Tissue Engineering Laboratory, Biomedical Engineering Faculty, Amirkabir University of Technology-Tehran Polytechnic, Tehran, Iran.
Department of Health Technology, Institute of Biotherapeutic Engineering and Drug Targeting, Center for Intestinal Absorption and Transport of Biopharmaceuticals, Technical University of Denmark, Kgs Lyngby, Denmark.
PLoS One. 2021 Feb 25;16(2):e0247727. doi: 10.1371/journal.pone.0247727. eCollection 2021.
Natural biopolymer-based hydrogels especially agarose and collagen gels, considering their biocompatibility with cells and their capacity to mimic biological tissues, have widely been used for in-vitro experiments and tissue engineering applications in recent years; nevertheless their mechanical properties are not always optimal for these purposes. Regarding the importance of the mechanical properties of hydrogels, many mechanical characterization studies have been carried out for such biopolymers. In this work, we have focused on understanding the mechanical role of agarose and collagen concentration on the hydrogel strength and elastic behavior. In this direction, Amirkabir Magnetic Bead Rheometry (AMBR) characterization device equipped with an optimized electromagnet, was designed and constructed for the measurement of hydrogel mechanical properties. The operation of AMBR set-up is based on applying a magnetic field to actuate magnetic beads in contact with the gel surface in order to actuate the gel itself. In simple terms the magnetic beads leads give rise to mechanical shear stress on the gel surface when under magnetic influence and together with the associated bead-gel displacement it is possible to calculate the hydrogel shear modulus. Agarose and Collagen gels with respectively 0.2-0.6 wt % and 0.2-0.5 wt % percent concentrations were prepared for mechanical characterization in terms of their shear modulus. The shear modulus values for the different percent concentrations of the agarose gel were obtained in the range 250-650 Pa, indicating the shear modulus increases by increasing in the agar gel concentration. In addition to this, the values of shear modulus for the collagen gel increase as function of concentration in the range 240-520 Pa in accordance with an approximately linear relationship between collagen concentration and gel strength.
天然生物聚合物水凝胶，特别是琼脂糖和胶原凝胶，由于其与细胞的生物相容性以及模拟生物组织的能力，近年来已广泛应用于体外实验和组织工程应用；然而，它们的机械性能并不总是满足这些应用的要求。鉴于水凝胶机械性能的重要性，许多针对这些生物聚合物的机械特性研究已经开展。在这项工作中，我们专注于理解琼脂糖和胶原浓度对水凝胶强度和弹性行为的机械作用。为此，我们设计并构建了配备优化电磁体的 Amirkabir 磁性珠流变仪（AMBR），用于测量水凝胶的机械性能。AMBR 装置的操作基于施加磁场以使与凝胶表面接触的磁性珠产生运动，从而激活凝胶本身。简单来说，当受到磁场影响时，磁性珠会在凝胶表面产生机械剪切应力，同时结合相关的珠-凝胶位移，就可以计算出水凝胶的剪切模量。为了进行机械特性表征，我们分别制备了 0.2-0.6wt%和 0.2-0.5wt%浓度的琼脂糖和胶原凝胶。不同浓度琼脂糖凝胶的剪切模量值在 250-650Pa 范围内，表明随着琼脂糖浓度的增加，剪切模量也随之增加。此外，胶原凝胶的剪切模量值随浓度的增加而增加，在 240-520Pa 范围内符合胶原浓度与凝胶强度之间的近似线性关系。
