Dept. of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT, UK.
School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
Mater Sci Eng C Mater Biol Appl. 2021 Oct;129:112383. doi: 10.1016/j.msec.2021.112383. Epub 2021 Aug 19.
Poly(vinyl alcohol) (PVA) cryogel is a biocompatible, synthetic hydrogel, compatible with magnetic resonance (MR) imaging. It is widely used as a biomaterial in tissue scaffolds and mimics to test various diagnostic techniques. The aim of this study is to characterise the effect of varying PVA concentration, molecular weight (MW) and manufacturing protocol on the viscoelastic mechanical properties and MR T relaxation time. Further to this MR imaging (MRI) was investigated as a method to quantify material homogeneity. Cylindrical samples of PVA, of varying MW, concentration and number of freeze thaw cycles (FTCs), were manufactured. Dynamic mechanical analysis was performed to evaluate the storage and loss moduli between frequencies of 0.5 and 10 Hz. MR T relaxation maps were imaged using a 7 T MRI instrument. Storage and loss moduli were shown to increase with MW, concentration, or the number of FTCs; with storage modulus ranging from 55 kPa to 912 kPa and loss modulus ranging from 6 kPa to 103 kPa. MR T relaxation time was shown to increase linearly with PVA concentration. The qualitative and quantitative heterogeneity of the PVA sample were identified through MR T relaxation time maps. Excitingly, PVA demonstrated a composition-dependent casual correlation between the viscoelastic mechanical properties and MR T relaxation time. In conclusion, this research thoroughly characterised the viscoelastic mechanical properties of PVA to support its extensive use as a biomaterial, and demonstrated the use of MRI to non-invasively identify sample heterogeneity and to predict the composition-dependent viscoelastic properties of PVA.
聚乙烯醇（PVA）水凝胶是一种生物相容性的合成水凝胶，与磁共振（MR）成像兼容。它广泛用作组织支架和模拟物的生物材料，用于测试各种诊断技术。本研究旨在描述 PVA 浓度、分子量（MW）和制造方案的变化对粘弹性力学性能和 MR T 弛豫时间的影响。此外，还研究了 MR 成像（MRI）作为量化材料均匀性的方法。制造了不同 MW、浓度和冻融循环（FTC）次数的 PVA 圆柱形样品。通过动态力学分析在 0.5 和 10 Hz 之间的频率下评估存储和损耗模量。使用 7 T MRI 仪器对 MR T 弛豫图谱进行成像。存储和损耗模量均随 MW、浓度或 FTC 次数的增加而增加；存储模量范围为 55 kPa 至 912 kPa，损耗模量范围为 6 kPa 至 103 kPa。MR T 弛豫时间随 PVA 浓度呈线性增加。通过 MR T 弛豫时间图谱确定了 PVA 样品的定性和定量异质性。令人兴奋的是，PVA 表现出粘弹性力学性能与 MR T 弛豫时间之间的组成依赖性因果关系。总之，本研究彻底描述了 PVA 的粘弹性力学性能，以支持其作为生物材料的广泛应用，并展示了使用 MRI 进行非侵入性识别样品异质性和预测 PVA 的组成依赖性粘弹性特性。
