Modified acellular porcine corneal matrix in deep lamellar transplantation of rabbit cornea

2020 ◽  
Vol 34 (8) ◽  
pp. 1092-1104
Author(s):  
Qian Wang ◽  
Hang Zhou ◽  
Yongqiang Sun ◽  
Chengbo Cao ◽  
Kunpeng Pang
Keyword(s):  
Enzymatic Degradation ◽  
Structural Integrity ◽  
Degradation Kinetics ◽  
Corneal Stroma ◽  
Crosslinking Density ◽  
Collagen Fibres ◽  
Visible Light Range ◽  
Structure And Ultrastructure ◽  
Better Than ◽  
Porcine Cornea

This study presents to develop a modified acellular porcine corneal matrix (MAPCM) to maintain high transparency, stability and biocompatibility as a rabbit deep cornea replacement using 1-ethyl-3–(3-dimethylaminopropyl)-carbodiimide crosslinking and a mild decellularization technique. Scaffolds are translucent and remain higher amount of glycosaminoglycans after decellularization than acellular porcine corneal matrix (APCM). Enzymatic degradation kinetics and mechanical properties of scaffolds are regulated by 1-ethyl-3–(3-dimethylaminopropyl)-carbodiimide -crosslinking density. The porous structure and ultrastructure of collagenous lamellae are maintained, and the pore size of MAPCM crosslinked with 0.5% (w/v) 1-ethyl-3–(3-dimethylaminopropyl)-carbodiimide is 13.26 ± 1.65 µm, similar to that of normal porcine cornea. The transmittance of MAPCM gets 79.1 ± 0.45 to 92.7 ± 1.4% in the visible light range. Results from a CCK-8 assay indicate that MAPCM gets higher cell proliferation rate of rabbit corneal stroma cells than APCM. Since collagen fibres structural integrity and regularity of MAPCM are retained after crosslinking, the opacity and stability of MAPCM are better than those of APCM within 4 weeks of animal implantation. In addition, there is no indication of an immune response or neovascularization in or around the transplanted disc. These results reveal that MAPCM may be a more suitable scaffold for corneal substitute construction.

scholarly journals The Influence of Bloom Index, Endotoxin Levels and Polyethylene Glycol Succinimidyl Glutarate Crosslinking on the Physicochemical and Biological Properties of Gelatin Biomaterials

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1003
Author(s):  
Zhuning Wu ◽  
Stefanie H. Korntner ◽  
Jos Olijve ◽  
Anne Maria Mullen ◽  
Dimitios I. Zeugolis
Keyword(s):  
Elastic Modulus ◽  
Polyethylene Glycol ◽  
Enzymatic Degradation ◽  
Structural Integrity ◽  
Biological Response ◽  
Biological Properties ◽  
Compression Stress ◽  
Free Amine ◽  
Amine Content ◽  
Physicochemical And Biological Properties

In the medical device sector, bloom index and residual endotoxins should be controlled, as they are crucial regulators of the device’s physicochemical and biological properties. It is also imperative to identify a suitable crosslinking method to increase mechanical integrity, without jeopardising cellular functions of gelatin-based devices. Herein, gelatin preparations with variable bloom index and endotoxin levels were used to fabricate non-crosslinked and polyethylene glycol succinimidyl glutarate crosslinked gelatin scaffolds, the physicochemical and biological properties of which were subsequently assessed. Gelatin preparations with low bloom index resulted in hydrogels with significantly (p < 0.05) lower compression stress, elastic modulus and resistance to enzymatic degradation, and significantly higher (p < 0.05) free amine content than gelatin preparations with high bloom index. Gelatin preparations with high endotoxin levels resulted in films that induced significantly (p < 0.05) higher macrophage clusters than gelatin preparations with low endotoxin level. Our data suggest that the bloom index modulates the physicochemical properties, and the endotoxin content regulates the biological response of gelatin biomaterials. Although polyethylene glycol succinimidyl glutarate crosslinking significantly (p < 0.05) increased compression stress, elastic modulus and resistance to enzymatic degradation, and significantly (p < 0.05) decreased free amine content, at the concentration used, it did not provide sufficient structural integrity to support cell culture. Therefore, the quest for the optimal gelatin crosslinker continues.

scholarly journals Difference in solid-state properties and enzymatic degradation of three kinds of poly(butylene succinate)/cellulose blends

RSC Advances ◽  
2017 ◽  
Vol 7 (56) ◽  
pp. 35496-35503 ◽  
Author(s):  
Xueyan Hu ◽  
Tingting Su ◽  
Wenjing Pan ◽  
Ping Li ◽  
Zhanyong Wang
Keyword(s):  
Solid State ◽  
Enzymatic Degradation ◽  
Butylene Succinate ◽  
Better Than

Mechanical and crystalline properties of PBS/CMC and PBS/CA blends were improved and their enzymolysis was better than for a PBS/CTA blend.

scholarly journals Contribution of image analysis to the description of enzymatic degradation kinetics for particulate food material

2006 ◽  
Vol 77 (4) ◽  
pp. 1096-1107 ◽  
Author(s):  
M.-F. Devaux ◽  
I. Taralova ◽  
J. Levy-Vehel ◽  
E. Bonnin ◽  
J.-F. Thibault ◽  
...  
Keyword(s):  
Image Analysis ◽  
Enzymatic Degradation ◽  
Degradation Kinetics ◽  
Food Material

scholarly journals Thermal Degradation and Water Uptake of Biodegradable Resin Prepared from Millet Flour and Wheat Gluten Crosslinked with Epoxydized Vegetable Oils

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Abdellatif A. Mohamed ◽  
S. Hussain ◽  
M. S. Alamri ◽  
M. A. Ibraheem ◽  
Akram A. Abdo Qasem
Keyword(s):  
Water Uptake ◽  
Epoxy Resins ◽  
Degradation Kinetics ◽  
Wheat Gluten ◽  
Heat Stability ◽  
Crosslinking Density ◽  
Cottonseed Oil ◽  
Ozawa Method ◽  
Heating Rates ◽  
Vital Wheat Gluten

The degradation temperatures (DTs), heat stability (IPDT), degradation kinetics, and water uptake of epoxy resin were investigated using thermogravimetric analysis. Epoxy resins were prepared by crosslinking epoxydized oils with vital wheat gluten (VG) and millet flour. The reactions included three oils (cottonseed, sesame, and sunflower) and three levels of zinc chloride (ZC) (1, 2, and 3%). The apparent activation energy (Ea) was calculated using the Flynn–Wall–Ozawa method. The DT increased at higher heating rates within the same ZC level of the same oil type. Cottonseed oil exhibited the highest DT. The highest IPDT was 637°C of the sunflower oil/millet resin (3% ZC), and the least was the cottonseed/millet (1% ZC) at 479°C. The sesame-millet resin exhibited the highest Ea (622 KJ/mol) followed by sunflower-gluten (496 KJ/mol) and sesame-gluten (454 KJ/mol). The profiles of all resins point to a multistep degradation, but some of the profiles display two dominant kinetic processes, and the remaining resins showed three processes. The variation in crosslinking density between the oils is attributable to the different amounts of oxirane rings which are associated with the double bonds of the fatty acid of the oils. Like other parameters, the water uptake was affected by the ZC content, where most of the resins did not reach water uptake equilibrium. Nonetheless, the 3% ZC resin reached equilibrium after 5 days of immersion.

scholarly journals Regulating the Balance of Th17/Treg via Electroacupuncture and Moxibustion: An Ulcerative Colitis Mice Model Based Study

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Jungang Sun ◽  
Hejiaozi Zhang ◽  
Chengyulin Wang ◽  
Mingxiao Yang ◽  
Shyang Chang ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Activity Index ◽  
Disease Activity Index ◽  
Distal Colon ◽  
Foxp3 Expression ◽  
Mice Model ◽  
Spleen Lymphocytes ◽  
Structure And Ultrastructure ◽  
The Relationship ◽  
Better Than

Aim. To investigate the relationship between the effects of electroacupuncture/moxibustion and the balance of Th17/Treg in treating ulcerative colitis (UC) and to preliminary compare the effects of the above two methods. Methods. DSS-induced UC mice were treated by electroacupuncture and moxibustion. Disease activity index (DAI) was scored; intestinal pathological structure and ultrastructure were observed. The levels of IL-2, IL-6, IL-10, IL-17A, IL-17F, and TGF-β in plasma were measured by ELISA. The percentages of Treg and Th17 in spleen lymphocytes were analyzed by flow cytometry. Also, the expressions of TLR2, TLR4, RORγt, and FOXP3 in the distal colon were detected by immunohistochemistry or western blot. Results. Both electroacupuncture and moxibustion can relieve UC. These effects are further supported by ELISA results. In addition, the ratio of Treg and Th17 in spleen lymphocytes and the expression of TLR2 and TLR4 are significantly improved. Also, the expression of RORγt and FOXP3 in distal colon were improved. Besides, the effect of moxibustion is better than that of electroacupuncture on TLR2, TLR4, and FOXP3 expression (P<0.05). Conclusion. Both electroacupuncture and moxibustion may ameliorate UC by regulating the balance of Th17/Treg. Whether moxibustion has better efficacy than electroacupuncture needs further study.

The Effect of Pressure Relief in Prosthetic Sockets on the Wear and Comfort of BK Amputees

2011 ◽  
Author(s):  
Gabi Nehme ◽  
Raymond Semaan ◽  
Ramzi Oueini
Keyword(s):  
Finite Element Analysis ◽  
Pressure Distribution ◽  
Design Of Experiment ◽  
Structural Integrity ◽  
Great Flexibility ◽  
Pressure Relief ◽  
Element Analysis ◽  
Relief Area ◽  
Design Scenario ◽  
Better Than

Great flexibility in prosthetic sockets, with long range of spring like action is needed while designing a socket. A finite element analysis is conducted to investigate the stress and displacement distribution for different socket cases where relief is needed. The relieved socket after optimization of the pressure distribution areas showed less wear and more comfort for amputees than the non-relieved socket. A Design of Experiment using 2 level factorial design is used to optimize the relief areas with respect to pressure distribution. Stresses and displacements were included in the model desirability. Higher deformation of the pressure relief areas is sought while preserving the socket structural integrity. A compromise with the structural integrity of the socket and the optimized values with high desirability of the Design of Experiment Model imply that Duraform socket A with 1.69mm relief area could be the best design scenario between several cases. Wear and skin analysis indicated that the relieved socket is significantly better than the unrelieved one.

Effect of nanosilver on the thermal stability and thermal decomposition kinetics of poly(acetoacetoxyethyl methacrylate–styrene)

2018 ◽  
Vol 50 (8) ◽  
pp. 710-719
Author(s):  
Shengtao Gao ◽  
Honglong Xing
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Thermal Degradation Kinetics ◽  
Face Centered Cubic ◽  
Transmission Electron ◽  
Face Centered ◽  
Kinetics Of ◽  
Better Than

Nanosilver/poly(acetoacetoxyethyl methacrylate–styrene) (nano-Ag/P(AAEM-St)) composites were synthesized via emulsifier-free emulsion with silver nitrate solution, AAEM, and St monomer copolymerization by ultrasonic. The morphology and structure of the composites were characterized by ultraviolet and visible spectroscopy, X-ray diffractometer, and transmission electron microscopy, respectively. The results show that Ag nanoparticles with face-centered cubic structure are homogeneously dispersed in the P(AAEM-St) matrix. The thermal stability and the thermal degradation kinetics of P(AAEM-St) were investigated using the thermogravimetric analysis and Kissinger and Flynn–Wall–Ozawa method, respectively. The results prove that the thermal stability of the pure P(AAEM-St) is better than that of the nano-Ag/P(AAEM-St) composites.

Photodynamically Crosslinked and Chitosan-incorporated Dentin Collagen

2011 ◽  
Vol 90 (11) ◽  
pp. 1346-1351 ◽  
Author(s):  
A. Shrestha ◽  
S. Friedman ◽  
A. Kishen
Keyword(s):  
Mechanical Properties ◽  
Enzymatic Degradation ◽  
Structural Integrity ◽  
Chemical Characterization ◽  
Collagen Matrix ◽  
Carboxymethyl Chitosan ◽  
Coherent Light ◽  
Transmission Electron ◽  
Human Dentin ◽  
Dentin Collagen

A lingering concern with restored root-filled teeth is the loss of structural integrity of the dentin and dentin-sealer interface over time. We hypothesized that crosslinking of dentin collagen with simultaneous incorporation of a biopolymer into collagen matrix would improve its structural stability. This study aimed to investigate the effects of combining chemical/photodynamic crosslinking of dentin collagen with the incorporation of carboxymethyl-chitosan (CMCS) on the resistance to enzymatic degradation and mechanical properties of dentin collagen. Ninety-six demineralized dentin collagen specimens (human, n = 72; and bovine, n = 24) were prepared and crosslinked chemically/ photodynamically, with/without CMCS. Glutaraldehyde and carbodiimides were used for chemical crosslinking, while rose Bengal activated with a non-coherent light (540 nm) at 20 J/cm2 was applied for photodynamic crosslinking. The crosslinked human dentin collagen was subjected to chemical characterization, 7 days enzymatic degradation, and transmission electron microscopy (TEM), while the bovine dentin collagen was used for tensile-testing. Crosslinked collagen showed significantly higher resistance to enzymatic degradation ( p < 0.01), stable ultrastructure, and increased tensile strength ( p < 0.05). Crosslinking CMCS with collagen matrix as observed in the TEM further improved the mechanical properties of dentin collagen ( p < 0.01). This study highlighted the possibility of improving the resistance and toughness of dentin collagen by chemically/photodynamically crosslinking collagen matrix with CMCS.

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