Keratin has natural characteristic for applying in biomaterial field as a biocompatible matrix like tissue regeneration, proliferation, and cell adhesion or drug career in the shape of microcapsules or microsphere. Because of the amino acid inherent structure, keratin extraction needs to be well designed to meet the particular requirement for applying in desired applications such as integrate with different molecules, drug releases, wound healing or biocompatible film. Keratinous sources such as wool, feathers are valuable by-products that abundantly present in nature. Although wool has valuable material in especially in textile industry, massive amount of low-grade wool cannot be utilized in textile and inevitably end up as a waste stream. Because of high cystine content of keratin, solubilization and extraction of keratin is a problematic process compared with other natural polymers such as collagen and chitosan. Using keratin in different level especially in large-scale requires understanding final properties of keratin which is strongly depends on producing procedure.. The interest towards drug career and microcapsules based on non-toxic, biodegradable and biocompatible polymers, such as proteins, is increasing considerably. In this work, keratin from wool fibers was extracted with oxidation, reduction, sulfitolysis, and superheated water hydrolysis methods. The effect of each method on obtained keratin properties are discussed and particularly reported how each extracted keratin influenced by the extraction process. In particular, all different samples of extracted keratin were characterized by molecular weight determination, FT-IR and NIR spectroscopy, amino acid analysis, and thermal behavior and the archived data were compared with reporting of previous studies with the emphasis of advantage and limitation of each extraction method. In the other part of the study, special attention are given to produce microcapsule and film from keratin-based material in line with biomaterial application. Microcapsules were prepared using water-soluble keratin, known as keratoses, with the aim of encapsulating hydrophilic molecules. The obtained keratin via oxidizing extraction of pristine wool, were utilized as shell part of the microcapsules which produced by sonication method. Production of the microcapsules was carried out by a sonication method. The microencapsulation and dye encapsulation yields were obtained by UV-spectroscopy. In addition, morphological structure of microcapsules was studied by light microscopy, SEM, and AFM and thermal properties of microcapsules were investigated by DSC. The molecular weights of proteins analyzed with gel-electrophoresis indicates the extracted keratoses has suitable molecular weight range for bio-application, and also the results confirmed that the hydrophilic dye (Telon Blue) was introduced inside the keratoses shells. The final microcapsules diameter ranged from 0.5 to 4 µm. One part of the experimental work is dedicated to producing keratin blend film with polyvinyl alcohol (PVA). PVA has been chosen because of its biocompatible and biodegradable properties which make this polymer as a promising candidate in the bio-field area. Blend of Polyvinyl alcohol (PVA) and keratoses were prepared with the aim of producing bio-compatible material proper for film and fiber structure mainly to improve the mechanical properties of obtained keratoses. Aqueous solution of keratoses and PVA was prepared for solution casting method. Blended films were characterized by, SEM, FT-IR spectroscopy and Differential scanning colorimetry and tensile properties.
|Titolo:||Keratin Based Material For Perspective Bio-Application|
|Data di pubblicazione:||12-gen-2018|
|Appare nelle tipologie:||8.1 Doctoral thesis Polito|