properties, and support of both growth and function of corneal epithelial and endothelial cells