Response To Selection Research Articles

Zn-Modified TiO2 Thin-Films for Real-Time Formaldehyde Sensing at Room Temperature

Abstract This study explores the fabrication and application of zinc-modified titanium dioxide (Zn-TiO2) thin-films for real-time recognition of volatile organic compounds (VOCs), with a particular emphasis on formaldehyde (HCHO) sensing at room temperature. The Zn-TiO2 thin-films were produced using an economical spray-pyrolysis method. Structural, morphological, and optical characterizations confirmed the successful integration of zinc with varied Wt.% (0, 2, 4, and 6) into the TiO2 lattice. The real-time monitoring capabilities of the sensors were assessed against a range of VOCs, highlighting its specificity for formaldehyde detection amidst diverse environmental constituents. The fabricated thin film sensors with zinc dopant were optimized to enhance the sensor's performance. 4 Wt.% Zn-TiO2 demonstrated excellent sensitivity to formaldehyde vapor at ambient conditions, showcasing a rapid and selective response. The underlying sensing mechanism was explored, emphasizing the role of zinc doping in tailoring the material's surface properties and facilitating enhanced adsorption of formaldehyde molecules. The study underscores the potential of Zn-modified TiO2 thin films as a reliable and efficient platform for real-time VOC monitoring, with a specific focus on HCHO sensing at room-temperature. The sensor shows remarkable stability and repeatability, making it a promising candidate for continuous monitoring applications.

Where does the processing of size meet the processing of space?

AbstractPrevious studies revealed an S-R compatibility effect between physical stimulus size and response location, with faster left (right) responses to small (large) stimuli, respectively, as compared to the reverse assignments. Here, we investigated the locus of interactions between the processing of size and spatial locations. In Experiment 1, we explored whether stimulus size and stimulus location interact at a perceptual level of processing when responses lack spatiality. The stimuli varied on three feature dimensions (color, size, location), and participants responded vocally to each feature in a separate task. Most importantly, we failed to observe a size-location congruency effect in the color-naming task where S-R compatibility effects were excluded. In Experiment 2, responses to color were spatial, that is, key-presses with the left and right hand. With these responses there was a congruency effect. In addition, we tested the interaction of the size-location compatibility effect with the Simon effect, which is known to originate at the stage of response selection. We observed an interaction between the two effects only with a subsample of participants with slower reaction times (RTs) and a larger size-location compatibility effect in a control condition. Together, the results suggest that the size-location compatibility effect arises at the response selection stage. An extended leaky, competing accumulator model with independent staggered impacts of stimulus size and stimulus location on response selection fits the data of Experiment 2 and specifies how the size-location compatibility effect and the Simon effect can arise during response selection.

Choice versus no choice: Practical considerations for increasing choices

AbstractChoice involves engaging in a selection response when multiple options are concurrently available. Choices can be incorporated into many components of behavior‐analytic treatment such as providing clients with a choice between multiple items, activities, or tasks. We reviewed the main characteristics of 38 behavior‐analytic articles that compared choice and no‐choice conditions. We coded the experimental arrangements of choice and no‐choice conditions and analyzed potential factors affecting preferences for choice and no choice. The findings suggest that the sizing of alternatives from which to choose, the timing of choice opportunities, and the timing of the delivery of the chosen option varied across the studies. Furthermore, preferences for choice shifted with differential reinforcement history and response effort manipulations of choice or no choice. The findings suggest that individual variables should be considered when providing choices, but more research is needed.

Neural mechanisms underlying robust target selection in response to microstimulation of the oculomotor system

Despite its prevalence in studying the causal roles of different brain circuits in cognitive processes, electrical microstimulation often results in inconsistent behavioral effects. These inconsistencies are assumed to be due to multiple mechanisms, including habituation, compensation by other brain circuits, and contralateral suppression. Considering the presence of reinforcement in most experimental paradigms, we hypothesized that interactions between reward feedback and microstimulation could contribute to inconsistencies in behavioral effects of microstimulation. To test this, we analyzed data from electrical microstimulation of the frontal eye field of male macaques during a value-based decision-making task and constructed network models to capture choice behavior. We found evidence for microstimulation-dependent adaptation in saccadic choice, such that in stimulated trials, monkeys’ choices were biased toward the target in the response field of the microstimulated site (Tin). In contrast, monkeys showed a bias away fromTinin non-stimulated trials following microstimulation. Critically, this bias slowly decreased as a function of the time since the last stimulation. Moreover, microstimulation-dependent adaptation was influenced by reward outcomes in preceding trials. Despite these local effects, we found no evidence for the global effects of microstimulation on learning and sensitivity to the reward schedule. By simulating choice behavior across various network models, we found a model in which microstimulation and reward-value signals interact competitively through reward-dependent plasticity can best account for our observations. Our findings indicate a reward-dependent compensatory mechanism that enhances robustness to perturbations within the oculomotor system and could explain the inconsistent outcomes observed in previous microstimulation studies.Significance StatementElectrical microstimulation has been used to study the causal contributions of certain brain areas or circuits to cognition and behavior. Nonetheless, the overall impact of microstimulation on behavior remains inconclusive, hinting at neural mechanisms that interact with experimental perturbation of neural activity. We hypothesized that this interaction could be driven by the reward feedback animals receive while performing tasks, either with or without external perturbations. Using computational modeling and data from microstimulation during a reward-dependent decision-making task, we found microstimulation and reward-value signals competitively interact within the oculomotor system. This interaction enhances the system’s robustness to both internal and external perturbations. Our results have important implications for employing microstimulation in basic and clinical research.

Excellent Wavelength Selectivity of p-AlGaN/n-Ga2O3 Solar-Blind UVC PD.

Due to the advantages of ultrawide bandgap, chemical stability, self-powered, and low cost, gallium oxide (Ga2O3) based photodetectors (PDs) are considered as one of the most promising solar-blind ultraviolet PDs, having garnered significant attention in fields such as missile warning and flame arc detection. High selective ratios and excellent responsivity are important to reduce the false alarm rate in solar-blind detection. However, due to the lack of p-type Ga2O3, existing Ga2O3-based PN PDs utilized heterostructures with narrower bandgap p-type semiconductors (e.g., p-GaN, p-SiC, etc.), inducing poor selective ratios with visible light and ultraviolet-A/B (UVA/B). Therefore, a high Al content AlGaN was used in this study to form a p-AlGaN/n-Ga2O3 solar-blind ultraviolet-C (UVC) PD. Since the bandgap of p-AlGaN aligned with the UVC region, the device exhibited exceptionally high selective ratios with R247nm/R360nm = 3.71 × 105 and R247nm/R300nm = 1.47 × 105 at 0 V, which surpassed the reported Ga2O3-based PN PDs. The formation of the type-II heterojunction facilitated the effective separation and transport of photogenerated carriers, resulting in high responsivity (0.36 A/W) under zero bias. Overall, the high selective ratios and high responsivity of the p-AlGaN/n-Ga2O3 PD in this paper provided a reliable pathway for self-powered solar-blind PDs with a low false alarm rate.

Avian TRIM13 attenuates antiviral innate immunity by targeting MAVS for autophagic degradation

ABSTRACT MAVS (mitochondrial antiviral signaling protein) is a crucial adaptor in antiviral innate immunity that must be tightly regulated to maintain immune homeostasis. In this study, we identified the duck Anas platyrhynchos domesticus TRIM13 (ApdTRIM13) as a novel negative regulator of duck MAVS (ApdMAVS) that mediates the antiviral innate immune response. Upon infection with RNA viruses, ApdTRIM13 expression increased, and it specifically binds to ApdMAVS through its TM domain, facilitating the degradation of ApdMAVS in a manner independent of E3 ligase activity. Furthermore, ApdTRIM13 recruits the autophagic cargo receptor duck SQSTM1 (ApdSQSTM1), which facilitates its interaction with ApdMAVS independent of ubiquitin signaling, and subsequently delivers ApdMAVS to phagophores for degradation. Depletion of ApdSQSTM1 reduces ApdTRIM13-mediated autophagic degradation of ApdMAVS, thereby enhancing the antiviral immune response. Collectively, our findings reveal a novel mechanism by which ApdTRIM13 regulates type I interferon production by targeting ApdMAVS for selective autophagic degradation mediated by ApdSQSTM1, providing insights into the crosstalk between selective autophagy and innate immune responses in avian species.

Application of RET Approach for Ratiometric Response Enhancement of ICT Fluorescent Hg2+ Probe based on Crown-containing Styrylpyridinium Dye.

Styrylpyridinium dye bearing azadithia-15-crown-5 ether receptor group SP and 4-alkoxy-1,8-naphthalimide fluorophore were linked using copper-catalyzed azide-alkyne cycloaddition click reaction to afford dyad compound NI-SP. Chemosensor NI-SP exhibited selective ratiometric fluorescent response to the presence of Hg2+ in aqueous solution due to the interplay between resonance energy transfer (RET) and intramolecular charge transfer (ICT) processes occurred upon excitation. The observed switching of the ratio of emission intensities in the blue and red channels R was higher than in the case of monochromophoric styrylpyridine derivative SP showing ratiometric response based on ICT mechanism only. Biological studies revealed that NI-SP penetrates into human lung adenocarcinoma A549 cells and accumulates in cytoplasm and lysosomes. When cells were pre-incubated with mercury (II) perchlorate, the ratio R was increased 2.6 times, which enables detection of intracellular Hg2+ ions and their quantitative analysis in the 0.7-6.0 μM concentration range.

Improving the Measurement of Gender in Surveys: Effects of Categorical Versus Open-Ended Response Formats on Measurement and Data Quality Among College Students

Abstract While researchers have some recommendations for measuring gender identity in surveys based on research and other sources that are summarized in a series of working group and panel reports, we continue to refine our understanding and practices. Gender identity is usually measured in surveys using a categorical selection response format with a small number of response options (e.g., “female,” “male,” “nonbinary”) and an open text response field to capture additional responses (“not listed, please tell us”). There is limited research guiding researchers on the use of other response formats. This study reports results from a between-subjects experiment embedded in a campus climate survey about university students’ attitudes about their campus and their behaviors and experiences related to inclusion and belonging at a large Midwestern university in 2021. Over 13,000 students were asked “What is your gender?” and subsequently randomly assigned to respond using either a categorical selection response format or an open response format (i.e., a place to specify their gender with no response options listed). We examine the distribution of responses, item nonresponse, response times, and concurrent validity (in terms of the association between gender and relevant survey outcomes) across the two response formats. Findings indicate the categorical selection response format is preferred for this population. While results show similar distributions in the categorization of responses across the formats and similar relationships with other survey outcomes, the selection format is associated with less item nonresponse and shorter response times.

The Restoring Force Triangle: A Mnemonic Device for Polymer Mechanochemistry.

In polymer mechanochemistry, mechanophores are specific molecular units within the macromolecular backbone that are particularly sensitive to tension. To facilitate understanding of this selective responsiveness, we introduce the restoring force triangle (RFT). The RFT is a mnemonic device intended to provide intuitive insight into how external tensile forces (i.e., stretching) can selectively activate scissile bonds, thereby initiating mechanically driven chemical reactions. The RFT utilizes two easily computable parameters: the effective bond stiffness constant, which measures a bond's resistance to elongation, and the bond dissociation energy, which is the energy required to break a bond. These parameters help categorize reactivity into thermal and mechanical domains, providing a useful framework for developing new mechanophores that are responsive to force but thermally stable. The RFT helps chemists intuitively understand how tensile force contributes to the activation of a putative mechanophore, facilitating the development of mechanochemical reactions and mechano-responsive materials.

A Data Driven Black Box Approach for the Inverse Quantification of Set-Theoretical Uncertainty

Abstract Inverse uncertainty quantification commonly uses the well established Bayesian framework. Recently, alternative interval methodologies have been introduced. However, in their current state of the art implementation, both techniques suffer from a large and usually unpredictable computational effort. Thus, both techniques are not applicable in a real-time context. To achieve a low-cost, real-time solution to this inverse problem, we introduce a deep-learning framework consisting of unsupervised auto-encoders and a shallow neural network. This framework is trained by means of a numerically generated dataset that captures typical relations between the model parameters and selected measured system responses. The performance and efficacy of the technique is illustrated using two distinct case studies. The first case involves the DLR AIRMOD, a benchmark case that has served as reference case for the inverse uncertainty quantification problem. The results demonstrate that the achieved accuracy is on par with the existing interval method found in literature, while requiring only a fraction of its computational resources. The second case study examines a resistance pressure welding process, which is known to require extremely fast monitoring and control due to the high process throughput. Based on the proposed method, and with only a limited selection of simulated responses of the process, it is possible to identify the interval uncertainty of the crucial parameters of the process. The computational cost in this case makes it possible for an inverse uncertainty quantification in a real-time setting.

Corti fluid is a medium for outer hair cell force transmission.

The mammalian cochlea amplifies sounds selectively to improve frequency resolution. However, vibrations around the outer hair cells (OHCs) are amplified non-selectively. The mechanism of the selective or non-selective amplification is unknown. This study demonstrates that active force transmission through the extracellular fluid in the organ of Corti (Corti fluid) can explain how the cochlea achieves selective sound amplification despite the non-frequency-selective action of OHCs. Computational model simulations and experiments with excised cochleae from young gerbils of both sexes were exploited. OHC motility resulted in characteristic off-axis motion of the joint between the OHC and Deiters cell (ODJ). Incorporating the Corti fluid dynamics was critical to account for the ODJ motion due to OHC motility. The incorporation of pressure transmission through the Corti fluid resulted in three distinct frequency tuning patterns depending on sites in the organ of Corti. In the basilar membrane, the responses were amplified near the best-responding frequency (BF). In the ODJ region, the responses were amplified non-selectively. In the reticular lamina, the responses were amplified near the BF but suppressed in lower frequencies. The suppressive effect of OHCs was further examined by observing the changes in tuning curves due to local inhibition of OHC motility. The frequency response of the reticular lamina resembled neural tuning, such as the hypersensitivity of tuning-curve tails after hair cell damage. Our results demonstrate how active OHCs exploit the elastic frame and viscous fluid in the organ of Corti to amplify and suppress cochlear vibrations for better frequency selectivity.Significance Statement Active outer hair cells have been considered to selectively amplify the basilar membrane vibrations near the sound's tonotopic location. However, recent observations from different labs showed that outer hair cells' action is non-selective-it spreads over the broad span of traveling waves. These observations challenge the existing theory pegged to basilar-membrane mechanics. The motion at the joint between the outer hair cell and the Deiters (ODJ) cell holds the key to account for the non-selective action of outer hair cells. We show that the characteristic motions at the ODJ are explained coherently when Corti fluid acts as the medium for outer hair cell force transmission. Our results demonstrate how non-selective outer hair cell action produces selective neural responses.

Novel Endoplasmic Reticulum-Targeted Luminescent Probe for Visualization of Carbon Monoxide in Drug-Induced Liver Injury.

Drug-induced liver injury (DILI) is a major hepatic dysfunction commonly caused by hepatotoxic drug overdose, resulting in a considerable number of fatalities worldwide. Recent studies have highlighted the regulatory and hepatoprotective effects of carbon monoxide (CO) during the liver injury process. However, precisely tracking the dynamic changes in the composition of CO in DILI is still a great challenge. In this work, leveraging the innovative "quencher-insertion" strategy, a unique endoplasmic reticulum (ER)-targetable lanthanide complex-based luminescence probe, ER-ANBTTA-Eu3+/Tb3+, has been developed for the selective and accurate monitoring of CO fluxes in live cells and laboratory animals. The new probe is composed of three covalently linked functional moieties: the terpyridine polyacid-Eu3+/Tb3+-mixed chelates as the long-lived luminophore, a p-toluenesulfonamide moiety as the ER-anchoring motif, and an allyloxy-nitrobenzyl ether moiety as the CO-specific recognition unit. Upon reaction with CO in the presence of Pd2+ ions, the Tsuji-Trost reaction leads to the cleavage of the allyloxy-nitrobenzyl group from the Eu3+/Tb3+-mixed chelates, which results in the restoration of Tb3+ emission at 538 nm and the attenuation of Eu3+ emission at 688 nm, leading to a dramatic increase of the I538/I688 ratio. In addition to the exceptional response sensitivity and selectivity toward CO, ER-ANBTTA-Eu3+/Tb3+ also exhibits the outstanding ER-locating capability, which allows the probe to be used for imaging of CO in the ER of live cells. Using this probe, combined with the time-gated luminescence imaging mode, the exogenous and endogenous CO in ER of live cells were monitored without the interference of background autofluorescence. Moreover, the upregulation of hepatic CO in DILI mice was successfully visualized. The results suggested the potential of ER-ANBTTA-Eu3+/Tb3+ for deeply exploring the functions of CO in DILI pathogenesis.

Detection of Silver and Mercury Ions Using Naphthalimide-Based Fluorescent Probe

A multifunctional fluorescent probe P based on a naphthalimide derivative for the detection of Ag+ and Hg2+ through a dual-signal was designed and characterized. P exhibited a large Stokes shift (107 nm), high selectivity, good sensitivity, and fast response time. By adjusting the testing medium and the order of reagent addition, multifunctional detection with P was achieved. The addition of Ag+ or Hg2+ to P solution in either ethanol or an ethanol–water mixture resulted in a significant quenching of fluorescence emission at 537 nm and caused a decrease in the absorbance at 440 nm accompanied by the appearance of a new absorption peak at around 340 nm, and there was an obvious color change from yellow to colorless. In contrast, the addition of other common metal ions and anions did not produce substantial spectral or color changes. The detection limit of probe P for Ag+ and Hg2+ was calculated to be 0.33 μM. The sensing mechanism was proposed and validated through MS and 1H NMR spectrometry methods. Additionally, P demonstrated the capability to recognize Ag+ and Hg2+ in living cells with satisfactory results.

Novel quinoline-based chemosensor as specific fluorescence sensing of copper ions in cancer cells and for organelle-specific imaging application

This work reports a simple synthesis of a quinoline-based organic molecule, (E)-N′-((6-methoxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene) picolinohydrazide (PHMQ), and its ability to distinguish Cu2+ ion. Through the use of spectroscopic and photometric titration techniques, PHMQ’s selectivity toward various cations and anions was examined. In just two minutes, PHMQ showed fast detection of Cu2+ ions, and clear spectral fluctuations proposed persistent PHMQ-Cu2+ complex formation. The calculated emission quenching constant (1.46 × 105 L/mol) and binding constant (1.25 × 104 L/mol) values suggested that strong emission quenching occurs between the PHMQ and Cu2+ ions. A linear reduction in fluorescence response was noted for Cu2+ ions concentrations between 2–26 μM, with a detection limit of 43.4 nM. Job’s plot, ESI-mass, NMR titration experiments, and density functional theory (DFT) simulations established a 1:1 stoichiometry for the PHMQ-Cu2+ complex. Additionally, PHMQ was efficaciously utilized to quantify Cu2+ ions in drinking and tap water samples and HeLa cells, illustrating durable cellular penetrability and a fluorescence ’Turn-Off’ response to Cu2+ ions. This sensor also established usefulness in mitochondrial-targeted imaging. For the detection of Cu2+ ions in biological and environmental environments, PHMQ is a promising detector due to its high sensitivity, selectivity, and quick response.

Highly effective fluorescence detection of UO22+ ions by an anionic Na/Eu heterometallic metal–organic framework with Lewis basic chelating sites

Uranium is a serious radioactive contaminant that can easily migrate into groundwater and surface water, posing a deadly threat to human health. Despite the development of various materials for detecting uranyl ions in water, rational design and synthesis of new uranium sensors with sensitivity, selectivity, and fast response remain challenging. Herein, we demonstrate a novel strategy for obtaining highly sensitive and selective UO22+ sensors by constructing heterometallic metal–organic framework with both an anionic skeleton and abundant chelating sites. Namely, the first anionic Na/Eu heterometallic metal–organic framework (Na/Eu-MOF) based UO22+ sensor is successfully synthesized by using sodium salt and europium salt as reactants, and abundant ether groups were introduced into its porous structure as chelating Lewis basic sites. Beneficial from the synergistic effect between the anionic skeleton and the chelating sites, Na/Eu-MOF achieved rapid, selective adsorption and fluorescence quenching toward uranyl ion. The detection limits of Na/Eu-MOF in deionized and lake water were determined to be 49.7 nM and 113.0 nM, respectively, which are lower than the maximum concentration of 130.0 nM in drinking water proposed by the United States Environmental Protection Agency, indicating potential environmental applications. The detection capability of Na/Eu-MOF is attributed to the combination system of energy competition and interactions between UO22+ ions and Na/Eu-MOF. This work offers a feasible strategy to construct an anionic heterometallic metal–organic framework with chelating sites for uranyl detection in an aqueous solution.

Coupling between conductive Co3(HITP)2 and SnO2 NPs for heterogeneous architectures: Toward sensitive chemiresistors for H2S at room temperature

Conductive metal–organic frameworks (C-MOF) having high surface area and reactivity offer great potential for chemiresistors. However, a highly sensitive, reversible, and high-speed gas sensor based on such materials still remains challenges. Herein, hybrid SnO2 NPs decorated Co3(HITP)2 NPs (SnO2@Co3(HITP)2) nanocomposites were synthesized as high active and conductive sensing material of chemiresistors for high-performance H2S detection at room temperature (RT). The SnO2@Co3(HITP)2 nanocomposites exhibit remarkably improved H2S sensing performance at RT, especially Sn1Co sensor shows higher response and excellent selectivity toward H2S gas under various measurement conditions. The enhanced gas sensing performance is discussed in terms of the adsorption behavior and the heterojunctions between Co3(HITP)2 and SnO2 using density functional theory (DFT) and band theory. The SnO2@Co3(HITP)2 hybrids discloses a novel strategy for designing high-performance Co3(HITP)2-based H2S gas sensors. Furthermore, Sn1Co sensor can successfully distinguish fresh meat from that stored for several days, demonstrating its ability in freshness of food detection.

Multi-Electrode Extended Gate Field Effect Transistors Based on Laser-Induced Graphene for the Detection of Vitamin C and SARS-CoV-2.

Despite the clinical data showing the importance of ascorbic acid (AA or vitamin C) in managing viral respiratory infections, biosensors for their simultaneous detection are lacking. To address this need, we developed a portable and wireless device for simultaneous detection of AA and SARS-CoV-2 virus by integrating commercial transistors with printed laser-induced graphene (LIG) as the extended gate. We studied the effect of laser printing pass number and showed that with two laser printing passes (2-pass LIG), the sensor sensitivity and limit of detection (LOD) for AA improved by a factor of 1.6 and 12.8, respectively. Using complementary characterization methods, we attribute the improved response to a balanced interplay of crystallinity, defect density, surface area, surface roughness, pore density and diameter, and mechanical integrity/stability. These factors enhance analyte transport, reduce noise/variability, and ensure consistent sensor performance, making 2-pass LIG the most effective material in this work. Our sensors exhibit promising performance for detecting AA with a selective response in the presence of common salivary interfering molecules, with sensitivity and LOD of 73.67 mV/dec and 54.04 nM in 1× phosphate buffered saline and 81.05 mV/dec and 78.34 nM in artificial saliva, respectively. We also showed that functionalization of the 2-pass LIG gate with S-protein antibody enables the detection of SARS-CoV-2 protein antigens with an ultralow LOD of 52 zg/mL─an improvement of more than 10-fold compared to 1-pass LIG─and 4 particles/mL for virion mimics with a selective response against influenza virus and multiple human coronavirus strains. With low signal drift/hysteresis and wireless capabilities, the developed device holds great potential for improving at-home monitoring and clinical decision-making.

Wearable Multifunctional Hydrogel for Oral Microenvironment Visualized Sensing Coupled with Sonodynamic Bacterial Elimination and Tooth Whitening.

Bacterial-driven dental caries and tooth discoloration are growing concerns as the most common oral health problems. Current diagnostic methods and treatment strategies hardly allow simultaneous early detection and non-invasive treatment of these oral diseases. Herein, a wearable multifunctional double network hydrogel combined with polyaniline and barium titanate (PANI@BTO) nanoparticles is developed for oral microenvironment visualized sensing and sonodynamic therapy. Due to the colorimetric properties of polyaniline, the hydrogel displays a highly sensitive and selective response for visualized sensing of oral acidic microenvironment. Meanwhile, the barium titanate in the hydrogel efficiently generates reactive oxygen species (ROS) under ultrasound irradiation, realizing non-invasive treatment in the oral cavity. Through bacterial elimination experiments and tooth whitening studies, the hydrogel can achieve the dual effect of effectively inhibiting the growth of cariogenic bacteria and degrading tooth surface pigments. Owing to the visualized sensing of the oral acidic microenvironment and efficient sonodynamic therapy function, the proposed hydrogel system offers a solution for the prevention of caries and tooth whitening, which is promising in developing the biomedical system targeting the simultaneous sensing and therapy for oral diseases.

Uncovering Integrated Dual-State ESIPT-Conductivity, Redox-Capacity, and Opto-Electronic Responses Toward Hg(II)/ Cr(III) of Aliphatic Fluorescent Polymers.

Excited-state intramolecular proton transfer (ESIPT)-associated dual-state emissive aliphatic dual-light emitting conducting polymers (DLECPs) having oxidation-reduction capacities are prepared polymerizing 2-acrylamido-2-methylpropane-1-sulfonic acid, methacrylic acid, and 2-methyl-3-(N-(2-methyl-1-sulfopropan-2-yl)acrylamido)propanoic acid monomers. Of as-synthesized DLECPs, nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies, fluorescent enhancements (I/I0), and computational investigation indicate intriguing photophysical features in DLECP3 (optimum composition). In DLECP3, ─CONH─, ─CON<, and ─COOH subluminophores are recognized by density-functional theory (DFT)/time-dependent-DFT calculations and experimental investigations. ESIPT-associated dual-state emission/conductivity, aggregation-enhanced emissions, selective opto-electronic responses toward Hg(II)/Cr(III) at 437/574nm, and redox properties of DLECP3 are supported by solid-state/solution spectroscopies, time-correlated single photon counting (TCSPC) measurements, dual-state excitation dependent emissions, microscopic images, electrochemical measurements, and DFT calculations. Here, preferential interaction of Hg(II)/Cr(III) with DLECP3 (amide)/DLECP3 (imidol) and reduction/oxidation of Hg(II)/Cr(III) to Hg(I)/Cr(VI) are substantiated by UV-vis, FTIR, and X-ray photoelectron spectroscopies; TCSPC measurements; NMR-titration; electrochemical studies; alongside computational calculations. The proton-electrical conductivities of DLECP3, Hg(II/I)-DLECP3, and Cr(III/VI)-DLECP3 in solids/solutions are 15.27 × 10-5/6.16 × 10-5, 19.60 × 10-5/25.52 × 10-5, and 26.69 × 10-5/27.60 × 10-5 S cm-1, respectively.

Mitochondria-Targeted NIR Ratiometric and Colorimetric Fluorescent Probe for Biothiols Based on a Thiol-Chromene Click Reaction.

In this work, a mitochondria-targeted NIR ratiometric and colorimetric fluorescent probe 1 was tactfully designed and synthesized by a novel design strategy of modifying chromene to pyridine for the first time. 1 exhibited a maximum absorption peak at 508 nm and a maximum fluorescence emission peak at 650 nm. Under the stimulus of biothiols (cysteine (Cys), homocysteine (Hcy), and glutathione (GSH)), the maximum absorption and fluorescence emission peaks of 1 blue-shifted to 448 and 541 nm, respectively, along with color changes from red to yellow under visible light and from red to green under a 365 nm ultraviolet (UV) lamp, which can be ascribed to the click reaction of biothiols with the α,β-unsaturated ketone of the chromene moiety with pyran ring-opening, phenol formation, and 1,6-elimination of the p-hydroxybenzyl moiety. 1 detected biothiols (Cys, GSH, and Hcy) with high sensitivity (LODs of 29, 23, and 16 nM for Cys, GSH, and Hcy, respectively), excellent selectivity, and fast response. Moreover, 1 can target mitochondria and image the fluctuation of intracellular biothiols by dual-emission channels.