Keratin Layer Research Articles

THE USE OF THE PAPANICOLAOU STAIN TO ROUTINE HISTOLOGICAL EXAMINATION: TEACHING THE BASIC MICROSCOPY OF SQUAMOUS CELL CARCINOMA

Introduction: The understanding of microscopy classes is imperative to the student in human pathology. Objective: To prepare the student to observe and understand, through tinctorial recognition, the main histologic features of Papanicolaou-stained well-differentiated carcinomas. Methods: A selected case of a well-differentiated carcinoma of the tongue was used for a Papanicolaou stain. Results: The Papanicolaou-stained slides showed, basically, basal cells in a faint to a dark blue color. The stratum spinosum stained light pink to a faint blue-green and the keratin layer and the keratin pearls stained bright orange. The connective tissue stained light green. Conclusion: The use of Papanicolaou stain was found very convenient as the beginner in histopathology can perform a ready identification of the well-differentiated squamous cell carcinoma aspects.

Human Hair Keratin for Biocompatible Flexible and Transient Electronic Devices.

Biomaterials have been attracting attention as a useful building block for biocompatible and bioresorbable electronics due to their nontoxic property and solution processability. In this work, we report the integration of biocompatible keratin from human hair as dielectric layer for organic thin-film transistors (TFTs), with high performance, flexibility, and transient property. The keratin dielectric layer exhibited a high capacitance value of above 1.27 μF/cm2 at 20 Hz due to the formation of electrical double layer. Fully solution-processable TFTs based on p-channel poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b]dithiophen-2-yl)-alt[1,2,5]thiadiazolo[3,4-c]-pyridine] (PCDTPT) and keratin dielectric exhibited high electrical property with a saturation field-effect mobility of 0.35 cm2/(Vs) at a low gate bias of -2 V. We also successfully demonstrate flexible TFTs, which exhibited good mechanical flexibility and electrical stability under bending strain. An artificial electronic synaptic PCDTPT/keratin transistor was also realized and exhibited high-performance synaptic memory effects via simple operation of proton conduction in keratin. An added functionality of using keratin as a substrate was also presented, where similar PCDTPT TFTs with keratin dielectric were built on top of keratin substrate. Finally, we observed that our prepared devices can be degraded in ammonium hydroxide solution, establishing the feasibility of keratin layer as various components of transient electrical devices, including as a substrate and dielectric layer.

Shape disparity of bovid (Mammalia, Artiodactyla) horn sheaths and horn cores allows discrimination by species in 3D geometric morphometric analyses.

The bony cranial structures of even-toed hoofed mammals are important for understanding ecology and behavior of ruminants. Horns, the cranial appendages of the family Bovidae, are covered in a layer of keratin that is often not preserved in the fossil record; however, this keratin sheath is intimately involved in the processes that influence horn shape evolution. To understand the relationship between these two components of horns, we quantified both core and sheath shape for four extant species using three-dimensional geometric morphometric analyses in separate, core- and sheath-specific morphospaces as well as a combined morphospace. We assessed correlations between the horn and sheath morphospaces using two-block partial least squares regression, a Mantel test of pairwise distances between species, and Procrustes ANOVA. We measured disparity in the combined morphospace as Procrustes distances between mean shapes of cores and sheaths within and between species and as Procrustes variance. We also tested whether core and sheath shapes could be discriminated by taxon with a canonical variate analysis. Results show that horn core and sheath morphospaces are strongly correlated. The differences in shape between a species' core and sheath were statistically significant, but not as great as those between the cores and sheaths of different species when close relatives were not considered, and core and sheath Procrustes variances are not significantly different within species. Cores and sheath shapes were highly identifiable and were assigned to the correct clade 93% of the time in the canonical variate analysis. Based on these tests, horn cores are distinguishable in geometric morphometric analyses, extending the possibility of using geometric morphometrics to study the ecology and evolution of bovid horns to the fossil record.

The effect of ethanol on rat tongue and the possible protective role of royal jelly: Light and scanning electron microscopic study

Background: Ethanol is the most commonly used and abused xenobiotic in the world. Royal jelly (RJ) has been considered as an antioxidant that protects against different agents.Aim of the work: This study aimed to investigate the effect of ethanol on the rat tongue and the possible protective role of royal jelly.Material and methods: Twenty five adult male rats were used in this study and were divided into 4 groups. Group I: 10 rats were divided equally into negative and positive controls. Group II: 5 rats received RJ at a dose of 100 mg/kg body weight by gastric tube daily for 30 days. Group III: 5 rats received ethanol at a dose of 10 ml/kg body weight from 30% v/v ethanol solution in distilled water by a gastric tube daily for 30 days. Group IV: 5 rats received both RJ and ethanol as the same previous doses by gastric tube for 30 days. Tongue sections were histologically prepared and examined.Results: The results revealed that group II was nearly as group I. Group III revealed by LM dorsal surface of the tongue was covered by irregularly arranged, short and long lingual papillae. Some papillae were thin, with blunted tips and others were completely absent. The epithelial lining of the ventral surface also showed an apparent reduction in thickness. The keratin layer of the ventral surfaces of the tongue appeared in some regions discontinuous and detached. Some skeletal muscle fibers revealed separations and vacuolations.Scanning electron microscope (SEM) examination revealed a noticeable atrophy of lingual papillae from being short to being absent in focal areas. They were irregularly arranged in different directions. Group IV revealed amelioration of these changes.Conclusion: Ethanol has damaging effects on the lingual papillae and muscles and royal jelly has a protective role for these effects.

Some lectin binding properties of the tongue of the mole rat, Nannospalax xanthodon

We investigated carbohydrate residues on the epithelial surface, in the epithelial cells and in gland cells of the tongue of the mole rat using histochemical methods. We used horseradish peroxidase-conjugated lectins from Helix pomatia (HPA), Arachishypogaea (PNA), Ulexeuropaeus (UEA I), Canavaliaensiformis (Con A). The most intense reactivity was observed in the keratin layer with HPA, UEA I and Con A, and in the epithelial cells with UEA I and Con A. In the glands, we found strong reactivity in serous cells with HPA and Con A, and in mucous cells with HPA and UEA I. PNA did not bind to epithelial or gland cells. Consequently, GlcNAc, fucose and α-D-mannose terminal glycoconjugates are distributed widely; GalNAc terminal glycoconjugates appeared in small amounts.

Cutaneous Horn of the Eyelid in 13 Cases.

Cutaneous horn of the eyelid is uncommon. The authors evaluate the features of benign, premalignant, and malignant tumors at the base of cutaneous horn of the eyelid. To describe the clinical and histopathologic features of cutaneous horn of the eyelid. A retrospective analysis of 13 cases of cutaneous horn of the eyelid treated between 1994 and 2014 was performed. Thirteen patients participated in this study. Main outcome measures include clinical and histopathologic features and outcomes of cutaneous horn. The mean patient age was 54 years (median 64 years, range 9-91 years), and 6 patients (46%) were women. The cutaneous horn affected the upper (n = 5), lower (n = 6) eyelid, or was not indicated (n = 2). The mean height of the cutaneous horn was 7.6 mm (median 8mm, range 4-12 mm) and mean basal diameter was 3.8 mm (median 3mm, range 2-6 mm). The cutaneous horn was comprised of superficial layers of keratin with hyperkeratosis and parakeratosis overlying a solid tumor at the base in all cases. The tumor base included benign (n = 6, 46%), premalignant (n = 4, 31%), and malignant (n = 3, 23%) conditions. The benign basal lesions included seborrheic keratosis (n = 1), nevus sebaceous of Jadassohn (n = 1), pseudoepitheliomatous hyperplasia (n = 1), trichilemmoma (n = 1), and inverted follicular keratosis (n = 2). Premalignant basal lesions were actinic keratosis (n = 4), and malignant basal lesions included squamous cell carcinoma (n = 2) and sebaceous gland carcinoma (n = 1). The clinical significance of cutaneous horn of the eyelid lies not in the horn itself but the nature of the underlying base. Malignancy was found in 23% of patients.

Detection of precancerous lesions in the oral cavity using oblique polarized reflectance spectroscopy: a clinical feasibility study.

.We developed a multifiber optical probe for oblique polarized reflectance spectroscopy (OPRS) in vivo and evaluated its performance in detection of dysplasia in the oral cavity. The probe design allows the implementation of a number of methods to enable depth resolved spectroscopic measurements including polarization gating, source–detector separation, and differential spectroscopy; this combination was evaluated in carrying out binary classification tasks between four major diagnostic categories: normal, benign, mild dysplasia (MD), and severe dysplasia (SD). Multifiber OPRS showed excellent performance in the discrimination of normal from benign, MD, SD, and MD plus SD yielding sensitivity/specificity values of 100%/93%, 96%/95%, 100%/98%, and 100%/100%, respectively. The classification of benign versus dysplastic lesions was more challenging with sensitivity and specificity values of 80%/93%, 71%/93%, and 74%/80% in discriminating benign from SD, MD, and SD plus MD categories, respectively; this challenge is most likely associated with a strong and highly variable scattering from a keratin layer that was found in these sites. Classification based on multiple fibers was significantly better than that based on any single detection pair for tasks dealing with benign versus dysplastic sites. This result indicates that the multifiber probe can perform better in the detection of dysplasia in keratinized tissues.

EFFECT OF DIFFERENT FEEDING BEHAVIORS ON THE LINING EPITHELIUM OF THE ROOF OF BUCCAL CAVITY OF TWO BIRD SPECIES

The present study represents a comparison between the morphology of the roof of the buccal cavity in two bird species; the common moorhen, Gallinula chloropus and the hoopoe, Upupa epops. The palate region of the common moorhen has a well-developed medial and two lateral ridges and carrying backwardly directed papillae. The palate region of the common moorhen is lined by keratinized stratified epithelium. While, the palate region of the hoopoe, has shallow medial and two lateral ridges which lack the palatine papillae on their surface. The lining epithelium of the palate region of the hoopoe is covered by a thin keratin layer that disappears posteriorly to become non-keratinized epithelium which carried tiny scattered papillae on its surface. Posteriorly, the pharyngeal region in both bird species is lined by non-keratinized epithelium.

IMPACT OF ORAL CONTRACEPTIVES ON THE PERIODONTIUM: A HISTOLOGICAL STUDY

Background: Sex hormones play an important role in periodontal tissue integration. Oral hormonal contraceptive pills (OCPs) were developed over 50 years ago. Different studies reported higher progression rate of gingival inflammation in females using OCPs. The present study was performed to evaluate histologically the influence of oral contraceptives on periodontal tissues.Materials and Methods: A total of thirty healthy female Wistar albino rats aging between 10 to 12 weeks and weighing 230 – 260 gm were enrolled in this study. The animals were divided into two groups, fifteen rats each. Group I (Control group), rats receiving no medication. Group II (Study group), rats received Microcept® monophasic combined oral contraceptive tablets for 36 days. Histological examination of the peridontium was accomplished using light microscopy. Results: Light microscopic examination of the control group revealed that the gingival epithelium was parakeratinized stratified squamous epithelium with long pointed rete pegs. Pyknotic nuclei were seen in the keratinous layer. Concerning the study group, the gingival epithelium revealed orthokeratinzed stratified squamous epithelium with short and blunt rete pegs and absence of nuclei in keratinous layer. Dentin and cementum showed external resorption.Conclusion: The current study showed that oral contraceptives exhibited histological changes on the periodontium which can be correlated to different clinical findings.

Clinical evaluation of ethanolic extract of curcumin (Curcuma longa) on wound healing in Black Bengal goats

Objective: This study was aimed at clinical evaluation of surgical wound healing in goats treated with ethanolic extract of turmeric (Curcuma longa) rhizomes through topical route. Materials and methods: Eighteen surgical wounds were made in nine goats. The goats were divided into three groups; Group 1 (test group) was treated with ethanolic extract of turmeric, Group 2 (standard group) was treated with Povidone iodine, and the Group 3 was kept as untreated control. Follow up information was recorded from day 0 to day 21 postoperatively. Some morphological characters such as swelling area of wound, elevation of suture line from the skin surface, width of the suture area and contraction length per week were considered to determine the healing process. Bacteriological evaluation was done by conventional bacteriological techniques, and the tissue biopsies were stained by hematoxylin and eosin stains for histopathological studies. Results: Swelling of suturing area (11.51±0.36 mm) and elevation of suture line (2.65±0.41 mm) were lowest in wounds treated with ethanolic extract of turmeric. In histopathological studies, it was seen that tissue debris and hemorrhages disappeared and a thin line of keratin layer reappeared on the epidermal surface of the wound treated with ethanolic extract of turmeric. Conclusion: Ethanol treated turmeric enhances wound healing process in goats. This result could help the veterinarian and the researchers to consider herbal product especially ethanolic extract of turmeric for the treatment and better healing of surgical wounds with minimal complications. http://doi.org/10.5455/javar.2017.d209 XML PubReader

Orthokeratinized Odontogenic Cyst with an Associated Keratocystic Odontogenic Tumor Component and Ghost Cell Keratinization and Calcifications in a Patient with Gardner Syndrome

Gardner syndrome (GS) is caused by mutations in the APC and besides adenomatous colorectal polyps includes such manifestations as osteomas, epidermoid cysts (ECs) and occasionally multiple pilomatricomas. More than 50% of ECs in patients with GS exhibit pilomatricoma-like ghost cell keratinization. The latter may be explained by the fact that the development of both GS and pilomatricoma is driven by activation of the Wnt/β-catenin signaling pathway. A 62-year-old, Caucasian male with history of GS presented with a unilocular, mixed radiopaque/radiolucent mandibular lesion causing divergence and external root resorption of involved teeth. Histopathologically, the lesion was composed of two cystic components, an orthokeratinized odontogenic cyst (OOC) and a smaller one with characteristics of keratocystic odontogenic tumor (KCOT) featuring, focally, ghost cells and an epithelial morule-like structure. Dystrophic calcifications essentially similar to those seen in pilomatricomas were observed in the fibrous connective tissue wall. The KCOT and OOC epithelia revealed strong and diffuse cytokeratin (AE1/AE3) and β-catenin immunoreactivity. CD10 positive immunostaining was seen in the keratin and superficial spinous cell layers in both OOC and KCOT. The intraepithelial and mural ghost cells showed a cytokeratin (+), β-catenin and CD10 (-) immunophenotype. The diagnosis of OOC with ghost cell calcifications in association with KCOT was rendered. The patient was lost to follow-up. Although a coincidental co-existence cannot be excluded, ghost cell calcifications mimicking pilomatricoma-like changes in an unusual odontogenic cyst combining OOC and KCOT features as seen in this patient with GS may be explained by the common molecular mechanisms underlying the pathogenesis of cutaneous pilomatricomas and GS.

The vest-collar as a rodent collar to prevent licking and scratching during experiments.

Various types of restraint collars have been used for research animals, and the Elizabethan collar (E-collar) is the most commonly used. However, animals can be choked by the E-collar or they tend to remove it; furthermore, repeated rubbing and scratching of the collar may chafe the neck. We developed a new restraint collar with a vest to overcome these limitations. The vest-collar (V-collar) can be worn similarly to a vest, in contrast to the E-collar, which is fixed around the neck. A cone-shaped collar is attached to the vest in the V-collar and is made of Eva foam to surround the chest softly, accompanied by a transparent polyvinyl chloride (PVC) film for visibility. To evaluate the performance of the V-collar, we conducted experiments with mice wearing the V-collar and the E-collar. Both groups showed normal weight gain and food intake. Glucose and stress hormone levels showed no significant differences, and no stress-associated leukocyte profiles were observed during the experiments. However, despite the short experimental duration, more than half of the mice in the E-collar group showed injury to the skin on the neck, with increased thickness of the epidermal and keratin layers. Moreover, inflammatory cell counts were higher in the E-collar group than in the V-collar group. In conclusion, the V-collar, in contrast to the E-collar, does not cause skin injuries in animals and is thus beneficial for animals and investigators. Investigators can effectively use the V-collar to enhance laboratory animal welfare.

Bio-inspired design of SiCf-reinforced multi-layered Ti-intermetallic composite

In reference to the well-evolved keratin layer of turtle shell, which has a collagen fiber-reinforced multi-layered structure, bio-mimicking SiCf-reinforced Ti-intermetallic multi-layers were successfully fabricated. The initial Ti and Al foils were firmly bonded to each other through the formed intermetallic layers. Additionally, SiCf and Ti were connected by the compound TiC0.75 formed through the reaction between the Ti matrix and the deposited C coating on SiC fibers. Along the longitudinal direction of SiCf, the ultimate tensile, flexural strengths and fracture toughness of the hybrid composite have been respectively enhanced of 53%, 74% and 75%, while the elongation remained almost similar to the Ti-intermetallic multi-layers composite. In-situ observations indicated that cracks were always initiated in the intermetallic region. The crack propagating paths were significantly changed and the cracks length was visibly prolonged through crack deflection and crack blunting. Due to the strong interfacial connection between the SiC fibers and the Ti matrix, the broken SiCf pieces could strengthen the Ti matrix. Herein, the hybrid composite could support higher external loads than the corresponding Ti–Al intermetallic multilayers without SiCf.

A closer look at the feather coloration in the male purple sunbird, Nectarinia asiatica

During the breeding season male, but not female, individuals of the purple sunbird possess colourful plumage of chiefly blue and black coloration with a splatter of orange and yellow on the chest. Representative feathers of these colours were collected from male birds during the breeding season and analyzed by reflectance and scanning electron microscopy. The rachis, which is the central support of a feather on which various barbs and barbules are arranged, is spongy and made up of keratin layers with rod-shaped melanosomes sparsely distributed within these layers. Barbs and barbules are the structural units of the feather and depending on how they are arranged provide a characteristic shape to the feather. X-Ray diffraction (XRD) analyses of the feathers revealed the presence of various metal elements that might contribute to the feathers’ colorations. Blue feathers are iridescent and contain mainly iron, copper, zinc and cobalt (in that order of abundance); black feathers were also found to contain mainly iron and copper, but chromium instead of zinc and cobalt, while yellow feathers were found to contain predominantly cobalt and nickel. The metal content of the feathers in an as yet unknown way may be involved in the production of the distinct absorbance and reflectance patterns that the brilliant plumage of the purple sunbird is renowned for.

Baleen wear reveals intraoral water flow patterns of mysticete filter feeding.

A survey of macroscopic and microscopic wear patterns in the baleen of eight whale species (Cetacea: Mysticeti) discloses structural, functional, and life history properties of this neomorphic keratinous tissue, including evidence of intraoral water flow patterns involved in filter feeding. All baleen demonstrates wear, particularly on its medial and ventral edges, as flat outer layers of cortical keratin erode to reveal horn tubes, also of keratin, which emerge as hair-like fringes. This study quantified five additional categories of specific wear: pitting of plates, scratching of plates, scuffing of fringes, shortening of fringes, and reorientation of fringes (including fringes directed between plates to the exterior of the mouth). Blue whale baleen showed the most pitting and sei whale baleen the most scratching; gray whale baleen had the most fringe wear. The location of worn baleen within the mouth suggests that direct contact with the tongue is not responsible for most wear, and that flowing water as well as abrasive prey or sediment carried by the flowing water likely causes pitting and scratching of plates as well as fringe fraying, scuffing, shortening, and reorientation. Baleen also has elevated vertical and horizontal ridges that are unrelated to wear; these are probably related to growth and may allow for age determination.

Prototheca wickerhamii in a dog with cutaneous, ocular and systemic manifestations and treatment with terbinafine

A two-year-old intact female collie presented with a tentative diagnosis of systemic blastomycosis based on compatible clinical signs and history and a positive urine Blastomyces antigen enzyme immunoassay. The dog...

Ophidian Spectaculitis and Spectacular Dysecdysis: A Histologic Description.

The histologic features of abnormal spectacles in 60 snakes from the 5 families of Boidae, Colubridae, Elapidae, Pythonidae, and Viperidae are described in a retrospective study conducted on specimens submitted to a private diagnostic service during a period of 15 years. Fifty-two snakes had inflammatory reactions in the spectacle. The stroma and outer epithelium of the spectacle were the layers most often involved in inflammatory disease. Lesions of the outer epithelium included edema, hyperkeratosis, and granulocyte infiltration occasionally with bacterial colonies and fungal elements. The stroma had infectious agents and inflammatory reactions in vessels and between the collagen fibrils. The inner epithelium had varying degrees of hyperplasia and hypertrophy, but no infectious agents were seen. Infectious agents in these cases included mites, bacterial disease, fungal disease, or a combination of bacterial and fungal disease. Special stains identified the bacteria most commonly involved to be Gram-positive cocci. Thirteen snakes had dysecdysis of the spectacle. Of these, 5 displayed a concurrent inflammatory reaction of the spectacle, while the remaining 8 snakes had extra keratin layers on a spectacle with an otherwise normal appearance. These keratin layers were attached to serocellular crusts located on the inner surface of the periocular scales. The cause for dyskeratotic lesions of the spectacle was not always apparent, and concurrent acariasis, other forms of dermatitis, trauma, suboptimal husbandry, and visceral disease were considered possible contributing factors. It was notable that only 4% of the submitted cases were found to have spectaculitis and/or spectacular dysecdysis.

Comparative morphology of the snake spectacle using light and transmission electron microscopy.

To determine the interspecific variation in the morphology of the snake spectacle. About 43 snakes of 14 different species, belonging to three different families: Boidae, Colubridae, and Pythonidae. The spectacles were examined by light and transmission electron microscopy. The thickness of the stromal layer was measured and the location of the blood vessels was noted. The shape of the transition zone located at the rim of the spectacle and the presence of pigment herein were also recorded. The spectacles of all species examined consisted of three layers. The outer epithelium was made of basal cells with overlaying keratin layers, the stroma comprised layers of organized collagen fibrils, and the inner epithelium was a layer of squamous cells with microvilli. Blood vessels were found in the stroma of all spectacles: in boas and pythons in the middle layers of the stroma and in colubrids adjacent to the inner epithelium. Boas and pythons were endowed with the thickest stromal layers (81-132μm) compared to colubrids (9-95μm). Boas and pythons had a convex transition zone, while the transition zone of the colubrids exhibited a steady increase in spectacle thickness toward the hinge region. The transition zone contained pigment in boas and pythons. The overall morphology of the spectacle was similar among the major families of snakes. However, the location of blood vessels and appearance of transition zone differed, as did the overall thickness of the spectacle.

Effect of Post-Polymerization Heat Treatment on a Denture Base Acrylic Resin: Histopathological Analysis in Rats

Aims: This work examined the histological effects, on the rat palatal mucosa, of a denture base acrylic resin, submitted or not to a post-polymerization heat-treatment. Methods: Fifteen adult female Wistar rats, with sixty days old, weighting 150 g - 250 g were divided in G1: animals being maintained under the same conditions as the experimental groups following described, but without the use acrylic palatal plates (control group); G2: use of heat-polymerized acrylic resin palatal plates made of Lucitone 550; G3: use of palatal plates identical to G2, but subjected to a post-polymerization treatment in a water bath at 55 0 C for 60 min. The plates covered all the palate and were fixed in the molar region with light-cured resin, thus being kept there for 14 days. After the sacrifice, the palate was removed, fixed in formaldehyde 10% and decalcified with EDTA. Sections were stained using haematoxylin and eosin. Images in duplicate were made from the central region of the cuts, to measure the thickness (μm) of the keratin layers (TKC), epithelium total (TET) and connective tissue (TCC). Statistical analyses were carried out by one-way ANOVA and Tukey post-tests (α=0.05). Results: According to the results there was significant difference in the thickness of keratin between G2 and G3, with G1 having the intermediate value and similar to the other groups. There was a significant difference in the connective tissue with G3 <G1 <G2 (p <0.0001). Conclusion: Regarding the total epithelium, group G3 presented a statistically significant difference with both G1 and with G2 (p <0.0001), which were similar to each other. When using the proposed heat treatment it was found to be effec- tive, from the viewpoint of biocompatibility, for the acrylic resin denture base investigated.

Dopamine-melanin nanofilms for biomimetic structural coloration.

This article describes the formation of dopamine-melanin thin films (50-200 nm thick) at an air/dopamine solution interface under static conditions. Beneath these films, spherical melanin granules formed in bulk liquid phase. The thickness of dopamine-melanin films at the interface relied mainly on the concentration of dopamine solution and the reaction time. A plausible mechanism underlining dopamine-melanin thin film formation was proposed based on the hydrophobicity of dopamine-melanin aggregates and the mass transport of the aggregates to the air/solution interface as a result of convective flow. The thickness of the interfacial films increased linearly with the dopamine concentration and the reaction time. The dopamine-melanin thin film and granules (formed in bulk liquid phase) with a double-layered structure were transferred onto a solid substrate to mimic the (keratin layer)/(melanin granules) structure present in bird plumage, thereby preparing full dopamine-melanin thin-film reflectors. The reflected color of the thin-film reflectors depended on the film thickness, which could be adjusted according to the dopamine concentration. The reflectance of the resulted reflectors exhibited a maximal reflectance value of 8-11%, comparable to that of bird plumage (∼11%). This study provides a useful, simple, and low-cost approach to the fabrication of biomimetic thin-film reflectors using full dopamine-melanin materials.