Controlled “off–on” fluorescent probe for the specific detection of hyperhomocysteinemia

Hyperhomocysteinemia is an established risk factor for atherosclerosis and vascular disease. Therefore, designing a hyperhomocysteinemia specific probe is of great significance for the early warning of cardiovascular diseases. However, developing probes that can efficiently and specifically recognize homocysteine (Hcy) remains a tremendous challenge. Therefore, we designed an Hcy-specific fluorescent probe (HSFP) with excellent selectivity and anti-interference capability. Interestingly, this probe can automatically “off–on” in water solution, but the fluorescence of HSFP remains “off” when Hcy is present in the solution. The spectroscopic data demonstrated that the fluorescence of HSFP attenuated 13.8 folds toward Hcy in water without interference from other biothiols and amino acids. Furthermore, HSFP can sensitively reflect the change of Hcy content in cells. Therefore, HSFP was further applied to detect hyperhomocysteinemia in vivo with high efficiency. In summary, we have developed an Hcy-specific fluorescent probe to efficiently detect Hcy in vivo and in vitro, which may contribute to basic or clinical research.

An Hcy-specific fluorescent probe (HSFP) with excellent selectivity and anti-interference capability was developed for the detection of hyperhomocysteinemia.     

A rapid “on–off–on” mitochondria-targeted phosphorescent probe for selective and consecutive detection of Cu2+ and cysteine in live cells and zebrafish

The detection of mitochondrial Cu²⁺ and cysteine is very important for investigating cellular functions or dysfunctions. In this study, we designed a novel cyclometalated iridium(iii) luminescence chemosensor Ir bearing a bidentate chelating pyrazolyl-pyridine ligand as a copper-specific receptor. The biocompatible and photostable Ir complex exhibited not only mitochondria-targeting properties but also an “on–off–on” type phosphorescence change for the reversible dual detection of Cu²⁺ and cysteine. Ir had a highly sensitive (detection limit = 20 nM) and selective sensor performance for Cu²⁺ in aqueous solution due to the formation of a non-phosphorescent Ir–Cu(ii) ensemble through 1 : 1 binding. According to the displacement approach, Ir was released from the Ir–Cu(ii) ensemble accompanied with “turn-on” phosphorescence in the presence of 0–10 μM cysteine, with a low detection limit of 54 nM. This “on–off–on” process could be accomplished within 30 s and repeated at least five times without significant loss of signal strength. Moreover, benefiting from its good permeability, low cytotoxicity, high efficiency, and anti-interference properties, Ir was found to be suitable for imaging and detecting mitochondrial Cu²⁺ and cysteine in living cells and zebrafish.

An iridium(iii) complex-based mitochondria targeting phosphorescent probe for selectively detecting Cu²⁺ and Cys in aqueous solution, living cells and zebrafish has been developed.     

A novel diarylethene-based fluorescent “turn-on” sensor for the selective detection of Mg2+

A new photochromic diarylethene derivative with a 4-methylphenol unit has been designed and synthesized. It displayed distinct photochromism and fluorescent ‘‘turn on’’ features to Mg²⁺ in acetonitrile solution. With the addition of Mg²⁺, there was an obvious increase of fluorescent emission intensity at 552 nm, accompanied by a clear change of fluorescent color from dark purple to green. Meantime, the 1 : 1 stoichiometry between the derivative and Mg²⁺ was verified by Job''s plot and HRMS. Furthermore, the sensor was successfully applied in the detection of Mg²⁺ in practical samples. Moreover, based on the multiple-responsive fluorescence switching behaviors, it also could be used to construct a molecular logic circuit with UV/vis lights and Mg²⁺/EDTA as input signals and the emission at 552 nm as the output signal.

A new photochromic diarylethene derivative with a 4-methylphenol unit has been designed and synthesized.     

“Off–On” fluorescent sensing of organophosphate pesticides using a carbon dot–Au(iii) complex

Herein, we report novel “off–on” fluorescent sensing of organophosphate pesticides using a carbon dot (CD)–Au(iii) complex/acetylcholinesterase (AChE) system. The above sensor utilizes the quenching of CD fluorescence by Au(iii) and its subsequent recovery by thiocholine, which is generated by AChE-catalyzed hydrolysis of acetylthiocholine (ATCh) and effectively scavenges Au(iii). In the presence of organophosphates, the catalytic activity of AChE is inhibited, allowing these species to be quantified based on the decreased recovery of CD fluorescence intensity. The developed sensor was used to analyze a real pesticide-spiked sample (4.48 μM), achieving a recovery of 99.85% and exhibiting a linear response range of 0.45–44.80 μM.

Herein, we report novel “off–on” fluorescent sensing of organophosphate pesticides using a carbon dot (CD)–Au(iii) complex/acetylcholinesterase (AChE) system.     

Two groups of copperII pyridine–triazole complexes with “open or close” pepper rings and their in vitro antitumor activities

Based on 1,2-dimethoxyphenyl (veratrole, open) and 1,2-methylenedioxyphenyl (pepper ring, close)-derived pyridine–triazole analogues, two groups of copper(ii) complexes, namely, Group I(C1–C3) and Group II(C4–C6) were synthesized and fully characterized. All ligands and complexes were tested in vitro by MTT assays on seven tumour cell lines (T24, Hep-G2, Sk-Ov-3, MGC-803, HeLa, A549 and NCI-H460) and one normal liver cell line (HL-7702). Surprisingly, the pepper-ring-derived complexes (C4–C6) showed significantly enhanced cytotoxicity compared with the 1,2-bimethoxyphenyl ring-derived complexes (C1–C3) and the standard anticancer drug cisplatin. Cellular uptake assays indicated that the Cu accumulation was consistent with cytotoxicity. In addition, flow cytometry and western blot analysis showed that the apoptosis of the leading complex C4 may be induced by the Bcl-2 family-mediated proteins through the mitochondrial dysfunction pathway. Furthermore, UV-vis and fluorescence spectroscopy assays revealed that C4 has stronger insertion-binding interactions with CT-DNA than C1 and the fluorescence of C1 and C4 with BSA is mainly quenched by static quenching.

The pepper ring-modified complexes (Group II, C4–C6) exhibited significant antitumor activity than veratrole-modified complexes (Group I, C1–C3) towards several cancer cells with IC₅₀ ranging from 3.45 to 8.59 μM.     

An innovative study on the “on–off–on” detection of sulfur ions based on a TSPP–riboflavin fluorescent probe

In this paper, 5,10,15,20-(4-sulphonatophenyl) porphyrin (TSPP) was synthesized by a facile route and used as a fluorescent probe to construct a sensor system based on the high water solubility and high quantum yield. It was found that when riboflavin (RF) was introduced into the TSPP solution, the fluorescence intensity of TSPP decreased for the peaks at 645 nm and 700 nm based on the principle of the electrostatic attractions and hydrophobic interactions between TSPP and riboflavin. When the fluorescence emission peak of riboflavin appeared at 550 nm, the fluorescence sensor system changed from the “on” state to the “off” state. When sulfur ions (S²⁻) were further introduced into the TSPP–riboflavin system, the fluorescence intensity of riboflavin was further decreased based on the specific reaction between S²⁻ and riboflavin. However, the fluorescence signal of TSPP was restored and the fluorescence sensing system changed from the “off” state to the “on” state. Therefore, TSPP was used as a fluorescent probe to construct an “on–off–on” fluorescent sensing system, the linear range of S²⁻ detected by this system is 5.0 × 10⁻⁹ to 3.6 × 10⁻⁵ M, and the detection limit (LOD) is 1.1 × 10⁻⁹ M. The sensing system has higher accuracy and sensitivity, and it can be successfully used in the sensing of S²⁻ in real samples.

In this paper, 5,10,15,20-(4-sulphonatophenyl) porphyrin (TSPP) was synthesized by a facile route and used as a fluorescent probe to construct a sensor system based on the high water solubility and high quantum yield.     

A highly selective “turn-on” water-soluble fluorescent sensor for gallium ion detection

In this work, a novel sensor, (E)-N′-(3-(tert-butyl)-2-hydroxybenzylidene)thiophene-2-carbohydrazide (1), based on salicylaldehyde and thiophene hydrazide moieties was designed and synthesized. The single-crystal structure of 1 was achieved and studied for understanding its functional properties. The interaction and recognition abilities of 1 with different metal ions were investigated. Sensor 1 showed excellent “turn-on” fluorescence with highly selective and specific recognition ability in the presence of gallium ions (Ga³⁺) in an aqueous solution. The sensing behavior of 1 with Ga³⁺ was also studied by photophysical experiments, ESI-MS analysis, and ¹H NMR titration. The limit of detection (LOD) and limit of quantification (LOQ) of 1 for the detection of Ga³⁺ in an aqueous solution were calculated as 58 nM, and 192 nM, respectively. DFT calculations were carried out to optimize the configuration of 1 and 1–Ga³⁺ complexes and rationalize the photophysical experimental data. Highly selective test strips based on sensor 1 were developed for Ga³⁺ detection. Sensor 1 was also used to detect Ga³⁺ in actual water samples, and a considerable recovery rate was obtained.

In this work, a highly selective water-soluble “turn-on” fluorescent sensor for gallium ion recognition was reported.     

The stable “F–SO2+” donor provides a mild and efficient approach to nitriles and amides

In this update, we developed a mild, efficient and practical method using fluorosulfuryl imidazolium salt A as an environment friendly promoter for conversion of oximes to nitriles or amides via β-elimination or Beckmann rearrangement in almost quantitative yield in 10 minutes. The target products were generated in gram-scale and could be collected through crystallization without silica gel column purification in excellent yield.

In this update, we developed a mild, efficient and practical method using stable “F–SO₂⁺” donor A as an environment friendly promoter for conversion of oximes to nitriles or amides via β-elimination or Beckmann rearrangement in excellent yields.

Nitriles and amides are important classes of organonitrogen compounds. Nitrile and amide play an important role in organic synthesis and are core structures of many agrochemicals, bioactive drugs, natural products, fine chemicals and functional materials.^1,2 Examples include tecovirimat (1), an antiviral indicated for the treatment of smallpox,³ which is also effective in treating monkeypox infections;⁴ PF-07321332 (2), which is a nitrile inhibitor of the SARS-CoV-2 main protease;⁵ P5TCN-2F, a polythiophene organic solar cells (OSCs) (3), revealed that the cyano-group leads to high-efficiency OSCs and improved polymer crystallinity (Scheme 1).⁶Open in a separate windowScheme 1Selected examples for valuable nitriles and amides.Owing to their widespread applications, there has been a push in recent decades to develop a more efficient, mild, Rosenmund–von Braun and safe approach to nitriles and amides. Sandmeyer and Braun reactions,⁷ formal acid–nitrile exchange,⁸ transition-metal-catalyzed cyanation of halides,⁹ and direct C–H cyanation are examples of traditional cyanide-based processes to nitriles (Scheme 2a(1)).¹⁰ Meanwhile, many cyanide-free synthetic methods have been developed, such as amide dehydration,¹¹ primary amine hydrogenation,¹² and cyanation with other nitrogen sources.¹³ Amides are commonly formed by reacting carboxylic acid or its derivatives with amines via condensation or transition metal-catalyzed coupling (Scheme 2a(2)).¹⁴ Aside from that, other protocols to amides have been reported, including carbonylative hydroamidation,¹⁵ nitrile hydrolysis,¹⁶ nitro-reduction amidation,¹⁷ and N-arylation of activated amides.¹⁸ The aforementioned strategies, however, were limited to toxic reagents, expensive transition-metal catalysts, complex reaction systems, and harsh conditions, especially when two or more components are used as raw materials, which may result in low atom utilization and more by-products. As a result, developing a solution to the aforementioned difficulties is critical.Open in a separate windowScheme 2Strategies for preparation of nitriles and amides.Oximes are simple and easily accessible class of chemical,¹⁸ particularly aldoximes and ketoximes, which could be converted to nitriles and amides efficiently by β-elimination and Beckman rearrangement,¹⁹ respectively (Scheme 2b). Various catalysts have been devised in recent years to facilitate the heterolysis of nitrogen–oxygen bond in order to achieve this transformation, but there are still certain drawbacks. Such as o-NosylOXY,²⁰ required microwave irradiation and high temperature. In 2020, Xu reported that HCl·DMPU assisted conversion of aldehydes into nitriles while HCl–DMPU is a solution emitting fumes.²¹ Recently, Ding, Qin and Fokin groups reported rapid and mild SO₂F₂-promoted dehydration of oxime.²² However, the use of a greenhouse gas SO₂F₂ is not safe as it may leak out in operation.²³ Although the organoselenium-catalyzed dehydration of aldoximes can produce nitriles under environment friendly conditions, it required for hours up to days.²⁴ To some extends, those disadvantages restrict its wide applications.In 2018, Dong and Sharpless reported a fluorosulfuryl imidazolium salt A, which showned unprecedented reactivity, selectivity, and scope as an “F–SO₂⁺” donor and is a far more reactive fluorosulfurylating agent than SO₂F₂.²⁵ Subsequently, it was developed for the crucial precursor of diazotransfer reagent, which enables the preparation of azides from primary amines.²⁶ Moreover, fluorosulfuryl imidazolium salt A provides a practical and efficient process to prepare unsymmetrical sulfamides via Sulfur(vi)–Fluoride Exchange (SuFEx) click chemistry.²⁷ Most recently, Liao and Wang groups reported that fluorosulfuryl imidazolium salt could produce SO₂F radical and enabled fluorosulfonylation of olefins.²⁸Inspired by the wide application of fluorosulfuryl imidazolium salt and its unprecedented reactivity, and upon viewing the limitations of the preparation of nitriles and amides from oximes, we tried to apply fluorosulfuryl imidazolium salt A for the β-elimination of aldoximes and Beckmann rearrangement of ketoximes after our continuous efforts on the utilization of SO₂F₂-promoted transformations.²⁹ As predicted, the alkylated imidazolium species served as good leaving groups and delivers the “F–SO₂⁺” fragment,^27,30 and aldoximes or ketoximes would react with “F–SO₂⁺”, with the assistance of the base, to generate the corresponding sulfonyl ester, and further produce the nitriles or amides via β-elimination or Beckmann rearrangement. As predicted, aldoximes or ketoximes would react with fluorosulfuryl imidazolium salt A, with the assistance of the base, to generate the corresponding sulfonyl ester, and futher produce the nitriles or amides via β-elimination or Beckmann rearrangement (Scheme 2c). When 4-bromobenzaldehyde oxime (1d) or acetophenone oxime (3a) were used as model substrates, 4-bromobenzonitrile (2d) or N-phenylacetamide (4a) were obtained in 98% yields under the optimal reaction conditions (the more details please see ESI Tables S1 and S2^†).Having established the optimal reaction conditions, we examined the scope and generality of this protocol from aryl aldoximes into nitriles. As shown in

Amino-BODIPY as the ratiometric fluorescent sensor for monitoring drug release or “power supply” selector for molecular electronics

The glutathione cleavable conjugates of amino-BODIPY dye with model drugs have been tested for monitoring the drug release via ratiometric fluorescence based on two excitation and one emission wavelength. As a self-immolative linker was used for the construction of conjugates, free amino-BODIPY was released with the drug. Different excitation profiles of the dye before and after conjugate cleavage and similar emission wavelengths that enabled monitoring the release of the drug via the OFF–ON effect were successfully tested inside the cancer cells. UV/Vis spectrometry could be used in the quantification of the conjugate/drug in an analyte irrespective of the cleavage grade. As the system functionality was based only on the altered acylamino-BODIPY present in the conjugate to amino-BODIPY released during the cleavage, the method could be applied as a ratiometric fluorescence theranostic system to other non-fluorescent drugs. Moreover, the present conjugates demonstrated their potential application in molecular electronics as a “power supply” selector enabling the application of two power sources for one “bulb” to maintain its light intensity.

Amino-BODIPY as the universal and highly fluorescent OFF–ON and ratiometric sensor for thiol-mediated drug release monitoring.     

The aggregation of Fe3+ and their d–d radiative transitions in ZnSe:Fe3+ nanobelts by CVD growth

Transition metal (TM) doped II–VI semiconductors have attracted great attention due to their luminescence and diluted magnetism. In this study, the Fe³⁺-doped ZnSe nanobelts (NBs) were grown by a facile CVD method. The surface morphology observed via SEM is smooth and clean and the elemental composition measured via EDS confirms that the Fe³⁺ ions were incorporated into ZnSe NBs successfully. The micro-Raman scattering spectra demonstrate that the as-prepared NBs have the zinc blende structure. Furthermore, the Raman spectra of the Fe³⁺-doped NBs were compared with those of pure and Fe²⁺-doped reference samples. The former with a higher signal-to-noise ratio, an enhanced 2LO mode, a stronger LO mode redshift and a larger intensity ratio of LO/TO mode as well as the lower acoustic phonon modes confirms the better crystallization and the stronger electron–phonon coupling on Fe³⁺-incorporation. The emission of single Fe³⁺ ion, assigned to the ⁴T₁ → ⁶A₁ transition, was observed at about 570 nm. Moreover, increasing the doping concentration of Fe³⁺ ions caused the formation of different Fe–Fe coupled pairs in the lattice, which emitted light at about 530–555 nm for an antiferromagnetic-coupled pair, possibly due to the stacking faults and at about 620–670 nm for a ferromagnetic-coupled pair.

Transition metal (TM) doped II–VI semiconductors have attracted great attention due to their luminescence and diluted magnetism.     

Alginate based antimicrobial hydrogels formed by integrating Diels–Alder “click chemistry” and the thiol–ene reaction

In recent years medical devices manufacturers have been looking for antimicrobial coatings which are biocompatible and non-toxic for a wide range of medical devices. The demand for these antimicrobial coatings has increased significantly, owing to the increased incidence of hospital-associated infections (HAIs). Hydrogels have been widely used in biomedical applications due to their hydrophilicity, biodegradability, non-toxicity and biocompatibility. In this work, sodium alginate (SA) based antibacterial hydrogels SA/PEG–HHC10 were designed and prepared by combining Diels–Alder (DA) click chemistry and the thiol–ene reaction. The hydrogels were first prepared using DA click chemistry with good mechanical strength, then the cysteine-terminated antimicrobial peptide HHC10–CYS (HHC10) was grafted into the hydrogel by the thiol–ene reaction between the oxy-norbornene group and the thiol group. The results showed that the antimicrobial hydrogels had a strong antibacterial property and good biocompatibility. Therefore, the antimicrobial hydrogels have significant potential application as coatings for implantable medical devices.

In recent years medical devices manufacturers have been looking for antimicrobial coatings which are biocompatible and non-toxic for a wide range of medical devices.     

The use of S2O82− and H2O2 as novel specific masking agents for highly selective “turn-on” fluorescent switching recognition of CN− and I− based on Hg2+–graphene quantum dots

In this study, we report that both CN⁻ and I⁻ can enhance the fluorescent intensity of Hg²⁺–graphene quantum dots (Hg²⁺–GQDs). However, the selectivity of the sensor was poor. Accordingly, simple specific masking agents can be directly used to solve this problem. Here, for the first time, we report the use of persulfate ion (S₂O₈²⁻) as a turn-on fluorescent probe of Hg²⁺–GQDs for selective CN⁻ detection, while hydrogen peroxide (H₂O₂) was selected for its sensing ability towards I⁻ ion detection. Interestingly, the signal was immediately measured after addition of the masking agent to Hg²⁺–GQDs and the sample because its interaction was very fast and efficient. The method had a linear response in the concentration ranges of 0.5–8 μM (R² = 0.9994) and 1–12 μM (R² = 0.9998) with detection limits of 0.17 and 0.20 μM for CN⁻ and I⁻, respectively. The sensor was successfully used for the dual detection of both CN⁻ and I⁻ in real water samples with satisfactory results. In conclusion, the specific masking agents in a Hg²⁺–GQDs system appeared to be good candidates for fluorometric “turn-on” sensors for CN⁻ and I⁻ with excellent selectivity over other ions.

In this study, we report that both CN⁻ and I⁻ can enhance the fluorescent intensity of Hg²⁺–graphene quantum dots (Hg²⁺–GQDs).     

“Activation” of vitamin D by the liver

Isolation of the liver from the circulation of rats eliminates almost completely their ability to convert [1,2]-(3)H vitamin D(3) into its biologically active metabolite, 25-hydroxycholecalciferol, as well as certain other metabolites. It is concluded that the liver is the major if not the only physiologic site of hydroxylation of vitamin D(3) (cholecalciferol) into 25-hydroxycholecalciferol.The osteodystrophy and the higher requirements for vitamin D observed in hepatic insufficiencies may be due to an inability of the liver to transform vitamin D into its metabolically active form.     

Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

In this study, the possibilities of a new “in situ” LED UV illumination NMR spectroscopic technique for performing an initiator-free thiol–ene “click” coupling reaction of an allyl-functionalized poly(allyl glycidyl ether) (PAGE) prepolymer with a number of mono- and di-oligo polyethylene glycol (PEG) thiols is demonstrated. The state-of-the-art setup constructed with LEDs as UV light sources that illuminate through optical fibers directly into an NMR testing tube at a fixed wavelength of 365 nm is appropriate for various polymeric materials and biologically active substances. The selected experimental protocol uses a series of periods of irradiation and dark periods, thus providing opportunities to conduct an effective thiol–ene “click” reaction and simultaneously study the kinetics of the photochemical reaction with the exposure time, as well as macromolecular association directly in a solution applying the whole types of NMR methods: from conventional ¹H or ¹³C NMR to diffusion NMR spectroscopy (DOSY). In addition, the molecular mass characteristics of the prepared copolymers were studied by gel-permeation chromatography (GPC). The observed differences in the reaction rates as well as in the size of species formed (the corresponding hydrodynamic radiuses R_h of aggregates) as a result of the coupling process of parent PAGE prepolymers and model PEG thiols were thoroughly discussed and the reaction pathway proposed.

An “In situ” LED UV illumination NMR setup for achievement of initiator-free coupling reactions of allyl-functionalized poly(allyl glycidyl ether) with polyethylene glycols thiols.     

The Vascular Basement Membrane as “Soil” in Brain Metastasis

Brain-specific homing and direct interactions with the neural substance are prominent hypotheses for brain metastasis formation and a modern manifestation of Paget's “seed and soil” concept. However, there is little direct evidence for this “neurotropic” growth in vivo. In contrast, many experimental studies have anecdotally noted the propensity of metastatic cells to grow along the exterior of pre-existing vessels of the CNS, a process termed vascular cooption. These observations suggest the “soil” for malignant cells in the CNS may well be vascular, rather than neuronal. We used in vivo experimental models of brain metastasis and analysis of human clinical specimens to test this hypothesis. Indeed, over 95% of early micrometastases examined demonstrated vascular cooption with little evidence for isolated neurotropic growth. This vessel interaction was adhesive in nature implicating the vascular basement membrane (VBM) as the active substrate for tumor cell growth in the brain. Accordingly, VBM promoted adhesion and invasion of malignant cells and was sufficient for tumor growth prior to any evidence of angiogenesis. Blockade or loss of the β1 integrin subunit in tumor cells prevented adhesion to VBM and attenuated metastasis establishment and growth in vivo. Our data establishes a new understanding of CNS metastasis formation and identifies the neurovasculature as the critical partner for such growth. Further, we have elucidated the mechanism of vascular cooption for the first time. These findings may help inform the design of effective molecular therapies for patients with fatal CNS malignancies.     

Polymers prepared through an “ATRP polymerization–esterification” strategy for dual temperature- and reduction-induced paclitaxel delivery

Clinically, the nanotherapy of tumors has been limited by the drug content, efficiency of targeted release, and bioavailability. In this study, we fabricated an amphiphilic block polymer, poly(2-methacryloyloxyethyl thiocticcarboxylate)-block-poly(N-isopropylacrylamide) (PMAOETC-b-PNIPAM), using an “ATRP polymerization–esterification” strategy for paclitaxel (PTX) delivery. The hydrophobic drug paclitaxel was encapsulated based on hydrogen bond interactions between PTX and the PMAOETC and PNIPAM blocks, together with hydrophobic interactions between PTX and PMAOETC segments, affording PTX-laden polymer micelles with ∼30% drug loading content. The critical micelle concentration of the PTX-loaded polymeric micellar aggregates was 34.53 mg l⁻¹, as determined through fluorescence spectroscopy, which indicated favorable stability during infinite dilution by body fluids. The phase transition temperature of the micelles was tunable (36.10–39.48 °C) via adjusting the lengths of the blocks. The PTX-laden micelles showed the release of a significant amount of PTX in cancerous tissue, while negligible cytotoxicity was shown against HCT-116 cells in PBS at pH 7.4 and 37 °C. Further in vivo anticancer studies revealed that antitumor treatment using the PTX-laden micelles caused a significant suppression in tumor volume compared with a free-PTX-treated group. This study provides a reference for improving drug content levels and optimizing the therapeutic effects of drug delivery systems from the perspective of polymer preparation.

A dual temperature- and reduction-responsive nanovehicle with 29.36% paclitaxel loading was fabricated using an “ATRP polymerization–esterification” method for tumor suppression.     

A “Turn-On” fluorescent probe for sensitive and selective detection of fluoride ions based on aggregation-induced emission

Based on the fluorophore of 2-(2′-hydroxyphenyl)benzothiazole (HBT) with aggregation-induced emission (AIE) properties, a highly selective and sensitive fluorescent probe PBT towards F⁻ was investigated. “Turn-On” fluorescence type signaling was realized by employing fluoride-selective cleavage of the latent thiophosphinated probe in mixed aqueous media. The probe is designed in such a way that the excited state intramolecular proton transfer (ESIPT) of the HBT moiety becomes blocked. The chemodosimetric approach of F⁻ to the probe results in the recovery of the ESIPT by removal of a free AIE-active HBT moiety through a subsequent hydrolysis process. The F⁻ detection limit of the probe was 3.8 nM in the dynamic range of 0.5 μM to 10 μM. In addition, the proposed probe has been used to detect F⁻ in water samples and toothpaste samples with satisfying results.

A “Turn-On” fluorescent probe PBT for sensitive and selective detection of fluoride ions based on aggregation-induced emission.