Structure Of Keratin Research Articles

Valorization of Waste Wool to Keratin with a Green Solvent Based on a Deep Eutectic Mixture of Choline Chloride and Lactic Acid

Abstract Waste wool, a by-product of sheep husbandry, is primarily composed of keratin, which has potential use in cosmetic products, biotechnology and medical applications. Traditional chemical methods for keratin extraction face limitations due to health and environmental concerns, and thus, green alternatives such as deep eutectic solvents (DESs) have been developed. The aim of the present study was to determine whether a natural DES composed of choline chloride and lactic acid can be used to extract keratin from sheep wool. The dissolution and keratin yield were investigated under different reaction times, temperatures, and wool-to-DES ratios. Fractions of water-soluble keratin and water-insoluble keratin aggregates were obtained by dialysis, centrifugation, and drying. The results showed that both the dissolution of wool and the yield of recovered keratin increased as the reaction time and temperature increased from 1 to 8 h and from 80 to 110 $$^{\circ }$$ ∘ C, respectively. With the longest reaction time of 8 hours and the highest temperature of 110 $$^{\circ }$$ ∘ C, the yield of water-soluble keratin increased to 23 %. Characterizations revealed that DES detached first the cuticular scales from the surface of wool fibres and subsequently degraded wool cortex layer. The extracted water-soluble keratin retained the characteristic amide structure of wool, but the secondary structure of keratin was converted to cross-$$\beta$$ β sheet form. Moreover, it had a narrow size distribution and a molecular weight of 10 kDa. The results of this study indicate that the proposed DES can be used as a green solvent for recovering keratin from sheep wool. Graphical Abstract

Design, development and characterization of a chimeric protein with disulfide reductase and protease domain showing keratinase activity

Keratin is one of the major components of solid waste, and the degradation products have extensive applications in various commercial industries. Due to the complexity of the structure of keratin, especially the disulfide bonds between keratin polypeptides, keratinolytic activity is efficient with a mixture of proteins with proteases, peptidases, and oxidoreductase activity. The present work aimed to create an engineered chimeric protein with a disulfide reductase domain and a protease domain connected with a flexible linker. The structure, stability, and substrate interaction were analyzed using the protein modeling tools and codon-optimized synthetic gene cloned, expressed, and purified using Ni2+-NTA chromatography. The keratinolytic activity of the protein was at its maximum at 70 °C. The suitable pH for the enzyme activity was pH 8. While Ni2+, Mg2+, and Na+ inhibited the keratinolytic activity, Cu2+, Ca2+, and Mn2+ enhanced it significantly. Biochemical characterization of the protease domain indicated significant keratinolytic activity at 70 °C at pH 10.0 but was less efficient than the chimeric protein. Experiments using feathers as the substrate showed a clear degradation pattern in the SEM analysis. The samples collected from the degradation experiments indicated the release of proteins (2-fold) and amino acids (8.4-fold) in a time-dependent manner. Thus, the protease with an added disulfide reductase domain showed excellent keratin degradation activity and has the potential to be utilized in the commercial industries.

Is Raman Spectroscopy of Fingernails a Promising Tool for Diagnosing Systemic and Dermatological Diseases in Adult and Pediatric Populations?

Background: Raman spectroscopy is a well-known tool used in criminology, molecular biology, and histology. It is also applied to diagnose bone mineral disorders by taking advantage of the similarity of the structure of keratin and bone collagen. Raman spectroscopy can also be used in dermatology and diabetology. The purpose of the present review is to critically evaluate the available research about the use of Raman spectroscopy in the mentioned areas of medicine. Methodology: PubMed was searched for peer-reviewed articles on the subject of use of Raman spectroscopy in bone mineral disorders, dermatology, and diabetes mellitus. Results: Nail keratin and bone collagen are related structural proteins that require disulfide bond for structural stability. Therefore, Raman spectroscopy of keratin may have potential as a diagnostic tool for screening bone quality and distinguishing patients at risk of fracture for reasons different from low bone mineral density (BMD) in the adult women population. Raman spectroscopy can also investigate the changes in keratin's structure in nails affected by onychomycosis and distinguish between healthy and onychomycosis nail samples. It could also reduce the need for nail biopsy by distinguishing between dermatophytic and non-dermatophytic agents of onychomycosis. Additionally, Raman spectroscopy could expedite the diagnostic process in psoriasis (by assessing the secondary structure of keratin) and in diabetes mellitus (by examining the protein glycation level). Conclusions: In adult populations, Raman spectroscopy is a promising and safe method for assessing the structure of fingernails. However, data are scarce in the pediatric population; therefore, more studies are required in children.

Keratin from Animal By-Products: Structure, Characterization, Extraction and Application-A Review.

Keratin is a structural fibrous protein and the core constituent of animal by-products from livestock such as wool, feathers, hooves, horns, and pig bristles. This natural polymer is also the main component of human hair and is present at an important percentage in human and animal skin. Significant amounts of keratin-rich animal tissues are discarded worldwide each year, ca. 12 M tons, and the share used for keratin extraction and added-value applications is still very low. An important stream of new potential raw materials, represented by animal by-products and human hair, is thus being lost, while a large-scale valorization could contribute to a circular bioeconomy and to the reduction in the environmental fingerprint of those tissues. Fortunately, scientific research has made much important progress in the last 10-15 years in the better understanding of the complex keratin architecture and its variability among different animal tissues, in the development of tailored extraction processes, and in the screening of new potential applications. Hence, this review aims at a discussion of the recent findings in the characterization of keratin and keratin-rich animal by-product structures, as well as in keratin recovery by conventional and emerging techniques and advances in valorization in several fields.

Exploring keratin composition variability for sustainable thermal insulator design

In pursuing sustainable thermal insulation solutions, this study explores the integration of human hair and feather keratin with alginate. The aim is to assess its potential in thermal insulation materials, focusing on the resultant composites' thermal and mechanical characteristics. The investigation uncovers that the type and proportion of keratin significantly influence the composites' porosity and thermal conductivity. Specifically, higher feather keratin content is associated with lesser sulfur and reduced crosslinking due to shorter amino acids, leading to increased porosity and pore sizes. This, in turn, results in a decrease in β-structured hydrogen bond networks, raising non-ordered protein structures and diminishing thermal conductivity from 0.044 W/(m·K) for pure alginate matrices to between 0.033 and 0.038 W/(m·K) for keratin-alginate composites, contingent upon the specific ratio of feather to hair keratin used. Mechanical evaluations further indicate that composites with a higher ratio of hair keratin exhibit an enhanced compressive modulus, ranging from 60 to 77 kPa, demonstrating the potential for tailored mechanical properties to suit various applications. The research underscores the critical role of sulfur content and the crosslinking index within keratin's structures, significantly impacting the thermal and mechanical properties of the matrices. The findings position keratin-based composites as environmentally friendly alternatives to traditional insulation materials.

Structural and retrospective bio-dosimetric study of gamma-irradiated human fingernails

Emergency involving ionising radiation is a rare occurrence, yet it can leave severe damage if a population is not equipped with necessary preparation. In such a situation, there is no viable way to know how much radiation dose is received by human beings. However, in present time only personnel of rescue teams have accessed to active dosimetry such as a personal dosimeter. Preliminary study has been made of human fingernails, a model in examining the potential of nails of the human fingers in retrospective and emergency bio-dosimetry applications, also offering effective atomic number near to that of soft human tissues at 7.4. Human fingernails were sampled from different age groups and exposed to 60Co gamma rays, delivering doses from 2 to 10 Gy. Structural alterations were observed, use being made of Raman spectroscopy and the crystalline structure of alpha keratin is studied using X-ray diffraction (XRD), while the elemental composition of the sample is determined by energy dispersive x-ray (EDX) analysis. Raman shows the ‘fingerprint’ of nail sample is identical in which the peak assignment concerns on the disulfide (S–S) bond and the alpha helix content at the amide 1 region. These are the few regions which displayed major Raman shift and intensity difference from a normal nail sample and an effected nail which have the same analogy as a non-irradiated nail and an irradiated nail sample. XRD shows the molecular structure of hard α-keratin from different age groups of fingernails, examining crystallite diameters (D) and crystallinity index (C.I.). The α-keratin characteristic bands can be seen in all groups of fingernails, albeit they become much weaker and shift to smaller angles with higher gamma doses. The results obtained by Raman spectroscopy and X-ray diffraction are complementary and suggest that the α-helix structure of keratin is partially destroyed by the presence of radiation.

Inheritance of the Secondary Structure of Keratin During Crystallization of Titanium Dioxide under Hydrothermal Conditions Using Wool Fibers as a Biotemplate

Inheritance of the Secondary Structure of Keratin During Crystallization of Titanium Dioxide under Hydrothermal Conditions Using Wool Fibers as a Biotemplate

A Review on Transdermal Drug Delivery System (TDDS)

The transdermal route of administration has numerous advantages over more traditional routes of medicine administration. They contain high bioavailability, lack of first- pass hepatic metabolism, stable tubemedicineconcns., and the fact that the treatment is non-invasive. The biggest hedge to the penetration of medicinalmotes is the external subcaste of the skin, the stratum corneum. therefore, exploration to ameliorate transdermal medicine delivery( TDD) is worthwhile this subcaste is the area of interest. This review composition is written togive content commentary recent advances in TDDS enhancement ways. ways that ameliorate the permeability of the skin have been used developed to ameliorate bioavailability and increase the choice of topical and transdermal medicines is a feasible option. This review describes improvement ways grounded on medicine/ vehicle optimization, e.g selection of medicines, prodrugs and ion dyads, supersaturated medicine results, eutectic systems, complexes, liposomes, vesicles and patches. Strengthening by changing the shell with moisturizing chemical enhancers partitioning and solubility goods affecting crustal lipid and keratin structure bandied Medium of action of penetration enhancers and retarders and they're implicit for clinical use operation is described

Identification of horn-derived animal medicines based on detection of keratin-derived characteristic peptides

Due to the highly stable structure of keratin, the extraction and dissolution steps of animal medicines rich in keratin are complex, which seriously restricts the detection efficiency and flux. Therefore, this study simplified the pre-treatment steps of horn samples and optimized the detection methods of characteristic peptides to improve the efficiency of identifying the specificity of horn-derived animal medicines. For detection of the characteristic peptides in horn-derived animal medicines treated with/without iodoace-tamide(IAA), the ion pair conditions of the characteristic peptides were optimized, and the retention time, intensity and other data of the specific peptides were compared between the samples treated with/without IAA. Two pre-treatment methods, direct enzymatic hydrolysis and total protein extraction followed by enzymatic hydrolysis, were used to prepare horn-derived animal medicine samples. The effects of different methods on the detection of specific peptides in the samples of Saiga antelope horn, water buffalo horn, goat horn, and yak horn were compared regarding the retention time of specific peptides and ion intensity. The results indicated that after direct enzymatic hydrolysis, the specific peptides in the samples without IAA treatment can be detected. Compared with the characteristic peptides in the samples treated with IAA, their retention time shifted back and the mass spectrometry response slightly decreased. The specific peptides of the samples without IAA treatment had good specificity and did not affect the specificity identification of horn-derived animal medicines. Overall, the process of direct enzymatic hydrolysis can be used to treat horn samples, omitting the steps of protein extraction and dithiothreitol and IAA treatment, significantly improving the pre-treatment efficiency without affecting the specificity identification of horn-derived animal medicines. This study provides ideas for quality research and standard improvement of horn-derived animal medicines.

Evaluation and formulation of Spirulina platensis proteins for potential applications in hair care products

Spirulina platensis, a blue-green algae belonging to family Phormidiaceae, is well-known for its unique nutritional profile and high protein content. This study aims to isolate its proteins, formulate them into a cream and evaluate its potential as a hair treatment. S. platensis were collected from Nuweiba, Egypt and its protein was extracted, analyzed and used to prepare a cream. The cream was applied on natural hair strands compared to a control cream containing no protein. Both hair strands groups were observed via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and evaluated by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, as well as, thermal analysis tests including thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). The SEM images of the test group showed more intact cuticle with the absence of cracks and holes, also, the TEM images showed stronger non-porous cuticle compared to the control group. The AFM images of the test group was smoother with lower roughness average and step height compared to the control group. On the other hand, the raman spectra showed different band intensities for disulfide bonds and C-S bonds as well as increased number of b sheet conformations in the test group which is responsible for the smoothing effect. The thermal analysis tests revealed a clear difference between both groups as an indication of improved keratin structure on the test group. S. platensis proteins could be introduced as a potential candidate for hair care products.

Nanotoxicity of two-dimensional nanomaterials on human skin and the structural evolution of keratin protein

Two-dimensional (2D) materials have been increasingly widely used in biomedical and cosmetical products nowadays, yet their safe usage in human body and environment necessitates a comprehensive understanding of their nanotoxicity. In this work, the effect of pristine graphene and graphene oxide (GO) on the adsorption and conformational changes of skin keratin using molecular dynamics simulations. It is found that skin keratin can be absorbed through various noncovalent driving forces, such as van der Waals (vdW) and electrostatics. In the case of GO, the oxygen-containing groups prevent tighter contact between skin keratin and the graphene basal plane through steric effects and electrostatic repulsion. On the other hand, electrostatic attraction and hydrogen bonding enhance their binding affinity to positively charged residues such as lysine and arginine. The secondary structure of skin keratin is better preserved in GO system, suggesting that GO has good biocompatibility. The charged groups on GO surface perform as the hydrogen bond acceptors, which is like to the natural receptors of keratin in this physiological environment. This work contributes to a better knowledge of the nanotoxicity of cutting-edge 2D materials on human health, thereby advancing their potential biological applications.

Topical Peroxisome Proliferator-Activated Receptor Agonist Induces Molecular Alterations Enhancing Barrier Function and Water-Holding Capacity of the Human Stratum Corneum In Vivo

The peroxisome proliferator-activated receptor (PPAR) ligands modulate a variety of skin functions but are rarely used in cosmetics. The aim of this double-blind, placebo-controlled, in vivo study was to determine the effect of a topically applied 0.1% PPAR ligand on the composition and physiological parameters of the stratum corneum (SC). By comparing verum and placebo groups post-treatment, we demonstrate (via lipidomic analysis of tape strips) an unstatistically significant trend toward an increase in long-chain triacylglycerols (C50–C56) and medium- and long-chain ceramides (C42–C50) at the superficial SC. By comparing treated and untreated skin using confocal Raman microspectroscopy, we found that the changes in lipid composition in the verum group led to a significant increase in the number of trans conformers and orthorhombic organisation of lipids at the exemplary SC depth. An increase in unfolded states in the secondary and tertiary keratin structures results in an increased ability to bind water. The concentrations of tightly and strongly bound water increase, while weakly bound and unbound water decrease in the entire SC, indicating a transformation of water mobility to a state of increased hydrogen bonding. Thus, the topical PPAR ligands improve the water-holding capacity and the barrier function of the SC.

Biotransformation of free-range chicken feather into functional protein hydrolysates using microwave alkaline pretreatment

Chicken feathers has great potential to produce functional peptides. However, due to the highly rigid structure of keratin, the biotransformation of feathers is hindered. In this study, we aimed to evaluate the influence of microwave-alkaline pretreatment (MAP) on enzymatic hydrolysis of free-range chicken feathers using two distinct enzymes in functional and technological terms. Four protein hydrolysates were prepared from the feathers treated in microwaves using the enzyme Flavourzyme® (PHFW) and Alcalase® (PHAW) and from untreated feathers using Flavourzyme® (PHF) and Alcalase® (PHA). A two-way ANOVA revealed a significant interaction effect between MAP and enzyme type on the antioxidant activity of the hydrolysates. The DPPH and ABTS radical scavenging capacities were higher in PHFW. Our findings suggest that the MAP enhances the action of the enzyme in hydrolytic cleavage, with Flavourzyme® demonstrating a superior ability to produce hydrolysates with high antioxidant capacity. For emulsifying capacity and emulsifier stability, only MAP had a significant effect, with higher values observed in hydrolysates obtained from treated feathers regardless of enzyme type. It can be concluded that the hydrolysates obtained from MAP feathers underwent conformational modification of proteins, promoting better enzyme action during hydrolysis, resulting in higher antioxidant activity and technological properties.

Effect of Penetration Enhancer on the Structure of Stratum Corneum: On-Site Study by Confocal Polarized Raman Imaging.

Keratin and lipid structures in the stratum corneum (SC) are closely related to the SC barrier function. The application of penetration enhancers (PEs) disrupts the structure of SC, thereby promoting infiltration. To quantify these PE-induced structural changes in SC, we used confocal Raman imaging (CRI) and polarized Raman imaging (PRI) to explore the integrity and continuity of keratin and lipid structures in SC. The results showed that water is the safest PE and that oleic acid (OA), sodium dodecyl sulfate (SDS), and low molecular weight protamine (LMWP) disrupted the ordered structure of keratin, while azone and liposomes had less of an effect on keratin. Azone, OA, and SDS also led to significant changes in lipid structure, while LMWP and liposomes had less of an effect. Establishing this non-invasive and efficient strategy will provide new insights into transdermal drug delivery and skin health management.

Umbilical therapy for promoting transdermal delivery of topical formulations: Enhanced effect and underlying mechanism

Umbilical paste therapy is a promising method to promote transdermal drug delivery of topical formulations. This work investigated the effect and mechanism of transdermal drug delivery through the umbilical skin. The transdermal permeation studies showed the phenomenon of higher cumulative penetration and faster penetration rates for drug through the umbilical skin compared with non-umbilical skin, namely umbilical pro-permeability. This special transdermal permeability of drugs is influenced by their molecular weight, logP value, ability to form hydrogen bonds, and molecular volume. The underlying mechanism of umbilical pro-permeability was elucidated from unique structure and regulation the effect of drugs on microcirculation in the umbilical skin. Mechanistic studies revealed that this phenomenon was not only associated with the structural and physiological properties of the skin but also to the interactions between drugs and different skin layers. The umbilical pro-permeation is attributed to the thinner stratum corneum layer, differences in stratum corneum lipid composition and keratin structure, and lower levels of intercellular tight junction proteins in the viable epidermis and dermis layer of the skin. Our research indicated that umbilical paste therapy enhanced the transdermal delivery and absorption of drugs by stimulating local blood flow through mast cell activation. Surprisingly, skin temperature modulation and calcitonin gene-related peptide and substance P levels did not appear to significantly affect this process. In conclusion, umbilical drug administration, as a straightforward and non-invasive approach to enhance transdermal drug delivery, presents novel concepts for continued investigation and practical implementation of transdermal drug delivery systems.

The coevolution of rostral keratin and tooth distribution in dinosaurs.

Teeth evolved early in vertebrate evolution, and their morphology reflects important specializations in diet and ecology among species. The toothless jaws (edentulism) in extant birds likely coevolved with beak keratin, which functionally replaced teeth. However, extinct dinosaurs lost teeth multiple times independently and exhibited great variation in toothrow distribution and rhamphotheca-like keratin structures. Here, we use rostral jawbone surface texture as a proxy for rostral keratin covering and phylogenetic comparative models to test for the influence of rostral keratin on toothrow distribution in Mesozoic dinosaurs. We find that the evolution of rostral keratin covering explains partial toothrow reduction but not jaw toothlessness. Toothrow reduction preceded the evolution of rostral keratin cover in theropods. Non-theropod dinosaurs evolved continuous toothrows despite evolving rostral keratin covers (e.g. some ornithischians and sauropodomorphs). We also show that rostral keratin covers did not significantly increase the evolutionary rate of tooth loss, which further delineates the antagonistic relationship between these structures. Our results suggest that the evolution of rostral keratin had a limited effect on suppressing tooth development. Independent changes in jaw development may have facilitated further tooth loss. Furthermore, the evolution of strong chemical digestion, a gizzard, and a dietary shift to omnivory or herbivory likely alleviated selective pressures for tooth development.

Recent Advances in Transdermal Drug Delivery System (TDDS): A Review

Abstract: The transdermal route of administration has many advantages over more traditional routes of drug administration. They contain high bioavailability, lack of first-pass hepatic metabolism, stable plasma drug concns., and fact that the treatment is non-invasive. The biggest barrier to the penetration of medicinal molecules is the outer layer of the skin, stratum corneum. Thus, research to improve transdermal drug delivery (TDD) is worthwhile this layer is the area of interest. This review article is written to provide coverage commentary recent advances in TDD improvement techniques. Techniques that improve the permeability of the skin have been used developed to improve bioavailability and increase the choice of topical and transdermal drugs is a viable option. This review describes enhancement techniques based on drug/vehicle optimization, e.g selection of drugs, prodrugs and ion pairs, supersaturated drug solutions, eutectic systems, complexes, liposomes, vesicles and particles. Strengthening by changing the shell with moisturizing chemical enhancers partitioning and solubility effects affecting crustal lipid and keratin structure discussed Mechanism of action of penetration enhancers and retarders and their potential for clinical use application is described.

Production and Applications of Keratinases in Industry

Keratin is an insoluble protein with fibrous structure. It is mainly found in hair,feathers,nail,wool and horn of various animals. These animal accessories can be utilized as animals feed, amino-acids and fertilizers. This insoluble protein is very difficult to degrade and has extreme stability because it has disulfide bonds, hydrogen and hydrophobic interaction present in it. But keratin can be easily digested by keratinase enzyme. Keratinase is an extracellular enzyme. It also degrades keratin in prokaryotic organisms. Microorganisms that produce keratinase are species of Bacillus, Actinobacteria and fungi. It can also be obtained from Streptomyces, Aspergillus, Fervidobacterium, Xanthomonas, Chryseobacteriumand Vibrio. Keratinases produced by microbes arevery diverse due to their chemical as well as physical properties. It is a vigorous enzyme that can survive broad pH and temperature. Their optimum pH range is neutral to alkaline and their optimum temperature reported is 40°C to 60°C. And thermophiles have also been reported for stable microbial activity. Microbial keratinases are cheaply available as compared to conventional producers for keratinases production. They have gained great significance in biotechnology by acting on strong, inflexible cross linked polypeptide structure of keratin instead of ordinary proteolytic enzyme papain, trypsin or pepsin. They are mostly extracted by degrading keratin as substrate. Keratin substrates include feather, hair, wool,horn and nails. This degradation process is helpful in converting keratinous wastes in to fertilizer and poultry feed. Other renowned biotechnological implementations include removing hair from leather by using keratinase, development of bio-polymer from keratinous fiber, delivering drug, hydrolysis of prion proteins and detergent industry. They are also used in converting biomass in to biofuel that significantly boosts power preservation and recycling. The main problem for producing enzymes on large scale is their costly production procedures. This hurdle is overcome by utilizing keratin waste eg feathers of chicken as fermentation substrate on industrial scale. The benefit of utilizing this left over is extremely cost effective fermentation process of keratinase and the effluents are environmental friendly. Keratinase enzyme has become popular and provided newly effective and efficient way for managing waste products by using them on industrial scales as substrates which gives rise to environmental friendly industries for nonstop development.

Composition and structure analysis of different depths in the stratum corneum using confocal Raman microscopy combined with two-dimensional correlation spectroscopy

The chemical composition and structure of the stratum corneum (SC) play a crucial role in the skin barrier function. Therefore, accurately determining the SC thickness and studying the changes in lipid and keratin structure and distribution within it are key aspects of skin barrier research. Currently, there are limited analytical tools and data analysis methods available for real-time and online studies of SC composition and structural changes. In this study, we focus on depth as a perturbation and employ confocal Raman microscopy combined with moving-window two-dimensional correlation spectroscopy (MW2D) technique to investigate the SC thickness. Additionally, we employ confocal Raman microscopy combined with perturbation-correlation moving-window two-dimensional correlation spectroscopy (PCMW2D) to precisely characterize the stratification of the SC. Furthermore, the two-dimensional correlation spectroscopy (2DCOS) method is utilized to examine the content of various conformations in the keratin secondary structure within the SC, as well as the subtle interrelationships between lipid and keratin structures.

Sustainable engineering of wool keratin towards cobalt atoms fixation for enhanced electrocatalytic water splitting

Developing sustainable bifunctional electrocatalysts based on non-noble metals for water splitting is crucial for modern society. Meanwhile, the utilization of biomaterials from waste streams in their fabrication enhances sustainability in the electrocatalytic sector. Herein, this novel approach has been demonstrated by selectively utilizing disulphide bonds, existed in natural wool keratin structure, to fabricate cobalt sulphide catalysts. The obtained Co9S8 nanoparticles, supported by nitrogen/phosphorus co-doped active carbons (Co9S8/N, P-ACs), exhibited a mesoporous system (SBET = 439.3 m2/g) and distinctive metal electronic environment. The as-prepared catalysts require a low overpotential of 90.7 mV and 245 mV to drive HER and OER at 10 mA cm−2 in the alkaline medium. The fabricated Co9S8/N,P-ACs|| Co9S8/N,P-ACs water electrolyzer possesses a low cell voltage (1.62 V at 10 mA cm−2) and a high stability with 9.8 % decay after 25 h of operation in the alkaline medium. Finally, density functional theory simulations confirm the octahedral sites in Co9S8 instead of CoO are the active sites, and an optimized d-band center is achieved by nitrogen, phosphorus-doped carbons.