Electrogenerated Chemiluminescence Detection in Paper-Based Microfluidic Sensors

TLDR

The study introduces the first integration of paper microfluidics with electrochemiluminescent detection. Inkjet‑printed paper microfluidic channels are paired with screen‑printed electrodes to form inexpensive, disposable sensors that generate orange luminescence via the Ru(bpy)₃²⁺ ECL reaction with analytes, enabling readout without a conventional photodetector. Using a conventional photodetector, the sensors detected 2‑(dibutylamino)ethanol at 0.9 µM and NADH at 72 µM, and a mobile phone camera could detect the same analyte at 250 µM by analyzing red‑pixel intensity.

Abstract

This paper describes the first approach at combining paper microfluidics with electrochemiluminescent (ECL) detection. Inkjet printing is used to produce paper microfluidic substrates which are combined with screen-printed electrodes (SPEs) to create simple, cheap, disposable sensors which can be read without a traditional photodetector. The sensing mechanism is based on the orange luminescence due to the ECL reaction of tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) with certain analytes. Using a conventional photodetector, 2-(dibutylamino)ethanol (DBAE) and nicotinamide adenine dinucleotide (NADH) could be detected to levels of 0.9 μM and 72 μM, respectively. Significantly, a mobile camera phone can also be used to detect the luminescence from the sensors. By analyzing the red pixel intensity in digital images of the ECL emission, a calibration curve was constructed demonstrating that DBAE could be detected to levels of 250 μM using the phone.