Hair Fibers Research Articles

225 Repair of oxidized hair fiber structure analyzed by infrared imaging spectroscopy

225 Repair of oxidized hair fiber structure analyzed by infrared imaging spectroscopy

Quantifying whole human hair scalp fibres of varying curl: A micro-computed tomographic study.

Scalp hair is a key feature of humans and its variability has been the subject of a broad range of studies. A small subset of these studies has focused on geometric quantification of human scalp hair fibres, however the use of race- and ethnicity-based classification systems makes it challenging to draw objective conclusions about fibre variability. Furthermore, sample preparation techniques for micro-imaging studies often alter the original form of hair fibres. This study sought to determine which of the commonly reported descriptors could be resolved using micro-computed tomography (micro-CT) for fibres of varying curl. Images obtained from micro-CT were used to reconstruct three-dimensional images that were then analysed. The study also explored the capabilities and limitations of micro-CT as an imaging modality by comparing and cross-validating findings with those obtained from scanning electron microscopy (SEM) and laser micrometry. The former deals with surface imaging while the latter deals with cross-sectional measurements. Micro-CT was found to be highly effective at resolving cross-sectional ellipsoidal parameters, but performed more poorly than SEM in reconstructing surface level details at a 2 resolution. The technique was, however, able to reveal the presence of the medulla in type VI (high curl) hair fibres. When compared with high curl fibres, greater intra-fibre variability was observed for the low and medium curl fibres, highlighting the importance more objective classificationsystems.

The kinetics of moisture sorption by hair.

The rate process of moisture sorption by human hair has been analysed in order to hints for helping deepen knowledge on the hair structure and to explain the behaviour of hair in response to moisture. The isotherms of moisture sorption by hair were recorded, via dynamic vapour sorption (DVS), for untreated (virgin) and treated (heat-shaped and bleached) hair, as well as for separated cuticle and cortex. By considering that, during moisture uptake, the hair fibres also swell, it is possible to introduce a time-dependent rate constant for describing the kinetics of the moisture sorption. This model allows for clearly separating the moisture sorption processes occurring in Cuticle and in Cortex and for proposing a role of chain entanglement in the two main compartments of the fibre. It may also provide some hints on the structural changes occurring in the fibre after different cosmetic treatments. The influence of the weight of the sample on the kinetics of the sorption process has also been noted and quantified. The analysis pointed to a transition occurring at around 30% relative humidity, assigned to the opening of the hair inner structure, and accommodation of more water molecules. This allowed for an estimate of the value of the activation energy of the water molecules reacting with the active sites, which was found to be in good agreement with results published in the literature. The analysis of the kinetics of moisture sorption by hair was shown not only to provide information on the chain entanglement inside the fibre and the effect of cosmetic treatments but also to demonstrate and quantify the influence of fibre density on the sorption process. It is thus suggested that, along with examination of the hysteresis, the analysis of sorption kinetics helps reveal a more complete picture of hair moisture management.

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy and Chemometrics for the Discrimination of Animal Hair Fibers for the Textile Sector.

Analyzing the composition of animal hair fibers in textiles is crucial for ensuring the quality of yarns and fabrics made from animal hair. Among others, Fourier transform infrared (FT-IR) spectroscopy is a technique that identifies vibrations associated with chemical bonds, including those found in amino acid groups. Cashmere, mohair, yak, camel, alpaca, vicuña, llama, and sheep hair fibers were analyzed via attenuated total reflection FT-IR (ATR FT-IR) spectroscopy and scanning electron microscopy techniques aiming at the discrimination among them to identify possible commercial frauds. ATR FT-IR, being a novel approach, was coupled with chemometric tools (partial least squares discriminant analysis, PLS-DA), building classification/prediction models, which were cross-validated. PLS-DA models provided an excellent differentiation among animal hair of both camelids and eight animal species. In addition, the combination of ATR FT-IR and PLS-DA was used to discriminate the cashmere hair from different origins (Afghanistan, Australia, China, Iran, and Mongolia). The model showed very good discrimination ability (accuracy 87%), with variance expression of 94.88% and mean squared error of cross-validation of 0.1525.

The Genomic Variation in Textured Hair: Implications in Developing a Holistic Hair Care Routine

Human hair is characterised by variability, determined by genetic and macromolecular factors. Whilst the European hair type has been a focus of extensive research, Afro-textured hair care faces challenges created by insufficient knowledge of its properties. Applications of hair care products that are incompatible with Afro-textured hair frequently have detrimental effects on the scalp. This highlights the need for partnerships to bridge the gap between research and hair care practices and address challenges related to Afro-textured hair. In this review, we performed data mining of the existing literature and in silico network analysis of the biomarkers relevant to Afro-textured hair. The approaches to hair maintenance are highlighted in the context of hair anatomy and growth cycles, organisation of keratins, surface lipids, and chemical bonds. We discuss a range of biomarkers affecting hair fibre’s shape and mechanical strength, with the gene interactive network pointing to the hierarchical organisation of important traits, notably hair shaft diameter, keratinization, and hair follicle patterning, which likely contribute to the increased sensitivity of hair to extrinsic factors. We propose that a better understanding of the genetic traits, molecular structure, and biomechanics of Afro-textured hair is required to initiate more effective hair care solutions that would benefit the wider population.

The Use of Waste Synthetic Hair Fibre in Cement Mortar

Cement mortar has low tensile strength and fracture strain; therefore, fibres are used to reinforce cement mortar. Synthetic hair is one of the most neglected of all the residual wastes that cause environmental problems in many developing countries. Therefore, this study used waste synthetic hair fibre in cement mortar production as a way to reduce the environmental effect generated by waste, and also to enhance the strength of the mortar for construction application. The study aimed to investigate the properties of cement mortar reinforced with waste synthetic hair fibres. 0, 2.5, 5, and 7.5% of synthetic hair fibre were used as a replacement for cement by weight in mortar. 100 × 100 × 100 mm cube, and 100mm diameter and 200mm length cylinder specimens were prepared, cured, and tested at ages 7, 14, and 28 days for tensile and compressive strengths, density, and water absorption. The highest compressive strength for the synthetic waste hair fibre reinforced mortar was 8.57N/mm2 as compared to 10.84N/mm2 achieved for the control at 28 days of curing. The synthetic waste hair fibre reinforced mortar achieved the highest tensile strength of 1.80N/mm2 as compared to 1.67N/mm2 achieved by the control at 28 days of curing, representing an increase of about 11% in tensile strength of the synthetic hair fibre reinforced mortar over the control. The highest density for the synthetic hair fibre reinforced mortar was 2114 kg/m3 as compared to the control of 2144 kg/m3. The lowest water absorption for the synthetic hair fibre reinforced mortar was 2.48% as compared to the control of 2.04%, respectively. It is concluded that the properties of cement mortar reinforced with waste synthetic hair fibres are acceptable for construction application and recommended that practitioners use 2.5% waste synthetic hair as a partial replacement for cement in producing mortar.

Characterisation of Three Ovine KRTAP13 Family Genes and Their Association with Wool Traits in Chinese Tan Sheep.

Understanding the genetic basis of wool traits is crucial for improving wool production. In this study, we investigated the ovine KAP13 gene family, which in humans contains multiple members, while only one member has been identified to date in sheep. Three ovine KRTAP13 genes, likely representing KRTAP13-1, KRTAP13-2, and KRTAP13-4, were identified through sequence analysis and phylogenetic comparisons. These genes are positioned on chromosome 1, between KRTAP15-1 and KRTAP27-1, in a pattern that is like the arrangement in humans but not identical. Analyses revealed multiple sequence variants of each gene in 356 sheep from a variety of wool, meat, and dual-purpose breeds. The effect of these genes on four fibre traits: mean fibre curvature (MFC), mean fibre diameter (MFD), coefficient of variation of fibre diameter (CVFD), and fibre diameter standard deviation (FDSD), was assessed in 240 lambs of the Chinese Tan sheep breed. An allele of KRTAP13-2 was revealed to be associated with a decrease in FDSD and CVFD in heterotypic fibres. No associations were found between KRTAP13-4 variation and wool traits, and an association analysis for KRTAP13-1 was not conducted because no variation was found in this gene in the Chinese Tan sheep studied. These findings suggest a potential role for KRTAP13-2 in regulating wool traits, particularly fibre diameter uniformity in larger heterotypic hair fibres, and suggest its potential use as a marker for improving wool traits.

The Proportion of Catagen and Telogen Hair Follicles in Occipital Scalp of Male Androgenetic Alopecia Patients: Challenging the Established Dogma.

The hair follicle can cycle throughout a lifetime, undergoing periods of growth (anagen), regression (catagen) and relative quiescence (telogen). The time that a hair follicle spends in each of these stages is crucial to determine the length of hair fibre that it produces. Perturbations in this regard can manifest in various hair diseases such as anagen effluvium, or acute and chronic telogen effluvium. The established 'dogma' when considering how many hair follicles there are in each stage has long been that the majority are in anagen (85%-90%), followed by telogen (10%-15%) and catagen (1%-2%). These values are based on various studies using different methodologies such as hair plucking, phototrichograms and histology. However, these methods have flaws when it comes to differentiating between catagen and telogen follicles. We sought to determine the catagen: telogen ratio through the exvivo stereomicroscopic examination of hundreds of hair follicles removed from the occipital scalp of 14 Caucasian males during routine hair transplantation procedures. Using this methodology, and in agreement with a similar observation by another research group, we found that the percentage of catagen hair follicles was higher (7.5%) than telogen (3.5%) in all patients assessed. Consequently, we believe that the percentage of catagen follicles is clearly underestimated and therefore challenge the current established dogma.

Characterisation of Ovine KRTAP19-3 and Its Impact on Wool Traits in Chinese Tan Sheep.

Wool, a natural fibre derived from sheep, can present a challenge to wool processing and manufacturing industries because of the variation in fibre traits. Genetic improvement offers one solution to this challenge, and having a better understanding of the genes that affect wool fibre traits is therefore important. Here, we describe ovine KRTAP19-3, a new member of the KAP19 gene family. Phylogenetic analysis revealed its relationship to other known KRTAP19 gene sequences, and an analysis of the nucleotide sequence variation in KRTAP19-3 from 288 sheep of a variety of breeds revealed six unique variant sequences. Among these variants, eleven single nucleotide polymorphisms (SNPs) were detected, with six located in the coding region. Three of these coding region SNPs were non-synonymous and would result in amino acid changes. Associations were observed between the presence of specific sequence variants in Chinese Tan sheep and wool trait variation, particularly an increase in fibre diameter variability in the heterotypic hair fibres. These findings enhance our understanding of the genes that encode sheep wool proteins.

Thermoporometry measurements of human hair via differential scanning calorimetry.

Hair fibres possess an inherently porous structure, which is affected by physical and chemical agents from the environment, as well as those from cosmetic treatments. The present work aims to investigate the potential of a calorimetric method for evaluating the changes of hair porosity, in terms of pore size and size distribution. The temperature of the phase transition from solid to liquid is known to be depressed if the liquid is confined within a pore. This shift in temperature can be measured by a calorimetric method like differential scanning calorimetry, DSC. This method is termed thermoporometry and it is the tool used for investigating hair porosity in this work. Virgin and bleached hair fibres are measured by DSC and, by using the equations developed for water behaviour confined in pores of a solid, the size and size distribution of the hair pores are evaluated, and the influence of the cosmetic treatment on the pores is discussed. Thermoporometry measurements of hair produced results in good agreement with those obtained by other methods for measuring hair porosity. The analysis of the data suggests that the fibre pores are mostly of a radius of 4 nm, and that the bleaching process increases the total volume of pores through the addition of smaller pores. A prolonged bleaching process appears to reduce the amount of fine pores produced by the first short process, resulting in fewer, but larger, cavities, most likely through a process of pore-merging.

Unveiling the potential of confocal raman spectroscopy in the analysis of oil permeation in human hair fibers

Unveiling the potential of confocal raman spectroscopy in the analysis of oil permeation in human hair fibers

Deep Hair Phenomics: Implications in Endocrinology, Development, and Aging

Hair quality is an important indicator of health in humans and other animals. Current approaches to assess hair quality are generally non-quantitative or are low throughput due to technical limitations of ‘splitting hairs’. We developed a deep learning-based computer vision approach for the high throughput quantification of individual hair fibers at a high resolution. Our innovative computer vision tool can distinguish and extract overlapping fibers for quantification of multivariate features including length, width, and color to generate single-hair phenomes (shPhenome) of diverse conditions across the lifespan of mice. Using our tool, we explored the effects of hormone signaling, genetic modifications, and aging on hair follicle output. Our analyses revealed hair phenotypes resultant of endocrinological, developmental, and aging-related alterations in the fur coats of mice. These results demonstrate the efficacy of our deep hair phenomics tool for characterizing factors that modulate the hair follicle and developing new diagnostic methods for detecting disease through the hair fiber. Finally, we have generated a searchable, interactive web tool for the exploration of our hair fiber data at skinregeneration.org.

Quantifying the effects of repeated dyeing: Morphological, mechanical, and chemical changes in human hair fibers

As hair dyeing gains popularity across all age groups, concerns about the potential damage caused by chemical treatments are also on the rise. Chemical dyes have a multifaceted impact on hair fibers, affecting their morphology, physical structure, and protein composition. In a comprehensive study, we investigated the alterations in morphological and mechanical properties, as well as the chemical composition of hair fibers following continuous dyeing. Our analysis employed various techniques, including atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and tensile strength measurements. To assess the cumulative damage resulting from repeated dyeing, we progressively increased the number of dyeing up to 10. Surprisingly, even a single dyeing session inflicted noticeable harm on the hair. However, the detrimental effects escalated significantly when hair underwent three or more consecutive dye treatments. While the mechanical properties and protein composition exhibited non-linear changes with increasing the number of dyeing, we observed that nanoscale damage to the cuticle surface intensified proportionally with the number of dyeing. These results highlight the critical need to consider the impacts of hair dyeing practices on both the health and the structural integrity of hair.

Evaluation of hair surface structure and morphology of patients with lichen planopilaris (LPP) by atomic force microscopy (AFM).

Lichen planopilaris (LPP) is a chronic lymphocytic skin disease manifested by progressive scarring alopecia. The diagnosis of LPP is made based on histopathological examination, although it is not always definite. The current study evaluates the effectiveness of non-invasive atomic force microscopy (AFM) hair examination in detecting morphological differences between healthy and diseased hair. Here, three to five hairs from lesional skin of 10 LPP patients were collected and examined at nine locations using AFM. At least four images were taken at each of the nine sites. Metric measurements were taken and metric (length, width, and scale step height) and morphological features (striated and smooth surface of scales, the presence of endocuticle and cortex, shape of scales edges, scratches, pitting, cracks, globules, and wavy edge) were compared with hair from healthy controls. In addition, areas on diseased hair where the process of pathological, unnatural delamination of the hair fiber occurs are described. There was a statistically significant difference in the number of scratches in the initial sections of the LPP hair, in the intensity of wavy edges along the entire length of the tested hair, and in the number of scales with pitting in the middle section of the hair. In addition, a statistically significant higher number of scales with striated surface was found in LPP group starting at 3.5cm from the root continuing towards the free end of the hair. Other morphological changes such as presence of cortex, globules, oval indentations, and rod-like macrofibrillar elements were also assessed, however, detailed results are not presented, as the differences shown in the number of these morphological changes were not significantly different. This publication outlines the differences between virgin, healthy Caucasian hair, and the hair of LPP patients. The results of this study can be used for further research and work related to LPP. This is the first attempt to characterize the hair of LPP patients using AFM.

Analysis of the Long Non-Coding and Messenger RNA Expression Profiles in the Skin Tissue of Super Merino and Small-Tailed Han Sheep.

Wool quality and yield are two important economic livestock traits. However, there are relatively few molecular studies on lncRNA for improving sheep wool, so these require further exploration. In this study, we examined skin tissue from the upper scapula of Super Merino (SM) and Small-Tailed Han (STH) sheep during the growing period. The apparent difference was verified via histological examination. High-throughput RNA sequencing identified differentially expressed (DE) long non-coding (lncRNAs) and messenger RNAs (mRNAs). The target gene of DE lncRNA and DE genes were enrichment analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). A Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR) was used to verify randomly selected DE lncRNAs and mRNAs. Finally, the DE, RAC2, WNT11, and FZD2 genes, which were enriched in the Wnt signaling pathway, were detected via immunohistochemistry. The results showed that a total of 20,888 lncRNAs and 31,579 mRNAs were identified in the skin tissues of the two sheep species. Among these, 56 lncRNAs and 616 mRNAs were differentially expressed. Through qRT-PCR, the trends in the randomly selected DE genes' expression were confirmed to be aligned with the RNA-seq results. GO and KEGG enrichment analysis showed that DE lncRNA target genes were enriched in GO terms as represented by epidermal and skin development and keratin filature and in KEGG terms as represented by PI3K-Akt, Ras, MAPK, and Wnt signaling pathways, which were related to hair follicle growth and development. Finally, immunohistochemistry staining results indicated that RAC2, WNT11, and FZD2 were expressed in dermal papilla (DP). The lncRNAs MSTRG.9225.1 and MSTRG.98769.1 may indirectly participate in the regulation of hair follicle growth, development, and fiber traits by regulating their respective target genes, LOC114113396(KRTAP15-1), FGF1, and IGF1. In addition, MSTRG.84658.1 may regulate the Wnt signaling pathway involved in the development of sheep hair follicles by targeting RAC2. This study provides a theoretical reference for improving sheep breeding in the future and lays a foundation for further research on the effects of MSTRG.84658.1 and the target gene RAC2 on dermal papilla cells (DPC).

Bleached Hair as Standard Template to Insight the Performance of Commercial Hair Repair Products

The increasing demand for effective hair care products has highlighted the necessity for rigorous claims substantiation methods, particularly for products that target specific hair types. This is essential because the effectiveness of a product can vary significantly based on the hair’s condition and characteristics. A well-defined bleaching protocol is crucial for creating a standardized method to assess product efficacy, especially for products designed to repair damaged hair. The objective of this study was to create a practical bleaching protocol that mimics real-world consumer experiences, ensuring that hair samples exhibit sufficient damage for testing. This approach allows for a reliable assessment of how well various products can repair hair. The protocol serves as a framework for evaluating hair properties and the specific effects of each product on hair structure. Color, brightness, lightness, morphology, and topography were primarily used to understand the big differences in the hair fiber when treated with two repair benchmark products, K18® and Olaplex®, in relation to the Bleached hair. The devised bleaching protocol proved to be a fitting framework for assessing the properties of hair and the unique characteristics of each tested product within the hair fiber. This protocol offers valuable insights and tools for substantiating consumer claims, with morphological and mechanical methods serving as indispensable tools for recognizing and validating claims related to hair. The addition of K18® and Olaplex® demonstrated an increase in hair brightness (Y) and lightness (L* and a*) in relation to the Bleached samples, which were considered relevant characteristics for consumers. Olaplex®’s water-based nature creates a visible inner sheet, effectively filling empty spaces and improving the disulfide linkage network. This enhancement was corroborated by the increased number of disulfide bonds and evident changes in the FTIR profile. In contrast, K18®, owing to the lipophilic nature of its constituents, resulted in the formation of an external layer above the fiber. The composition of each of the products had a discrete impact on the fiber distribution, which was an outcome relevant to the determination of spreadability by consumers.

Effect of temperature and relative humidity on the moisture recovery and specific resistance of yak hair fiber

This study measured the moisture regain and specific resistance values of yak hair fiber in a humidified environment to provide a theoretical basis for the development and utilization of yak hair fiber in the fields of textile, electronics and manufacturing. The effects of temperature and relative humidity on moisture absorption and electrical resistance of yak hair fiber were measured, and the effects of ambient temperature and humidity on the moisture regain and specific resistance of yak hair fiber were evaluated when using a new type of water-cooled textile air conditioner as a humidifying device, and the amino acid structure and crystallinity were compared between yak hair fiber and wool fiber. The experimental results show that temperature and relative humidity have a greater effect on the moisture regain rate and specific resistance value of the fiber, and the higher the temperature and relative humidity, the higher the moisture regain rate of yak hair fiber and the lower the specific resistance. When the temperature was 30 °C and the relative humidity was 85%, the fiber had the lowest specific resistance value and the highest moisture return rate. In terms of amino acid species, there is not much difference in chemical structure between yak hair fiber and wool fiber. The crystallinity of yak hair fiber is lower than that of wool fiber.

Gamma radiation’s influence on the tensile characteristics of waste animal fiber reinforced biocomposites

This study involves the preparation of polymer composites using untreated and treated chicken feather, leather, and cow hair fiber in combination with unsaturated polyester resin (UPR) and analyzing the effect of gamma radiation on tensile properties. These fibers were incorporated into the resin matrix at various weight percentages (2%, 5%, 7%, 10%, 12%, and 15%). Additionally, the nanoparticle ZnO was added in the composites as filler to improve the mechanical properties. The composites that utilized treated chicken feather fibers yielded superior results in comparison to those that relied on untreated fibers. Prepared composites outperformed neat composites when inorganic components were added as filler to UPR. Composite materials’ mechanical properties, particularly their tensile strength and modulus, can be improved by combining cow hair feather and chicken feather mixed fibers with ZnO filler and gamma radiation modification, according to this study. The morphological and spectroscopic analysis provides supporting evidence for the mechanical strength between the fibers and the resin. Ionizing gamma radiation modification of the fiber resulted in superior tensile characteristics. The optimized composites of animal fibers were then subjected to gamma radiation of variable dose of 0, 2.5, 5 and 7.5 kGy. The tensile properties were found to be the maximum at 5 kGy. Scanning electron microscopy was used to investigate the structural changes caused by the incorporation of animal fibers (chicken feather and cow hair) and ZnO. Composite material and UPR functional group identification were achieved by means of Fourier Transform Infrared Spectroscopy (FTIR).

Effects of KRTAP20-1 Gene Variation on Wool Traits in Chinese Tan Sheep.

Chinese Tan sheep lambs are recognised for having tight 'spring-like' curly wool when young, but this phenotype disappears with age. This wool consists of shorter, fine wool fibres (which are usually unmedullated) and heterotypic hair fibres (which are frequently medullated), which are referred to as 'halo hair'. Both the wool and hair fibres consist of α-keratin proteins embedded in a keratin-associated protein (KAP) matrix. Of these KAPs, the KAP20-1 gene (designated KRTAP20-1) and its effect on four fibre traits (mean fibre curvature, mean fibre diameter, fibre diameter standard deviation, and coefficient of variation of fibre diameter) of Tan lambs was studied. Seven previously identified KRTAP20-1 variants (A, B, D, E, F, G, and H) of KRTAP20-1 were revealed, but the previously identified variant C was not present. Of the seven variants detected, only two (A and G) were common and present at frequencies greater than 5%, and the effect of these on the fibre traits of the finer wool fibres was assessed. It was found that variant G was associated with an increased mean fibre curvature in these wool fibres. This suggests that KRTAP20-1 might possibly be expressed differentially in the two fibre types, which may be of future value in breeding.

Utilization of poplar fibers in needle punched nonwovens

The focus of this study is to conduct pioneering research on utilizing poplar seed hair fibers in needle punched nonwovens. These fibers were blended with hollow PET fibers at two different weight ratios to obtain needle punched webs for the first time. The weight, thickness, abrasion resistance, bursting and tensile properties, hydrophobic/oleophilic surface characteristics of the nonwovens are analyzed elaborately. Finally, it has been demonstrated that poplar fiber-containing nonwovens have superior rose oil absorption compared to solely PET nonwoven fabrics. When compared the maximum adsorption capacities, the incorporation of 37.3 wt.% and 21.7 wt.% poplar fiber into PET nonwoven increased the oil absorption by approximately 35 and 24 times, respectively. Although pristine PET nonwoven was able to remove only 16% of MB dye from aqueous dye solution, addition of poplar fiber enhanced the removal process and the solution had been decolorized to nearly colorless. The results indicated that poplar blended nonwoven fabrics treated with NaClO2 show the high-performance removal of MB dye from wastewater, with the increased percentage of 40% and 67% for PET-PO30 and PET-PO60 fabric, respectively. Therefore, developing industrial scale surfaces with non-traditional and sustainable poplar seed fibers, marks a significant advancement for the textile industry.