Human Keratin Research Articles

Bio-responsive alginate-keratin composite nanogels with enhanced drug loading efficiency for cancer therapy

This article presents a novel dual-stimuli responsive nanogel prepared from human hair keratin and alginate through simple crosslinking method. Keratin offer the crosslinking structure and bio-responsive ability and alginate ameliorated properties of nanogels including particle size, stability and drug loading capacity. The resultant keratin-alginate nanogels (KSA-NGs) could function as promising vectors for doxorubicin hydrochloride (DOX) with a super-high drug-loading rate of 52.9% (w/w) and dual-stimuli responsive behavior to GSH and trypsin. Cellular uptake results indicated DOX loaded KSA-NGs (DOX@KSA-NGs) are efficiently internalized in 4T1 and B16 cells in vitro, with a fast DOX release into cells under intracellular GSH and trypsin levels. In vitro cytotoxicity results further manifested that DOX@KSA-NGs behaved equivalent inhibition effects on tumor cells to DOX. In vivo experiments showed that DOX@KSA-NGs had a better anti-tumor effect and lower side effects compared to free drugs. These bio-responsive KSA-NGs have potential applications as nanocarriers for cancer therapy.

Homo- and heteropolymer self-assembly of recombinant trichocytic keratins.

In the past two decades, keratin biomaterials have shown impressive results as scaffolds for tissue engineering, wound healing, and nerve regeneration. In addition to its intrinsic biocompatibility, keratin interacts with specific cell receptors eliciting beneficial biochemical cues. However, during extraction from natural sources, such as hair and wool fibers, natural keratins are subject to extensive processing conditions that lead to formation of unwanted by-products. Additionally, natural keratins suffer from limited sequence tunability. Recombinant keratin proteins can overcome these drawbacks while maintaining the desired chemical and physical characteristics of natural keratins. Herein, we present the bacterial expression, purification, and solution characterization of human hair keratins K31 and K81. The obligate heterodimerization of the K31/K81 pair that results in formation of intermediate filaments is maintained in the recombinant proteins. Surprisingly, we have for the first time observed new zero- and one-dimensional nanostructures from homooligomerization of K81 and K31, respectively. Further analysis of the self-assembly mechanism highlights the importance of disulfide crosslinking in keratin self-assembly.

Fabrication of bi-layer scaffold of keratin nanofiber and gelatin-methacrylate hydrogel: Implications for skin graft

Bi-layer scaffold composed of human hair keratin/chitosan nanofiber mat and gelatin methacrylate (GelMA) hydrogel was fabricated by using electrospinning and photopolymerization techniques. To prepare the nanofiber layer, the blend solution of human hair keratin and chitosan (mixture ratio: 5/5) was electrospun using formic acid as a solvent in the presence of poly(ethylene glycol), followed by cross-linking with glutaraldehyde. The tensile strength of the human hair keratin/chitosan nanofiber mat was much higher than that of pure human hair keratin nanofiber mat. Meanwhile, the blend nanofiber mat was relatively more compatible with HaCaT cell proliferation and keratinocyte differentiation than the pure chitosan nanofiber mat. The bi-layer scaffold was prepared by photopolymerization of GelMA under the cross-linked nanofiber mat. To evaluate the feasibility as a skin graft, human fibroblast was encapsulated in the hydrogel layer and HaCaT cells were cultured on the nanofiber layer and they were co-cultured for 10days. As a result, the encapsulated fibroblasts proliferated in the hydrogel matrix and HaCaT cells formed a cell layer on the top of scaffold, mimicking dermis and epidermis of skin tissue.

Cultivation of human dermal fibroblasts and epidermal keratinocytes on keratin-coated silica bead substrates.

Human hair keratin is promising as a bioactive material platform for various biomedical applications. To explore its versatility further, human hair keratin was coated onto monolayers of silica beads to produce film-like substrates. This combination was hypothesized to provide a synergistic effect in improving the biochemical properties of the resultant composite. Atomic force microscopy analysis showed uniform coatings of keratin on the silica beads with a slight increase in the resulting surface roughness. Keratin-coated silica beads had higher surface energy and relatively lower negative charge than those of bare silica beads. To investigate cell response, human dermal fibroblasts (HDFs), and human epidermal keratinocytes (HEKs) were cultured on the substrates over 4days. Results showed that keratin coatings significantly enhanced the metabolic activity of HDFs and encouraged cell spreading but did not exert any significant effects on HEKs. HDF expression of collagen I was significantly more intense on the keratin-coated compared to the bare silica substrates. Furthermore, HDF secretion of various cytokines suggested that keratin coatings triggered active cell responses related to wound healing. Collectively, our study demonstrated that human hair keratin-coated silica bead monolayers have the potential to modulate HDF behavior in culture and may be exploited further. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2789-2798, 2017.

Somatic loss of estrogen receptor beta and p53 synergize to induce breast tumorigenesis

BackgroundUpregulation of estrogen receptor beta (ERβ) in breast cancer cells is associated with epithelial maintenance, decreased proliferation and invasion, and a reduction in the expression of the receptor has been observed in invasive breast tumors. However, proof of an association between loss of ERβ and breast carcinogenesis is still missing.MethodsTo study the role of ERβ in breast oncogenesis, we generated mouse conditional mutants with specific inactivation of ERβ and p53 in the mammary gland epithelium. For epithelium-specific knockout of ERβ and p53, ERβF/F and p53F/F mice were crossed to transgenic mice that express the Cre recombinase under the control of the human keratin 14 promoter.ResultsSomatic loss of ERβ significantly accelerated formation of p53-deficient mammary tumors. Loss of the receptor also resulted in the development of less differentiated carcinomas with stronger spindle cell morphology and decreased expression of luminal epithelial markers.ConclusionsOur results show that synergism between ERβ and p53 inactivation functions to determine important aspects of breast oncogenesis and cancer progression.

Abstract 3947: Intratumor heterogeneity impacts treatment response in rectal carcinoma

Abstract Individual response to radiochemotherapy (RCT) in rectal cancer patients is highly variable and the underlying mechanisms of treatment resistance of cancer cells are poorly understood. Recent studies revealed a considerable degree of genomic tumor heterogeneity. We hypothesize that this heterogeneity has a direct impact on treatment response as subpopulations of cancer cells are resistant to currently used RCT and facilitate tumor growth under treatment. To address this highly relevant clinical issue, patient-derived rectal cell lines were established. The tissue was derived from a 59-year-old male presenting with an adenocarcinoma of lower rectum (T3,N1,M0), who was treated by neoadjuvant RCT (50.4 Gy plus 5-FU) and low anterior resection. The neoadjuvant treatment induced a shrinkage of the tumor (staging of the surgical specimen: ypT3,N0), suggesting a partial response to RCT. A biopsy of the treatment naïve tumor was implanted heterotopically into an immunodeficient nude mouse. After in vivo growth, the tumor was dissociated and introduced to an in vitro culture where murine stromal cells were depleted using antibody-based columns. The cell line proved to be of human origin by immunofluorescence for human Keratin 20 as well as genotyping using short tandem repeat profiling. The characterization of the genome by array CGH and spectral karyotyping (SKY) revealed a highly complex near-triploid karyotype with numerous chromosomal imbalances, which are specific for colorectal cancers, including gains in chromosomes 7, 13 and 20. We also observed other structural abnormalities including an isochromosome 1q. Multiplex-FISH by consecutive hybridization of probes for 15 gene loci, which are known to be relevant in colorectal cancer genesis, revealed a significant degree of clonal heterogeneity of the cell line. Single cell sorting was then performed to establish single cell derived cell lines from the genomically well characterized parental cell line. Exposure of the single cell derived cell lines to irradiation in combination with 3 uM 5-FU revealed substantial differences in treatment response. Analyses of the genome by array CGH and transcriptome by RNA-Seq of the respective single cell derived cell lines are currently underway. This will allow the comparison of the respective sensitivities to RCT to the identified aberration profiles. These data will facilitate the understanding of therapy resistance and potentially allow a reliable prediction of the patient’s response. A tailored therapy is an important step towards individualized treatment in colorectal cancer patients to avoid therapy resistance. Citation Format: Rüdiger Meyer, Nicole E. McNeil, Darawalee Wangsa, Lena Anthuber, Noam Auslander, Danny Wangsa, Zhongqiu Zhang, Daniel Rosenberg, Eytan Ruppin, Jens K. Habermann, Thomas Ried. Intratumor heterogeneity impacts treatment response in rectal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3947. doi:10.1158/1538-7445.AM2017-3947

The Surface Protein SdrF Mediates Staphylococcus epidermidis Adherence to Keratin.

Staphylococcus epidermidis, a major component of skin flora, is an opportunist, often causing prosthetic device infections. A family of structurally related proteins mediates staphylococcal attachment to host tissues, contributing to the success of S. epidermidis as a pathogen. We examined the ability of the surface protein SdrF to adhere to keratin, a major molecule expressed on the skin surface. A heterologous Lactococcus lactis expression system was used to express SdrF and its ligand-binding domains. Adherence to keratin types 1 and 10, human foreskin keratinocytes, and nasal epithelial cells was examined. SdrF bound human keratins 1 and 10 and adhered to keratinocytes and epithelial cells. Binding involved both the A and B domains. Anti-SdrF antibodies reduced adherence of S. epidermidis to keratin and keratinocytes. RNA interference reduced keratin synthesis in keratinocytes and, as a result, SdrF adherence. Direct force measurements using atomic force microscopy showed that SdrF mediates bacterial adhesion to keratin 10 through strong and weak bonds involving the A and B regions; strong adhesion was primarily mediated by the A region. These studies demonstrate that SdrF mediates adherence to human keratin and suggest that SdrF may facilitate S. epidermidis colonization of the skin.

Peptide—protein interactions within human hair keratins

We selected 1235 decapeptides from human hair proteins encoded by human genes of keratins and keratin associated proteins. The peptides were linked to glass arrays and screened for their affinity towards a solution of human hair extracted keratin fraction. Based on the physicochemical properties of the peptides, ten variables were studied: content of different types of amino acid side chains (cysteine, hydrophobic, polar, basic, acidic, aromatic rings, amide, alcohol side chains), isoelectric point, and net charge. We found differences statistically significant on the binding affinity of peptides based on their content of cysteine, hydrophobic and polar amino acids, mainly containing alcohols. These results point to the formation of hydrophobic interactions and disulfide bonds between small peptides and human hair keratins as the main driving forces for the interaction of possible cosmetic peptides, namely designed to strength human hair. As so, our results enlighten the nature of the interaction of keratin based materials with human hair, which are claimed to enhance hair fiber strength, and enable a more directed and sustained hair care peptide design.

Cell Penetration and Secondary Structure of a Synthetic Peptide with Anti-HIV Activity

Peptidic drugs have many advantages as compared to small chemical molecules; however, they also possess some limitations as their poor membrane transducing properties. Our group has recently reported the potent anti-HIV antiviral activity of CIGB-210, a peptide derived from human keratin 10. Previous experiments showed that this peptide is internalized in MT4 cells. The aim of this study was to expand our knowledge on the uptake of CIGB-210 by assessing the peptide penetration in four other human cell lines. Cells were treated with 10, 20 and 40 µM of fluorescein-labelled CIGB-210 and the percentage of fluorescent cells was determined by flow cytometry at 15 min, 1 and 24 h. The uptake of fluorescein-labelled CIGB-210 in THP-1, HEp-2, HepG2 and PC-3 cell lines was directly proportional to both, peptide concentration and incubation times. However, some differences in the kinetics of cell entry were found. While the initial uptake was faster in HepG2 and PC-3 cells, after 24 h of incubation the percentage of fluorescence cells was equalized, although HEp-2 cells exhibited the higher numbers. The efficiency of CIGB-210 uptake was lower than a control cell penetrating peptide. However, despite the differences found, CIGB-210 was capable of transducing four human cell lines of different origins without any help. Finally, circular dichroism spectrometry data indicated that the peptide adopt a mostly disordered structure in aqueous solution, with an estimated alpha helical content of less than 5%. This study contributes to the characterization of CIGB-210 as a novel drug candidate against HIV/AIDS.

Reprogramming Postnatal Human Epidermal Keratinocytes Toward Functional Neural Crest Fates.

During development, neural crest (NC) cells are induced by signaling events at the neural plate border of all vertebrate embryos. Initially arising within the central nervous system, NC cells subsequently undergo an epithelial to mesenchymal transition to migrate into the periphery, where they differentiate into diverse cell types. Here we provide evidence that postnatal human epidermal keratinocytes (KC), in response to fibroblast growth factor 2 and insulin like growth factor 1 signals, can be reprogrammed toward a NC fate. Genome-wide transcriptome analyses show that keratinocyte-derived NC cells are similar to those derived from human embryonic stem cells. Moreover, they give rise in vitro and in vivo to NC derivatives such as peripheral neurons, melanocytes, Schwann cells and mesenchymal cells (osteocytes, chondrocytes, adipocytes, and smooth muscle cells). By demonstrating that human keratin-14+ KC can form NC cells, even from clones of single cells, our results have important implications in stem cell biology and regenerative medicine. Stem Cells 2017;35:1402-1415.

Metal-Chelation-Assisted Deposition of Polydopamine on Human Hair: A Ready-to-Use Eumelanin-Based Hair Dyeing Methodology.

Permanent dyeing of gray hair has become an increasingly active area in the cosmetics industry because of the increasingly aging population in developed countries. So far, p-phenylenediamine (PPD) and related diamine-based monomeric compounds have been widely used for the dyeing processes, but toxicological studies have revealed such compounds to be carcinogenic and allergenic. Here, we for the first time demonstrated that polydopamine, a mimic of human eumelanin, gives rise within a commercially acceptable period of time (i.e., 1 h) to deep black colors (i.e., natural Asian hair colors) in human keratin hairs in the presence of ferrous ions. The dyed hairs showed excellent resistance to conventional detergents, and the detailed color was readily varied by changing the kind of metal ion used. SEM images and FT-IR-ATR spectra suggested that the extent of polydopamine aggregation was crucial for the dyeing efficiency. High-resolution (15 T) FT-ICR mass spectrometry performed on the products detached from hairs with either 0.1 N HCl or NaOH indicated that similar polydopamine products were recruited into the hair matrices whether in the presence or absence of metal-based chelating. Polydopamine chains were determined using EPR and ICP-OES to use chelation of ferrous ions to self-assemble as well as to bind keratin surfaces in the dyeing conditions. Also, mice subjected to skin toxicity tests showed much greater viability and much less hair loss with our dyeing agents than with PPD. In conclusion, this study showed that a safe eumelanin mimic may be used to permanently dye gray hair, and showed three kinds of deposition mechanisms (i.e., innate binding ability of polydopamine, metal-assisted self-assembly of polydopamine, and metal-related bridging between keratin surface and polydopamine) to be involved.

Keratin Hydrogel Enhances In Vivo Skeletal Muscle Function in a Rat Model of Volumetric Muscle Loss.

Volumetric muscle loss (VML) injuries exceed the considerable intrinsic regenerative capacity of skeletal muscle, resulting in permanent functional and cosmetic deficits. VML and VML-like injuries occur in military and civilian populations, due to trauma and surgery as well as due to a host of congenital and acquired diseases/syndromes. Current therapeutic options are limited, and new approaches are needed for a more complete functional regeneration of muscle. A potential solution is human hair-derived keratin (KN) biomaterials that may have significant potential for regenerative therapy. The goal of these studies was to evaluate the utility of keratin hydrogel formulations as a cell and/or growth factor delivery vehicle for functional muscle regeneration in a surgically created VML injury in the rat tibialis anterior (TA) muscle. VML injuries were treated with KN hydrogels in the absence and presence of skeletal muscle progenitor cells (MPCs), and/or insulin-like growth factor 1 (IGF-1), and/or basic fibroblast growth factor (bFGF). Controls included VML injuries with no repair (NR), and implantation of bladder acellular matrix (BAM, without cells). Initial studies conducted 8 weeks post-VML injury indicated that application of keratin hydrogels with growth factors (KN, KN+IGF-1, KN+bFGF, and KN+IGF-1+bFGF, n = 8 each) enabled a significantly greater functional recovery than NR (n = 7), BAM (n = 8), or the addition of MPCs to the keratin hydrogel (KN+MPC, KN+MPC+IGF-1, KN+MPC+bFGF, and KN+MPC+IGF-1+bFGF, n = 8 each) (p < 0.05). A second series of studies examined functional recovery for as many as 12 weeks post-VML injury after application of keratin hydrogels in the absence of cells. A significant time-dependent increase in functional recovery of the KN, KN+bFGF, and KN+IGF+bFGF groups was observed, relative to NR and BAM implantation, achieving as much as 90% of the maximum possible functional recovery. Histological findings from harvested tissue at 12 weeks post-VML injury documented significant increases in neo-muscle tissue formation in all keratin treatment groups as well as diminished fibrosis, in comparison to both BAM and NR. In conclusion, keratin hydrogel implantation promoted statistically significant and physiologically relevant improvements in functional outcomes post-VML injury to the rodent TA muscle.

Cell and Growth Factor-Loaded Keratin Hydrogels for Treatment of Volumetric Muscle Loss in a Mouse Model.

Wounds to the head, neck, and extremities have been estimated to account for ∼84% of reported combat injuries to military personnel. Volumetric muscle loss (VML), defined as skeletal muscle injuries in which tissue loss results in permanent functional impairment, is common among these injuries. The present standard of care entails the use of muscle flap transfers, which suffer from the need for additional surgery when using autografts or the risk of rejection when cadaveric grafts are used. Tissue engineering (TE) strategies for skeletal muscle repair have been investigated as a means to overcome current therapeutic limitations. In that regard, human hair-derived keratin (KN) biomaterials have been found to possess several favorable properties for use in TE applications and, as such, are a viable candidate for use in skeletal muscle repair. Herein, KN hydrogels with and without the addition of skeletal muscle progenitor cells (MPCs) and/or insulin-like growth factor 1 (IGF-1) and/or basic fibroblast growth factor (bFGF) were implanted in an established murine model of surgically induced VML injury to the latissimus dorsi (LD) muscle. Control treatments included surgery with no repair (NR) as well as implantation of bladder acellular matrix (BAM). In vitro muscle contraction force was evaluated at two months postsurgery through electrical stimulation of the explanted LD in an organ bath. Functional data indicated that implantation of KN+bFGF+IGF-1 (n = 8) enabled a greater recovery of contractile force than KN+bFGF (n = 8)***, KN+MPC (n = 8)**, KN+MPC+bFGF+IGF-1 (n = 8)**, BAM (n = 8)*, KN+IGF-1 (n = 8)*, KN+MPCs+bFGF (n = 9)*, or NR (n = 9)**, (*p < 0.05, **p < 0.01, ***p < 0.001). Consistent with the physiological findings, histological evaluation of retrieved tissue revealed much more extensive new muscle tissue formation in groups with greater functional recovery (e.g., KN+IGF-1+bFGF) when compared with observations in tissue from groups with lower functional recovery (i.e., BAM and NR). Taken together, these findings further indicate the general utility of KN biomaterials in TE and, moreover, specifically highlight their potential application in the treatment of VML injuries.

半永久染毛料によるヒト毛髪由来の透明型ケラチンフィルムの染色と退色

半永久染毛料による染色と退色に関して，透明型ケラチンフィルムを使用して調べた。市販されている4種の製品を使用したところ，3製品においてケラチンフィルムの明確な着色がみられた。着色と退色は分光光度計によるスペクトル（300～800nm）分析と分光測色計による色差変化により測定ができた。着色は染色回数と染色時間に依存しており，濃い着色を得るには染色時間よりも，染色の回数を増やすことが重要であった。異なる2種類の染毛料で連続して染色したケラチンフィルムは，個々の染色で得られたスペクトルを加算した平均的なスペクトルが得られた。過酸化水素を含有している酸化染毛剤の処理により形成されるダメージ分子のシステイン酸は，染色回数を重ねても半永久染毛料においては検出されなかった。染色ケラチンフィルムからの水洗による色落ちを調べたところ，色差値の低下は蒸留水よりも水道水の方が約2倍も高く，金属イオンが原因物質であった。ソーラーシミュレータを用いた光照射により経時的な退色を観察することができた。これらの退色においては染色に使用した製品間での相違がみられた。ケラチンフィルムは半永久染毛料による染色と退色を簡便に検出し，評価するのに有用であることが明らかとなった。

Topical application of probiotics in skin: adhesion, antimicrobial and antibiofilm invitro assays.

When skin dysbiosis occurs as a result of skin disorders, probiotics can act as modulators, restoring microbial balance. Several properties of selected probiotics were evaluated so that their topical application could be considered. Adhesion, antimicrobial, quorum sensing and antibiofilm assays were carried out with several probiotic strains and tested against selected skin pathogens. All tested strains displayed significant adhesion to keratin. All lactobacilli with the exception of Lactobacillus delbrueckii, showed antimicrobial activity against skin pathogens, mainly due to organic acid production. Most of them also prevented biofilm formation, but only Propioniferax innocua was able to break down mature biofilms. This study demonstrates that although all tested probiotics adhered to human keratin, they showed limited ability to prevent adhesion of some potential skin pathogens. Most of the tested probiotics successfully prevented biofilm formation, suggesting that they may be successfully used in the future as a complement to conventional therapies in the treatment of a range of skin disorders. The topically used probiotics may be a natural, targeted treatment approach to several skin disorders and a complement to conventional therapies which present many undesirable side effects.

Keratose/poly (vinyl alcohol) blended nanofibers: Fabrication and biocompatibility assessment

Increasing interest in using keratin-based materials for biomedical application has prompted the development of keratin/PVA nanofibers. To date, several kinds of keratins (including wool, feather, and human hair reductive keratins)/PVA blended nanofibers have been fabricated but limited to the in vitro studies. However, few studies focused on the in vivo biocompatibility test of keratin/PVA nanofibers. Herein, the keratose (oxidative keratin)/PVA nanofiber, a novel type of keratin/PVA nanofiber, was fabricated with an electrospinning technique. The obtained nanofibers possess uniform fibrous structure, suitable hydrophilicity and mechanical properties, which could be affected by the mass ratio of keratose to PVA. Furthermore, the biocompatibility tests of keratose/PVA nanofibers have been performed by subcutaneous implantation into SD rats. H&E staining and Masson's trichrome staining revealed that the implants were highly compatible with body tissue, and no acute toxic effects as well as no tissue damage were observed. The implants were fully degraded within four weeks. Beyond this, the analysis of proinflammatory cytokines in rat serum indicated that the implants induced normal immune response and had no immunogenicity. These results demonstrate that keratose/PVA nanofibers have the potential for biomedical applications due to the favorable biocompatibility and biodegradability.

Membrane-Active Epithelial Keratin 6A Fragments (KAMPs) Are Unique Human Antimicrobial Peptides with a Non-αβ Structure.

Antibiotic resistance is a pressing global health problem that threatens millions of lives each year. Natural antimicrobial peptides and their synthetic derivatives, including peptoids and peptidomimetics, are promising candidates as novel antibiotics. Recently, the C-terminal glycine-rich fragments of human epithelial keratin 6A were found to have bactericidal and cytoprotective activities. Here, we used an improved 2-dimensional NMR method coupled with a new protocol for structural refinement by low temperature simulated annealing to characterize the solution structure of these kerain-derived antimicrobial peptides (KAMPs). Two specific KAMPs in complex with membrane mimicking sodium dodecyl sulfate (SDS) micelles displayed amphipathic conformations with only local bends and turns, and a central 10-residue glycine-rich hydrophobic strip that is central to bactericidal activity. To our knowledge, this is the first report of non-αβ structure for human antimicrobial peptides. Direct observation of Staphylococcus aureus and Pseudomonas aeruginosa by scanning and transmission electron microscopy showed that KAMPs deformed bacterial cell envelopes and induced pore formation. Notably, in competitive binding experiments, KAMPs demonstrated binding affinities to LPS and LTA that did not correlate with their bactericidal activities, suggesting peptide-LPS and peptide-LTA interactions are less important in their mechanisms of action. Moreover, immunoprecipitation of KAMPs-bacterial factor complexes indicated that membrane surface lipoprotein SlyB and intracellular machineries NQR sodium pump and ribosomes are potential molecular targets for the peptides. Results of this study improve our understanding of the bactericidal function of epithelial cytokeratin fragments, and highlight an unexplored class of human antimicrobial peptides, which may serve as non-αβ peptide scaffolds for the design of novel peptide-based antibiotics.

Characterization and study of physical properties and antibacterial activities of human hair keratin–silver nanoparticles and keratin–gold nanoparticles coated cotton gauze fabric

Human hairs are considered as major waste from barbershops. It contains an important protein called keratin. Keratin from human hair exhibits biocompatibility, wound-healing property, biodegradability, and antibacterial property. Silver and gold nanoparticles are commonly used in wound-healing applications. These nanoparticles possess excellent functional properties like antibacterial, wound healing and biocompatibility and applicable in biomedical field. In this study, silver and gold nanoparticles were used along with human hair keratin for the production of antibacterial materials. The functional properties of these two materials are synergized for wound-healing applications. Silver and gold nanoparticles were synthesized by chemical reduction method. The synthesized nanoparticles were characterized using UV–Visible, particle size, and zeta potential analyses. The prepared materials were characterized by scanning electron microscopy, Fourier transform infrared, and energy-dispersive X-ray spectroscopic analyses and they were measured for the physical properties such as air permeability, water contact angle, moisture content, and water absorbency. Furthermore, the antibacterial activities were evaluated against burn wound bacteria. Superior antibacterial activities and adequate physical properties found in keratin/nanoparticles immobilized cotton samples.

Feather keratin hydrogel for wound repair: Preparation, healing effect and biocompatibility evaluation

Keratins are highly attractive for wound healing due to their inherent bioactivity, biocompatibility and physical properties. However, nearly all wound healing studies have focused on human hair keratins, and the wound-repair effects and in vivo biocompatibilities of feather keratins are not clear. Feather keratins are derived from chicken feathers, which are considered to be the major waste in the poultry industry, and the quality of feather keratin is easier to control than that of human hair keratin due to human hair perming and colouring-dyeing. Thus, we extracted keratins from chicken feathers, and a feather keratin hydrogel was then prepared and used to test the in vivo wound-healing properties and biocompatibility. The results indicated that feather keratins displayed wound-healing and biodegradation properties similar to those of human hair keratins and were also highly compatible with those of the tissue and devoid of immunogenicity and systematic toxicity. Collectively, these results suggested that feather keratin hydrogel could be used for biomedical applications, particularly effective wound healing.

Optimization, preparation and characterization of rutin-quercetin dual drug loaded keratin nanoparticles for biological applications

Objective(s): Response surface methodology (RSM) by central composite design (CCD) was applied to statistically optimize the preparation of Rutin-Quercetin (Ru-Qr) dual drug loaded human hair keratin nanoparticles as well as evaluate the characteristics. Materials and Methods: The effects of three independent parameters, namely, temperature (X1:10-40 C), surfactant (X2: SDS (1), SLS (2), Tween-20 (3)), and organic solvents (X3: acetone (1), methanol (2), chloroform (3)) were investigated to optimize the preparation of dual drug loaded keratin nanoparticles, and to understand the effects of dependent parameters namely, drug releasing capacity, average particle size, total antioxidant power, zeta potential, and polydispersity index of Ru-Qr nanoparticles. Optimization was executed by CCD and RSM using statistical software (Design Expert, version 8.0.7.1, Stat-Ease, Inc., Minneapolis, MN, USA). The optimal Ru-Qr dual drug loaded keratin nanoparticles were obtained at temperature (X1): 40UC, SDS (X2), and acetone (X3). Results: Under this conditions to achieve highest drug releasing capacity of 98.3%, average size of nanoparticles are 125 nm, total antioxidant power 98.68%, zeta potential 28.09 mV, and polydispersity index of 0.54. Although majority of the experimental values were relatively well matched with the predicted values. Conclusion: This optimization study could be useful in pharmaceutical industry, especially for the preparation of new nano-therapeutic formulations encapsulated with drug molecules. This nanotechnology based drug delivery system is to overcome multi drug resistance and site specific action without affecting other organs and tissues. The methodology adopted in this work shall be useful in improvement of quality of human health.