Electrical and Computer Engineering Department, Baylor University, One Bear Place #97356, Waco, TX 76798, USA.
Biosensors (Basel). 2020 Dec 24;11(1):4. doi: 10.3390/bios11010004.
An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.
一种基于光学腔的生物传感器（OCB）已被开发用于即时检测（POC）应用。这种无标记生物传感器采用低成本组件和简单的制造工艺，通过差分检测方法降低整体成本，同时实现高灵敏度。为了实验证明其检测限（LOD），我们进行了链霉亲和素和 C 反应蛋白（CRP）的生物传感实验。进一步优化了光学腔结构，以提高灵敏度和更易于控制流体。我们利用聚合物溶胀特性来微调光学腔宽度，这显著提高了产生可测量样品的成功率。我们以三重复制的方式测试了四种不同浓度的链霉亲和素，OCB 的 LOD 被确定为 1.35 nM。OCB 还成功地使用生物素化 CRP 抗体检测了三种不同浓度的人 CRP。CRP 检测的 LOD 为 377 pM。所有测量均在 30 分钟内使用 15 µL 的小样本量完成。通过减小检测面积、改进功能化和钝化工艺以及增加样品体积，预计 OCB 的 LOD 将进一步降低到飞摩尔范围。总的来说，本工作中展示的 OCB 的性能表明，它有很大的潜力成为一种有前途的 POC 生物传感器。
