Collagen Fibers In Skin Research Articles

Histological profile of collagen fibers on Bligon goat skin soaked in weak acids and bases solution at different concentration

Strong acids and bases has been widely applied in commercial gelatin industry, but the application of weak acids and bases has not been much done. Application of a solution of strong acids and bases could be expected to affect human health and uneconomical , therefore it requires further study on the possibility of the their application in the production process of gelatin. Quantity and quality of gelatin associated with changes in the ir structure of collagen fibers. Research has been conducted on the histological profile of collagen fibers from Bligon goat skin soaked in weak acids and bases. Weak acid (CH 3 COOH 0.5 M) and weak base (Ca(OH) 2 100 g/L) was used as a soak solution, each of which was made into three concentration levels (3, 6 and 9% v/v). Samples of skin composites made duplo size 3x3 cm and each soaked for 4 days and were then made histological preparations. Subsequent histological profiles were analyzed descriptively. Results showed that the changes in the structure of skin collagen fibers in CH 3 COOH 0.5 M more significant than Ca(OH) 2 100 g/L and control (without soaked) for the same level of concentration. Key words : Histological , collagen fibers, b ligon goat skin, w eak acids and bases

Skin collagen fiber molecular order: a pattern of distributional fiber orientation as assessed by optical anisotropy and image analysis.

BackgroundBirefringence can reveal much of the morphology, molecular order, heterogeneity of fiber orientation, and nonlinear optical properties of biopolymers such as collagen. However, the detailed characterization of skin collagen fibers using optical anisotropy methods remains elusive. A clear understanding of collagen fiber organization in skin tissues may be important in the interpretation of their structural-functional relationships under normal and pathological conditions. In this study, fiber orientation in collagen bundles (CBs) and their supramolecular organization were examined in rat skin using polarization microscopy and image analysis.Methodology/Principal FindingsImage variations with rotation of the microscope stage and selection of the in-depth focus plane were investigated in unstained sections of varying thicknesses from rat skin fragments. Total birefringence (image analysis) and form and intrinsic birefringence (Sénarmont’s method) were estimated. Based on the birefringent images, CBs were found to contain intercrossing points with a twisted helical distribution of collagen fibers (chiral elements) and frequently presented circular structures. Collagen fibers were observed to extend from the surface level to deeper planes, creating a 3D-network of oriented intertwined CBs. At least three levels of birefringent brilliance intensity were revealed by image analysis, indicating a heterogeneous spatial organization of the CBs. Slight differences in optical retardations were found for CBs immersed in some of the fluids used in a comparison of 170- and 240-day old rats.Conclusion/SignificancePolarization microscopy studies provide detailed high-quality structural information on rat skin CBs. A 3D-network structure based on image analysis and birefringence compensation for collagen fibers is suggested for CBs. Form and intrinsic birefringence evaluation can reveal differences in the rat skin associated with age at the levels of collagen fiber crystallinity and macromolecular organization. These findings may inspire future studies of the feedback mechanisms by which spatial, bioelectrical and biomechanical information is transmitted from CBs to skin cells.

YAG laser treatment causes rapid degeneration and regeneration of collagen fibres in pig skin and facilitates fibroblast growth

The non-ablative laser therapies have been speculated to cause microinjury in the dermal collagen fibres and increase collagen synthesis in the fibroblasts, leading to remodelling of the extracellular matrix. This study investigated the effects of neodymium YAG laser treatment on pig skin, especially focusing on its extracellular matrix molecules. The dorsal areas of a minipig were subjected to laser treatment, and samples were obtained by punch biopsies, and histological, immunohistochemical, and biochemical analyses were performed. The laser treatment caused degeneration of collagen fibres and fibrils, which were reconstituted within 24 hours, whereas there was no inflammation and no apparent damage on elastic fibres. Small blood vessels disappeared by the laser treatment, which re-appeared in 3 days. Biochemically, the amounts of collagen decreased up to day 3 after the treatment and then increased at day 7. When fibroblasts in dermal tissue at day 28 were counted, more fibroblasts in the treated tissue were observed than non-treated control. These results suggest that, although the laser treatment transiently degenerates collagen fibres and fibrils, it restores and increases them, mainly by an increase in dermal fibroblasts, assuring its minimal complication of skin.

Dissolution and regeneration of collagen fibers using ionic liquid

Native skin collagen fibers were successfully dissolved in the ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), and regenerated in different precipitators. The observation by polarized optical microscopy showed that the crystal structure of collagen fibers had been destroyed by [BMIM]Cl during the heating. Temperature-dependent FTIR was applied to detect the structural change of collagen/[BMIM]Cl during dissolving. The structure of regenerated collagen was characterized by FTIR and XRD. It showed that the triple helical structure of collagen had been partly destroyed during the dissolution and regeneration. The film forming ability and the thermostability of the regenerated collagen was highly dependent on the precipitating treatment. The possible mechanisms of dissolving of collagen in [BMIM]Cl and the regeneration in the precipitators have been proposed. The collagen/cellulose composite with different forms (film, fiber, gel) can be successfully prepared by using [BMIM]Cl as medium.

Skin Collagen Fiber-Biotemplated Synthesis of Size-Tunable Silver Nanoparticle-Embedded Hierarchical Intertextures with Lightweight and Highly Efficient Microwave Absorption Properties

The bioinspired approach to the construction of well-ordered microstructures is a crucial intersection of the branches of materials science and biotechnology. In this study, size-tunable silver nanoparticles (Ag NPs) have been successfully prepared on a skin collagen fiber (SCF) biotemplate, which shows a hierarchical interwoven structure in nature having novel, special, and highly compact interlaced, biosupported Ag NPs chains. Conductivity measurements indicate that these novel Ag NPs/SCF@BT composites are semiconductive and have a typical percolation threshold of 0.85% (w/w) silver fraction. The enhancement of dielectric loss properties of Ag NPs/SCF@BT can be expressed by the Debye dipolar polarization model with three kinds of coexistent dielectric polarizations, in which the unique multiple reflection and scattering absorption characteristics are due to the special natural mesostructure of the SCF biosupport. Subsequently, it was found that the reflection loss (RL) values of the Ag NPs/SCF@BT0.35 co...

One-step seeding growth of controllable Ag@Ni core–shell nanoparticles on skin collagen fiber with introduction of plant tannin and their application in high-performance microwave absorption

Controllable magnetic Ag@Ni core–shell nanoparticles (NPs) have been designed and constructed on the bayberry tannin (BT) grafted skin collagen fiber (SCF) though a simple one-step route. Due to the mild and naturally occurring reduction ability of BT, when the SCF-BT made contact with the mixture of Ag+/Ni2+ solution, BT was able to preferentially reduce Ag+ into Ag NPs, and subsequently, the formed Ag NPs served as in situ seeds for the over growth of magnetic Ni shell by the reduction of NaBH4. The systematic TEM and EDS analysis confirmed that the as-prepared Ag@Ni NPs on SCF-BT were a typical core–shell structure. Magnetic study of core–shell NPs indicated that their magnetic properties could be tuned by modulating their shell thickness with the change of Ag+/Ni2+ molar ratio. The diameter and size distribution of SCF-supported Ag@Ni core–shell NPs also can be controlled by varying the grafting degree of BT on SCF, as characterized by TEM. A novel and important application of these SCF-supported Ag@Ni core–shell NPs composites is use as high-performance microwave absorption materials in the whole X-band, C-band and some part of S-band with maximum reflection loss (RL) of −51 dB. The further analysis of electromagnetic parameters indicated that the enhancement of dielectric loss properties of SCF-supported Ag@Ni core–shell NPs is introduced by the multiple defective site polarization and interfacial polarization in bimetallic interface. In addition, owing to the combinated magnetic property on the nickel shell, the SCF-supported Ag@Ni core–shell NPs also exhibited a significant eddy current effect and anisotropic energy effect for the microwave absorption. To the best of our knowledge, this is the first time to explore tailoring the magnetic property, electromagnetic property and microwave absorption performance of functional core–shell NPs by tuning their core–shell microstructures. The present work has a significant potential for the development of novel, lightweight, low-cost, flexible and highly efficient microwave absorbing materials.

Skin rejuvenating effects of chemical peeling: a study in photoaged hairless mice

Chemical peeling is a dermatologic treatment for skin aging. However, the mechanism by which the chemical peel achieves its results is not clear. We investigated the effects of chemical peeling and the mechanism of wrinkle reduction in photoaged hairless mice skin. After inducing photoaged skin in hairless mice by repetitive ultraviolet-B irradiation applied over 14 weeks, we applied trichloroacetic acid (TCA) 30%, TCA 50%, and phenol on areas of the same size on the backs of the mice. Punch biopsies were obtained 7, 14, 28, and 60 days after the procedure for histologic and immunohistochemical analyses. Histologic examination showed an increase in dermal thickness, collagen fibers, and elastic fibers in the dermis of intervention groups compared with control groups. These increases were maintained significantly for 60 days. This study demonstrates that chemical peeling reduces wrinkles and regenerates skin by increasing dermal thickness and the amount of collagen and elastic fibers in photoaged skin.

Colour-producing β-keratin nanofibres in blue penguin (Eudyptula minor) feathers

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins (Eudyptula minor) composed of parallel β-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of β-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.

Skin collagen fiber-based radar absorbing materials

By using skin collagen fiber (CF) as raw material, Schiff base structure containing CF (Sa-CF) was synthesized through CF-salicylaldehyde reaction. Then a novel radar absorbing material (Fe-Sa-CF) was prepared by chelating reaction between Sa-CF and Fe3+. The coaxial transmission and reflection method was used to analyze the complex permittivity and complex magnetic permeability of these CF-based materials, and the radar cross section (RCS) method was used to investigate their radar absorbing properties in the frequency range of 1.0–18.0 GHz. Experimental results indicated that the conductivity of CF increased from initial 1.08×10−11 to 2.86×10−6 S/cm after being transferred into Fe-Sa-CF, and its dielectric loss tangent (tanδ) in the frequency range of 1.0–17.0 GHz also increased. These facts suggest that the Fe-Sa-CF is electric-loss type radar absorbing material. In the frequency range of 3.0–18.0 GHz, Sa-CF (1.0 mm in thickness) exhibited somewhat radar absorbing property with maximum radar reflection loss (RL) of −4.73 dB. As for Fe-Sa-CF, the absorbing bandwidth was broadened, and the absorbing intensity significantly increased in the frequency range of 1.0–18.0 GHz where a maximum radar RL of −9.23 dB was observed. In addition, the radar absorbing intensity of Fe-Sa-CF can be further improved by increasing membrane thickness. When the thickness reached to 2.0 mm, the RL values of Fe-Sa-CF were −15.0–−18.0 dB in the frequency range of 7.0–18.0 GHz. Consequently, a kind of novel radar absorbing material can be prepared by chemical modification of collagen fiber, which is characterized by thin thickness, low density, broad absorption bandwidth and high absorption intensity.

Selective removal of tannins from Polygonum cuspidatum extracts using collagen fiber adsorbent

To investigate the selective removal of tannins from Polygonum cuspidatum extracts by using collagen fiber adsorbent, and to evaluate the adsorption and desorption performances of collagen fiber adsorbent to tannins. The adsorbent was prepared from bovine skin collagen fiber through crosslinking reaction of glutaraldehyde, and then used for the selective removal of tannins from P. cuspidatum extracts. Gelatin-turbidity method, gelatin-ultraviolet spectrometry method and HPLC were used for detection of tannins in the solutions. Ethanol-water solutions with varying concentration were used to test their desorption ability of tannins in order to choose proper desorption solution. On the basis of batch experimental results, the column adsorption and desorption tests were carried out, by using gelatin-turbidity method for detection of tannins. The collagen fiber adsorbent exhibited excellent adsorption selectivity to tannins. It was found that tannins of P. cuspidatum were completely removed, while nearly no adsorption of active components (resveratrol as representative) was found. Moreover, the collagen fiber adsorbent could be regenerated by using 30% ethanol-water solution and then reused. The collagen fiber adsorbent can be considered as a promising material for selective removal of tannins from P. cuspidatum extracts.

Ex vivo and in vivo second-harmonic-generation imaging of dermal collagen fiber in skin: comparison of imaging characteristics between mode-locked Cr:forsterite and Ti:sapphire lasers

Second-harmonic-generation (SHG) microscopy is an interesting new tool for observing dermal collagen fiber in skin. However, conventional SHG microscopy using a mode-locked Ti:sapphire laser suffers from low penetration depth and a slow image acquisition rate caused by scattering and absorption in tissue, making it difficult to use for in vivo applications on human skin. We develop an SHG microscope equipped with a mode-locked Cr:forsterite laser with a long wavelength and compare its imaging characteristics with that of a Ti:sapphire-laser-based SHG microscope for the measurement of dermal collagen fiber in animal and human skins. The results indicate the suitability of the Cr:forsterite laser-based SHG microscope for in vivo imaging of human skin.

Realignment of Collagen Fibers in Mouse Skin under Biaxial Loads

Realignment of Collagen Fibers in Mouse Skin under Biaxial Loads

Magnolia ovovata extract and its active component magnolol prevent skin photoaging via inhibition of nuclear factor κB

Transcriptional activity of nuclear factor κB (NF-κB) is induced by environmental signals including inflammation, UV irradiation and oxidative stress. It was shown that the NF-κB activity greatly contributes to the skin photoaging process. Thus, it is plausible that NF-κB inhibitors could directly prevent skin photoaging. In this study, we found that Magnolia ovovata extract inhibited NF-κB-mediated gene expression and demonstrated that external swabbing with Magnolia extract preventing skin photoaging processes through keratinocyte hyperproliferation and degradation of collagen fibers in mice skin. We have identified magnolol as the solely responsible active compound in Magnolia extract. Magnolol effectively inhibited the NF-κB-dependent transcription, but no effect was observed with other inducible transcription factors such as activator protein-1 (AP-1) and cyclic-AMP responsive element-binding protein (CREB). In addition, magnolol was effective in inhibiting the production of basic fibroblast growth factor (bFGF) and matrix metalloprotease-1 (MMP-1) from the cells overexpressing p65, a major subunit of NF-κB. Although magnolol did not affect the phosphorylation and degradation of IκBα, it inhibited the nuclear translocation of the activated NF-κB. These findings suggest that Magnolia extract and its active component magnolol can be used to prevent the skin photoaging via inhibiting NF-κB by external topical application.

Microwaves Determine the Orientational Distribution of Collagen Fibers in a Whole Cobra Skin

The orientation of collagen fibers was determined in a small region of a cobra skin using Osaki’s microwave method, and compared with the mechanical breaking method. The microwave method provided the orientational distribution of collagen fibers in the whole cobra skin. The collagen fibers were, on average, aligned almost parallel to the direction of the cranial to caudal end in the dorsum of the trunk and caudal regions, while they were aligned randomly in the abdomen. The degree of collagen-fiber orientation decreased gradually from the dorsum to the abdomen, and was relatively small in the cranial region, compared with that in the other dorsum regions. The results obtained using Osaki’s microwave method indicate that the orientational distribution of collagen fibers in cobra skin is closely related to the style of functional motion, such as shrinkage and expansion, of the cobra.

Selective removal of tannins from medicinal plant extracts using a collagen fiber adsorbent

AbstractA novel adsorbent, used for the selective removal of tannins from medicinal plant extracts, was prepared from bovine skin collagen fiber. Some typical active constituents of medicinal plants were selected as probe molecules to investigate the adsorption selectivity of the collagen fiber adsorbent to tannins. In batch adsorption experiments, the extent of adsorption of condensed tannins, including larch tannin, black wattle tannin and bayberry tannin, was 100%. The extent of adsorption of tannic acid and the hydrolyzable tannins was also 100%. In contrast, for the most active constituents of medicinal plants, their amounts adsorbed by collagen fiber adsorbent were limited. For procyanidin, the common active constituents in medicinal plant extracts, its extent of adsorption was also low, although it has a similar basic structure to condensed tannins. In comparison with traditionally used polyamide adsorbent, the collagen fiber adsorbent exhibited an obvious advantage in adsorption selectivity over tannins. Therefore, this study provides a novel and effective method for selective removal of tannins from medicinal plant extracts. Copyright © 2005 Society of Chemical Industry

Do changes in the mechanical properties of articular cartilage promote catabolic destruction of cartilage and osteoarthritis?

Osteoarthritis (OA) is a joint disease characterized by cartilage degeneration, a thickening of subchondral bone, and formation of marginal osteophytes. Previous mechanical characterization of cartilage in our laboratory suggests that energy storage and dissipation is reduced in osteoarthritis as the extent of fibrillation and fissure formation increases. It is not clear whether the loss of energy storage and dissipation characteristics is a result of biochemical and/or biophysical changes that occur to hyaline cartilage in joints. The purpose of this study is to present data, on the strain rate dependence of the elastic and viscous behaviors of cartilage, in order to further characterize changes that occur in the mechanical properties that are associated with OA. We have previously hypothesized that the changes seen in the mechanical properties of cartilage may be due to altered mechanochemical transduction by chondrocytes. Results of incremental tensile stress-strain tests at strain rates between 100%/min and 10,000%/min conducted on OA cartilage indicate that the slope of the elastic stress-strain curve increases with increasing strain rate, unlike the reported behavior of skin and self-assembled collagen fibers. It is suggested that the strain-rate dependence of the elastic stress-strain curve is due to the presence of large quantities of proteoglycans (PGs), which protect articular cartilage by increasing the apparent stiffness. The increased apparent stiffness of articular cartilage at high strain rates may limit the stresses borne and prolong the onset of OA. It is further hypothesized that increased compressive loading of chondrocytes in the intermediate zone of articular cartilage occurs as a result of normal wear to the superficial zone or from excessive impact loading. Once the superficial zone of articular cartilage is worn away, the tension is decreased throughout all cartilage zones leading to increased chondrocyte compressive loading and up-regulation of mechanochemical transduction processes that elaborate catabolic enzymes.

Estudio de fibras colágenas y elásticas del tejido conjuntivo de pacientes con y sin hernia inguinal primaria

There are few studies looking for collagen matrix defects in patients with inguinal bernia. To study the skin connective tissue in patients with and without inguinal bernia. Skin from the surgical wound was obtained from 23 patients with and 23 patients without inguinal bernia. The samples were processed for conventional light microscopy. Collagen fibers were stained with Van Giesson and elastic fibers with Weigert stain. Patients without hernia had compact collagen tracts homogeneously distributed towards the deep dermis. In contrast, patients with hernia had zones in the dermis with thinner and disaggregated collagen tracts. Connective tissue had a lax aspect in these patients. Collagen fiber density was 52% lower in patients with hernia, compared to subjects without hernia. No differences in elastic fiber density or distribution was observed between groups. Patients with inguinal bernia have alterations in skin collagen fiber quality and density.

Jones-matrix imaging of biological tissues with quadruple-channel optical coherence tomography.

Two-dimensional depth-resolved Jones-matrix images of scattering biological tissues were measured with novel double-source double-detector polarization-sensitive optical coherence tomography (OCT). The Jones matrix can be determined in a single scan with this OCT system. The experimental results show that this system can be effectively applied to the measurement of soft tissues, which are less stable than hard tissues. Polarization parameters such as diattenuation, birefringence, and orientation of the fast axis can be extracted through decomposition of the measured Jones matrix. The Jones matrix of thermally treated porcine tendon showed a reduction of birefringence from thermal damage. The Jones matrices of porcine skin and bovine cartilage also revealed that the density and orientation of the collagen fibers in porcine skin and bovine cartilage are not distributed as uniformly as in porcine tendon. Birefringence is sensitive to changes in tissue because it is based on phase contrast.

Use of hair pores to determine the orientation of collagen fibers in skin

Most people are interested in recovery of skin defects caused by burn, scald or trauma from the aesthetic and functional point of view. It will occupy an important role for successful skin graft for patients with such skin defects that the orientation of collagen fibers in the grafted skin matches to the fiber orientation in surrounding skin. There have been, to my best knowledge, no methods for determining the orientation of collagen fibers in the skin from the clinical point of view. Recently, the author has found a new method for directly determining the collagen-fiber orientation without cutting samples from a calf leather by analyzing the anisotropic shape of hair pore. Its principle is based on the quantitative evaluation of collagen-fiber orientation by approximating a hair pore to an ellipse. The results obtained by the new method using hair pores were supported by the microwave method, mechanical measurements and scanning electron microscopy. Such a method will be applicable for determining the orientational distribution of collagen fibers in skins of animals and humans and give a valuable probe for performing skin grafting based on the scientific data of hair pores.

Viscoelastic properties of human skin and processed dermis.

The purpose of this work is to attempt to determine the elastic spring constant for collagen and elastic fibers (elastin) in skin and to determine if the values of these elastic constants are similar to those reported for other tissues. We studied the viscoelastic mechanical properties of human skin and dermis by measuring the incremental stress-strain behavior. Elastic stress-strain curves were used to obtain the elastic spring constant of elastin and collagen while the collagen fibril length was obtained from the slope of viscous stress-strain curves. Our results suggest that the elastic spring constant for elastin is about 4.0 MPa while that for collagen is about 4.4 GPa. The former value is similar to that calculated for ligamentum nuchae while the latter value is about 70% of the value found for tendon and self-assembled type I collagen fibers. The differences between the elastic constants for collagen molecules in tendon and skin is hypothesized to reflect the higher molecular tilt angle and lower D period found in skin compared to tendon as well as a shorter fibril length. The differences in the collagen types present in skin and tendon may influence collagen self-assembly and the resulting viscoelastic properties.