An anthracene extended viologen-incorporated ionic porous organic polymer for efficient aerobic photocatalysis and antibacterial activity

A new conjugated ionic porous organic polymer (AN-POP), incorporated with anthracene-extended viologen, has been rationally designed and prepared to explore its dual functions in photocatalytic oxidation and bacterial killing. Compared with its anthracene-free counterpart (BD-POP), AN-POP showed a superior photocatalytic oxidation performance and antibacterial activity demonstrating the critical role of an anthracene-extended viologen structure.

A Practical and High-Affinity Fluorescent Probe for Uridine Diphosphate Glucuronosyltransferase 1A1: A Good Surrogate for Bilirubin

This study aimed to develop a practical and high-affinity fluorescent probe for uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1), a key conjugative enzyme responsible for the elimination and detoxification of many potentially harmful compounds. Several substrates derived from N-butyl-4-phenyl-1,8-naphthalimide were designed and synthesized on the basis of the substrate preference of UGT1A1 and the principle of photoinduced electron transfer (PET). Following the preliminary screening, substrate 2 was found with a high specificity and high affinity toward UGT1A1, while such biotransformation brought remarkable changes in fluorescence emission. Both inhibition kinetic analyses and molecular docking simulations demonstrated that 2 could bind on UGT1A1 at the same ligand-binding site as bilirubin. Furthermore, this newly developed probe was successfully used for sensing UGT1A1 activities and the high-throughput screening of UGT1A1 modulators in complex biological samples. In conclusion, a practical and high-affinity fluorescent probe for UGT1A1 was designed and well-characterized, which could serve as a good surrogate for bilirubin to investigate UGT1A1-ligand interactions.

A practical strategy to design and develop an isoform-specific fluorescent probe for a target enzyme: CYP1A1 as a case study

The development of isoform-specific probe(s) for a target enzyme with multiple homologs is always challenging. Herein, a practical strategy was used to design and develop an isoform-specific probe for CYP1A1, a key cytochrome P450 isoenzyme involved in xenobiotic metabolism and bioactivation. On the basis of the subtle differences in 3D structure and substrate preference between CYP1A1 and its homolog CYP1A2, we proposed that it was possible to design a CYP1A1-specific probe via local modification of the reaction site on known CYP1A substrates. To validate this hypothesis, 4-hydroxy-1,8-naphthalimide (HN) was selected as the basic fluorophore due to its excellent optical properties, while a series of O-alkylated HN derivatives were prepared to evaluate their specificity towards CYP1A1. Our results revealed that the introduction of a chloroethyl to HN could get the best isoform selectivity towards CYP1A1 over other CYPs including CYP1A2. The newly developed probe NBCeN exhibited excellent specificity, high sensitivity, and a ratiometric fluorescence response following CYP1A1-catalyzed O-dechloroethylation. NBCeN was successfully used to real-time monitor the activity of CYP1A1 in complex biological samples and to rapidly screen CYP1A1 modulators in living systems. NBCeN could also be used for two-photon imaging of intracellular CYP1A1 in living cells and tissues with high ratiometric imaging resolution and deep tissue penetration. All these findings demonstrated that local modification of non-specific substrates was a practical strategy to develop an isoform-specific probe for a target isoenzyme, while NBCeN could serve as a specific imaging tool to explore the biological functions of CYP1A1 in complex biological systems.

A rapid-response fluorescent probe for the sensitive and selective detection of human albumin in plasma and cell culture supernatants

A rapid-response fluorescent probeACDMwas developed for selective and sensitive detection of human albumin (HA)viabinding on a non-drug binding site.

A highly selective marker reaction for measuring the activity of human carboxylesterase 1 in complex biological samples

NMHN hydrolysis was found to be a highly selective marker reaction for sensing the activity of human carboxylesterase 1 (hCE1).

A Two-Photon Ratiometric Fluorescent Probe for Imaging Carboxylesterase 2 in Living Cells and Tissues

In this study, a two-photon ratiometric fluorescent probe NCEN has been designed and developed for highly selective and sensitive sensing of human carboxylesterase 2 (hCE2) based on the catalytic properties and substrate preference of hCE2. Upon addition of hCE2, the probe could be readily hydrolyzed to release 4-amino-1,8-naphthalimide (NAH), which brings remarkable red-shift in fluorescence (90 nm) spectrum. The newly developed probe exhibits good specificity, ultrahigh sensitivity, and has been successfully applied to determine the real activities of hCE2 in complex biological samples such as cell and tissue preparations. NCEN has also been used for two-photon imaging of intracellular hCE2 in living cells as well as in deep-tissues for the first time, and the results showed that the probe exhibited high ratiometric imaging resolution and deep-tissue imaging depth. All these findings suggested that this probe holds great promise for applications in bioimaging of endogenous hCE2 in living cells and in exploring the biological functions of hCE2 in complex biological systems.

An optimized ratiometric fluorescent probe for sensing human UDP-glucuronosyltransferase 1A1 and its biological applications

This study aimed to develop a practical ratiometric fluorescent probe for highly selective and sensitive detection of human UDP-glucuronosyltransferase 1A1 (UGT1A1), one of the most important phase II enzymes. 4-Hydroxy-1,8-naphthalimide (HN) was selected as the fluorophore for this study because it possesses intramolecular charge transfer (ICT) feature and displays outstanding optical properties. A series of N-substituted derivatives with various hydrophobic, acidic and basic groups were designed and synthesized to evaluate the selectivity of HN derivatives toward UGT1A1. Our results demonstrated that the introduction of an acidic group to HN could significantly improve the selectivity of UGT1A1. Among the synthesized fluorescent probes, NCHN (N-3-carboxy propyl-4-hydroxy-1,8-naphthalimide) displayed the best combination of selectivity, sensitivity and ratiometric fluorescence response following UGT1A1-catalyzed glucuronidation. UGT1A1-catalyzed NCHN-4-O-glucuronidation generated a single fluorescent product with a high quantum yield (Φ=0.688) and brought remarkable changes in both color and fluorescence in comparison with the parental substrate. The newly developed probe has been successfully applied for sensitive measurements of UGT1A1 activities in human liver preparations, as well as for rapid screening of UGT1A1 modulators, using variable enzyme sources. Furthermore, its potential applications for live imaging of endogenous UGT1A1in cells have also been demonstrated.

A highly selective long-wavelength fluorescent probe for the detection of human carboxylesterase 2 and its biomedical applications

A highly selective long-wavelength fluorescent probe for the detection of human carboxylesterase 2 (hCE2) has been developed and well characterized. The probe can be used for measuring the real activities of hCE2 in complex biological systems.