Development of LEDs-based microplate reader for bioanalytical assay measurements

Abstract

The optical design for an LEDs-based microplate reader that can perform fluorescence intensity (top and bottom), absorbance, luminescence and time-resolved fluorescence measurements is described. The microplate reader is the first microplate reader in the marketplace that incorporates LEDs as excitation light sources. Absorbance measurements over the 0–3.5 optical density range for caffeine solution are presented. Additionally, fluorescence intensity readings collected at 535 and 625 nm from a green and a red RediPlateTM are reported. Furthermore, fluorescence decay lifetime measurements obtained for Eu (europium) and Sm (samarium) standard solutions using 370 nm excitation are presented. The microplate reader detection limits for the fluorescence intensity top, fluorescence intensity bottom, fluorescence polarization and time-resolved fluorescence modes are 1.5 fmol 100 µL−1 fluorescein (384-well plate), 25 fmol 100 µL−1 fluorescein (384-well plate), 5 mP at 10 nM fluorescein (black 384-well plate) and 30 amol 100 µL−1 europium solution (white 384-well plate), respectively.

High-power white LED-based system incorporating a CCD Offner imaging spectrometer for real-time fluorescence qPCR measurements

“…Here, it is worth noting that the use of LEDs in bioanalytical instrumentation offers several benefits over the usage of lasers and lamps due to their long lifetime (>100 000 h), very low cost, small size, low maintenance, modularity, power stability and low power consumption [10,11]. An essential enabler for using LEDs as an efficient excitation light source and for collecting and shaping radiation emitted from the LED package is the usage of plastic optics that utilize the principle of total internal reflection (TIR) in guiding light [12,13] to the reaction vessel.…”