Fluorescence for spatially and temporally resolved electrochemical imaging

Extending the detection capabilities of traditional spectroelectrochemical investigations, closed-bipolar electrochemical imaging (c-BPI) has demonstrated its unique ability to spatially resolve and individually address millions to even billions of individual points of detection without the need for any direct electrical connections. Coupling optical and electrochemical signals, the key challenge becomes resolving the optical response at individual closed-bipolar electrodes within an array to successfully image electrochemical heterogeneity. At the heart of this challenge is the choice between electrochemiluminescence or electrogenerated fluorescence reporting systems and the key tradeoff between spatial resolution and photon efficiency. Working to address this tradeoff, we focus on fluorescence as a useful closed-bipolar imaging tool with great potential for sensing the ultra-transient. We consider the advantages as well as the present challenges of electrofluorogenic reporting strategies in order to offer solutions through an examination of existing direct and indirect approaches towards electrochemical fluorescence imaging applicable to closed-bipolar sensing systems.