Department of Health Technology, Technical University of Denmark, Lyngby, Denmark.
PLoS One. 2022 Feb 25;17(2):e0263282. doi: 10.1371/journal.pone.0263282. eCollection 2022.
Microdroplet arrays (MDAs) are powerful tools for digital immunoassays, high-throughput screening and single cell analysis. However, MDAs are usually produced with cleanroom processes, which are associated with high costs and low availability. Furthermore, in order to obtain robust and stable MDAs based on hydrophilic spots surrounded by a hydrophobic background, the chemistry must be strictly controlled, which is challenging using shared equipment. Here, we developed a new method to fabricate MDA substrates independently from the cleanroom. A small and low-cost in-house built system to collimate the light source was assembled for photopatterning a negative resist, and spots with diameters down to 4 μm were obtained, with only 3% to 5% spot-to-spot variation across the same sample and high batch-to-batch reproducibility. The use of a negative photoresist enabled the formation of a hydrophobic coating in solution which yielded high-quality MDAs. The feasibility for carrying out digital assays was demonstrated by measuring anti-Tau antibody in sample buffers containing bovine serum albumin, with no noticeable surface fouling. The reported, robust, cost-effective, and fast process could hence lower the threshold to fabricate and use MDAs for digital immunoassays and other microcompartmentalization-based applications.
微滴阵列（MDAs）是数字免疫分析、高通量筛选和单细胞分析的强大工具。然而，MDAs 通常是通过洁净室工艺生产的，这与高成本和低可用性有关。此外，为了获得基于亲水斑点被疏水背景包围的稳健和稳定的 MDAs，化学必须严格控制，这在使用共享设备时具有挑战性。在这里，我们开发了一种新的方法，可以在不依赖洁净室的情况下制造 MDA 基板。组装了一个小型、低成本的内部构建系统来准直光源，用于对负性抗蚀剂进行光图案化，得到的斑点直径可低至 4 μm，在同一样品上的斑点之间变化仅为 3%至 5%，并且具有很高的批间重现性。使用负性光致抗蚀剂可以在溶液中形成疏水涂层，从而产生高质量的 MDAs。通过在含有牛血清白蛋白的样品缓冲液中测量抗 Tau 抗体，证明了进行数字分析的可行性，没有明显的表面污垢。因此，所报道的稳健、经济高效且快速的工艺可以降低制造和使用 MDAs 进行数字免疫分析和其他基于微分隔的应用的门槛。
