Wenger Lukas, Hubbuch Jürgen
Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Front Bioeng Biotechnol. 2022 Mar 8;10:849271. doi: 10.3389/fbioe.2022.849271. eCollection 2022.
Hydrogels are polymer-based materials with a high water content. Due to their biocompatible and cell-friendly nature, they play a major role in a variety of biotechnological applications. For many of these applications, diffusibility is an essential property influencing the choice of material. We present an approach to estimate diffusion coefficients in hydrogels based on absorbance measurements of a UV area imaging system. A microfluidic chip with a y-junction was employed to generate a fluid-hydrogel interface and the diffusion of lysozyme from the fluid into the hydrogel phase was monitored. Employing automated image and data processing, analyte concentration profiles were generated from the absorbance measurements and fits with an analytical solution of Fick's second law of diffusion were applied to estimate diffusion coefficients. As a case study, the diffusion of lysozyme in hydrogels made from different concentrations (0.5-1.5% (w/w)) of an unmodified and a low-melt agarose was investigated. The estimated diffusion coefficients for lysozyme were between 0.80 ± 0.04×10 m s for 1.5% (w/w) low-melt agarose and 1.14 ± 0.02×10 m s for 0.5% (w/w) unmodified agarose. The method proved sensitive enough to resolve significant differences between the diffusion coefficients in different concentrations and types of agarose. The microfluidic approach offers low consumption of analyte and hydrogel and requires only relatively simple instrumentation.
水凝胶是一种具有高含水量的聚合物基材料。由于其生物相容性和对细胞友好的特性，它们在各种生物技术应用中发挥着重要作用。对于许多这些应用来说，扩散性是影响材料选择的一个关键特性。我们提出了一种基于紫外区域成像系统吸光度测量来估算水凝胶中扩散系数的方法。采用带有Y型交叉点的微流控芯片来产生流体 - 水凝胶界面，并监测溶菌酶从流体向水凝胶相的扩散。通过自动图像和数据处理，从吸光度测量中生成分析物浓度分布，并应用与菲克第二扩散定律的解析解拟合来估算扩散系数。作为一个案例研究，研究了溶菌酶在由不同浓度（0.5 - 1.5%（w/w））的未改性琼脂糖和低熔点琼脂糖制成的水凝胶中的扩散。溶菌酶的估算扩散系数在1.5%（w/w）低熔点琼脂糖的0.80 ± 0.04×10⁻¹⁰ m² s⁻¹和0.5%（w/w）未改性琼脂糖的1.14 ± 0.02×10⁻¹⁰ m² s⁻¹之间。该方法被证明足够灵敏，能够分辨不同浓度和类型琼脂糖的扩散系数之间的显著差异。微流控方法消耗的分析物和水凝胶较少，并且只需要相对简单的仪器设备。
