Three-dimensional remodeling of collagen fibers within cervical tissues in pregnancy

The cervix is a collagen-rich connective tissue that must remain closed during pregnancy while undergoing progressive remodeling in preparation for delivery,which begins before the onset of the preterm labor process.Therefore,it is important to resolve the changes of collagen flbers during cervical remodeling for the prevention of preterm labor.Herein,we assessed the spatial organization of collagen flbers in a three-dimensional(3D)context within cervical tissues of mice on day 3,9,12,15 and 18 of gestation.We found that the 3D directional variance,a novel metric of alignment,was higher on day 9 than that on day 3 and then gradually decreased from day 9 to day 18.Compared with two-dimensional(2D)approach,a higher sensitivity was achieved from 3D analysis,highlighting the importance of truly 3D quantification.Moreover,the depthdependent variation of 3D directional variance was investigated.By combining multiple 3D directional variance-derived metrics,a high level of classification accuracy was acquired in distinguishing different periods of pregnancy.These results demonstrate that 3D directional variance is sensitive to remodeling of collagen fibers within cervical tissues,shedding new light on highly-sensitive,early detection of preterm birth(PTB).

A method of removing retardance induced by scattering of collagenous fiber bundles

In this work,we report a method of removing scattering induced retardance in polarization sensitive fnll field optical coherence tomography(PS-FFOCT).First,the Mueller matrix that describes its operation is derived.The thickness invariant retardance induced by the scattering of collagenous fiber bundles is then used to find the accurate values of the birefringence of the layers that consist collagenous fibers.Finally,the initial en face birefringent images of in vitro beef tendon samples are presented to demonstrate the capability of our method.

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments

Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.

Anti-abrasion collagen fiber-based membrane functionalized by UiO-66-NH_(2)with ultra-high efficiency and stability for oil-in-water emulsions separation

Membrane separation strategies offer promising platform for the emulsion separation.However,the low mechanical strength of membrane separation layers and the trade-off between separation flux and efficiency present significant challenges.In this study,we report a CFM@UiO-66-NH_(2)membrane with high separation flux,efficiency and stability,through utilizing a robust anti-abrasion collagen fiber membrane(CFM)as the multifunctional support and UiO-66-NH_(2)by an in-situ growth as the separation layer.The high mechanical strength of the CFM compensated for the weakness of the separation layer,while the charge-breaking effect of UiO-66-NH_(2),along with the size sieving of its constituent separating layers and the capillary effect of the collagen fibers,contributed to the potential for efficient separation.Additionally,the CFM@UiO-66-NH_(2)membrane exhibited superhydrophilic properties,making it suitable for separating oil-in-water microemulsions and nanoemulsions stabilized by anionic surfactants.The membrane demonstrated remarkable separation efficiencies of up to 99.960%and a separation flux of370.05 L·m^(-2)·h^(-1).Moreover,it exhibits stability,durability,and abrasion resistance,maintaining excellent separation performance even when exposed to strong acids and alkalis without any damage to its structure and performance.After six cycles of reuse,it achieved a separation flux of 417.97 L·m^(-2)·h^(-1)and a separation efficiency of 99.747%.Furthermore,after undergoing 500 cycles of strong abrasion,the separation flux remained at 124.39 L·m^(-2)·h^(-1),with a separation efficiency of 99.992%.These properties make it suitable for the long-term use in harsh operating environments.We attribute these properties to the electrostatic effect resulting from the amino group on UiO-66-NH_(2)and its in-situ growth on the CFM,which forms a size-screening separation layer.Our work highlights the potential of the CFM@UiO-66-NH_(2)membrane as an environmentally friendly size-screening material for the efficient emulsion wastewater separation.

Rapid and efficient characterization of cervical collagen orientation using linearly polarized colposcopic images

Collagen provides tissue strength and structural integrity.Quanti fication of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the cervix.In this study,for the first time,a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented.A total of 24 colposcopic images were captured using a cross-polarized imaging system with white LED light sources.In the preprocessing stage,the Red channel of the RGB image was chosen,which contains no information of the blood vessels because of the low-absorption of blood cells in the red region.OrientationJ,which is an ImageJ plug-in,was used to estimate the local orientation of the collagen fibers.The result shows that in the nonpregnant cervix,the middle zone(Zone 2)has circumferentially aligned collagen fibers while the inner zone(Zone 1)has randomly arranged.The collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region(anterior,posterior,left,and right quadrant).This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic.

Macromolecule’s Orientation in a Nanofiber by Bubble Electrospinning

In the search for sustainable alternatives to harmful synthetic fibers,an increasing amount of research focuses on biomimicry and natural fibers.Sea silk is an exceptional textile material.It is a kind of natural silk produced using the long silky filaments secreted by a specific bivalve mollusk(Pinna nobilis);now at edge of extinction.This paper suggests a simple but effective way to prepare artificial sea silk from Mytilus edulis.A sea silk solution is prepared using a Mytilus edulis protein,and a polyvinyl alcohol(PVA)solution is mixed with the sea silk solution in order to produce artificial sea silk through a bubble electrospinning technique.The effects of the sea silk concentration on the nanofiber’s morphology and mechanical properties are studied experimentally.

Electrical stimulation does not enhance nerve regeneration if delayed after sciatic nerve injury: the role of fibrosis

Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed repair of peripheral nerve tissue. In this study, a rat model of sciatic nerve transec- tion injury was repaired with a biodegradable conduit at 1 day, 1 week, 1 month and 2 months after injury, when the rats were divided into two subgroups. In the experimental group, rats were treated with electrical stimuli of frequency of 20 Hz, pulse width 100 ms and direct current voltage of 3 V; while rats in the control group received no electrical stimulation after the conduit operation. His- tological results showed that stained collagen fibers comprised less than 20% of the total operated area in the two groups after delayed repair at both 1 day and 1 week but after longer delays, the collagen fiber area increased with the time after injury. Immunohistochemical staining revealed that the expression level of transforming growth factor ~ （an indicator of tissue fibrosis） decreased at both 1 day and 1 week after delayed repair but increased at both 1 and 2 months after delayed repair. These findings indicate that if the biodegradable conduit repair combined with electrical stimulation is delayed, it results in a poor outcome following sciatic nerve injury. One month after injury, tissue degeneration and distal fibrosis are apparent and are probably the main reason why electrical stimulation fails to promote nerve regeneration after delayed repair.

Adsorptive Recovery of Uranium from Nuclear Fuel Industrial Wastewater by Titanium Loaded Collagen Fiber

Effective recovery of UO2+2 from wastewater is essential for nuclear fuel industry and related industries.In this study,a novel adsorbent was prepared by loading titanium(Ti4+) onto collagen fiber(TICF),and its physical and chemical properties as well as adsorption to UO2+2 in nuclear fuel industrial wastewater were investigated.It is found that TICF can effectively recover UO2+2 from the wastewater with excellent adsorption capacity.The adsorption capacity is 0.62 mmol·g-1 at 303 K and pH 5.0 when the initial concentration of UO2+2 is 1.50 mmol·L-1.The adsorption isotherms can be described by the Langmuir equation and the adsorption capacity increases with temperature.The effect of co-existed F on the adsorption capacity for UO2+2 is significant,which can be eliminated by adding aluminum ions as complexing agent,while the other co-existed ions in the solutions,including HCO-3,Cl-,NO-3,Ca2+,Mg2+ and Cu2+,have little effect on the adsorption capacity for UO2+2.The saturated TICF after UO2+2 adsorption can be regenerated by using 0.2 mol·L-1 nitrate(HNO-3) as desorption agent,and the TICF can be reused at least three times.Thus the TICF is a new and effective adsorbent for the recovery of UO2+2 from the wastewater.

Effect of Zhenwu Tang Granule on pressure-overloaded left ventricular myocardial hypertrophy in rats

BACKGROUND： In the perspective of traditional Chinese medicine, few studies have focused on the compound preparations though there are many investigations. The present study was undertaken to investigate the effect of Zhenwu Tang Granule on chronic pressure-overloaded left ventricular hypertrophy in rats.METHODS： The study was performed at the laboratory of Guangzhou Institute of Respiratory Disease. Male SD rats were divided randomly into 3 groups： sham operation group （n=8）, operation group （n=15） and traditional Chinese medicine （TCM） group （n=15）.The model of myocardial hypertrophy was made by gradually constricting the abdominal aorta. Sixteen weeks later, cardiac ultrasonography was performed in all groups in order to ascertain post-operational left ventricular （LV） hypertrophy. And Zhenwu Tang Granule was added at a dose of 12 g/kg in the mixed feedstuff for 8 weeks in the TCM group. In the 24th week, weight, structure as well as function of the heart in each group were measured by high-frequency ultrasonography, and Masson＇s staining was performed on the cardiac muscles. Meanwhile, total collagen volume fraction （CVF-T） and non-coronary vessel collagen volume fraction （CVF-NV） were analyzed.RESULTS： There was an increase in the weight of the heart in the operation group, with the left ventricule dominated （P〈0.05）. The heart was enlarged, with diastolic interventricular septal distance （IVSd） and left ventricular posterior wall distance （LVPWd） dominated （P〈0.01）.There was a significant decrease in the cardiac function （P〈0.05）. The weight （P〈0.01） and volume of the heart decreased in the TCM group compared with the operation group, with IVSd and systolic left ventricular posterior wall dominated （P〈0.01）. And the cardiac function was improved （P〈0.05）. Significant interstitial and collagen hyperplasia was shown in the operation group based on pathological analysis, and various improvements were proved in the TCM group, i.e. there was a significant decrease in CVF-T and CVF-NV （P〈0.01） compared with the operation group; but no difference （P〉0.05） was found when compared with the pseudo-operation group.CONCLUSION： Zhenwu Tang Granule could reduce the weight and volume of the heart, improve the cardiac function, inhibit hyperplasia of collagen, and reverse myocardial hypertrophy in rats with pressure-overloaded left ventricular hypertrophy.

Fibrosis of corpus cavernosum in animals following cavernous nerve ablation

Aim: To investigate alterations of smooth muscle celis and collagen fibers in corpus cavernosum following cavernous neurectomy and its relation to the expression of transforming growth factor-β1 (TGF-β1). Methods: Ten adult male SD rats (neurectomy group) were subject to a bilateral cavernous nerve (CN) resection aseptically under an operating microscope, with 6 sham-operated rats as the control. Fifteen weeks after the operation, the penile speci mens were collected and prepared for quantitative-analyzing of ratio of smooth muscle to collagen fibers in corpus cavernosum with confocal microscopy, and for detecting the expression of TGF-β1 by RT-PCR and western-blot. Resulte: Smooth muscle celis that show red color after fluorescent-labeling with tetramethylrhodamine isothiocyanate phalloidin and collagen fibers that produce green autofluorescence after paraformaldehyde fixation were clearly iden tified under the confocal microscope. Quantification of fluorescent intensity showed that the ratio of smooth muscle to collagen fibers in corpus cavernosum in neurectomy group was 0.265±0.125, which was significantly lower than that in sham-operated group (0.760±0.196, P<0.01). RT-PCR and western-blot analyses revealed a significantly higher expression of TGF-β1 in the penile tissues of the neurectomy animals than that in sham-operated group. Conclusion: Bilateral ablation of CN can lead to fibrosis of corpus cavernosum, which may be related to an increased expression of TGF-β1 induced by hypoxia in cavernous tissue after denervation.

A collagen-based electrolyte-locked separator enables capacitor to have high safety and ionic conductivity

The conventional liquid electrolytes(LEs) have a high level of ionic conductivity;however, they often suffer from the poor processability and safety risks of potential leakage. Although solid-state electrolytes(SSEs) can solve these inherent problems of LEs, the ionic conductivity of most SSEs is several magnitudes lower than these of LEs. Herein, we report a novel strategy by building liquid ion-transport channels in a solid framework and prepared an electrolyte-locked separator(ELS) using a collagen fiber membrane(CFm). The liquid electrolyte was primarily infiltrated in the smaller voids of CFm, and its ionic conductivity could attain to 9.0×10-3 S cm-1 when the electrolyte absorption(EA) reached up to 112.0%. After centrifuging treatment, the electrolyte retentions(ER) and ionic conductivities of ELS were 108.93% and 8.37×10-3 S cm-1, respectively, which were much higher than those of commercial cellulose separator(CS), exerting excellent liquid-locking performances. In particular, the electrical double-layer capacitors(EDLC) assembled by ELS or CS were characterized and exhibited similar electrochemical performance,demonstrating the satisfactory ability and applicability of ELS for commercial use. In addition, the ELSbased EDLC exhibited favorable flexibility with relative lower loss of capacitance under different angles of bending.

Mechanics of formation and rupture of human aneurysm

The mechanical response of the human arterial wall under the combined loading of inflation, axial extension, and torsion is examined within the framework of the large deformation hyper-elastic theory. The probability of the aneurysm formation is explained with the instability theory of structure, and the probability of its rupture is explained with the strength theory of material. Taking account of the residual stress and the smooth muscle activities, a two layer thick-walled circular cylindrical tube model with fiber-reinforced composite-based incompressible anisotropic hyper-elastic materials is employed to model the mechanical behavior of the arterial wall. The deformation curves and the stress distributions of the arterial wall are given under normal and abnormal conditions. The results of the deformation and the structure instability analysis show that the model can describe the uniform inflation deformation of the arterial wall under normal conditions, as well as formation and growth of an aneurysm under abnormal conditions such as the decreased stiffness of the elastic and collagen fibers. From the analysis of the stresses and the material strength, the rupture of an aneurysm may also be described by this model if the wall stress is larger than its strength.

A 3D biophysical model for cancer spheroid cell-enhanced invasion in collagen-oriented fiber microenvironment

The process of in situ tumors developing into malignant tumors and exhibiting invasive behavior is extremely complicated.From a biophysical point of view,it is a phase change process affected by many factors,including cell-to-cell,cell-to-chemical material,cell-to-environment interaction,etc.In this study,we constructed spheroids based on green fluorescence metastatic breast cancer cells MDA-MB-231 to simulate malignant tumors in vitro,while constructed a three-dimensional(3D)biochip to simulate a micro-environment for the growth and invasion of spheroids.In the experiment,the 3D spheroid was implanted into the chip,and the oriented collagen fibers controlled by collagen concentration and injection rate could guide the MDA-MB-231 cells in the spheroid to undergo directional invasion.The experiment showed that the oriented fibers greatly accelerated the invasion speed of MDA-MB-231 cells compared with the traditional uniform tumor micro-environment,namely obvious invasive branches appeared on the spheroids within 24 hours.In order to analyze this interesting phenomenon,we have developed a quantitative analyzing approach to explore strong angle correlation between the orientation of collagen fibers and invasive direction of cancer cell.The results showed that the oriented collagen fibers produced by the chip can greatly stimulate the invasion potential of cancer cells.This biochip is not only conducive to modeling cancer cell metastasis and studying cell invasion mechanisms,but also has the potential to build a quantitative evaluation platform that can be used in future chemical drug treatments.

Characterization of Amino Terminated Hyperbranched Collagen Fiber and Adsorption Thermodynamics to Cr(Ⅵ)

In this study, a novel adsorption material amino terminated hyperbranched polyamide collagen fiber( CF-HBPN)was prepared by loading amino terminated hyperbranched polyamide( HBPN) which was synthesized by polycondensation of methacrylate and diethylenetriamine onto the surface of collagen fiber( CF) with glutaraldehyde as the cross-linking agent. X-ray photoelectron spectroscopy( XPS) and thermogravimetric analysis( TGA) were employed to characterize the structures of CF and CFHBPN. In addition,the adsorption property of CF-HBPN toward Cr( Ⅵ) and adsorption thermodynamic were studied as well. The experimental results indicated that the Cr( Ⅵ) 's removal rate by CF-HBPN was 3. 09 higher than that of CF under the same conditions. Langmuir single layer adsorption model was found more suitable to describe the adsorption process than Freundlich adsorption model. The adsorption process was an endothermic reaction. The adsorption efficiency was enhanced with the increase of temperature. X-ray diffraction( XRD) was employed to elucidate the difference between CF-HBPN and Cr( Ⅵ) loaded CF-HBPN[CF-HBPN-Cr( Ⅵ) ].

NON-LINEAR SPECTRAL IMAGING MICROSCOPY STUDIES OF HUMAN HYPERTROPHIC SCAR

Skin scar is unique to humans,the major significant negative outcome sustained after thermal injuries,traumatic injuries,and surgical procedures.Hypertrophic scar in human skin is investigated using non-linear spectral imaging microscopy.The high contrast images and spectroscopic intensities of collagen and elastic fibers extracted from the spectral imaging of normal skin tissue,and the normal skin near and far away from the hypertrophic scar tissues in a 10-year-old patient case are obtained.The results show that there are apparent differences in the morphological structure and spectral characteristics of collagen and elastic fibers when comparing the normal skin with the hypertrophic scar tissue.These differences can be good indicators to differentiate the normal skin and hypertrophic scar tissue and demonstrate that non-linear spectral imaging microscopy has potential to noninvasively investigate the pathophysiology of human hypertrophic scar.

Effects of aging on the architecture of the ileocecal junction in rats

AIM: To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats. METHODS: Histology, immunohistochemistry(IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups. RESULTS: The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions(ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type Ⅰ?fibers, a decrease in collagen type Ⅲ fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers. CONCLUSION: The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.

Effects of AT1 Antagonist on MMP2, MMP9 Expression and Collagen Remodeling in Left Ventricle of Rabbit Undergoing Chronic Pressure Overload

Objectives To study the effects of AT1 antagonist on MMP2, MMP9 expression and collagen remodeling in left ventricle of rabbit undergoing chronic pressure overload. Methods 30 rabbits were randomly divided into 3 groups ( n = 10, each group), including sham operation group, abdominal aorta banded group (banded group), abdominal aorta banded +valsartan group (valsartan group). Twelve weeks after operation, hemodynamic parameters were acquired, then collagen volume fraction (CVF) and MMP2, MMP9 expression of left ventricle were measured by using VG and immunohistochemical stain. Results Compared with sham operation group, both MMP2 and MMP9 expression were enhanced in banded group; meanwhile, LVW/BW, LVEDP and CVF increased significantly. Compared with banded group, both MMP2 and MMP9 expression were weakened in valarstan group; simultaneously, LVW/BW, LVEDP and CVF decreased significantly. Conclusions Expression of MMP2 and MMP9 was enhanced in left ventricle of rabbit undergoing chronic pressure overload, which may be associated with collagen proliferation, ventricule remodeling and impaired heart function; Valsartan could inhibit collagen proliferation, prevent ventricule remodeling and preserve heart function by inhibiting abnormal expression of MMP2 and MMP9.

The improvement of dispersity,thermal stability and mechanical properties of collagen fibers by silane modification:an exploration for developing new leather making technology

The effect of hydrophobic modification on the performances of collagen fibers(CFs)was investigated by using silane coupling agents with different alkyl chains as hydrophobic modifiers.It was found silane could be easily grafted onto CF surface through covalent bonds under 5%water content.This modification led to the transformation of surface wettability of CF from hydrophilic to hydrophobic.Interestingly,the change of surface wettability resulted in substantial improvement of the modified CF properties,presenting well dispersity of collagen fibers,higher thermal stability and enhanced mechanical properties in comparison with natural CF.The degree of improvement mainly depended on the length of alkyl chain in silane.Longer alkyl chain produced strong hydrophobicity and subsequently more superior performances of the modified CF.When the length of alkyl chain increased to 18 carbon atoms,the modified CF possessed durable superhydrophobicity even exposed to aqueous solutions of different pH,UV,and organic solvents,and had excellent thermal and mechanical properties like leather fibers.In general,this work clearly revealed that the properties of CF are closely and positively related to the hydrophobicity,which is suggestive in developing new leather making technology.

Composite nanofiltration membrane with tannic acid coordinated collagen fibers for enhanced molecule separation

Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages.In this work,a novel thin-fiilm composite(TFC)nanofiltration(NF)membrane was fabricated through a facial interfacial polymerization(IP)process by initiate the crosslinking reaction between collagen fibers(CFs)and tannic acid(TA).The increased TA concentrations endowed the TFC membrane with a higher crosslinking degree,a thicker active layer and a rougher top surface.At optimized condition with 0.60 mg TA decoration,the TFC-3 membrane exhibited a high water permeability of 23.49 L m^(-2)h^(-1)bar^(-1)with high rejections above 98.0%for congo red,reactive blue 19,coomassie blue G-250,and methyl blue.Furthermore,the membrane preserved remarkable salt retentions(93.3%for Na_(2)SO_(4),83.4%for MgSO_(4),36.2%for MgCl_(2),and 26.4%for NaCl)and satisfying operation stability.This facial fabrication method offered a new insight to employ biomass for molecular precise separation.

The improvement of dispersity, thermal stability and mechanical properties of collagen fibers by silane modification: an exploration for developing new leather making technology

The effect of hydrophobic modification on the performances of collagen fibers(CFs)was investigated by using silane coupling agents with different alkyl chains as hydrophobic modifiers.It was found silane could be easily grafted onto CF surface through covalent bonds under 5%water content.This modification led to the transformation of surface wettability of CF from hydrophilic to hydrophobic.Interestingly,the change of surface wettability resulted in substantial improvement of the modified CF properties,presenting well dispersity of collagen fibers,higher thermal stability and enhanced mechanical properties in comparison with natural CF.The degree of improvement mainly depended on the length of alkyl chain in silane.Longer alkyl chain produced strong hydrophobicity and subsequently more superior performances of the modified CF.When the length of alkyl chain increased to 18 carbon atoms,the modified CF possessed durable superhydrophobicity even exposed to aqueous solutions of different pH,UV,and organic solvents,and had excellent thermal and mechanical properties like leather fibers.In general,this work clearly revealed that the properties of CF are closely and positively related to the hydrophobicity,which is suggestive in developing new leather making technology.