A dual-signal ratiometric electrochemical aptasensor based on Thi/Au/ZIF-8 and catalytic hairpin assembly for ultra-sensitive detection of aflatoxin B1.

A dual-signal ratiometric electrochemical aptasensor has been developed  for AFB1 detection using thionine/Au/zeolitic imidazolate framework-8 (Thi/Au/ZIF-8) nanomaterials and catalytic hairpin assembly (CHA) reaction. Thi/Au/ZIF-8 combined with DNA hairpin 2 (H2) was used as a signal probe. [Fe(CN)6]3-/4- was served as another signal probe, and the IThi/Au/ZIF-8/I[Fe(CN)6]3-/4- ratio was for the first time utilized to quantify AFB1. AFB1-induced CHA was used to expand the ratio of electrical signals. In the presence of AFB1, H2/Thi/Au/ZIF-8 bound to the electrode via CHA, enhanced  the current signal of Thi/Au/ZIF-8. H2 contained the DNA phosphate backbone hindered [Fe(CN)6]3-/4- redox reaction and resulted in a lower [Fe(CN)6]3-/4- current signal. This aptasensor exhibited high specificity for AFB1, a linear range of 0.1 pg mL-1 to 100 ng mL-1, and a detection limit of 0.089 pg mL-1. It demonstrated favorable sensitivity, selectivity, stability, and repeatability. The aptasensor was suitable for detecting AFB1 in peanuts and black tea and holds potential for real sample applications.

Flow-Through Amperometric Biosensor System Based on Functionalized Aryl Derivative of Phenothiazine and PAMAM-Calix-Dendrimers for the Determination of Uric Acid.

A flow-through biosensor system for the determination of uric acid was developed on the platform of flow-through electrochemical cell manufactured by 3D printing from poly(lactic acid) and equipped with a modified screen-printed graphite electrode (SPE). Uricase was immobilized to the inner surface of a replaceable reactor chamber. Its working volume was reduced to 10 µL against a previously reported similar cell. SPE was modified independently of the enzyme reactor with carbon black, pillar[5]arene, poly(amidoamine) dendrimers based on the p-tert-butylthiacalix[4]arene (PAMAM-calix-dendrimers) platform and electropolymerized 3,7-bis(4-aminophenylamino) phenothiazin-5-ium chloride. Introduction of the PAMAM-calix-dendrimers into the electrode coating led to a fivefold increase in the redox currents of the electroactive polymer. It was found that higher generations of the PAMAM-calix-dendrimers led to a greater increase in the currents measured. Coatings consisted of products of the electropolymerization of the phenothiazine with implemented pillar[5]arene and PAMAM-calix-dendrimers showing high efficiency in the electrochemical reduction of hydrogen peroxide that was formed in the enzymatic oxidation of uric acid. The presence of PAMAM-calix-dendrimer G2 in the coating increased the redox signal related to the uric acid assay by more than 1.5 times. The biosensor system was successfully applied for the enzymatic determination of uric acid in chronoamperometric mode. The following optimal parameters for the chronoamperometric determination of uric acid in flow-through conditions were established: pH 8.0, flow rate 0.2 mL·min-1, 5 U of uricase per reactor. Under these conditions, the biosensor system made it possible to determine from 10 nM to 20 µM of uric acid with the limit of detection (LOD) of 4 nM. Glucose (up to 1 mM), dopamine (up to 0.5 mM), and ascorbic acid (up to 50 µM) did not affect the signal of the biosensor toward uric acid. The biosensor was tested on spiked artificial urine samples, and showed 101% recovery for tenfold diluted samples. The ease of assembly of the flow cell and the low cost of the replacement parts make for a promising future application of the biosensor system in routine clinical analyses.

Novel fluorescent probes based on sulfur and nitrogen co-doped carbon dots for determination of three N-substituted phenothiazine derivatives in dosage forms.

In the current work, sulfur and nitrogen co-doped carbon dots (S,N-CDs) as simple, sensitive, and selective turn-off fluorescent nanosensors were utilized for analysis of three phenothiazine derivatives, including acetophenazine (APZ), chlorpromazine (CPH), and promethazine (PZH). S,N-CDs were synthesized through a green one-pot microwave-assisted technique using widely available precursors (thiourea and ascorbic acid). HRTEM, EDX, FTIR spectroscopy, UV-Vis absorption spectroscopy, and fluorescence spectroscopy were used to characterize the as-synthesized CDs. When excited at 330 nm, the carbon dots produced a maximum emission peak at 410 nm. The cited drugs statically quenched the S,N-CDs fluorescence as revealed by the Stern-Volmer equation. The current method represents the first spectrofluorimetric approach for the determination of the studied drugs without the need for chemical derivatization or harsh reaction conditions. The importance of the proposed work is magnified as the cited drugs do not have any fluorescent properties. The fluorescence of the developed sensor exhibited a linear response to APZ, CPH, and PZH in the concentration ranges of 5.0-100.0, 10.0-100.0, and 10.0-200.0 µM with detection limits of 1.53, 1.66, and 2.47 µM, respectively. The developed fluorescent probes have the advantages of rapidity and selectivity for APZ, CPH, and PZH analysis in tablets with acceptable % recoveries of (98.06-101.66 %). Evaluation of the method's greenness was performed using the Complementary Green Analytical Procedure Index (ComplexGAPI) and Analytical GREEnness metric (AGREE) metrics, indicating that the method is environmentally friendly. Validation of the proposed method was performed according to ICHQ2 (R1) guidelines.

Ultra-high throughput-based screening for the discovery of antiplatelet drugs affecting receptor dependent calcium signaling dynamics.

Distinct platelet activation patterns are elicited by the tyrosine kinase-linked collagen receptor glycoprotein VI (GPVI) and the G-protein coupled protease-activated receptors (PAR1/4) for thrombin. This is reflected in the different platelet Ca2+ responses induced by the GPVI agonist collagen-related peptide (CRP) and the PAR1/4 agonist thrombin. Using a 96 well-plate assay with human Calcium-6-loaded platelets and a panel of 22 pharmacological inhibitors, we assessed the cytosolic Ca2+ signaling domains of these receptors and developed an automated Ca2+ curve algorithm. The algorithm was used to evaluate an ultra-high throughput (UHT) based screening of 16,635 chemically diverse small molecules with orally active physicochemical properties for effects on platelets stimulated with CRP or thrombin. Stringent agonist-specific selection criteria resulted in the identification of 151 drug-like molecules, of which three hit compounds were further characterized. The dibenzyl formamide derivative ANO61 selectively modulated thrombin-induced Ca2+ responses, whereas the aromatic sulfonyl imidazole AF299 and the phenothiazine ethopropazine affected CRP-induced responses. Platelet functional assays confirmed selectivity of these hits. Ethopropazine retained its inhibitory potential in the presence of plasma, and suppressed collagen-dependent thrombus buildup at arterial shear rate. In conclusion, targeting of platelet Ca2+ signaling dynamics in a screening campaign has the potential of identifying novel platelet-inhibiting molecules.

Targeting autophagy by antipsychotic phenothiazines: potential drug repurposing for cancer therapy.

Cancer is recognized as the major cause of death worldwide and the most challenging public health issues. Tumor cells exhibit molecular adaptations and metabolic reprograming to sustain their high proliferative rate and autophagy plays a pivotal role to supply the high demand for metabolic substrates and for recycling cellular components, which has attracted the attention of the researchers. The modulation of the autophagic process sensitizes tumor cells to chemotherapy-induced cell death and reverts drug resistance. In this regard, many in vitro and in vivo studies having shown the anticancer activity of phenothiazine (PTZ) derivatives due to their potent cytotoxicity in tumor cells. Interestingly, PTZ have been used as antiemetics in antitumor chemotherapy-induced vomiting, maybe exerting a combined antitumor effect. Among the mechanisms of cytotoxicity, the modulation of autophagy by these drugs has been highlighted. Therefore, the use of PTZ derivatives can be considered as a repurposing strategy in antitumor chemotherapy. Here, we provided an overview of the effects of antipsychotic PTZ on autophagy in tumor cells, evidencing the molecular targets and discussing the underlying mechanisms. The modulation of autophagy by PTZ in tumor cells have been consistently related to their cytotoxic action. These effects depend on the derivative, their concentration, and also the type of cancer. Most data have shown the impairment of autophagic flux by PTZ, probably due to the blockade of lysosome-autophagosome fusion, but some studies have also suggested the induction of autophagy. These data highlight the therapeutic potential of targeting autophagy by PTZ in cancer chemotherapy.

Phenothiazines: Nrf2 activation and antioxidant effects.

Phenothiazines (PTZs) are an emerging group of molecules showing effectiveness toward redox signaling and reduction of oxidative injury to cells, via the activation on Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (Nrf2). Although several electrophilic and indirect Nrf2 activators have been reported, the risk of "off-target" effect due to the complexity of their molecular mechanisms of action, has aroused research interest toward non-electrophilic and direct modulators of Nrf2 pathway, such as PTZs. This review represents the first overview on the roles of PTZs as non-electrophilic Nrf2 activator and free radical scavengers, as well as on their potential therapeutic effects in oxidative stress-mediated diseases. Here, we provide a collective and comprehensive information on the PTZs ability to scavenge free radicals and activate the Nrf2 signaling pathway, with the aim to broaden the knowledge of their therapeutic potentials and to stimulate innovative research ideas.

Modified exfoliated graphene functionalized with carboxylic acid-group and thionine on a screen-printed carbon electrode as a platform for an electrochemical enzyme immunosensor.

An enzyme immunoassay was developed based on the coulometric measurement of immunoglobulin M (IgM) against Hantaan viruses (HTNV) by using virus-like particles (VLPs) as recognition molecules. The surface functionalization of screen-printed carbon electrodes (SPCEs) was achieved through paste-exfoliated graphene that was modified with a COOH group and a thionine mediator through supramolecular-covalent scaffolds, on SPCEs by using the binder contained in the ink. After the covalent immobilization of the antibody, the sensor was used for the sandwich enzyme immunoassay of IgM against HTNV. By using HTNV VLPs as the second recognization molecules, the resulting sensor efficiently monitored the reaction of IgM against HTNV and anti-IgM antibody with high specificity. By attaching HTNV nucleocapsid protein antibody conjugate with horseradish peroxidase (HRP) onto VLPs, the signal response of the assay was derived from the coulometric measurement of H2O2 reduction mediated by thionine on the electrode surface after the application of a potential (- 0.2 V vs. Ag/AgCl). The ratio of charges measured before or after H2O2 addition was used to quantify IgM because these charges could be used as background charges or total charges, respectively. The ratio exhibited good agreement with IgM concentration within a range 0.1 to 1000 pg mL-1, and a detection limit of 0.06 pg mL-1 was obtained. The assay demonstrated high sensitivity and specificity toward HTNV-specific IgM in serum.

An electrochemical biosensor for T4 polynucleotide kinase activity assay based on host-guest recognition between phosphate pillar[5]arene@MWCNTs and thionine.

T4 polynucleotide kinase helps with DNA recombination and repair. In this study, an electrochemical biosensor was developed for a T4 polynucleotide kinase activity assay and inhibitor screening based on phosphate pillar[5]arene and multi-walled carbon nanotube nanocomposites. The water-soluble pillar[5]arene was employed as the host to complex thionine guest molecules. The substrate DNA with a 5'-hydroxyl group initially self-assembled on the gold electrode surface through chemical adsorption of the thiol group, which was phosphorylated in the presence of T4 polynucleotide kinase. Titanium dioxide nanoparticles served as a bridge to link phosphorylated DNA and phosphate pillar[5]arene and multi-walled carbon nanotube composite due to strong phosphate-Ti4+-phosphate chemistry. Through supramolecular host-guest recognition, thionine molecules were able to penetrate the pillar[5]arene cavity, resulting in an enhanced electrochemical response signal. The electrochemical signal is proportional to the T4 polynucleotide kinase concentration in the range of 10-5 to 15 U mL-1 with a detection limit of 5 × 10-6 U mL-1. It was also effective in measuring HeLa cell lysate-related T4 polynucleotide kinase activity and inhibitor screening. The proposed method offers a unique sensing platform for kinase activity measurement, holding great potential in nucleotide kinase-target drug development, clinical diagnostics, and inhibitor screening.

A New Phenothiazine-Based Fluorescent Sensor for Detection of Cyanide.

A new fluorescent sensor for the detection of CN- was developed based on the conjugation of phenothiazine fluorophore and benzofuran unit. By the nucleophilic attacking of CN- to the fluoroacetylamino group in the sensor, the additional reaction of CN- and carbonyl group induced the ICT (intramolecular charge transfer) effect in the molecule and caused the fluorescence quenching sensor. The titration experiments show that the sensor has good sensitivity, selectivity and quick response for CN-. In addition, the fluorescent detection of CN- in the living cell and zebrafish experiments demonstrated the value of the sensor in tracing the CN- in biological systems.

Phenothiazine-based fluorescent probes for the detection of hydrazine in environment and living cells.

As an important chemical raw material, hydrazine brings convenience to people's lives and provides opportunities for human development. However, the misuse or leakage of hydrazine has brought pollution to the environment, including water, soil and living organisms. At the same time, hydrazine poses a potential threat to human health as a carcinogen. Despite the enormous challenges, it is crucial to develop an effective method to detect hydrazine in environmental samples. In this work, we have synthesized a series of probes based on phenothiazine fluorophore by the introduction of different substituents and developed a novel probe for the detection of hydrazine. The probe is capable of detecting hydrazine in aqueous solutions with high sensitivity and selectivity, and can be easily fabricated into paper test strips for use in in situ samples. In addition, the probe is effective in detecting hydrazine in water, soil, cells, and zebrafish, providing an excellent tool for detecting hydrazine in the environment.

Host-guest systems for the SAMPL9 blinded prediction challenge: phenothiazine as a privileged scaffold for binding to cyclodextrins.

Model systems are widely used in biology and chemistry to gain insight into more complex systems. In the field of computational chemistry, researchers use host-guest systems, relatively simple exemplars of noncovalent binding, to train and test the computational methods used in drug discovery. Indeed, host-guest systems have been developed to support the community-wide blinded SAMPL prediction challenges for over a decade. While seeking new host-guest systems for the recent SAMPL9 binding prediction challenge, which is the focus of the present PCCP Themed Collection, we identified phenothiazine as a privileged scaffold for guests of ß cyclodextrin (ßCD) and its derivatives. Building on this observation, we used calorimetry and NMR spectroscopy to characterize the noncovalent association of native ßCD and three methylated derivatives of ßCD with five phenothiazine drugs. The strongest association observed, that of thioridazine and one of the methyl derivatives, exceeds the well-known high affinity of rimantidine with ßCD. Intriguingly, however, methylation of ßCD at the 3 position abolished detectible binding for all of the drugs studied. The dataset has a clear pattern of entropy-enthalpy compensation. The NMR data show that all of the drugs position at least one aromatic proton at the secondary face of the CD, and most also show evidence of deep penetration of the binding site. The results of this study were used in the SAMPL9 blinded binding affinity-prediction challenge, which are detailed in accompanying papers of the present Themed Collection. These data also open the phenothiazines and, potentially, chemically similar drugs, such as the tricyclic antidepressants, as relatively potent binders of ßCD, setting the stage for future SAMPL challenge datasets and for possible applications as drug reversal agents.

A phenothiazine urea derivative broadly inhibits coronavirus replication via viral protease inhibition.

Coronavirus (CoV) replication requires efficient cleavage of viral polyproteins into an array of non-structural proteins involved in viral replication, organelle formation, viral RNA synthesis, and host shutoff. Human CoVs (HCoVs) encode two viral cysteine proteases, main protease (Mpro) and papain-like protease (PLpro), that mediate polyprotein cleavage. Using a structure-guided approach, a phenothiazine urea derivative that inhibits both SARS-CoV-2 Mpro and PLpro protease activity was identified. In silico docking studies also predicted the binding of the phenothiazine urea to the active sites of structurally similar Mpro and PLpro proteases from distantly related alphacoronavirus, HCoV-229 E (229 E), and the betacoronavirus, HCoV-OC43 (OC43). The lead phenothiazine urea derivative displayed broad antiviral activity against all three HCoVs tested in cellulo. It was further demonstrated that the compound inhibited 229 E and OC43 at an early stage of viral replication, with diminished formation of viral replication organelles, and the RNAs that are made within them, as expected following viral protease inhibition. These observations suggest that the phenothiazine urea derivative readily inhibits viral replication and may broadly inhibit proteases of diverse coronaviruses.

New phenothiazine conjugates as apoptosis inducing agents: Design, synthesis, In-vitro anti-cancer screening and 131I-radiolabeling for in-vivo evaluation.

Phenothiazines (PTZs) are a group of compounds characterized by the presence of the 10H-dibenzo-[b,e]-1,4-thiazine system. PTZs used in clinics as antipsychotic drugs with other diverse biological activities. The current aim of the study is to investigate and understand the effect of potent PTZs compounds using a group of In-vitro and In-vivo assays. A total of seventeen novel phenothiazine derivatives have been designed, synthesized, and evaluated primarily in-vitro for their ability to inhibit proliferation activity against NCI-60 cancer cell lines, including several multi-drug resistant (MDR) tumor cell lines. Almost all compounds were active and displayed promising cellular activities with GI50 values in the sub-micromolar range. Four of the most promising derivatives (4b, 4h, 4g and 6e) have been further tested against two selected sensitive cancer cell lines (colon cancer; HCT-116 and breast cancer; MDA-MB231). The apoptosis assay showed that all the selected compounds were able to induce early apoptosis and compound 6e was able to induce additional cellular necrosis. Cell cycle assay showed all selected compounds were able to induce cell cycle arrest at sub-molecular phase of G0-G1 with compound 6e induced cell cycle arrest at G2M in HCT-116 cells. Accordingly, the apoptotic effect of the selected compounds was extensively investigated on genetic level and Casp-3, Casp-9 and Bax gene were up-regulated with down-regulation of Bcl-2 gene suggesting the activation of both intrinsic and extrinsic pathways. In-vivo evaluation of the antitumor activity of compound 4b in solid tumor bearing mice showed promising therapeutic effect with manifestation of dose and time dependent toxic effects at higher doses. For better evaluation of the degree of localization of 4b, its 131I-congener (131I-4b) was injected intravenously in Ehrlich solid tumor bearing mice that showed good localization at tumor site with rapid distribution and clearance from the blood. In-silico study suggested NADPH oxidases (NOXs) as potential molecular target. The compounds introduced in the current study work provided a cutting-edge phenothiazine hybrid scaffold with promising anti-proliferation action that may suggest their anti-cancer activity.

Tumor Stimulus-Activatable Pretheranostic Agent: One Key to Three Locks.

The uncontrollable distribution of antitumor agents remains a large obstacle for specific and efficient cancer theranostics; thus, efficient construction of tumor-specific systems is highly desirable. In this work, a general design of tumor stimulus-activatable pretheranostic agents was put forward via a series of structures-tunable triphenylamine derivatives (TPA-2T-FSQ, TPA-2T-BSZ, and TPA-2T-ML) with phenothiazine, benzothiazine, and thiomorpholine as identifying groups of hypochlorite (HClO), respectively. Notably, the sulfur atom in phenothiazine of TPA-2T-FSQ was more easily oxidized to sulfoxide groups by HClO, transforming into an electron acceptor to form an excellent push-pull electronic system, which was beneficial to a large redshift of absorbance and emission wavelengths. Based on this, TPA-2T-FSQ resorted to a key of overexpressed HClO in the tumor to open "three locks", viz, NIR fluorescence, photothermal, and photoacoustic signals for multimodal diagnostic and treatment of the tumor. This study provided an elegant design to adopt tumor stimulus-triggerable pretheranostic for improving theranostic accuracy and efficiency, which was regarded as a promising candidate for precision medicine.

Quantification of solution-free red blood cell staining by sorption kinetics of Romanowsky stains to agarose gels.

The imaging and quantification of stained red blood cells (RBCs) are important for identifying RBCs in hematology and for diagnosing diseased RBCs or parasites in cytopathology. Romanowsky staining has been used traditionally to produce hues in blood cells using a mixture of anionic eosin Y and cationic methylene blue and azure B. While Romanowsky stains have been widely used in cytopathology, end-users have experienced problems with varying results in staining due to the premature precipitation or evaporation of methanol, leading to the inherent inconsistency of solution-based Romanowsky staining. Herein, we demonstrate that the staining and destaining of blood smears are controllable by the contact time of agarose gel stamps. While the extent of staining and destaining is discernable by the hue values of stamped red blood cells in micrographs, the quantification of adsorbed and desorbed Romanowsky dye molecules (in particular, eosin Y, methylene blue and azure B) from and to the agarose gel stamps needs a model that can explain the sorption process. We found predictable sorption of the Romanowsky dye molecules from the pseudo-second-order kinetic model for adsorption and the one phase decay model for desorption. Thus, the method of agarose gel stamping demonstrated here could be an alternative to solution-based Romanowsky staining with the predictable quantity of sorption and timing of contact.

Taming multiple binding poses in alchemical binding free energy prediction: the ß-cyclodextrin host-guest SAMPL9 blinded challenge.

We apply the Alchemical Transfer Method (ATM) and a bespoke fixed partial charge force field to the SAMPL9 bCD host-guest binding free energy prediction challenge that comprises a combination of complexes formed between five phenothiazine guests and two cyclodextrin hosts. Multiple chemical forms, competing binding poses, and computational modeling challenges pose significant obstacles to obtaining reliable computational predictions for these systems. The phenothiazine guests exist in solution as racemic mixtures of enantiomers related by nitrogen inversions that bind the hosts in various binding poses, each requiring an individual free energy analysis. Due to the large size of the guests and the conformational reorganization of the hosts, which prevent a direct absolute binding free energy route, binding free energies are obtained by a series of absolute and relative binding alchemical steps for each chemical species in each binding pose. Metadynamics-accelerated conformational sampling was found to be necessary to address the poor convergence of some numerical estimates affected by conformational trapping. Despite these challenges, our blinded predictions quantitatively reproduced the experimental affinities for the ß-cyclodextrin host and, to a lesser extent, those with a methylated derivative. The work illustrates the challenges of obtaining reliable free energy data in in silico drug design for even seemingly simple systems and introduces some of the technologies available to tackle them.

Phenothiazines reduced autophagy in ischemic stroke through endoplasmic reticulum (ER) stress-associated PERK-eIF2α pathway.

BACKGROUND: Neuroprotective effects have been the main focus of new treatment modalities for ischemic stroke. Phenothiazines, or chlorpromazine plus promethazine (C + P), are known to prevent the generation of free radicals and uptake of Ca2+ by plasma membrane; they have a potential as a treatment for acute ischemic stroke (AIS). This study aims to investigate the role of endoplasmic reticulum (ER) stress-associated PERK-eIF2α pathway underlying the phenothiazine-induced neuroprotective effects after cerebral ischemia/reperfusion (I/R) injury. METHODS: A total of 49 male Sprague Dawley rats (280-320 g) were randomly divided into 4 groups (n = 7 per group): (1) sham, (2) I/R that received 2 h of middle cerebral artery occlusion (MCAO), followed by 6 or 24 h of reperfusion, (3) MCAO treated by C + P without temperature control and (4) MCAO treated by C + P with temperature control. Human neuroblastoma (SH-SY5Y) cells were used in 5 groups: (1) control, (2) oxygen-glucose deprivation (OGD) for 2 h followed by reoxygenation (OGD/R), (3) OGD/R with C + P; (4) OGD/R with PERK inhibitor, GSK2656157, and (5) OGD/R with C + P and GSK2656157. The molecules of ER stress, unfolded protein response (UPR) (Bip, PERK, p-PERK, p-PERK/PERK, eIF2α, p-eIF2α, p-eIF2α/eIF2α), autophagy (ATG12, LC3II/I), and apoptosis (BAX, Bcl-XL) were measured at mRNA levels by real time PCR and protein levels by Western blotting. RESULTS: In ischemic rats followed by reperfusion, expression of Bip, p-PERK/PERK, p-eIF2α/eIF2α, ATG12, and LC3II/I, as well as BAX were all significantly increased. These markers were significantly reduced by C + P at both 6 and 24 h of reperfusion. Anti-apoptotic Bcl-XL expression was increased, while pro-apoptotic BAX expression was decreased by C + P. In SH-SY5Y cell lines, both C + P and GSK2656157 significantly reduced the level of autophagy and apoptosis after I/R, respectively. The combination of GSK2656157 and C + P did not promote the same effect, suggesting that C + P did not induce any neuroprotective effect by inhibiting autophagy and apoptosis through the PERK-eIF2α pathway when this pathway was already blocked by GSK2656157. In general, the reduction in body temperature by phenothiazines was associated with better neuroprotection but it did not reach significant levels. CONCLUSION: The combined treatment of C + P plays a crucial role in stroke therapy by inhibiting ER stress-mediated autophagy, thereby leading to reduced apoptosis and increased neuroprotection. Our findings highlight the PERK-eIF2α pathway as a central mechanism through which C + P exerts its beneficial effects. The results from this study may pave the way for the development of more targeted and effective treatments for stroke patients.

Surfactant-Free Formate/O2 Biofuel Cell with Electropolymerized Phenothiazine Derivative-Modified Enzymatic Bioanode.

A formate (HCOO-) bioanode was developed by utilizing a phenothiazine-based electropolymerized layer deposited on sucrose-derived carbon. The electrode modified with NAD-dependent formate dehydrogenase and the electropolymerized layer synergistically catalyzed the oxidation of the coenzyme (NADH) and fuel (HCOO-) to achieve efficient electron transfer. Further, the replacement of carbon nanotubes with water-dispersible sucrose-derived carbon used as the electrode base allowed the fabrication of a surfactant-free bioanode delivering a maximum current density of 1.96 mA cm-2 in the fuel solution. Finally, a separator- and surfactant-free HCOO-/O2 biofuel cell featuring the above bioanode and a gas-diffusion biocathode modified with bilirubin oxidase and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) was fabricated, delivering a maximum power density of 70 µW cm-2 (at 0.24 V) and an open-circuit voltage of 0.59 V. Thus, this study demonstrates the potential of formic acid as a fuel and possibilities for the application of carbon materials in bioanodes.

Phenothiazines Inhibit SARS-CoV-2 Entry through Targeting Spike Protein.

Novel coronavirus disease 2019 (COVID-19), a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has brought an unprecedented public health crisis and continues to threaten humanity due to the persistent emergence of new variants. Therefore, developing more effective and broad-spectrum therapeutic and prophylactic drugs against infection by SARS-CoV-2 and its variants, as well as future emerging CoVs, is urgently needed. In this study, we screened several US FDA-approved drugs and identified phenothiazine derivatives with the ability to potently inhibit the infection of pseudotyped SARS-CoV-2 and distinct variants of concern (VOCs), including B.1.617.2 (Delta) and currently circulating Omicron sublineages XBB and BQ.1.1, as well as pseudotyped SARS-CoV and MERS-CoV. Mechanistic studies suggested that phenothiazines predominantly inhibited SARS-CoV-2 pseudovirus (PsV) infection at the early stage and potentially bound to the spike (S) protein of SARS-CoV-2, which may prevent the proteolytic cleavage of the S protein, thereby exhibiting inhibitory activity against SARS-CoV-2 infection. In summary, our findings suggest that phenothiazines can serve as a potential broad-spectrum therapeutic drug for the treatment of SARS-CoV-2 infection as well as the infection of future emerging human coronaviruses (HCoVs).