Wool Keratin Research Articles

Wool keratin-stabilized silver nanoparticles

In this paper, we explored a facile method to prepare stable silver nanoparticles (Ag NPs) using extracted wool keratin as the capping agent. The formation of Ag NPs was investigated by UV–Vis spectroscopy, X-ray photo-electron spectrometer and X-ray diffraction spectrometer. The morphology of the NPs was detected by scanning electron microscopy in vacuum and atomic force microscopy in fluid. The possible interactions between the silver core and the capping agent have been investigated using Fourier transform infrared spectroscopy. The effects of keratin concentration on the incubation of the NPs were studied by UV–Vis spectra. It was found that under alkaline condition the process of incubation was much faster than that under neutral pH condition. The photoluminescence properties of the Ag NPs were also investigated. We believe that this work is helpful for the high-value utilization of wool and other keratin-rich bioresource.

Effect of wool keratin proteins and peptides on hair water sorption kinetics

Most beauty care products and treatments primarily affect the cuticle layers of hair fibers. The resulting damage has an adverse effect on hair water absorption. Water changes a wide variety of properties of human hair and is therefore of fundamental interest. Wool proteins are mild, natural, biodegradable, and sustainably produced with multiple functionalities and potential for use in the personal care and detergent market. In this study, the effect on hair water sorption of two types of keratin samples obtained from wool is investigated. Modifications of hair water sorption due to a bleaching treatment have been demonstrated, with lower values of water sorption capacity and an increase of the fibers permeability. Applications of keratin peptides and proteins to bleached hair improved the water sorption properties of the fibers and reduced their permeability.

Preparation and Application of Soluble Wool Keratin

Preparation and Application of Soluble Wool Keratin

Characterisation of keratin biomass from butchery and wool industry wastes

The chemical and structural characteristics of wool and horn–hoof were compared with the aim of better addressing possible exploitation of protein biomasses available as waste from textile industry and butchery. Amino acid analysis showed that wool has a higher amount of cystine and a lower amount of the amino acids that favour α-helix formation than horn–hoof. The difference in the α-helix content is confirmed by FTIR spectroscopy. Electrophoresis separation patterns showed two characteristic protein fractions related to low-sulphur proteins (between 60,000 and 45,000 Da) in wool, while different low-sulphur proteins are present in horn–hoof. These data are partially confirmed by DSC analyses that showed different endothermic peaks at temperatures higher than 200 °C in the horn–hoof thermograms, probably due to denaturation of α-keratins at different molecular weights. Moreover, wool keratin was more hygroscopic and showed a higher extractability with reducing agents than horn–hoof. On the basis of these results, waste wool is a more suitable source than horn–hoof for uses involving protein extraction, but application can be envisaged also in surfactant foams for fire extinguishers and slow-release nitrogen fertilizer.

Study of Whisker and Glass Fibre Reinforced Wool Keratin Films and Their Preparation

This paper presents the related theories and current situation of regenerated keratin materials, as well as fibre reinforced composite materials, which are used to evaluate the feasibility of glass fibres and whisker reinforced wool keratin films. Although blending biopolymers is the traditional way to improve the mechanical properties of keratin materials, wool keratin, which consists of only a few percentages in composite materials, would not have an outstanding performance biologically. In this article, we examine the processes of developing fibre reinforced keratin materials, including the dissolution of wool fibres, dispersion of reinforcements, and interface study of the reinforcements/matrix. The results suggest that both glass fibres and whiskers distribute uniformly and bond well with keratin matrix through observations with an optical microscope and scanning electron microscope (SEM). Moreover, the effects of reinforcement alignment, as well as fibre concentration, can be used to predict the tensile strength (TS) of regenerated keratin materials for further experiments.

Gel formation of solutions of fibrillar proteins during flow in a longitudinal field

The effect of gel formation in the jets of salt-containing solutions of fibrillar proteins (silk fibroin and wool keratin) in a longitudinal hydrodynamic field modeling the process of natural-silk formation in silk glands is studied. Structural transformations in macromolecules are monitored via birefringence measurements, optical rotatory dispersion, and polarization ultramicroscopy. Gel formation under the action of a longitudinal rate gradient is accompanied by the α → β-conformation transition and by the attainment of high degrees of orientation.

Preparation and biodegradation of electrospun PLLA/keratin nonwoven fibrous membrane

As a kind of natural protein, wool keratin was used to improve the cell affinity of poly( l -lactic acid) (PLLA). After small keratin particles were prepared from keratin solution by spray-drying process, they were blended with PLLA solution. PLLA/keratin nonwoven fibrous membrane was produced by electrospinning the blend solutions. The release rate of keratin from the composite membrane was detected by Fourier transform infrared (FTIR) after PLLA/keratin membranes were degraded in PBS up to 4 weeks. The chemical compositions of the PLLA/keratin surface were examined by X-ray photoelectron spectroscope. Although more than half of the keratin was removed from PLLA/keratin membrane during the first few hours of degradation, some keratin particles were still embedded in the PLLA fibers. Osteoblast cells were used to evaluate the cellular behaviors of the composite membrane. After 7 days culturing, more cells were observed on PLLA/keratin membranes than on pure PLLA membranes. MTT assay and alkaline phosphatase (ALP) activity results suggested that keratin could improve the interactions between osteoblast cells and the polymeric membranes.

Wool keratin: A novel building block for layer-by-layer self-assembly

We utilize the extracted water-soluble wool keratin as the building block for the layer-by-layer (LbL) assembly. By adjusting the solution pH, keratin can be used as polycation or polyanion. Experimental results indicate that multilayer films of keratin together with other synthetic polyelectrolytes have been fabricated successfully. We have found that the average thickness of each bilayer of the keratin containing film is evidently larger than that of usual multilayer films previously reported. This feature is helpful to fabricate relatively thick films in less deposition cycles. The use of keratin in LbL assembly is helpful to prepare a biocompatible surface for tissue engineering.

Fabrication and degradation of poly( l-lactic acid) scaffolds with wool keratin

As a natural protein, wool keratin was used to improve the cell affinity of poly( l-lactic acid) (PLLA). Small keratin particles were prepared from keratin solution by the spray-drying process. Keratin particles were blended with PLLA/1,4-dioxane solution and paraffin micro-spheres which were used as progens. After the mixture was molded and dried, the paraffin micro-spheres were removed by cyclohexane. PLLA/keratin scaffolds with controlled pore size and well interconnectivity were fabricated. Keratin releasing rate was detected by Fourier transform infrared (FTIR) after the scaffold was immersed into PBS up to 4 weeks. The surface chemical structure was examined by X-ray photoelectron spectroscope (XPS). The results suggested that the keratin could be held into the scaffold which was expected to improve the interactions between osteoblasts and the polymeric scaffolds.

Use of Sericin in Feltproofing of Wool

A new process for feltproofing of wool fibers based on the biopolymer sericin is reported. The susceptibility of wool to sericin has been enhanced by creation of new active sites along the wool keratin molecules, such as cysteic acid and S-cystine sulphonate residues, by pretreatment with hydrogen peroxide and sodium sulphite. The sericin-combining capacity of wool has been even enhanced by carrying out the reaction in the presence of different crosslinkersnamely dimethylol dihydroxy ethylene urea, dimethyl dihyroxy ethylene urea, and epichlorohydrin, which are able to link sericin with the available sites of wool. The effect of these treatments on some of the inherent properties of wool as well as on its morphological structure is also reported. The felting resistance of wool tops treated with the system H2O2 /Na2SO3/sericin/ECH (felt ball density 0.045 g /cm3) is close to that of the machine washable wool obtained commercially (felt ball density 0.039 g /cm3).

Thermal Denaturation of Hydrated Wool Keratin by1H Solid-State NMR

Thermal denaturation of hydrated keratin in wool was investigated by NMR using 1H wide-line spectra to obtain the phase composition and 1H spin-diffusion experiments using a double-quantum filter to obtain the domain sizes for the wool fibers. The denaturation process detected by DSC takes place for wool fibers in deuterated water in the temperature range 140-144 degreeC. The phase composition measured by 1H wide line NMR spectra reveals a rigid, semirigid and an amorphous phase for temperatures in the range 25-160 degreeC. A dramatic change in the phase composition was detected around 142 degreeC, corresponding to the denaturation temperature. The morphological domain sizes measured by 1H spin-diffusion NMR experiments were obtain from the solutions of the spin-diffusion equations for two-dimensional rectangular and cylindrical morphologies. The keratin mobility gradient in the interfacial region at different denaturation temperatures was measured from the 1H spin-diffusion data. A qualitative model describing the denaturation process of hydrated keratin protein was developed that explains the changes in domain thickness, spin diffusivities, phase composition, and thermodynamic parameters.

Kinetics of Photo-Induced Chemiluminescence Decay from Polymers

Previous studies showed that the decay of photo-induced chemiluminescence (PICL) in polymers does not obey classical first or second order kinetics. This study demonstrates that plotting PICL second-order decay from three fibrous polymers (polypropylene, polyamide 6 and wool keratin) in a modified form gives excellent linear plots. The existence of a significantly less reactive fraction of macroperoxy radicals in heterogeneous polymers can explain the deviation from classical behaviour and this fraction can be quantified from the gradient of the modified plots. This unreactive fraction could be due to either dispersive or diffusive effects in a disordered heterogeneous polymer medium. Both dispersive and diffusive models give very good fits to the PICL decay profiles using three fitting parameters.

Characterizing Wool Keratin

Keratin from wool is a reactive, biocompatible, and biodegradable material. As the biological structural component of skin (soft keratins) and of nails, claws, hair, horn, feathers, and scales (hard keratins) pure keratin comprises up to 90% by weight of wool. Wool was treated in alkaline solutions to extract from 68% to 82% keratin within 2 to 5 hours of exposure at 65∘C. The keratin products were water‐soluble and were confirmed to contain intermediate filament and microfibrillar component‐proteins of fractured, residual cuticle, and cortical cells. Oxidation of wool by peroxycarboximidic acid in alkaline hydrogen peroxide produced keratin products with distinct microcrystalline structures: descaled fibers, fibrous matrices, and lyophilized powders. Morphology and confirmation of peptide functionality were documented by SEM, Amino Acid Analysis, SDS‐PAGE gel electrophoresis, MALDI‐TOF/TOF, and FTIR analyses. The reactivity of keratin from wool models the reactivity of keratin from low‐value sources such as cattle hair.

Preparation of Water Soluble Wool Keratin and Its Application for Human Hair

Preparation of Water Soluble Wool Keratin and Its Application for Human Hair

Amineborane: a unique reductive bleaching agent that protects cystine disulphide bonds in keratins

This paper reports a new application for amineboranes in the bleaching of wool, a typical example of keratin fibre. It has been found in this investigation that amineboranes are unique reductive bleaching agents that do not attack cystine disulphide bonds in wool keratin and do not impart permanent set to the fibre during bleaching. Selected amineborane compounds can be used in conjunction with oxidative agents such as hydrogen peroxide in aqueous media to further enhance the whitening effect and prevent disulphide bond disruption in keratins. The results of this study have suggested that the researched technology outperforms existing bleaching methods on a number of levels and may be an important step towards a new commercial bleaching technology.

Fabrication of Poly(L-Latic Acid) Scaffolds with Wool Keratin for Osteoblast Cultivation

As a natural protein, wool keratin was used to improve the cell affinity of poly(L-lactic acid) (PLLA). Small keratin particles were prepared from keratin solution by the spray-drying process. Keratin particles were blended with PLLA/1,4 dioxane solution and paraffin micro-spheres which were used as progens. After the mixture was molded and dried, the paraffin micro-spheres were removed by cyclohexane. PLLA/keratin scaffolds with controlled pore size and well interconnectivity were fabricated. Keratin releasing rate was detected by Fourier transform infrared (FTIR) after the scaffold was immersed into PBS up to 4 weeks. The surface chemical structure was examined by X-ray photoelectron spectroscope (XPS). The results suggested that the keratin could be held into the scaffold which was expected to improve the interactions between osteoblasts and the polymeric scaffolds.

Genetic Polymorphism of Type 1 Intermediate Filament Wool Keratin Gene in Native Indian Sheep Breeds

Information is presented on the genetic polymorphism of the Type 1 intermediate filament wool keratin gene in 15 native Indian sheep breeds belonging to different agro-ecological regions of India. The study analyzed random blood samples of the 638 sheep by the PCR-RFLP technique. Restriction digestion analysis of a 480 bp PCR fragment of the first exon region with MspI revealed two allelic variants (M = 0.748 and N = 0.252) and three genotypes (MM = 0.543, MN = 0.410, and NN = 0.047) across the 15 sheep breeds. The allelic frequency differences for both alleles across the Indian breeds, irrespective of their geographic distribution, color pattern, and utility traits, were observed to be statistically insignificant by a chi-square test (P > 0.05). According to the pattern of occurrence of allelic variants (M > N), the Indian breeds exhibited similarity to some of the reported European sheep breeds. The average heterozygosity was 0.420, and none of the breeds deviated from Hardy-Weinberg equilibrium. The predominance of the M over the N allele supported its ancestry in Indian sheep too.

Synthesis of Two Peptide Mimetics as Markers for Chemical Changes of Wools Keratin During Skin Unhairing Process

The sheep skins unhairing process with preliminary alkaline treatment of the wool leads to two unnatural dipeptide mimetics lysinoalanine (Lys(*) - Ala) and ornithinoalanine (Orn(*)- Ala) obtaining. They are result from the keratin hydrolysis process. The changes of wool keratin make it resistant to sulphide degradation. We synthesized and characterized these unnatural dipeptides under the experimental conditions. The structures and mechanism of Lys(*) - Ala and Orn(*)- Ala obtaining were elucidated. The using of newly synthesized products as markers for control of wool's keratin changes during skin unhairing process was demonstrated. The developments have also been the result of economic and environmental pressures to meet environmental regulations.

Sorption of ammonia on oxidized and succinylated wool keratin

Sorption of ammonia on oxidized and succinylated wool keratin

Powderization of Wool Keratin by Alkali Hydrolysis in Higher Alcohol/Water Binary Systems

Abstract We successfully powderized keratin fibers under mild conditions. Wool keratin was hydrolyzed in a binary system, consisting of a higher alcohol phase and an alkali aqueous solution phase.