scholarly journals Vancomycin-releasing cross-linked collagen sponges as wound dressings

2019 ◽  
Author(s):  
Jan Miroslav Hartinger ◽  
Peter Lukáč ◽  
Petr Mitáš ◽  
Mikuláš Mlček ◽  
Michaela Popková ◽  
...  
Keyword(s):  
Phosphate Buffer Solution ◽  
Collagen Type I ◽  
Wound Dressings ◽  
Homogeneous Distribution ◽  
Infrared Spectrometry ◽  
Type I ◽  
Micro Computed Tomography ◽  
Buffer Solution ◽  
Microbiological Testing

The study presents a novel vancomycin-releasing collagen wound dressing derived from Cyprinus carpio collagen type I cross-linked with carbodiimide which retarded the degradation rate and increased the stability of the sponge. Following lyophilization, the dressings were subjected to gamma sterilization. The structure was evaluated via scanning electron microscopy images, micro-computed tomography, and infrared spectrometry. The structural stability and vancomycin release properties were evaluated in a phosphate buffer solution. Microbiological testing and a rat model of a wound infected with methicillin-resistant Staphylococcus aureus (MRSA) were then employed to test the efficacy of the treatment of the infected wound. Following an initial mass loss due to the release of vancomycin, the sponges remained stable. After 7 days of exposure in phosphate buffered saline (37°C), 60% of the material remained with a preserved collagen secondary structure together with a high degree of open porosity (over 80%). The analysis of the release of the vancomycin revealed the homogeneous distribution of the antibiotic both across and between the sponges. The release of vancomycin was retarded as proved by in vitro testing and further confirmed by the animal model from which measurable concentrations were observed in blood samples 24 hours after the subcutaneous implantation of the sponge, which was more than observed following i. p. administration. The sponge was also highly effective in terms of reducing the number of colony-forming units in biopsies extracted from the infected wounds 4 days following the inoculation of the wounds with the MRSA solution.

Collagen fibrillogenesis in vitro: interaction of types I and V collagen

1986 ◽  
Vol 44 ◽  
pp. 210-211
Author(s):  
Arthur J. Wasserman ◽  
Kathy C. Kloos ◽  
David E. Birk
Keyword(s):  
Type I Collagen ◽  
Corneal Stroma ◽  
Minor Component ◽  
Homogeneous Distribution ◽  
Type I ◽  
Type V Collagen ◽  
Fibril Morphology ◽  
Type V ◽  
In Vitro Interaction

Type I collagen is the predominant collagen in the cornea with type V collagen being a quantitatively minor component. However, the content of type V collagen (10-20%) in the cornea is high when compared to other tissues containing predominantly type I collagen. The corneal stroma has a homogeneous distribution of these two collagens, however, immunochemical localization of type V collagen requires the disruption of type I collagen structure. This indicates that these collagens may be arranged as heterpolymeric fibrils. This arrangement may be responsible for the control of fibril diameter necessary for corneal transparency. The purpose of this work is to study the in vitro assembly of collagen type V and to determine whether the interactions of these collagens influence fibril morphology.

scholarly journals Collagen-Based Electrospun Materials for Tissue Engineering: A Systematic Review

2021 ◽  
Vol 8 (3) ◽  
pp. 39
Author(s):  
Britani N. Blackstone ◽  
Summer C. Gallentine ◽  
Heather M. Powell
Keyword(s):  
Systematic Review ◽  
Tissue Engineering ◽  
Collagen Type I ◽  
The Body ◽  
Pool Data ◽  
Type I ◽  
High Concentrations ◽  
Increased Strength

Collagen is a key component of the extracellular matrix (ECM) in organs and tissues throughout the body and is used for many tissue engineering applications. Electrospinning of collagen can produce scaffolds in a wide variety of shapes, fiber diameters and porosities to match that of the native ECM. This systematic review aims to pool data from available manuscripts on electrospun collagen and tissue engineering to provide insight into the connection between source material, solvent, crosslinking method and functional outcomes. D-banding was most often observed in electrospun collagen formed using collagen type I isolated from calfskin, often isolated within the laboratory, with short solution solubilization times. All physical and chemical methods of crosslinking utilized imparted resistance to degradation and increased strength. Cytotoxicity was observed at high concentrations of crosslinking agents and when abbreviated rinsing protocols were utilized. Collagen and collagen-based scaffolds were capable of forming engineered tissues in vitro and in vivo with high similarity to the native structures.

scholarly journals Relative rates of biosynthesis of collagen type I, type V and type VI in calf cornea

1991 ◽  
Vol 274 (2) ◽  
pp. 615-617 ◽  
Author(s):  
P Kern ◽  
M Menasche ◽  
L Robert
Keyword(s):  
Type I Collagen ◽  
Collagen Type ◽  
Corneal Stroma ◽  
Collagen Type I ◽  
Type I ◽  
Type Vi Collagen ◽  
Sds Page ◽  
Proline Incorporation ◽  
Type V

The biosynthesis of type I, type V and type VI collagens was studied by incubation of calf corneas in vitro with [3H]proline as a marker. Pepsin-solubilized collagen types were isolated by salt fractionation and quantified by SDS/PAGE. Expressed as proportions of the total hydroxyproline solubilized, corneal stroma comprised 75% type I, 8% type V and 17% type VI collagen. The rates of [3H]proline incorporation, linear up to 24 h for each collagen type, were highest for type VI collagen and lowest for type I collagen. From pulse-chase experiments, the calculated apparent half-lives for types I, V and VI collagens were 36 h, 10 h and 6 h respectively.

scholarly journals Plant Recombinant Human Collagen Type I Hydrogels for Corneal Regeneration

2021 ◽  
Author(s):  
Michel Haagdorens ◽  
Elle Edin ◽  
Per Fagerholm ◽  
Marc Groleau ◽  
Zvi Shtein ◽  
...  
Keyword(s):  
Collagen Type ◽  
Collagen Type I ◽  
Collagen Fibrils ◽  
Type I ◽  
Safe Alternative ◽  
Human Donor ◽  
Human Collagen ◽  
Donor Corneas

Abstract Purpose To determine feasibility of plant-derived recombinant human collagen type I (RHCI) for use in corneal regenerative implants Methods RHCI was crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to form hydrogels. Application of shear force to liquid crystalline RHCI aligned the collagen fibrils. Both aligned and random hydrogels were evaluated for mechanical and optical properties, as well as in vitro biocompatibility. Further evaluation was performed in vivo by subcutaneous implantation in rats and corneal implantation in Göttingen minipigs. Results Spontaneous crosslinking of randomly aligned RHCI (rRHCI) formed robust, transparent hydrogels that were sufficient for implantation. Aligning the RHCI (aRHCI) resulted in thicker collagen fibrils forming an opaque hydrogel with insufficient transverse mechanical strength for surgical manipulation. rRHCI showed minimal inflammation when implanted subcutaneously in rats. The corneal implants in minipigs showed that rRHCI hydrogels promoted regeneration of corneal epithelium, stroma, and nerves; some myofibroblasts were seen in the regenerated neo-corneas. Conclusion Plant-derived RHCI was used to fabricate a hydrogel that is transparent, mechanically stable, and biocompatible when grafted as corneal implants in minipigs. Plant-derived collagen is determined to be a safe alternative to allografts, animal collagens, or yeast-derived recombinant human collagen for tissue engineering applications. The main advantage is that unlike donor corneas or yeast-produced collagen, the RHCI supply is potentially unlimited due to the high yields of this production method. Lay Summary A severe shortage of human-donor corneas for transplantation has led scientists to develop synthetic alternatives. Here, recombinant human collagen type I made of tobacco plants through genetic engineering was tested for use in making corneal implants. We made strong, transparent hydrogels that were tested by implanting subcutaneously in rats and in the corneas of minipigs. We showed that the plant collagen was biocompatible and was able to stably regenerate the corneas of minipigs comparable to yeast-produced recombinant collagen that we previously tested in clinical trials. The advantage of the plant collagen is that the supply is potentially limitless.

Bacterial chemotaxis to fungal propagules in vitro and in soil

1983 ◽  
Vol 29 (9) ◽  
pp. 1104-1109 ◽  
Author(s):  
D. K. Arora ◽  
A. B. Filonow ◽  
J. L. Lockwood
Keyword(s):  
Sandy Loam ◽  
Phosphate Buffer Solution ◽  
Bacterial Chemotaxis ◽  
Macrophomina Phaseolina ◽  
Buffer Solution ◽  
Erwinia Herbicola ◽  
Cochliobolus Victoriae ◽  
Fungal Propagules ◽  
Loam Soil

Erwinia herbicola, Pseudomonas fluorescens, and P. putida were strongly attracted in vitro to substances exuded by conidia of Cochliobolus victoriae and sclerotia of Macrophomina phaseolina, but not to phosphate buffer solution. Numbers of bacteria attracted to propagules of C. victoriae or M. phaseolina in an unsterilized sandy loam soil were significantly (P = 0.05) greater than background populations occurring in soil saturated with buffer. Chemotactic response was greater to C. victoriae than to M. phaseolina both in vitro and in soil. Results suggest that living fungal propagules may act as attractants for motile bacteria in soil.

Surface Morphological Changes Accompanying Dissolution of Bioactive Glass: Effect of Residual Stress

2008 ◽  
Vol 47-50 ◽  
pp. 1302-1306 ◽  
Author(s):  
John A. Nychka ◽  
Ding Li
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Bioactive Glass ◽  
Morphological Changes ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Mechanochemical Effect ◽  
Dissolution Behaviour ◽  
Glass Surfaces

We report our observations concerning the time evolution of surface morphology occurring during the in vitro immersion of bioactive glass surfaces in contact with phosphate buffer solution. We compare regions under intentionally produced residual stresses via micro-indentation to those where no indentation was performed. The sign of the residual stress is shown to be important for predicting dissolution behaviour; compression retards dissolution, whereas tension enhances dissolution. We analyze our results with a simple model for the work of bond dissociation. We report that a highly constrained residual compressive stress state, such as in an indent, leads to a work deficit in comparison to tension, which accounts for the slower dissolution rate of compressed bioactive glass. Such a mechanochemical effect suggests that the presence of residual stresses from the manufacture of biomedical implants and devices could lead to accelerated or delayed dissolution and that careful control of residual stresses should be sought for predictable performance in dissolvable materials.

scholarly journals WNT-5A regulates TGF-β-related activities in liver fibrosis

2017 ◽  
Vol 312 (3) ◽  
pp. G219-G227 ◽  
Author(s):  
Leonie Beljaars ◽  
Sara Daliri ◽  
Christa Dijkhuizen ◽  
Klaas Poelstra ◽  
Reinoud Gosens
Keyword(s):  
Liver Fibrosis ◽  
Functional Role ◽  
Collagen Type ◽  
Collagen Type I ◽  
Matrix Proteins ◽  
Type I ◽  
Human Livers

WNT-5A is a secreted growth factor that belongs to the noncanonical members of the Wingless-related MMTV-integration family. Previous studies pointed to a connection between WNT-5A and the fibrogenic factor TGF-β warranting further studies into the functional role of WNT-5A in liver fibrosis. Therefore, we studied WNT-5A expressions in mouse and human fibrotic livers and examined the relation between WNT-5A and various fibrosis-associated growth factors, cytokines, and extracellular matrix proteins. WNT-5A gene and protein expressions were significantly increased in fibrotic mouse and human livers compared with healthy livers. Regression or therapeutic intervention in mice resulted in decreased hepatic WNT-5A levels paralleled by lower collagen levels. Immunohistochemical analysis showed WNT-5A staining in fibrotic septa colocalizing with desmin staining indicating WNT-5A expression in myofibroblasts. In vitro studies confirmed WNT-5A expression in this cell type and showed that TGF-β significantly enhanced WNT-5A expression in contrast to PDGF-BB and proinflammatory cytokines IL-1β and TNF-α. Additionally, TGF-β induces the expression of the WNT receptors FZD2 and FZD8. After silencing of WNT-5A, reduced levels of collagen type I, vimentin, and fibronectin in TGF-β-stimulated myofibroblasts were measured compared with nonsilencing siRNA-treated controls. Interestingly, the antifibrotic cytokine IFNγ suppressed WNT-5A in vitro and in vivo. IFNγ-treated fibrotic mice showed significantly less WNT-5A expression compared with untreated fibrotic mice. In conclusion, WNT-5A paralleled collagen I levels in fibrotic mouse and human livers. WNT-5A expression in myofibroblasts is induced by the profibrotic factor TGF-β and plays an important role in TGF-β-induced regulation of fibrotic matrix proteins, whereas its expression can be reversed upon treatment, both in vitro and in vivo. NEW & NOTEWORTHY This study describes the localization and functional role of WNT-5A in human and mouse fibrotic livers. Hepatic WNT-5A expression parallels collagen type I expression. In vivo and in vitro, the myofibroblasts were identified as the key hepatic cells producing WNT-5A. WNT-5A is under control of TGF-β and its activities are primarily profibrotic.

The Study of Albumin Release from Silica/Albumin as a Potential Drug Delivery Carrier

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Shafiyah Pondi ◽  
Jon Efendi ◽  
Ho Chin Siong ◽  
Lai Sin Yuan ◽  
Sheela Chandren ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Fumed Silica ◽  
In Vitro Release ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Drug Delivery Carrier ◽  
High Interaction ◽  
Uv Visible

The drug-delivery field has been an attractive as well as challenging area for research. With the emerging of new formulated drugs and pharmaceutical compounds, development of good drug-delivery system (DDS) is crucially required. This study aims to utilize albumin as the drug template in silica/albumin/drug (S/A/D) system. Prior to designing this system, the interaction between silica and albumin was investigated. It is hypothesized that high interaction between silica and albumin may result in slower drug release over time, which is preferred for a good DDS. Silica and albumin (S/A) materials were prepared by using fumed silica and tetraethyl orthosilicate (TEOS) as the silica precursors. Three different S/A samples were prepared; fumed silica with albumin (FS/A), fumed silica with pre-treated albumin by sodium borohydrate (FS/A-N), and silica sol (TEOS) with albumin (SS/A). In-vitro release of albumin in phosphate buffer solution (pH 7) was carried out to examine the interaction between albumin and silica. The concentration of albumin was detected at 280 nm by UV-visible spectrophotometer. All samples were characterized by diffuse reflectance-UV-visible spectrophotometer (DR-UV), Fourier transform infrared spectrophotometer (FTIR) dan thermogravimetric-differential thermal analysis (TG-DTA). DR-UV results show that SS/A exhibited the lowest absorption intensity at 280 nm, which indicates better interaction between silica and albumin. This result was supported by the presence of Si-O stretching band of silanol at 952 cm-1 from the FTIR spectrum. Release study of albumin demonstrated that the release of albumin from SS/A was slowest compared to those of FS/A and FS/A-N. 

Drug-loaded ultrafine poly(vinyl alcohol) fibre mats prepared by electrospinning

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Chunxue Zhang ◽  
Xiaoyan Yuan ◽  
Lili Wu ◽  
Jing Sheng
Keyword(s):  
Drug Release ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Phosphate Buffer Solution ◽  
Poly Vinyl Alcohol ◽  
High Porosity ◽  
Buffer Solution ◽  
Drug Molecules ◽  
Alcohol Fibre

AbstractSubmicron poly(vinyl alcohol) (PVA) fibre mats embedded with Aspirin and bovine serum albumin (BSA) were prepared by electrospinning of their aqueous solutions. Fibre morphology was investigated by scanning electron microscopy. The composition of the fibre mats was characterized by Fourier transform IR spectroscopy and X-ray photoelectron spectroscopy. The in vitro drug release was investigated by immersing the fibre mats in phosphate buffer solution at 37°C. Results indicated that the morphology of fibre mats was influenced by the amount of drug, and more beaded and irregularly shaped fibres were found with increasing drug amounts. There were drug molecules distributed on the surface of the PVA fibres. Studies of in vitro drug release showed that both Aspirin and BSA were released more quickly from PVA fibre mats than from PVA films because of the large surface area and high porosity of the fibre mats.

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