Publication June 2009, 25

DEVELOPMENT OF A NEW DEVICE FOR ULTRASENSITIVE ELECTROCHEMILUMINESCENCE MICROSCOPY IMAGING
 
Abstract
Electrochemiluminescence (ECL) is widely used in biosensors and immunoassays thanks to the high sensitivity and specificity of the electrochemically triggered luminescence signal. So far, no applications have been reported on the use of ECL as a probe for ultrasensitive lowlightmicroscopeimaging. This work reports the development of a new transparent electrochemical cell for ECL imaging suitable for single cell analysis. The system is based on the use of a microscope placed in a dark box equipped with a CCD camera and a potentiostat. Transparent conducting glass coated with fluorine-doped tin oxide (FTO) has been used, and a three electrode configuration has been designed. The electrochemical cell was optimized using 8 μm diameter polystyrene beads coated with a Ru(bpy)32+ complex in order to simulate living cells. The Ru(bpy)3 2+ immobilized on the microbeads can be imaged and quantified at a concentration as low as 1 × 10-19 mol/μm2. Microscope imaging showed that the ECL signal was detected only in correspondence to the beads present on the electrode surface, and the probe could be accurately localized with a spatial resolution of 0.4 μm. The new ECL imaging device can be used in conjunction with other chemiluminescence-based imaging methods for ultrasensitive multiplex imaging on cells and tissues.

Figure:  Microscope imaging 20× objective/30 ms. (A) Transmitted light image and (B) ECL image of Ru(bpy)3 2+- conjugated polystyrene microbeads. (C) Overlay of the reflected light image and the false color elaborated CL image.

 
Link: http://pubs.acs.org/doi/abs/10.1021/ac900756a
Publication Date: June 2009, 25