Tailoring Mechanical Properties of Collagen-Based Scaffolds for Vascular Tissue Engineering: The Effects of pH, Temperature and Ionic Strength on Gelation

Abstract

Collagen gels have been widely studied for applications in tissue engineering because of their biological implications. Considering their use as scaffolds for vascular tissue engineering, the main limitation has always been related to their low mechanical properties. During the process of in vitro self-assembly, which leads to collagen gelation, the size of the fibrils, their chemical interactions, as well as the resulting microstructure are regulated by three main experimental conditions: pH, ionic strength and temperature. In this work, these three parameters were modulated in order to increase the mechanical properties of collagen gels. The effects on the gelation process were assessed by turbidimetric and scanning electron microscopy analyses. Turbidity measurements showed that gelation was affected by all three factors and scanning electron images confirmed that major changes occurred at the microstructural level. Mechanical tests showed that the compressive and tensile moduli increased by four-and three-fold, respectively, compared to the control. Finally, viability tests confirmed that these gels are suitable as scaffolds for cellular adhesion and proliferation.

Strain-driven criticality underlies nonlinear mechanics of fibrous networks

“…This is a direct consequence of the scalingκ ∼ ϕ ∝ (a/ l 0 ) 2 , which remains invariant to changes in fibril thickness for a given total protein concentration. The structure of collagen networks, including fibril thickness, mesh size, homogeneity, and presumably connectivity, depends in detail on concentration and polymerization conditions in nontrivial ways [37,38]. However, under the basic assumptions mentioned above,κ remains a constant.…”

Nanoscale Imaging of Collagen Gels with Focused Ion Beam Milling and Scanning Electron Microscopy

“…The fibril network of a collagen gel is tightly linked to the polymerization conditions, including collagen source, collagen concentration, pH, temperature, and salt content, presence of other proteins and molecules, and other physical and chemical factors (15)(16)(17). Altering these variables changes the rate of polymerization and the resulting diameter distributions and organization of fibrils within the collagen network.…”

Bioprinting of Organs and Tissues

“…Очевидно, что ре-шение данной проблемы путем биопечати является далеким будущим. Между тем замещение кожи, костной и хрящевой ткани является для ученых уже сейчас достижимой задачей [14][15][16][17][18].…”

“…Проводимые за рубежом и в России разработки матриксов (скаффолдов) как носителей кле-ток при трансплантации можно разбить на две большие группы: создание матриксов из биостабильных матери-алов (биостабильные синтетические полимеры, спла-вы, керамика) и из биодеградируемых материалов ис-кусственного или природного происхождения [35] Наиболее часто в биопечати в качестве скаффол-дов используют гидрогели, в состав которых могут вхо-дить следующие вещества: альгиновая кислота или альгинат [36,37], хитозан [38], желатин [39], гиалуроно-вая кислота [40,41], агароза [42], коллаген [43,44], плю-роник [45], матригель [46], метилцеллюлоза [47,48], метилцеллюлоза [49], фибрин [50].…”