Keratinous Materials Research Articles

先天性甲肥厚合并疑似Ogna型单纯型大疱性表皮松解症一家系调查

A 23-year-old male patient presented with repeated painful erosion on the soles of both feet for 10 years, and with walking difficulties for half a month. Skin examination showed thick dark-brown finger and toe nails with distal protuberance, and hard keratinous materials under the nails. Obvious hyperkeratosis and maceration occurred on the soles of both feet, which appeared milky-white in color; diffuse papulovesicles were observed on the soles and lateral margins of both feet with scattered erosions. Vesicles were observed on the wrist and forehead. Follicular papules and fine scales were scattered on the extensor aspect of the forearm and elbow, and diffuse white patches were observed on the surface of the tongue. The above clinical manifestations were consistent with pachyonychia congenita. Peripheral blood samples were obtained from the patient, his parents and grandmother, and subjected to whole-exome sequencing. Sequencing showed two mutations in both the patient and his father, including base deletions at position 516-518 (c.516-518 del CAA) in exon 1 of the KRT6A gene, which caused pachyonychia congenita-K6a, and a base substitution at position 3 970 (c.3970 C>T) in exon 27 of the PLEC gene, which may cause epidermolysis bullosa simplex Ogna. The same mutation in the PLEC gene was found in the patient′s grandmother. The patient was diagnosed with pachyonychia congenita complicated by suspected epidermolysis bullosa simplex Ogna. After 9-month treatment with acitretin, the nails became lighter in color, plantar skin lesions were obviously relieved, and scattered millet-like vesicles in the wrist completely subsided. The patient was followed up at present. Key words: Pachyonychia congenita; Epidermolysis bullosa simplex; Acitretin; Keratin-6A gene; PLEC gene

Thiol-ene photoclick reaction: An eco-friendly and facile approach for preparation of MPEG-g-keratin biomaterial.

Wool keratin is a natural material with excellent properties, which is considered as scaffold biomaterial for tissue engineering. Polyethylene glycol can improve the mechanical properties of keratin materials because of its excellent biocompatibility and plasticity. In the present work, poly (ethylene glycol) methyl ether methacrylate (MPEGMA) was grafted onto keratin by thiol‐ene photoclick reaction. The results of FTIR and SDS‐PAGE verified the successful reaction between MPEGMA and keratin. Compared with the keratin, circular dichroism and XRD results showed that the β‐sheet ratio increased in MPEG‐g‐keratin. Additionally, it can be found that the exposure of keratin hydrophobic amino acids increased quickly and the micelle size became larger due to the introduction of MPEG from the results of fluorescence spectroscopy and particle size analysis. The MPEG‐g‐ keratin was formed into a membrane to further study the application of the modified keratin. Compared with the keratin membrane, the flexibility and biocompatibility of modified keratin have been improved. This work provides an eco‐friendly and facile approach for preparation of the keratin biomaterials.

A study on the prevalence of keratinophilic fungal biota of semi-arid region of Rajasthan, India

Keratinophilic fungi are morphologically and physiologically allied molds that produce the keratinase enzyme which degrades the keratin materials in or on the soil. Fifty soil samples were collected from various habitats of Rajasthan namely Jaipur, Ajmer, Alwar and Sikar in India. Out of 154 isolates, a total of 31 keratinophilic fungal species of 16 genera was recovered, including Chrysosporium tropicum (11.04%), Chrysosporium indicum (9.09%), Trichophyton mentagrophytes (8.44%), Fusarium solani (7.79%), Trichophyton rubrum (7.14%), Microsporum canis (5.84%), and Aspergillus terreus (4.19%). The frequency of these keratinophilic fungi is also discussed in relation to soil pH. The most of the fungi (47.40%) were isolated from the soil samples with pH 7.00 to 7.99. Chrysosporium indicum (5.84%) reported since 8.00–8.99 pH, while Fusarium solani (5.19%), Microsporum canis (4.55%) and Trichophyton mentagrophytes (4.55%) between 7.00 and 7.99 pH. This study stipulates that the soils of Rajasthan may be major reservoirs of certain keratinophilic fungi.

Valorization of keratin from food wastes via crosslinking using non-toxic oligosaccharide derivatives

Oligosaccharide derivatives were developed to crosslink keratin materials from poultry feathers, swine bristles and ox hairs to valorize these major wastes from meat industry. Global butchery generates more than 8,600,000 tons of keratinous wastes annually. Keratin was considered a promising resource for developing bio-based products as alternatives to petroleum products. Regenerated keratin products, such as films, usually showed insufficient mechanical properties, and required external crosslinking. However, most crosslinkers for proteins are either toxic, expensive, or with low efficiencies under mild conditions. In this research, regenerated keratin films were crosslinked by oxidized sucrose, a safe and potent bio-polyaldehyde. The crosslinker with verified low toxicity improved both tensile strength and elongation of keratin films, surpassing many other safe crosslinkers. Mechanism of the crosslinking reaction was proposed as forming Schiff bases and aminals and verified via 1H NMR and 13C NMR. Relationship between tensile properties and crosslinking degree of keratin films was also quantified.

Submicron amino acid particles reinforced 100% keratin biomedical films with enhanced wet properties via interfacial strengthening

Keratin films with wet stability and strength suitable for biomedical applications were developed via reinforcement with submicron cysteine particles for improved interfaces. Keratin products regenerated from wool or human hair were widely investigated as wound dressing and tissue engineering scaffolds for their satisfactory biomedical properties. However, regenerated keratin scaffolds usually did not have good mechanical properties, and also could not stand humid or wet biological environment due to poor moisture stability. Reinforcements for keratin materials were usually polysaccharides or synthetic polymers, and thus usually had non-ideal interfacial properties due to limited compatibility. In this research, submicron cystine particles were employed to reinforce keratin films for their high compatibility with keratin and bio-safety. Transition of primary and secondary structures of keratin due to matrix-reinforcement interaction was analyzed. The keratin films showed unprecedented pliancy, good tensile properties under humid conditions and biocompatibility, and thus had good potential for biomedical engineering applications.

DNA Extraction from Keratin and Chitin.

DNA extracted from keratinous and chitinous materials can be a useful source of genetic information. To effectively liberate the DNA from these materials, buffers containing relatively high levels of DTT, proteinase K, and detergent are recommended, followed by purification using either silica column or organic methods.

Effects of Graphene Oxide on the Structure and Properties of Regenerated Wool Keratin Films.

Much research has focused on improvement of the structural and mechanical properties of regenerated keratin materials by physical or chemical methods in recent years. In this research, regenerated keratin materials were modified with graphene oxide (GO). The properties of modified keratin films and the mechanism of interaction between GO and keratin macromolecules were studied. The SEM and XRD test results showed that the orientation of keratin macromolecules could be effectively improved by GO, which favored improvement of the keratin material’s crystallinity and made the films more uniform and compact. The thermal stability and mechanical properties of GO-modified keratin films were also improved significantly. At the same time, the reaction mechanism between keratin and GO materials was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), FT-IR, and Raman spectroscopy. It was shown that there was no chemical reaction between GO and keratin molecules, and the interaction between them was mainly via hydrogen bonding and van der Waals forces.

Extraction of Keratin from Rabbit Hair by a Deep Eutectic Solvent and Its Characterization

Keratin from a variety of sources is one of the most abundant biopolymers. In livestock and textile industries, a large amount of rabbit hair waste is produced every year, and therefore it is of great significance to extract keratin from waste rabbit hair in terms of the treatment and utilization of wastes. In this study, a novel, eco-friendly and benign choline chloride/oxalic acid deep eutectic solvent at a molar ratio of 1:2 was applied to dissolve waste rabbit hair, and after dissolution keratin was separated by dialysis, filtration, and freeze-drying. The dissolution temperature effect was discussed, and the resulting keratin powder was characterized by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, protein electrophoresis, thermogravimetry and differential scanning calorimetry, and amino acid analysis. During the dissolution process, the α-helix structure of rabbit hair was deconstructed, and the disulfide bond linkages were broken. The solubility of rabbit hair was significantly enhanced by increasing dissolution temperature, and reached 88% at 120 °C. The keratin produced by dissolving at 120 °C displayed flaky powders after freeze-drying, and had a molecular weight ranging from 3.8 to 5.8 kDa with a high proportion of serine, glutamic acid, cysteine, leucine, and arginine. Such features of molecular weight and amino acid distribution provide more choices for the diverse applications of keratin materials.

Starch Modified With Chitosan and Reinforced With Feather Keratin Materials Produced by Extrusion Process: An Alternative to Starch Polymers

Starch (potato), chitosan, and feather keratin are used for processing biodegradable films produced by extrusion. The morphology of the films is examined with a scanning electron microscope and showed the excellent dispersion of keratin. The dispersion is the result of compatibility between the polysaccharides and proteins, as well as the proper operation of the extrusion process. Water solubility of the starch‐chitosan films decreased with an increase of keratin materials. The storage modulus increased up to 137% for the composites with unmodified ground quill, and by 192% for composites with modified ground quill. In a tensile test, the composites with unmodified and modified quill reached outstanding increments up to 8160 and 7250% in elastic modulus, respectively, compared to the matrix. They also reached up to 3800% and 3150% in maximum strength, respectively, compared to the matrix. The lysozyme test showed relevant changes in the degradability rate, because the weight loss of the films at 3 weeks decreased from 53% for starch‐chitosan matrix and up to 34% for composites with 5 wt% of modified quill. The results corroborated that chicken feather materials can be useful for the development of a manufacturing process for starch composites, and the decomposition of starch‐chitosan composites can be controlled depending on the content and type of keratin.

Synthesis of keratin foaming agent

The samples of technical protein foaming agents based on keratin materials like wool were obtainedby method of alkaline hydrolysis. The optimal parameters for the hydrolysis of keratin-containing rawmaterials were established: the duration of the process was 3 hours, the concentration of the NaOH reagentsolution was 5%, the reaction temperature was 403K, the feedstock ratio was NaOH = 1:7.5. Conductedby IR-spectroscopic studies of the hydrolysis reaction products were shown the identify of the samplesof keratin foaming agents, obtaining at 403K and at 433K. It is established that at a temperature above403K the quality of the product of hudrolysis significantly not improve. Proposed structure of the sampleshas α-helical configuration of laying chain and samples of amino acids with peptide bonds. The samplesobtained by hydrolysis of keratin materials are natural surfactants and after modification ther can used asfoaming agents in fire fighting and foamers for construction.

Wear resistance of Polymethyl Methacrylate (PMMA) with the Addition of Bone Ash, Hydroxylapatite and Keratin

In this study mechanichal and tribological properties of keratin, bone ash and hydroxylapatite by adding to PMMA ( known as the main prosthesis material) were investigated. Hydroxylapatite, bone ash, and keratin materials were added as PMMA in to the content of PMMA, in the proportions of %1, %3 and %5, respectively. The resulting mixtures were put into the molds and solidified in order to obtain samples to be used in the wear experiments. Each experiment was conducted by preparing three experimental samples. The wear data were compared according to the average values of the experimental samples. In the wear test, the results were also evaluated according to the average values obtained from each group and the results of the control group. It was observed that, the wear resistance of the PMMA including 3%, 5% bone ash and PMMA including 5% keratin flour were higher than the values of the control group.

The Thermodynamics of Trichocyte Keratins.

This chapter is an attempt at an excursion into the world of keratins with the help of thermodynamics.After briefly introducing some of the thermodynamic concepts involved in deciphering the behaviour of keratins, we willuse them to look into the process of aggregation of keratin molecules into intermediate filaments, and keratin fibres, and then for analysing how keratin materials react to mechanical, thermal and moisture stresses, respectively.In most of the cases entropy appears to be the major driving force of the response occurring in keratins under environmental assault. This fact points to the important role played for keratins by temperature, which, asidefrom influencing the kinetics of the processes (accelerating or decelerating the rates of the rates), helps increase or decrease the entropic contribution to the Gibbs free energy and, thus, allows thermodynamically the occurrence of the observed behaviour of keratins.

Chitosan–Starch–Keratin Composites: Improving Thermo-Mechanical and Degradation Properties Through Chemical Modification

Chitosan–starch polymers are reinforced with different keratin materials obtained from chicken feather. Keratin materials are treated with sodium hydroxide; the modified surfaces are rougher in comparison with untreated surfaces, observed by Scanning Electron Microscopy. The results obtained by Differential Scanning Calorimetry show an increase in the endothermic peak related to water evaporation of the films from 92 °C (matrix) up to 102–114 °C (reinforced composites). Glass transition temperature increases from 126 °C in the polymer matrix up to 170–200 °C for the composites. Additionally, the storage modulus in the composites is enhanced up to 1614% for the composites with modified ground quill, 2522% for composites with modified long fiber and 3206% for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73% for chitosan-starch matrix up to 16% for the composites with 5 wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiating chitosan–starch films with sustainable features.

Valorization of keratin based waste

Abstract Keratin is considered a major animal product. It can be obtained from the sources such as animal feathers, hair, hoof, and nails. Such keratinous materials have high protein content, consisting of at least 17 amino acids which can be used for purposes such as nutrition in animal feed or fertilizers. However, these materials are hardly digestible because of the highly-structured di-sulphide linked polypeptides which must be cleaved before utilization. Degradation of keratin waste can therefore provide an inexpensive source of digestible protein and amino acids. Methods known to degrade keratin include hydrolysis under pressure while using steam, enzymatic hydrolysis or chemical hydrolysis with e.g. base, acid or other reactive agent such as ozone, hydrogen peroxide etc. Current paper is a review of the recent trends in the valorization of the keratinous substances, namely wool, feather and hair. In this review, various upcoming and established techniques to utilize these wastes are studied and their methods, advantages and disadvantages are compiled. A near-complete degradation is deemed possible using certain methods as in the cases of the ionic liquids, the reduction using thiols and tertiary-phosphines, the High Density Steam Flash Explosion, and the enzymatic keratinolysis. The cost and time required however, may make them infeasible. Thus, the optimum method may be chosen based on their product, its value, cost of the process and the time required for its completion.

Evaluation of Keratinolytic Activity Succeeds by Keratinophilic Fungi in Jaipur, India

Earth has innate background for fungi that cover individual kingdom since evolution. The keratinophilic fungi are allied moulds that produce the keratinase enzyme to degrade the keratinous materials in or on the soil. Keratinous materials are insoluble and resistant to degradation by common proteinase enzymes. It is important to study the microorganism producers of such enzymes for use in the biotechnology industry. In order to present study, two isolates of fungi were evaluated to determine if they had the ability to degrade keratin as nutrient substrate. They were grown in an inundated culture medium containing poultry feathers. Among species, best keratin substrate degradation activity as well as keratinase enzyme activity was recorded in Arthoderma multifidium (KU578107) followed by Chrysosporium tropicum (KU578108) gradually leading manner day by days.

Measurement of 239Pu in keratinous materials: A potential non-invasive bioassay for monitoring human exposure

The use of hair, toenail, and fingernail as non-invasive monitors of occupational and environmental exposure to 239Pu are reported. Volunteers from US national laboratories and individuals with suspected environmental exposure to Pu were recruited to participate in the study. The exposure history of cases was assessed using a short questionnaire. Levels of Pu in keratinous materials collected from the exposed individuals were above the limit of detection in 5 of 7 cases with concentrations ranging from 0.055 to 0.78ng/kg. To our knowledge, this is the first time that Pu has been measured in hair and nail samples collected from actinide workers in the United States. The 239Pu levels in the hair and nails collected from the exposure group are comparable to individuals from Minsk, Belarus and Dubna, Russia and lower than individuals living near the Semipalatinsk region of Kazakhstan and in the Gomel region of Belarus.

Biodegradation of Wool by Bacteria and Fungi and Enhancement of Wool Quality by Biosurfactant Washing

ABSTRACTBiodegradation of Ryeland and Shetland wool by Bacillus subtilis W3 and Streptomyces albidoflavus were investigated. The effect of treating raw wool with Rhamnolipid was also studied. It is shown that the wool surface morphology is improved with effective displacement of surface contaminants revealing a smooth outer cuticle layer after just 2 days. These results have important practical implications for the establishment of a quick and easy biodegradable process for wool scouring finishing in textile industry or for the pre-treatment of keratinous waste materials before degradation by bacteria or fungi. This methodology provides an environmentally friendly alternative to conventional chemical pre-treatments.

Re‐evaluation of the hydrogen stable isotopic composition of keratin calibration standards for wildlife and forensic science applications

Determination of non-exchangeable hydrogen isotopic compositions (δ2 H values) of bulk complex organic materials is difficult due to uncontrolled H isotope exchange between the organic material and ambient water vapor. A number of calibration keratinous materials with carefully measured hydrogen isotopic compositions of the non-exchangeable fraction were proposed to enable stable isotope laboratories to normalize their 2 H measurements. However, it was recently reported that high-temperature carbon-reactor methods for measuring the hydrogen isotopic composition of nitrogenous organic materials is biased by the production of HCN in the reactor. As a result, the reported values of these calibration materials needed to be re-evaluated. We evaluated the non-exchangeable δ2 HVSMOW values of keratins EC1 (CBS) and EC2 (KHS), USGS hair standards, and a range of other nitrogenous widely used organic laboratory calibration materials (collagen and chitin) using pre-treatment with a preparation device designed to eliminate residual moisture and quantify exchangeable H. The revised non-exchangeable δ2 HVSMOW values of EC-1 (CBS) and EC-2 (KHS) keratin standard materials were -157.0±0.9 and -35.3±1.1 ‰, respectively. The revised values of USGS42 and USGS43 were -72.2±0.9 and -44.2±1.0 ‰, respectively, in excellent agreement with previous results. For routine H isotope analyses, with proper sample pre-treatment, we show that the Comparative Equilibration approach can provide accurate and reproducible non-exchangeable δ2 H values among laboratories regardless of the reactor type used. © 2017 Her Majesty the Queen in Right of Canada Rapid Communications in Mass Spectrometry © 2017 John Wiley & Sons Ltd. Reproduced with the permission of the Environment and Climate Change Canada.

A review of terrestrial, aerial and aquatic keratins: the structure and mechanical properties of pangolin scales, feather shafts and baleen plates.

Keratinous materials, omnipresent as the hard and durable epidermal appendages of animals, are among the toughest biological materials. They exhibit diverse morphologies and structures that serve a variety of amazing and inspiring mechanical functions. In this work, we provide a review of representative terrestrial, aerial and aquatic keratinous materials, pangolin scales, feather shafts and baleen plates, and correlate their hierarchical structures to respective functions of dermal armor, flight material and undersea filter. The overlapping pattern of pangolin scales provides effective body coverage, and the solid scales show transverse isotropy and strain-rate sensitivity, both important for armor function. The feather shaft displays a distinct shape factor, hierarchical fibrous structure within the cortex, and a solid shell-over-foam design, which enables synergistic stiffening and toughening with exceptional lightness to fulfill flight. Baleen plates exhibit a sandwich-tubular structure that features anisotropic flexural properties to sustain forces from water flow and remarkable fracture toughness that ensures reliable undersea functioning. The latest findings regarding the structural design principles and mechanical properties are presented in order to advance current understanding of keratinous materials and to stimulate the development of new bioinspired materials.

Structure and mechanical behavior of human hair

The understanding of the mechanical behavior of hair under various conditions broadens our knowledge in biological materials science and contributes to the cosmetic industry. The hierarchical organization of hair is studied from the intermediate filament to the structural levels. The effects of strain rate, relative humidity, and temperature are evaluated. Hair exhibits a high tensile strength, 150–270MPa, which is significantly dependent on strain rate and humidity. The strain-rate sensitivity, approximately 0.06–0.1, is comparable to that of other keratinous materials and common synthetic polymers. The structures of the internal cortex and surface cuticle are affected by the large tensile extension. One distinguishing feature, the unwinding of the α-helix and the possible transformation to β-sheet structure of keratin under tension, which affects the ductility of hair, is analytically evaluated and incorporated into a constitutive equation. A good agreement with the experimental results is obtained. This model elucidates the tensile response of the α-keratin fibers. The contributions of elastic and plastic strains on reloading are evaluated and correlated to structural changes.