M. L. Lambri^1,2, E. D. Giordano^2,3, P. B. Bozzano⁴, F. G. Bonifacich², J. I. Pérez-Landazábal^5,6, G. I. Zelada², D. Gargicevich², V. Recarte^5,6, O. A. Lambri^2*

Journal of Renewable Materials, Vol.4, No.4, pp. 251-257, 2016, DOI:10.7569/JRM.2016.634111

Abstract The denaturation processes of collagen in the temperature range between 450 K and 670 K are revealed through studies performed on cow rib bones by means of mechanical spectroscopy, differential scanning calorimetry, thermogravimetry, scanning electron microscopy and infrared spectroscopy. The conformational change of the collagen molecules from a triple helix structure to a random coil was found at around 510 K. It was determined that the transformation is developed through the viscous movement of fibrils with an activation energy of (127 ± 8) kJ/mol. The second stage of massive bulk deterioration of the collagen was found at around 600 K,… More >

Lilan Gao^1,2,*, Qingxian Yuan^1,2, Ruixin Li^3,*, Lei Chen^1,2, Chunqiu Zhang^1,2, Xizheng Zhang^1,2

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 85-98, 2018, DOI: 10.3970/mcb.2018.00329

Abstract Silk fibroin-typeⅡcollagen scaffold was made by 3D printing technique and freeze-drying method, and its mechanical properties were studied by experiments and theoretical prediction. The results show that the three-dimensional silk fibroin-typeⅡ collagen scaffold has good porosity and water absorption, which is (89.3%+3.26%) and (824.09%+93.05%), respectively. With the given strain value, the stress of scaffold decreases rapidly firstly and then tends to be stable during the stress relaxation. Both initial and instantaneous stresses increase with increase of applied strain value. The creep strains of scaffold with different stress levels show the two stages: the rapidly increasing stage and the second stable… More >

Pranav S. Sapkal^1*, Abhaykumar M. Kuthe¹, Divya Ganapathy², Shantanu C. Mathankar³, Sudhanshu Kuthe⁴

Molecular & Cellular Biomechanics, Vol.13, No.2, pp. 115-136, 2016, DOI:10.3970/mcb.2016.013.131

Abstract Biphasic calcium phosphate scaffolds with 20/80 HA/TCP ratio were fabricated using the 3D-Bioplotting system to heal critical size defects in rabbit tibia bone. Four different architectures were printed in a layer by layer fashion with lay down patterns viz. (a) 0°– 90°, (b) 0°– 45°– 90°– 135°, (c) 0°–108°– 216° and (d) 0°– 60°– 120°. After high-temperature sintering scaffolds were coated with collagen and were further characterized by (FTIR) Fourier Transform Infrared Spectroscopy, (SEM) Scanning Electron Microscopy, (XRD) X-Ray diffraction, Porosity analysis and Mechanical testing. Scaffold samples were tested for its ability to induce cytotoxicity in Balb/c 3T3 cells at… More >

Ricky Martinez^†, Hai-Chao Han^‡

Molecular & Cellular Biomechanics, Vol.9, No.1, pp. 55-76, 2012, DOI:10.3970/mcb.2012.009.055

Abstract The stability of arteries is essential to normal arterial functions and loss of stability can lead to arterial tortuosity and kinking. Collagen is a main extracellular matrix component that modulates the mechanical properties of arteries and collagen degradation at pathological conditions weakens the mechanical strength of arteries. However, the effects of collagen degradation on the mechanical stability of arteries are unclear. The objective of this study was to investigate the effects of collagen degradation on the critical buckling pressure of arteries. Arterial specimens were subjected to pressurized inflation testing and fitted with nonlinear thick-walled cylindrical model equations to determine their… More >

Min Zhang^∗, Fa-Ming Chen^†, Yong-Jin Chen^∗,‡, Shun Wu^∗, Xin Lv^∗, Rui-Ni Zhao^∗

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 43-60, 2011, DOI:10.3970/mcb.2011.008.043

Abstract To investigate the role of mechanical pressure on cartilage thickness and type II collagen synthesis, and the role of G protein in that process, in vitro organ culture of mandibular cartilage was adopted in this study. A hydraulic pressure-controlled cellular strain unit was used to apply hydrostatic pressurization to explant cultures. The explants were compressed by different pressure values (0 kPa, 100 kPa, and 300 kPa) after pretreatment with or without a selective and direct antagonist (NF023) for the G proteins. After 4, 8 and 12 h of cell culture under each pressure condition, histological sections of the explants were… More >

J.S. Ren^*

Molecular & Cellular Biomechanics, Vol.7, No.4, pp. 213-224, 2010, DOI:10.3970/mcb.2010.007.213

Abstract Dynamic analysis of an axially stretched arterial wall with collagen fibers distributed in two preferred directions under a suddenly applied constant internal pressure along with the possibility of the formation and rupture of aneurysm are examined within the framework of nonlinear dynamics. A two layer tube model with the fiber-reinforced composite-based incompressible anisotropic hyper-elastic material is employed to model the mechanical behavior of the arterial wall. The maximum amplitudes and the phase diagrams are given by numerical computation of the differential relation. It is shown that the arterial wall undergoes nonlinear periodic oscillation and no aneurysms are formed under the… More >

Masanori Kobayashi, Myron Spector

Molecular & Cellular Biomechanics, Vol.6, No.4, pp. 217-228, 2009, DOI:10.3970/mcb.2009.006.217

Abstract In order to achieve successful wound repair by regenerative tissue engineering using mesenchymal stem cells (MSCs), it is important to understand the response of stem cells in the scaffold matrix to mechanical stress.
To investigate the clinical effects of mechanical stress on the behavior of cells in scaffolds, bone marrow-derived mesenchymal stem cells (MSCs) were grown on a type-I collagen-glycosaminoglycan (GAG) scaffold matrix for one week under cyclic stretching loading conditions.
The porous collagen-GAG scaffold matrix for skin wound repair was prepared, the harvested canine MSCs were seeded on the scaffold, and cultured under three kinds of cyclic… More >

Donald F. Ward Jr.^*, William A. Williams^*, Nicole E. Schapiro^*, Samuel R. Christy^*, Genevieve L. Weber^*, Megan Salt, Robert F. Klees^*, Adele Boskey^†, George E. Plopper ^∗,‡

Molecular & Cellular Biomechanics, Vol.4, No.4, pp. 177-188, 2007, DOI:10.3970/mcb.2007.004.177

Abstract Focal adhesion kinase (FAK) is a key integrator of integrin-mediated signals from the extracellular matrix to the cytoskeleton and downstream signaling molecules. FAK is activated by phosphorylation at specific tyrosine residues, which then stimulate downstream signaling including the ERK1/2 pathway, leading to a variety of cellular responses. In this study, we examined the effects of FAK point mutations at tyrosine residues (Y397, Y925, Y861, and Y576/7) on osteogenic differentiation of human mesenchymal stem cells exposed to collagen I and cyclic tensile strain. Our results demonstrate that FAK signaling emanating from Y397, Y925, and to a lesser extent Y576/7, but not… More >

J. S. Ren^*

Molecular & Cellular Biomechanics, Vol.4, No.1, pp. 55-66, 2007, DOI:10.3970/mcb.2007.004.055

Abstract Formation and rupture of aneurysms due to the inflation of an artery with collagen fibers distributed in two preferred directions, subjected to internal pressure and axial stretch are examined within the framework of nonlinear elasticity. A two layer tube model with a fiber-reinforced composite based incompressible anisotropic hyperelastic constitutive material is employed to model the stress-strain behavior of the artery wall with distributed collagen fibers. The artery wall takes up a uniform inflation deformation, and there are no aneurysms in the artery under the normal condition. But an aneurysm may be formed in arteries when the stiffness of the fibers… More >

S.M. Pradhan¹, K.S.Katti¹, D.R. Katti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.2, pp. 181-201, 2014, DOI:10.3970/cmes.2014.098.181

Abstract Multiscale modeling of collagen fibril is carried out by incorporating the material properties of collagen obtained from steered molecular dynamics into the finite element model of collagen fibril with inclusion of crosslinks. The results indicate that the nonbonded interactions between collagen and mineral contribute to the significant enhancement of the elastic modulus of collagen fibril at all the crosslink densities in both the low strain and high strain regimes. The crosslinks are found to play an important role in the mechanical response of collagen fibril, the enhancement in elastic modulus ranging from 5-11% for various crosslink densities compared to the… More >