Harvie Andrew J, Yadav Surendra K, de Mello John C
Department of Chemistry, NTNU, Trondheim, Norway.
HardwareX. 2021 Sep 2;10:e00228. doi: 10.1016/j.ohx.2021.e00228. eCollection 2021 Oct.
We report a sensitive, fixed-wavelength, lock-in-based optical detector built from a light-emitting diode, two colour filters, a photodetector, a small number of discrete analogue components, and a low-cost microcontroller development board. We describe the construction, operating principle, use and performance of the optical detector, which may be used for both absorption and fluorescence measurements in either a 10-mm pathlength cuvette or a low-volume (<100 μl) flow-cell. For illustrative purposes the detector is applied here to a cholesterol assay based on the enzyme-mediated conversion of (non-emissive) Amplex Red into the fluorescent dye resorufin, providing a detection limit of 200 nM - some four orders of magnitude lower than the typical concentration of cholesterol in human serum. (The resorufin molecule itself is detectable down to concentrations of 20 nM). The system may be readily adapted to other biomolecules through a simple change of enzyme.
我们报告了一种基于锁相放大器的灵敏、固定波长光学探测器，它由一个发光二极管、两个滤光片、一个光电探测器、少量分立模拟元件和一个低成本微控制器开发板构成。我们描述了该光学探测器的构造、工作原理、用途及性能，它可用于10毫米光程比色皿或小体积（<100微升）流通池的吸收和荧光测量。为便于说明，该探测器在此应用于基于酶介导将（非发射性的）Amplex Red转化为荧光染料试卤灵的胆固醇测定，检测限为200 nM，比人血清中胆固醇的典型浓度低约四个数量级。（试卤灵分子本身在浓度低至20 nM时即可检测到）。通过简单更换酶，该系统可轻松适用于其他生物分子。
