Imaging GPCR Dimerization in Living Cells with Cucurbit[7]uril and Hemicyanine as a "Turn-On" Fluorescence Probe.

Although multiple forms of dimers have been described for GPCR, their dynamics and function are still controversially discussed field. Fluorescence microscopy allows GPCR to be imaged within their native context; however, a key challenge is to site-specifically incorporate reporter moieties that can produce high-quality signals upon formation of GPCR dimers. To this end, we propose a supramolecular sensor approach to detect agonist-induced dimer formation of μ-opioid receptors (μORs) at the surface of intact cells.

Magnetic Liposomes Infused with GPCR-Expressing Cell Membrane for Targeted Extraction Using Minimum Organic Solvent: An Investigative Study of Trace THC in Sewage.

Trace analysis of lipophilic substances in complex environmental, food, or biological matrices has proven to be a challenge, on account of their high susceptibility to adsorption by particulate matter and liquid-solid interfaces. For this purpose, liquid-liquid extraction (LLE) is often employed as the separation method, which uses water-immiscible organic solvents. As an alternative, magnetic solid-phase extraction (MSPE) allows for adsorption, separation, and recovery of analytes from large volumes of aqueous samples with minimum usage of organic solvents.

A light-up fluorescence probe for wash-free analysis of Mu-opioid receptor and ligand-binding events.

With the aggravated burden of opioid use disorder spreading worldwide, demands for new forms of opioid receptor agonist/antagonist constitute immense research interest. The Mu-opioid receptor (MOR) is currently in the spotlight on account of its general involvement in opioid-induced antinociception, tolerance and dependence. MOR binding assay, however, is often complicated by difficulty in MOR separation and purification, as well as the tedious procedure in standard biolayer interferometry and surface plasmon resonance measurements.

Cucurbituril-protected dual-readout gold nanoclusters for sensitive fentanyl detection.

A large number of cases showed that fentanyl (FEN) has become the main cause of death from illegal drug overdose owing to its potent effect on respiratory depression, which has emerged as a grave threat to public health and safety. However, traditional analytical methods require cost-prohibitive equipment, complex pretreatment procedures, and technically trained experts, thus highlighting the urgent need to develop a cost-effective, straightforward, and highly sensitive method to detect FEN. This work demonstrated a dual-readout sensor FGGC-AuNCs@Q7 for FEN detection, which is based on the molecular recognition and self-assembly between the macrocycle cucurbit[7]uril (Q7) and FEN, accompanying spontaneous visual Tyndall effect and fluorescence optical responses of the gold nanoclusters within seconds.

Label-free tumor cell screening based on IDO1-mediated tryptophan metabolism at single cell level.

Indoleamine 2,3-dioxygenase 1 (IDO1) plays a critical role in inflammatory and immunometabolism programming through catalyzing the oxidation of tryptophan (Trp) into downstream N-formylkynurenine. IDO1 is typically up-regulated in malignant tumors, making it a potential biomarker for cancer diagnosis. Here we show an effective strategy for tumor cell detection by integrating IDO1 activity assay with single cell-encapsulated droplets on a microfluidic platform for high-throughput bioanalysis.

Induction of CYP450 by illicit drugs: Studies using an in vitro 3D spheroidal model in comparison to animals.

Information regarding the metabolism of illicit drugs is under urgent need for toxicological assessment. Its development, however, is limited by the currently available animal models. To this end, we proposed three-dimensional (3D) HepaRG spheroids as an in vitro model to study the effects of illicit drugs on hepatic cytochrome P450 (CYP450) enzymes and potential drug-drug interactions (DDIs).

Teaching PCR for Simultaneous Sensing of Gene Transcription and Downstream Metabolites by Cucurbit[8]uril-Mediated Intervention of Polymerase Activity.

The target of typical PCR analysis is restricted to nucleic acids. To this end, we report here a novel strategy to simultaneously detect genetic and metabolic markers using commercial PCR kits with cucurbit[8]urils (CB[8]) implemented to manipulate the activity of Taq DNA polymerase. CB[8] binds with the nonionic surfactants and displaces them from the polymerase surface, resulting in decreased enzyme activity.

Using dual exonucleases to finely distinguish structural adjustment of aptamers for small-molecule detection.

The binding of small molecules to their DNA aptamers can modulate their susceptibility to digestion by exonucleases, however, absolute differentiation between digestion and inhibition has never been reported. Here, we show that the digestion of aptamers by T7 exonuclease can be completely inhibited upon binding of small-molecule targets and exploit this finding for the first time to achieve sensitive, label-free small-molecule detection. We use a quinine-binding aptamer to show that target binding entirely halts T7 exonuclease digestion, leaving behind an intact double-stranded product that retains strong target affinity.

Orally administered mesoporous silica capped with the cucurbit[8]uril complex to combat colitis and improve intestinal homeostasis by targeting the gut microbiota.

Rationale: Inflammatory bowel diseases (IBDs) are still awaiting innovative treatments that can maximize the efficiency of site-specific drug release in the colon while enhancing intestinal homeostasis.

Methods: Herein, we present multilayer-coated mesoporous silica (MSs) which release payload drugs specifically in the colon tract in the presence of azoreductase produced by the gut microbiota, and simultaneously rejuvenate the tryptophan metabolism of the microbiome to induce activation of the aryl hydrocarbon receptor (AHR) for increased anti-inflammatory effects. The MSs were prepared by using cucurbit[8]uril (CB[8]) as a supramolecular "handcuff" to assemble chitosan/hyaluronic acid multilayers on the periphery of a mesoporous silica core.

Displacement Induced Off-On Fluorescent Biosensor Targeting IDO1 Activity in Live Cells.

We show how the macrocyclic host cucurbit[8]uril (CB[8]) and a fluorescent dye form a biosensing ensemble while its cavity simultaneously traps tryptophan, the upstream substrate of IDO1 enzymes, therefore providing a label-free method to monitor the activity of IDO1 in real time. Incubation of malignant HeLa and HepG2 cells overexpressing IDO1 with the associative biosensor resulted in its spontaneous uptake and a fluorescence switch-on response , which can be traced to the displacement of tryptophan from CB[8] upon IDO1-catalyzed oxidation. The results, for the first time, establish a supramolecular sensing concept for the detection of intracellular enzymatic activity in live cells, thus allowing direct cell-based analysis and inhibitor screening compatible with commercial instruments including microplate reader, fluorescent microscopy, and flow cytometry.