Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
Talanta. 2022 Feb 1;238(Pt 2):123056. doi: 10.1016/j.talanta.2021.123056. Epub 2021 Nov 9.
We report the use of a laser-based fabrication process in the creation of paper-based flow-through filters that when combined with a traditional lateral flow immunoassay provide an alternative pathway for the detection of a pre-determined analyte over a wide concentration range. The laser-patterned approach was used to create polymeric structures that alter the porosity of the paper to produce porous flow-through filters, with controllable levels of porosity. When located on the top of the front end of a lateral flow immunoassay the flow-through filters were shown to block particles (of known sizes of 200 nm, 500 nm, 1000 nm and 3000 nm) that exceed the effective pore size of the filter while allowing smaller particles to flow through onto a lateral flow immunoassay. The analyte detection is based on the use of a size-exclusive filter that retains a complex (∼3 μm in size) formed by the binding of the target analyte with two antibodies each of which is tagged with different-sized labels (40 nm Au-nanoparticles and 3 μm latex beads), and which is larger than the effective pore size of the filter. This method was tested for the detection of C-reactive protein in a broad concentration range from 10 ng/ml to 100,000 ng/ml with a limit-of-detection found at 13 ng/ml and unlike other reported methods used for analyte detection, with this technique we are able to counter the Hook effect which is a limiting factor in many lateral flow immunoassays.
我们报告了一种基于激光的制造工艺在纸基流动过滤器中的应用，当与传统的侧向流动免疫分析结合使用时，为在宽浓度范围内检测预定分析物提供了另一种途径。激光图案化方法用于创建改变纸张孔隙率的聚合物结构，以产生具有可控孔隙率的多孔流动过滤器。当位于侧向流动免疫分析的前端顶部时，流动过滤器被证明可以阻挡超过过滤器有效孔径的颗粒（已知尺寸为 200nm、500nm、1000nm 和 3000nm 的颗粒），同时允许较小的颗粒流过侧向流动免疫分析。分析物的检测基于使用尺寸排他性过滤器，该过滤器保留了由目标分析物与两种抗体结合形成的复合物（大小约为 3μm），每个抗体都带有不同尺寸的标记（40nm 金纳米颗粒和 3μm 乳胶珠），并且大于过滤器的有效孔径。该方法用于在 10ng/ml 至 100000ng/ml 的宽浓度范围内检测 C 反应蛋白，检测限为 13ng/ml，与用于分析物检测的其他报道方法不同，使用这种技术，我们能够对抗许多侧向流动免疫分析中的限制因素——钩状效应。
