Time-resolved luminescence imaging of hydrogen peroxide using sensor membranes in a microwell format

We demonstrate an optical imaging scheme for hydrogen peroxide in a microwell-based format using the europium(III) tetracycline complex as the fluorescent probe, which is incorporated into a polyacrylonitrile-co-polyacrylamide polymer matrix. The resulting sensor membranes are integrated into a 96-microwell plate. Hydrogen peroxide can be visualized by means of time-resolved luminescence lifetime imaging. The imaging system consists of a fast, gated charge-coupled device (CCD) camera and a pulsed array of 96 light emitting diodes (LEDs). Fluorescence lifetime images are acquired in different modes (rapid lifetime determination, RLD, and phase delay rationing, PDR) and compared with conventional intensity-based methods with respect to sensitivity and the dynamic range of the sensor. The lowest limits of detection can be achieved by the RLD method. The response time of the sensor is comparatively high, typically in the range of 10 to 20 minutes, but the response is reversible. The largest signal changes are observed at pH values between 6.5 and 7.5.