Dual-Site Chemosensor for Visualizing •OH-GSH Redox and Tracking Ferroptosis-Inducing Pathways In Vivo.

Oxidative stress, characterized by an imbalance between oxidative and antioxidant processes, results in excessive accumulation of intracellular reactive oxygen species. Among these responses, the regulation of intracellular hydroxyl radicals (•OH) and glutathione (GSH) is vital for physiological processes. Real-time in situ monitoring these two opposing bioactive species and their redox interactions is essential for understanding physiological balance and imbalance. In this study, we developed a dual-site fluorescence chemosensor OG-3, which can independently image both exogenous and endogenous •OH and GSH in separate channels both within cells and in vivo, eliminating issues of spatiotemporal inhomogeneous distribution and cross-interference. With its imaging capabilities of monitoring •OH-GSH redox, OG-3 elucidated two different pathways for ferroptosis induction: (i) inhibition of system xc- to block cystine uptake (extrinsic pathway) and (ii) GPX4 inactivation, leading to the loss of antioxidant defense (intrinsic pathway). Moreover, we assessed the antiferroptotic function and effects of ferroptosis inhibitors by monitoring •OH and GSH fluctuations during ferroptosis. This method provides a reliable platform for identifying potential ferroptosis inhibitors, contributing to our understanding of relevant metabolic and physiological mechanisms. It shows potential for elucidating the regulation of ferroptosis mechanisms and investigating further strategies for therapeutic applications.

Dual-Site Chemosensor for Monitoring ·OH-Cysteine Redox in Cells and In Vivo.

The reaction between hydroxyl radical (·OH) and cysteine (Cys) plays an important role in the redox balance of living cells. A deeper insight into this intracellular reaction modulation and process is necessary and draws great interest. A highly effective technique consists of the real-time visualization of the two bioactive species and the perception of their respective changes by using a fluorescent probe. In this study, a dual-site chemosensor SPI based on phenothiazine-cyanine was developed, which realized quantitative detection and real-time imaging of ·OH and Cys at their own fluorescence channels (·OH: λex = 485 nm, λem = 608 nm; Cys: λex = 426 nm, λem = 538 nm) without spectral crosstalk. The fluorescent sensor showed excellent anti-interference and selectivity for common biological substances, apart from the successful imaging of exogenous and endogenous ·OH and Cys. We further visualized the redox dynamic reaction and explored the correlation of ·OH and Cys generated by different inhibitors (sulfasalazine and (1S, 3R)-RSL3). Notably, the chemosensor also possesses the capacity to clearly monitor ·OH and Cys in living mice and zebrafish. This study reports on the first chemosensor to investigate the process of intracellular redox modulation and control between ·OH and Cys, which show potential to further explore some metabolic and physiological mechanisms.

Liquid Metal-Doped Conductive Hydrogel for Construction of Multifunctional Sensors.

Interest in wearable and stretchable multifunctional sensors has grown rapidly in recent years. The sensing elements must accurately detect external stimuli to expand their applicability as sensors. However, the sensor's self-healing and adhesion to a target object have been major challenges in developing such practical and versatile devices. In this study, we prepared a hydrogel (LM-SA-PAA) composed of liquid metal (LM), sodium alginate (SA), and poly(acrylic acid) (PAA) with ultrastretchable, excellent self-healing, self-adhesive, and high-sensitivity sensing capabilities that enable the conformal contact between the sensor and skin even during dynamic movements. The excellent self-healing performance of the hydrogel stems from its double cross-linked networks, including physical and chemical cross-linked networks. The physical cross-link formed by the ionic interaction between the carboxyl groups of PAA and gallium ions provide the hydrogel with reversible autonomous repair properties, whereas the covalent bond provides the hydrogel with a stable and strong chemical network. Alginate forms a microgel shell around LM nanoparticles via the coordination of its carboxyl groups with Ga ions. In addition to offering exceptional colloidal stability, the alginate shell has sufficient polar groups, ensuring that the hydrogel adheres to diverse substrates. Based on the efficient electrical pathway provided by the LM, the hydrogel exhibited strain sensitivity and enabled the detection of various human motions and electrocardiographic monitoring. The preparation method is simple and versatile and can be used for the low-cost fabrication of multifunctional sensors, which have broad application prospects in human-machine interface compatibility and medical monitoring.

A highly selective and sensitive CdS fluorescent quantum dot for the simultaneous detection of multiple pesticides.

The abuse of pesticides has introduced a large number of residues in soil and drinking water, which can then enter the food chain and the human body. Monitoring pesticide residues and developing simple and fast detection systems for pesticide residues is urgently needed. In this study, we presented one-pot prepared CdS fluorescent quantum dots (QDs) and explored their sensing application for organic pesticides. The CdS QDs can sensitively and selectively detect three different pesticides, dichlorvos (DDVP), paraquat, and glufosinate-ammonium, through different fluorescence responses. Paraquat can effectively quench the fluorescence of the QDs and DDVP can cause remarkable fluorescent enhancement. Glufosinate-ammonium can induce both 150 nm fluorescent blueshifting and 30-fold fluorescent enhancement. The probe exhibited low detection limits for the three pesticides: 1.44 µM for paraquat, 0.23 mM for DDVP, and 49.8 µM for glufosinate-ammonium. Furthermore, based on the results, we utilized the powerful functions of smartphones to establish a concentration-gray value standard curve through RGB values and gray values to realize the qualitative detection and quantitative analysis of DDVP. It is believed that this work presents a new platform for the simultaneous detection of multiple pesticides using a single QDs probe. The present on-site method using a smartphone is of great potential for water monitoring in rural areas.

Di-(2-picolyl)-N-(2-quinolinylmethyl)amine-Functionalized Triarylboron: Lewis Acidity Enhancement and Fluorogenic Discrimination Between Fluoride and Cyanide in Aqueous Solution.

Triarylboron-based Lewis acids as fluoride sensors face a stimulating academic challenge because of the high hydration enthalpy of fluoride, and are usually influenced by a competing response for cyanide ion. Herein, we present a new triarylborane functionalized by a metal-ion ligand, di-(2-picolyl)-N-(2-quinolinylmethyl)amine, with subsequent metalation. In aqueous solution, this triarylborane (QB) can capture fluoride and cyanide anions through chelation induced by the synergy of boron and metal ions. Moreover, this triarylborane moiety acts as a fluorescent reporter of the binding, allowing for discrimination between fluoride and cyanide anions through dual-channel fluorescence changes. The different chelation models and fluorogenic responses of this sensor toward F- and CN- were verified by the single-crystal structures of 2-to-2 adduct for KCN and 1-to-1 for KF.

A TBET-based ratiometric probe for Au(3+) and its application in living cells.

In this paper, we designed and synthesized a novel TBET-based ratiometric fluorescent chemodosimeter, RH-Au, for Au(3+). It was found that the probe RH-Au displayed highly selective, sensitive and naked-eye detection upon the addition of Au(3+). The probe RH-Au can be used in the pH range 6.0-7.5 and the detection limit was determined to be as low as 2.91 nM (0.57 ppb). We also demonstrated a successful application of imaging Au(3+) in living cells using RH-Au.

Truxene-cored π-expanded triarylborane dyes as single- and two-photon fluorescent probes for fluoride.

Fluoride anion (F(-)) significantly affects chemical, biological, and environmental processes. Fluoride recognition and detection have received increasing attention. Convenient, effective, and sensitive fluorescent probes for F(-) should urgently be designed and synthesized. In this study, we describe a strategy for constructing two triarylborane-based fluoride fluorescent probes: 2,7,12-tri(2-(5-(dimesitylboryl)thiophen-2-yl)ethynyl)-5,5',10,10',15,15'-hexaethyltruxene (C3B3) with π-3A (acceptor) configuration and 2,7-di(N,N-diphenylamino)-12-(5-(dimesitylboryl)thiophen-2-yl)-5,5',10,10',15,15'-hexaethyltruxene (N2SB) with 2D (donor)-π-A configuration. The loss of color of the tetrahydrofuran solution of these probes from greenish yellow suggests that they can conveniently monitor F(-) at a low concentration (10 µM) free of apparatus. The different structural features of these probes varied their fluorescent responses to F(-). The single-photon fluorescence intensity of C3B3 declined to 90% upon the addition of 4.5 equivalents of F(-) to its tetrahydrofuran solution. However, the single-photon fluorescence intensity of N2SB was enhanced six-fold upon addition of 2.5 equivalents of the F(-). Under the experimental conditions, the detection limits of the two probes for F(-) can reach 12-13 µM (C3B3) and 3-5 µM (N2SB). The ability of the two probes in detecting F(-) in their toluene solutions in the two-photon mode was also investigated. The sensitive two-photon fluorescence responses of both probes make them excellent two-photon fluorescence probes.

Semisynthesis of N-acyl homoserinelactone derivatives and the antifeedant activity against Mythimna separata.

Seven homoserine-lactone (HL) acylated derivatives (HL1-HL7) were synthesized to determine the differences in antifeedant affects. The differences between these derivatives and tutin against Mythimna separata were tested. The structural assignments of these semisynthetic compounds were examined based on their infrared radiaion (IR), electrospray ionization mass spectrometry (ESIMS), and ¹H- and ¹³C-nuclear magnetic resonance (¹³C-NMR) spectral data. Compound HL1 (N-(4-nitrobenzoyl)-homoserinelactone) is the optimized insecticidal agent among these compounds. In addition, the antifeedant activities between homoserinelactone and 7-hydroxycoumarin, tutin derivatives with the same acidylated substitutions were compared, which could help design and synthesize stronger novel botanical insecticides.

Spatiotemporally controlled and multifactor involved assay of neuronal compartment regeneration after chemical injury in an integrated microfluidics.

Studies on the degeneration and regeneration of neurons as individual compartments of axons or somata can provide critical information for the clinical therapy of nervous system diseases. A controllable in vitro platform for multiple purposes is key to such studies. In the present study, we describe an integrated microfluidic device designed for achieving localized stimulation to neuronal axons or somata. We observed neuronal compartment degeneration after localized chemical stimulation and regeneration under the accessorial function of an interesting compound treatment or coculture with desired cells in controllable chambers. In a spatiotemporally controlled manner, this device was used to investigate hippocampal neuronal soma and axon degeneration after acrylamide stimulation, as well as subsequent regeneration after treatment with the monosialoganglioside GM1 or with cocultured glial cells (astrocytes or Schwann cells). To gain insight into the molecular mechanisms that mediate neuronal injury and regeneration, as well as to investigate whether acrylamide stimulation to neurons induces changes in Ca(2+) concentrations, the related neuronal genes and real-time Ca(2+) signal in neurons were also analyzed. The results showed that neuronal axons were more resistant to acrylamide injury than neuronal somata. Under localized stimulation, axons had self-destruct programs different from somata, and somatic injury caused the secondary response of axon collapse. This study provides a foundation for future in-depth analyses of spatiotemporally controlled and multifactor neuronal compartment regeneration after various injuries. The microfluidic device is also useful in evaluating potential therapeutic strategies to treat chemical injuries involving the central nervous system.

Di-(2-picolyl)amine functionalized tetraphenylethylene as multifunctional chemosensor.

In this study, we successfully developed a new multifunctional chemosensor 4',4‴-(2,2-diphenylethene-1,1-diyl)bis(N,N-bis (pyridin-2-ylmethyl)-[1,1'-biphenyl]-4-amine (T-D), based on the cooperation of tetraphenylethylene and di-(2-picolyl)amine (DPA), for sensitive, selective, and quick detection of Cu2+, PO43- and pesticide glyphosate in aqueous solution. In our research, we made full use of the Cu2+-indicator displacement strategy to achieve the construction of an "on-off-on" fluorescent switch platform. Due to the presence of the DPA moiety in T-D, Cu2+ could be captured quickly to form the complex T-D-Cu and caused fluorescence quenching. With the addition of PO43- and glyphosate, the system could rapidly restore the fluorescence by squeezing Cu2+ from T-D-Cu and blocking the photo induced electron transfer (PET) process to display the aggregation-induced emission. To demonstrate the possibility of practical applications, we detected PO43- and glyphosate in spiked real samples. The detection limit for PO43- and glyphosate reached 19 nM and 25 nM, respectively. Furthermore, test strips using T-D-Cu solution simplified the detection process of glyphosate. More importantly, the sensor could be used in visual semi-quantitative determination of PO43- concentrations in both living cells and living zebra fish. Therefore, the chemosensor presented here will not only be a powerful tool for the detection of phosphate anions in aqueous solution and biological systems, but also provides a new template for the design of other multifunctional chemosensors.

Non-biological fluorescent chemosensors for pesticides detection.

The ongoing poisoning of agricultural products has pushed the security problem to become an important issue. Among them, exceeding the standard rate of pesticide residues is the main factor influencing the quality and security of agricultural products. Moreover, the abuse of pesticides has introduced a large amount of residues in soil and drinking water, which will enter the food chain to the human body, leading to neurological disorders and cancer. Therefore, great efforts have been devoted to developing fluorescent sensors for detecting pesticide in a facile, quickly, sensitive, selective, accurate manner, which exhibit greater advantages than some traditional methods. In this review, we mainly focus on summarizing the non-biological fluorescent probes for organic pesticides detection with the detection limit of micromole to nanomole, including organic functional small molecules, calixarenes and pillararenes, metal organic framework systems, and nanomaterials. Meanwhile, we described the different sensing mechanisms for pesticides detection of these mentioned fluorescent sensors, the detection limit of each pesticide, the application in detecting actual samples, as well as their respective advantages and development prospects associated with present non-biological fluorescent sensors.

(E)-3-(1-Phenyl-ethyl-idene)indolin-2-one.

In the title mol-ecule, C(16)H(13)NO, the indoline-2-one ring system is nearly planar [maximum atomic deviation = 0.082 (2) Å] and is oriented at a dihedral angle of 66.60 (12)° with respect to the phenyl ring. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into supra-molecular dimers.

Photophysical properties and stimuli-responsive crystal-state luminescence switching of morpholine-modified naphthalic anhydride derivative.

Stimuli-response organic solid-state luminescence switching materials are attracting increasing interest due to their smart photophysical properties. In this study, a morpholine-modified naphthalic anhydride derivative, 4-(4-morpholinyl)naphthalic anhydride (MBC), was synthesized and studied. Its two crystal polymorphs, MBC-G and MBC-O, were obtained under different crystallization conditions. These two distinct crystals show significantly different solid-state luminescence behaviors: a green emission at 535 nm for MBC-G, and an orange emission at 572 nm for MBC-O. Upon fiercely grinding the MBC-G crystal or melting and then quickly cooling it, a phase transition occurs from MBC-G to MBC-O, accompanied by a fluorescence change from green to orange. The reverse transformation from MBC-O to MBC-G can be achieved by recrystallization. The X-ray single crystal structures show that the green emission should be attributed to molecular J-aggregation in the crystal packing, and the orange emission may originate from molecular H-aggregation. This switchable color nature gives MBC the promising candidate for potential smart anti-counterfeiting and light-emitting materials.

Organic Crystal Growth: Directly from Amorphous Solid Powder to Single Crystals.

Preparation of organic crystals mainly depends on solution-deposition, sublimation, and melt-deposition techniques. Solid-state growth methods are generally not suitable for organic crystal growth due to the unprocurable mass transfer. Herein, we report two pyridine-substituted fluorenone compounds with extraordinary crystal-growth capacity, and these compounds can directly and quickly form single crystals from their amorphous solid powder by heating under antisolvent-assistance conditions. The novel experimental phenomenon and crystal growth mechanism were investigated in depth. The results indicate that multiple intermolecular hydrogen-bonding sites and planar aromatic structure (prone to π-π interactions) of these molecules dominate the mass transfer during crystal growth by providing enough energy. This discovery enhances our knowledge of solid-state methods for single-crystal growth.

Employing a fluorescent and colorimetric picolyl-functionalized rhodamine for the detection of glyphosate pesticide.

The ongoing poisoning of agricultural products has pushed the security problem to become an important issue. Among them, exceeding the standard rate of pesticide residues is the main factor influencing the quality and security of agricultural products. Monitoring pesticide residues and developing simple, yet ultrasensitive detection systems for pesticide residues are urgently needed. In this study, we successfully developed a novel rhodamine derivative as fluorescent and colorimetric chemosensor R-G for the rapid, selective and ultrasensitive detection of glyphosate pesticide residue in aqueous solution. Through a Cu2+-indicator displacement strategy, glyphosate can displace an indicator (R-G) from a Cu2+-indicator complex due to its strong affinity to bind with Cu2+ to give a turn-on fluorescence and distinct color change. Moreover, a test strip was also fabricated to achieve a facile detection of glyphosate pesticide. To demonstrate the possibility of practical applications, glyphosate was detected on the surface of cabbage and in a spiked soil sample. The detection limit of 4.1 nM and the response time of 2 min indicate that the method is enough sensitive and rapid to detect the glyphosate residue at or below levels that pose a health risk.

(E)-1,1'-Dibutyl-3,3'-biindolinyl-idene-2,2'-dione.

In the title mol-ecule, C(24)H(26)N(2)O(2), the two indol-2-one units, which are connected by a C=C double bond, are almost coplanar with an inter-planar angle of 6.8 (1)°. On cooling from 293 to 120 K, the space group changes from P2(1)/n to P2(1). Two intra-molecular C-H⋯O hydrogen bonds occur.

9-Ethyl-9H-carbazole-3-carbaldehyde.

The title mol-ecule, C(15)H(13)NO, approximates a planar conformation except for the alkyl chain (ethyl group) bonded to the N atom with a maximum deviation from the least-squares plane through the 15 planar atoms of 0.120 (2) Šfor the O atom. The distance of the formyl O atom from the plane of the carbazole ring is 0.227 (2) Å. The N-C bond lengths in the central ring are significantly different, reflecting the electron-withdrawing properties of the aldehyde group. As a consequence, charge transfer may occur from the carbazole N atom to the substituted benzene ring.

2-Chloro-N-isopropyl-N-phenyl-acetamide.

In the title compound, C(11)H(14)ClNO, the herbicide propachlor, there are significant differences between the three N-C bond lengths [N-C(carbon-yl) = 1.354 (3) Å, N-C(phen-yl) = 1.444 (2) Šand N-C(isoprop-yl) = 1.496 (3) Å], indicating the presence of π delocalization involving the carbonyl group. The N atom lies 0.074 (2) Šfrom the plane defined by the the three bonded C atoms.

1-[4-(3,5-Difluoro-benz-yloxy)-2-hy-droxy-phen-yl]ethanone.

The title compound, C(15)H(12)F(2)O(3), has been obtained by the reaction of 2,4-dihy-droxy-lacetonephenone, potassium carbonate and 3,5-difluoro-benzyl bromide. The hy-droxy group is involved in an intra-molecular O-H⋯O hydrogen bond in each of the two independent mol-ecules in the asymmetric unit. The dihedral angle between the aromatic rings is 0.5 (2)° in one molecule and 1.9 (2)° in the other. In the crystal, weak C-H⋯O inter-actions link the mol-ecules into tetra-meric units aligned perpendicular to b.