BioPRIA, Department of Chemical Engineering, Monash University, Australia.
CSIRO Manufacturing, Clayton, Australia.
Colloids Surf B Biointerfaces. 2017 Oct 1;158:197-202. doi: 10.1016/j.colsurfb.2017.07.005. Epub 2017 Jul 3.
Paper has been used to engineer many types of bio-diagnostics. A major issue to most paper-based bio-diagnostics is the biomolecule instability causing the short shelf-life of the diagnostics. Commercial papers contain various polymeric additives. Polyamidoamine-epichlorohydrin (PAE), a polyelectrolyte typically used as wet-strength agent, is commonly used in filter papers and paper towels, which are often used as substrate in bioactive paper. However, the effect of cellulose or polymeric additives on antibody bioactivity is unknown. This limits paper optimization for diagnostic applications. In this study, model papers were made with and without PAE addition. IgM Anti-A blood typing antibody was physisorbed and dried on paper, aged for up to 9 weeks at different relative humidity (RH) conditions and the antibody activity was measured. The antibody bioactivity was represented as blood typing efficiency measured by image analysis. The surface chemical composition was measured using X-ray photoelectron spectroscopy (XPS). Antibody bioactivity loss was promoted by elevated RH, corresponding to increased paper water content. PAE significantly reduces the paper water content under ambient environment. Antibody bioactivity is higher on paper made with PAE under the high humidity conditions (57.6%-84.3% RH). However, under conditions of humidity saturation (100%RH), PAE shows little effect on reducing paper water content nor on protecting antibody bioactivity. These results demonstrate the water content of paper to be associated with antibody bioactivity loss.
纸张已被用于设计多种生物诊断试剂。对于大多数基于纸张的生物诊断试剂来说，一个主要问题是生物分子不稳定，导致诊断试剂的保质期较短。商业纸张含有各种聚合添加剂。聚酰胺-表氯醇（PAE）是一种常用的湿强剂，通常用于滤纸和纸巾中，这些纸常被用作生物活性纸的基底。然而，纤维素或聚合添加剂对抗体生物活性的影响尚不清楚。这限制了纸张在诊断应用中的优化。在这项研究中，制备了含有和不含有 PAE 添加的模型纸张。IgM 抗 A 血型抗体通过物理吸附在纸上，并在不同相对湿度（RH）条件下干燥和老化，最长可达 9 周，然后测量抗体的活性。抗体生物活性通过图像分析测量的血型鉴定效率来表示。使用 X 射线光电子能谱（XPS）测量表面化学组成。抗体生物活性的损失是由高 RH 促进的，这与纸张含水量的增加相对应。PAE 在环境条件下显著降低纸张的含水量。在高湿度条件（57.6%-84.3% RH）下，含有 PAE 的纸张上的抗体生物活性更高。然而，在湿度饱和（100%RH）条件下，PAE 对降低纸张含水量和保护抗体生物活性几乎没有影响。这些结果表明纸张的含水量与抗体生物活性的损失有关。
