A sensitive and compact optical detector based on digital lock-in amplification

HardwareX

Surendra K. Yadav¹  Andrew J. Harvie²  John C. de Mello³ 

[1] Department of Chemistry, NTNU, Trondheim, Norway;Corresponding authors.;Department of Chemistry, NTNU, Trondheim, Norway;

关键词: Bioassays;    Fluorescence;    3D printing;    Open hardware;    Digital signal processing;    Lock-in;   

DOI  :  

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown