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As one of the most important minerals in the body, potassium is vital for the heart and neurons. Methods that can non‐invasively and accurately monitor changes in potassium balances would benefit disease diagnoses as well as offer insight into pathologies. Among the sensing approaches, fluorescent probes serve as a unique detection method for its simplicity, tunable detection range, and bioimaging ability. The design of new probes with highly selective K⁺receptors and transduction functionality remains a challenge that is motivated by numerous sensing and detection applications. In this minireview, fluoroionophores are summarized that undergo transduction, producing fluorescence signals when interacting with, e. g., potassium ions. The properties of ionophores (afford selective interaction with potassium) and fluorophores (generate signal read‐out) are discussed. Molecular structure design and sensing mechanisms are included along with cell imaging applications. The selectivity towards K⁺and the absorption/emission characteristics of the probes are of particular interest.

Chemoresistance is one of the major challenges for cancer treatment, more recently ascribed to defective mitochondrial outer membrane permeabilization (MOMP), significantly diminishing chemotherapeutic agent‐induced apoptosis. A boron‐dipyrromethene (BODIPY) chromophore‐based triarylsulfonium photoacid generator (BD‐PAG) was used to target mitochondria with the aim to regulate mitochondrial pH and further depolarize the mitochondrial membrane. Cell viability assays demonstrated the relative biocompatibility of BD‐PAG in the dark while live cell imaging suggested high accumulation in mitochondria. Specific assays indicated that BD‐PAG is capable of regulating mitochondrial pH with significant effects on mitochondrial membrane depolarization. Therapeutic tests using chlorambucil in combination with BD‐PAG revealed a new strategy in chemoresistance suppression.

Acid‐sensing ion channels (ASICs), present in both central and peripheral neurons, respond to changes in extracellular protons. They play important roles in many symptoms and diseases, such as pain, ischemic stroke and neurodegenerative diseases. Herein, we report a novel approach to activate ASICs with the precision of light using organic photoacid generators (PAGs), which are molecules that release H⁺upon light illumination, and have been recently used in biomedical studies. The PAGs showed low toxicity in dark conditions. Under LED light illumination, ASICs activation and consequent calcium ion influx was monitored and analysed by fluorescence microscopy, and showed a strong light‐dependent response. This approach allows the activation of ASICs with the precision of light, and may be valuable to help better elucidate the molecular mechanism of ASICs and unveil their roles in physiology, pathophysiology, and behaviour.