Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Abstract

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/ medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host− guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Cobalt(III) Carbene Complex with an Electronic Excited-State Structure Similar to Cyclometalated Iridium(III) Compounds

“…Coordination complexes and organometallic compounds of ruthenium(II) and iridium(III) are among the most widely used substance classes for applications in lighting, 1 , 2 sensing, 3 photocatalysis, 4 − 9 upconversion, 10 , 11 solar energy conversion, and phototherapy. 12 − 18 Research on precious-metal-based compounds continues to be important because they are comparatively robust and often promise excellent performance.…”

Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor

“…The many advantages of optical sensing schemes triggered an increasing interest in easy-to-prepare and simple-to-handle nanosensors to determine the pH in biofilms with a high accuracy and over extended periods of time. However, many nanosensors reported so far can only map very narrow pH ranges or have a relatively high aggregation tendency in biological systems, which makes them unsuitable for this task 20 , 31 . Moreover, the broad application of such nanosensors for pH measurements in biofilms requires either commercial systems, which are not yet available, or at least sensor particles that can be easily prepared from commercial components without the need for an elaborate synthesis 26 , 32 .…”

Recent advances in tin ion detection using fluorometric and colorimetric chemosensors

“…Up to now, there are numerous published review articles on several analytes [70][71][72][73][74][75] but to the best of our knowledge, this is the first review article on chromogenic and fluorogenic tin chemosensors. In this study, we will focus on the chromogenic and fluorogenic chemosensors that have already been developed for the detection of tin ions since 2012.…”