Pranav S. Sapkal^1,*, Abhaykumar M. Kuthe¹, Shantanu Mathankar², Akash A. Deshmukh

Molecular & Cellular Biomechanics, Vol.14, No.2, pp. 125-136, 2017, DOI:10.3970/mcb.2017.014.123

Abstract β-TCP-Zirconia scaffolds with different architectures were fabricated by means of 3D-Bioplotting in order to enhance the mechanical and in-vitro ability of the scaffold to heal large size bone defects. In the present study scaffold architecture with different strand orientations (0°-90°, 0°-45°-135°-180°, 0°-108°-216° and 0°-72°-144°-36°-108°) were fabricated, characterized and evaluated for mechanical strength and cell proliferation ability. β-TCP powder (25 µm) and PVA (Polyvinyl Alcohol) was acquired from Fisher Scientific, India. Zirconia (18 to 32 µm) was procured from Lobachemie, India. In brief 7.5%, PVA in distilled water was used as a binder and was mixed with 10 grams of (70/30)… More >

Idalba A. Hidalgo A.^∗, Felipe Sojo^†, Francisco Arvelo^†, Marcos A. Sabino^∗,‡

Molecular & Cellular Biomechanics, Vol.10, No.2, pp. 85-105, 2013, DOI:10.3970/mcb.2013.010.085

Abstract The electrospinning technique is a method used to produce nano and microfibers using the influence of electrostatic forces. Porous three dimensional networks of continuous and interconnected fibers as scaffolds were obtained from a poly (lactic acid) solution. The concentration of the polymeric solution, 12.5% m/w, as well as the conditions of voltage (V=11kV) and tip-metallic collector distance (H=13cm) were established to develop these scaffolds through the electrospinning process. The characteristics of the scaffolds, such as fiber diameter, sintering and the biomimetics of the characteristics of a native extra cellular matrix were verified by Scanning Electron Microscopy (SEM). The orientation induced… More >

Hana Chang^*, Melissa L. Knothe Tate^∗,†,‡

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 297-318, 2011, DOI:10.3970/mcb.2011.008.297

Abstract In the preceding study (Part A), we showed that prescribed seeding conditions as well as seeding density can be used to subject multipotent stem cells (MSCs) to volume changing stresses and that changes in volume of the cell are associated with changes in shape, but not volume, of the cell nucleus. In the current study, we aim to control the mechanical milieu of live cells using these prescribed seeding conditions concomitant to delivery of shape changing stresses via fluid flow, while observing adaptation of the cytoskeleton, a major cellular transducer that modulates cell shape, stiffness and remodeling. We hypothesize that… More >

Joshua A. Zimmermann^*, Melissa L. Knothe Tate^∗,†,‡

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 275-296, 2011, DOI:10.3970/mcb.2011.008.275

Abstract Shape and fate are intrinsic manifestations of form and function at the cell scale. Here we hypothesize that seeding density and protocol affect the form and function of live embryonic murine mesenchymal stem cells (MSCs) and their nuclei. First, the imperative for study of live cells was demonstrated in studies showing changes in cell nucleus shape that were attributable to fixation per se. Hence, we compared live cell and nuclear volume and shape between groups of a model MSC line (C3H10T1/2) seeded at, or proliferated from 5,000 cells/cm2 to one of three target densities to achieve targeted development contexts. Cell… 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 >

R. Khanna^1,2, D. R. Katti¹, K. S. Katti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 530-556, 2012, DOI:10.3970/cmes.2012.087.530

Abstract Here we report a new in situ nanoindentation technique developed to evaluate the composite mechanical behavior of cell-biomaterial construct under physiological conditions over the time scale of bone nodule generation. Using this technique, mechanical behavior of osteoblast cell-substrate interfaces on tissue engineered materials (chitosan-polygalacturonic acid-nanohydroxyapatite (CPH) films) is investigated. Mechanical behavior of cells in the elastic regime over the time scale of cell adhesion (1 day), proliferation (4 days), development (8 days) and maturation (22 days) of bone nodules is evaluated. Our results indicate that the elastic properties of flat cells are higher (indicating stiffer response, after 4 days, as… More >

K.W. Luczynski¹, A. Dejaco¹, O. Lahayne¹, J. Jaroszewicz², W.Swieszkowski², C. Hellmich¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 505-529, 2012, DOI:10.3970/cmes.2012.087.505

Abstract A 71 volume-% macroporous tissue engineering scaffold made of poly-l-lactide (PLLA) with 10 mass-% of pseudo-spherical tri-calcium phosphate (TCP) inclusions (exhibiting diameters in the range of several nanometers) was microCT-scanned. The corresponding stack of images was converted into regular Finite Element (FE) models consisting of around 100,000 to 1,000,000 finite elements. Therefore, the attenuation-related, voxel-specific grey values were converted into TCP-contents, and the latter, together with nanoindentation tests,entered a homogenization scheme of the Mori-Tanaka type, as to deliver voxel-specific (and hence, finite element-specific) elastic properties. These FE models were uniaxially loaded, giving access to the macroscopic Young's modulus of the… More >

G. Mattei^1,2, A. Tirella^1,2, A. Ahluwalia^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 483-504, 2012, DOI:10.3970/cmes.2012.087.483

Abstract Biological function is intricately linked with structure. Many biological structures are characterised by functional spatially distributed gradients in which each layer has one or more specific functions to perform. Reproducing such structures is challenging, and usually an experimental trial-and-error approach is used. In this paper we investigate how the gravitational sedimentation of discrete solid particles (secondary phase) within a primary fluid phase with a time-varying dynamic viscosity can be used for the realisation of stable and reproducible continuous functionally graded materials (FGMs). Computational models were used to simulate the distribution of a particle phase in a fluid domain. Firstly a… More >

Marcello Lappa¹

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.2, pp. 141-152, 2006, DOI:10.3970/fdmp.2006.002.141

Abstract Numerical simulations and computer-graphics animation can be used as useful tools to discern the physicochemical environmental factors affecting the surface kinetics of growing biological tissues as well as their relative importance in determining growth. A mathematical formalism for such kinetics is proposed through parametric investigation and validated through focused comparison with experimental results. The study relies on the application of a CFD moving boundary (Volume of Fluid) method specially conceived for the simulation of these problems. In the second part of the analysis the case of two samples hydrodynamically interacting in a rotating bioreactor is considered. The interplay between two… More >

Milica Radisic^1,2, Gordana Vunjak-Novakovic³

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 1-16, 2006, DOI:10.3970/fdmp.2006.002.001

Abstract To engineer cardiac tissue in vitro with properties approaching those of native tissue, it is necessary to reproduce many of the conditions found in vivo. In particular, cell density must be sufficiently high to enable contractility, which implies a three-dimensional culture with a sufficient oxygen and nutrient supply. In this review, hydrogels and scaffolds that support high cell densities are examined followed by a discussion on the utility of scaffold perfusion to satisfy high oxygen demand of cardiomyocytes and an overview of new bioreactors developed in our laboratory to accomplish this task more simply. More >