Multianalyte Sensing of Addictive Over-the-Counter (OTC) Drugs

A supramolecular sensor array composed of two fluorescent cucurbit­[<i>n</i>]­uril-type receptors (probe <b>1</b> and probe <b>2</b>) displaying complementary selectivities was tested for its ability to detect and quantify drug-related amines. The fluorimetric titration of the individual probes showed highly variable and cross-reactive analyte-dependent changes in fluorescence. An excellent ability to recognize a variety of analytes was demonstrated in qualitative as well as quantitative assays. Importantly, a successful quantitative analysis of several analytes of interest was achieved in mixtures and in human urine. The throughput and sensitivity surpass those of the current state-of-the-art methods that usually require analyte solid-phase extraction (SPE). These results open up the opportunity for new applications of cucurbit­[<i>n</i>]­uril-type receptors in sensing and pave the way for the development of simple high-throughput assays for various drugs in the near future

Selective Anion Sensing by Chiral Macrocyclic Receptors with Multiple Hydrogen-Bonding Sites

Chiral macrocycles featuring sulfonamide and/or amide groups as anion-binding sites were synthesized. X-ray crystal structures and DFT calculations have shown that they adopt different conformations that may lead to unique binding behavior. Indeed, various anions could be sensed by their colorimetric and/or fluorescence signal output. The chiral macrocycles showed chiral recognition for chiral anions. Furthermore, a multisensor array with two or four chiral receptors discriminated seven phosphate anions (AMP, ADP, ATP, CMP, GMP, Pi, and PPi) with 100% classification accuracy

Host–Guest Complexes of Pentiptycene Receptors Display Edge-to-Face Interaction

The pentiptycene receptors form edge-to-face complexes with a variety of aromatic guests including nitroaromatics. X-ray diffractometry revealed that compounds <b>1</b>, <b>2</b>, and <b>3</b> form host–guest assemblies with a thienyl fragment (from a neightboring molecule of <b>1</b>), benzene and nitrobenzene, respectively. X-ray studies of the three crystal structures reported here strongly suggest the edge-to-face to be a predominant binding mode between the aromatic guests and electron-rich faces of the pentiptycene aromatic cavity

Selective Anion Sensing by Chiral Macrocyclic Receptors with Multiple Hydrogen-Bonding Sites

Chiral macrocycles featuring sulfonamide and/or amide groups as anion-binding sites were synthesized. X-ray crystal structures and DFT calculations have shown that they adopt different conformations that may lead to unique binding behavior. Indeed, various anions could be sensed by their colorimetric and/or fluorescence signal output. The chiral macrocycles showed chiral recognition for chiral anions. Furthermore, a multisensor array with two or four chiral receptors discriminated seven phosphate anions (AMP, ADP, ATP, CMP, GMP, Pi, and PPi) with 100% classification accuracy

Intramolecular Indicator Displacement Assay for Anions: Supramolecular Sensor for Glyphosate

One of the well-known strategies for anion sensing is an indicator (dye) displacement assay. However, the disadvantage of the dye displacement assays is the low sensitivity due to the excess of the dye used. To overcome this setback, we have developed an “Intramolecular Indicator Displacement Assay (IIDA)”. The IIDAs comprise a receptor and a spacer with an attached anionic chromophore in a single-molecule assembly. In the resting state, the environment-sensitive anionic chromophore is bound by the receptor, while the anionic substrate competes for binding into the receptor. The photophysical properties of the dye exhibit change in fluorescence when displaced by anions, which results in cross-reactive response. To illustrate the concept, we have prepared IID sensors <b>1</b> and <b>2</b>. Here, the characterization of sensors and microtiter arrays comprising the IIDA are reported. The microtiter array including IID sensors <b>1</b> and <b>2</b> is capable of recognizing biological phosphates in water. The utility of the IIDA approach is demonstrated on sensing of a phosphonate herbicide glyphosate and other biologically important anions such as pyrophosphate in the presence of interferent sodium chloride

Supramolecular Sensor for Cancer-Associated Nitrosamines

A supramolecular assay based on two fluorescent cucurbit­[<i>n</i>]­uril probes enables the recognition and quantification of nitrosamines, including cancer-associated nitrosamines, compounds that are difficult to recognize. The cross-reactive sensor leverages weak interactions and competition among the probe, metal, and guest, yielding high information density in the signal output (variance) and enabling the recognition of structurally similar guests