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7. Supplementary Information.docx from Time-dependent ECM alterations of young tendons in response to stress relaxation—a model for the Ponseti method

Author

LEE, Mu-Huan, Tsai, Hung-Pei, Lavy, Chris, Mouthuy, Pierre-Alexis, and Czernuszka, Jan

Abstract

The Ponseti method corrects a clubfoot by manipulation and casting which causes stress relaxation on the tendons. Here, we examined the effect of long-term stress relaxation on tendon extracellular matrix (ECM) by an (1) ex vivo stress relaxation test, (2) an in vitro tenocyte culture with stress relaxation and (3) an in vivo rabbit study. Time-dependent tendon lengthening and ECM alterations including crimp angle reduction and cleaved elastin were observed, which illustrated the mechanism of tissue lengthening behind the treatment—a material-based crimp angle reduction resulted from elastin cleavage. Additionally, in vitro and in vivo results observed restoration of these ECM alterations along with increased elastin level after 7 days of treatment, and the existence of neovascularization and inflammation, indicating the recovery and adaptation from the tendon in reaction to the treatment. Overall, this study provides the scientific background and information that helps explain the Ponseti method.

Published
2023
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24. Carbonated hydroxyapatite‐assisted visible light degradation of methylene blue.

Author

Asimeng, Bernard Owusu, Obeng, Ernest Emmanuel, Obeng‐Gyasi, Obed, Alipoormazandarani, Niloofar, Annan, Ebenezer, Nyankson, Emmanuel, Efavi, Johnson Kwame, Tiburu, Elvis Kwason, Foster, E. Johan, and Czernuszka, Jan T.

Subjects
VISIBLE spectra, INFRARED spectroscopy, WATER pollution, SCANNING electron microscopy, ULTRAVIOLET-visible spectroscopy
Abstract

Carbonated hydroxyapatite (CHAp) material was prepared from calcite and phosphate‐containing solution using the wet chemical precipitation method. The CHAp material was used to remove methylene blue (MB) from simulated contaminated water and further degraded the MB with the help of visible light (VL). The structure of the CHAp was characterized using X‐ray diffractometry, infrared spectroscopy, Branuer–Emmett–Teller analysis, and scanning electron microscopy, while the energy bandgap, Eg, reaction rate constant and MB removal/degradation efficiencies were studied using UV‐Vis spectroscopy. The characterization data revealed that the CHAp was a type‐B carbonate‐substituted hydroxyapatite material with a nonmicroporous network with an Eg of 2.26–2.82 eV. The Eg allowed VL entrapment that resulted in reactive free radicals that degraded the MBs in the CHAp. The reaction rate constant, K, and removal efficiencies, R, were modeled using the exponential decay function and descriptive statistics (DS), respectively. In close approximation, the K values of the reaction under VL were doubled when compared to the reaction under dark conditions. Under dark and under VL efficiencies, the DS showed a negative and zero skewness for MB removal by CHAp, respectively. The findings show that VL exposure on the CHAp causes a faster reaction rate constant and a higher MB removal efficiency within the time constraints, which would revolutionize dye removal from water industries in terms of cost‐effectiveness. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Trilayer scaffold with cardiosphere‐derived cells for heart valve tissue engineering.

Author

Chen, Qi, Bruyneel, Arne, Carr, Carolyn, and Czernuszka, Jan

Subjects
HEART valves, HEART cells, TISSUE engineering, BIOPOLYMERS, TISSUE scaffolds
Abstract

Natural polymers collagen, glycosaminoglycans, and elastin are promising candidate materials for heart valve tissue engineering scaffolds. This work produced trilayer scaffolds that resembled the layered structures of the extracellular matrices of native heart valves. The scaffolds showed anisotropic bending moduli (in both dry and hydrated statuses) depending on the loading directions (lower in the With Curvature direction than in the Against Curvature direction), which mimicked the characteristic behavior of the native heart valves. The interactions between cardiosphere‐derived cells and the scaffolds were characterized by multiphoton microscopy, and relatively similar cell distributions were observed on different layers (a cell density of 3,000–4,000 mm−3 and a migration depth of 0.3–0.4 mm). The trilayer scaffold has represented a forwarding step from the previous studies, in attempting to better replicate a native heart valve structurally, mechanically, and biologically. [ABSTRACT FROM AUTHOR]

Published
2020
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35. Characteristics and young's modulus of collagen fibrils from expanded skin using anisotropic controlled rate self-inflating tissue expander

Author

Manssor, Nur Aini S., Radzi, Zamri, Yahya, Noor Azlin, Mohamad Yusof, Loqman, Hariri, Firdaus, Khairuddin, Nurul Hayah, Abu Kasim, Noor Hayaty, Czernuszka, Jan T., Manssor, Nur Aini S., Radzi, Zamri, Yahya, Noor Azlin, Mohamad Yusof, Loqman, Hariri, Firdaus, Khairuddin, Nurul Hayah, Abu Kasim, Noor Hayaty, and Czernuszka, Jan T.

Abstract

Mechanical properties of expanded skin tissue are different from normal skin, which is dependent mainly on the structural and functional integrity of dermal collagen fibrils. In the present study, mechanical properties and surface topography of both expanded and nonexpanded skin collagen fibrils were evaluated. Anisotropic controlled rate self-inflating tissue expanders were placed beneath the skin of sheep's forelimbs. The tissue expanders gradually increased in height and reached equilibrium in 2 weeks. They were left in situ for another 2 weeks before explantation. Expanded and normal skin samples were surgically harvested from the sheep (n = 5). Young's modulus and surface topography of collagen fibrils were measured using an atomic force microscope. A surface topographic scan showed organized hierarchical structural levels: collagen molecules, fibrils and fibers. No significant difference was detected for the D-banding pattern: 63.5 ± 2.6 nm (normal skin) and 63.7 ± 2.7 nm (expanded skin). Fibrils from expanded tissues consisted of loosely packed collagen fibrils and the width of the fibrils was significantly narrower compared to those from normal skin: 153.9 ± 25.3 and 106.7 ± 28.5 nm, respectively. Young's modulus of the collagen fibrils in the expanded and normal skin was not statistically significant: 46.5 ± 19.4 and 35.2 ± 27.0 MPa, respectively. In conclusion, the anisotropic controlled rate self-inflating tissue expander produced a loosely packed collagen network and the fibrils exhibited similar D-banding characteristics as the control group in a sheep model. However, the fibrils from the expanded skin were significantly narrower. The stiffness of the fibrils from the expanded skin was higher but it was not statistically different.

Published
2016

44. A Process to Make Collagen Scaffolds with an Artificial Circulatory System Using Rapid Prototyping

Author

MANCHESTER UNIV (UNITED KINGDOM) MATERIALS SCIENCE CENTER, Sachlos, Eleftherios, Reis, Nuno, Ainsley, Chris, Derby, Brian, Czernuszka, Jan T., MANCHESTER UNIV (UNITED KINGDOM) MATERIALS SCIENCE CENTER, Sachlos, Eleftherios, Reis, Nuno, Ainsley, Chris, Derby, Brian, and Czernuszka, Jan T.

Abstract

Tissue engineering aims to produce biological substitutes to restore or repair damaged human tissues or organs. The principle strategy behind tissue engineering involves seeding relevant cell(s) onto porous 3D biodegradable scaffolds. The scaffold acts as a temporary substrate where the cells can attach and then proliferate and differentiate. Collagen is the major protein constituent of the extracellular matrix in the human body and therefore an attractive scaffold material. Current collagen scaffolds are foams which limit the mass transport of oxygen and nutrients deep into the scaffold, and consequently cannot support the growth of thick-cross sections of tissue (greater than 500 micrometers). We have developed a novel process to make collagen and collagen-hydroxyapatite scaffolds containing an internal artificial circulatory system in the form of branching channels using a sacrificial mould, casting and critical point drying technique. The mould is made using a commercial rapid prototyping system, the Model-Maker II, and is designed to possess a series of connected shafts. The mould is dissolved away and the solvent itself removed by critical point drying with liquid carbon dioxide. Processed hydroxyapatite has been characterised by XRD and FTIR analysis. Tissue engineering with collagen scaffolds possessing controlled internal microarchitecture may be the key to growing thick cross-sections of human tissue., This article is from the Mat. Res. Soc. Symp. Proc. Vol. 758 p187-192, 2003. Prepared in cooperation with Dept. of Materials, University of Oxford, UK. This article is from ADA417756 Materials Research Society Symposium Proceedings, Volume 758 Held in Boston, Massachusetts on December 3-5, 2002. Rapid Prototyping Technologies

Published
2003

50. Magnetic Resonance Imaging of Ferumoxide-Labeled Mesenchymal Stem Cells Seeded on Collagen Scaffolds—Relevance to Tissue Engineering

Author

Terrovitis, John V., primary, Bulte, Jeff W.M., additional, Sarvananthan, Sajiram, additional, Crowe, Lindsey A., additional, Sarathchandra, Padmini, additional, Batten, Puspa, additional, Sachlos, Eleftherios, additional, Chester, Adrian H., additional, Czernuszka, Jan T., additional, Firmin, David N., additional, Taylor, Patricia M., additional, and Yacoub, Magdi H., additional

Published
2006
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