Herein, we investigated the local organization, fluorescence dynamics, and dynamic heterogeneity in low transition temperature mixtures (LTTMs) composed of 1-butyl-3-methylimidazolium chloride (BmimCl; Tm = 343 K), 1-ethyl-3-methylimidazolium chloride (EmimCl; Tm = 353 K), and acetamide (ACM; Tm = 352 K) using steady-state and time-resolved fluorescence spectroscopy. Both mixtures exhibit pronounced excitation-wavelength-dependent emission behavior, with an overall shift of ~ 170 nm in the emission maxima, suggesting the presence of various local molecular environments within the mixtures. Fluorescence lifetime analyses reveal three decay components (~ 300 ps, ~ 1.7-1.9 ns, and ~ 5.5-5.9 ns), indicating tri-exponential fluorescence decay with contributions occurring over different timescales. Time-resolved fluorescence anisotropy studies at different excitation wavelengths at 298 K yield rotational relaxation times ([Formula: see text]) of 18.34-20.65 ns and 12.69-16.55 ns for BmimCl-ACM and EmimCl-ACM, respectively. Furthermore, the temperature-dependent reorientational dynamics exhibit a fractional viscosity dependence, with exponents of 0.47 for BmimCl-ACM and 0.85 for EmimCl-ACM, confirming the presence of dynamic heterogeneity in these LTTMs, with the former system displaying a greater extent of heterogeneity. Complementary 2D [1]1H-[1]H NOESY experiments reveal stronger cross-peaks for BmimCl-ACM, suggesting closer spatial association between the components compared with the EmimCl-ACM system. Overall, the combined optical spectroscopy and NMR results demonstrate that BmimCl-ACM forms a more strongly associated molecular structure compared to the EmimCl-ACM system. These findings underline how subtle variations in imidazolium cation structure govern molecular organization and dynamics in LTTMs, providing useful guidelines for the rational design of environmentally benign solvent systems.

The increasing prevalence of salicylic acid as an unauthorized adulterant in milk and its derived products poses serious concerns for human health and safety. In this study, a fluorescent probe based on boron-doped carbon dot-integrated poly(N-isopropylacrylamide) microgels (BCQDs@PNIPAM) was developed for the selective and sensitive detection of salicylic acid. The incorporation of carbon quantum dots (CQDs) within the PNIPAM microgel matrix not only imparts strong fluorescence but also minimizes their inherent tendency to self-aggregate, thereby enabling a stimuli-responsive sensing platform for salicylic acid detection. The biocompatibility of the developed probe was further evaluated through seed germination and bacterial assays. Moreover, the introduction of electron-deficient boron into the CQDs enhances their fluorescence performance, improving selectivity and quick response with "turn-on" signal for salicylic acid. Using this strategy, the probe demonstrated a linear detection range of 1-240 µM with a low limit of detection (LOD) of 54 nM. The feasibility of the sensing platform was demonstrated in real samples, highlighting its potential in quality control in food products. In addition, the enhanced fluorescence characteristics of the hybrid microgels enabled their application in security and anti-counterfeiting systems. Overall, this work offers a reliable and sustainable sensing platform for ensuring milk quality and safety, with promising implications for food surveillance and public health protection.

Mitochondrial potassium ion (K[+]) homeostasis and oxygen (O2) level are closely involved in diverse cellular physiological and pathological processes. However, imaging these two parameters within the same subcellular remains challenging because combination of different probes often suffers from spectral crosstalk and mismatched cellular internalization kinetics. Herein, we constructed mitochondria-targeted polymer-lipid hybrid nanoparticles, TPP-KO NPs, for dual-responsive imaging of K[+] and O2 dynamics. The nanoprobes were fabricated by a facile self-assembly strategy and were designed with a spatially isolated core-shell architecture to separate the K[+]- and O2-sensing moieties. In aqueous solution, TPP-KO NPs exhibited concentration-dependent responses to K[+] and O2, rapid response kinetics, good colloidal stability, and favorable photostability. Cellular evaluations confirmed their favorable biocompatibility and mitochondrial localization. In living cells, TPP-KO NPs provided distinguishable optical signals of mitochondrial K[+] fluctuations and O2 dynamics under the specific excitation and emission ranges after K[+]-modulating or hypoxic treatments. This dual-responsive nanoprobe system provides an imaging platform for monitoring of mitochondrial K[+] and O2 dynamics in living cells, which holds great potential for exploring the mitochondrial K[+]-O2 microenvironment.

For the purpose of selectively detecting Co[2+] and Cu[2+] ions using a combination of colorimetric and fluorometric responses, a novel coumarin-imidazole-thiazole based chemosensor 6-chloro-3-(2-(2-(4-(diphenylamino)phenyl)-1H-phenanthro[9,10-d]imidazol-1-yl)thiazol-4-yl)-2H-chromen-2-one (TDC2) was created and thoroughly studied. When TDC2 interacts with Co[2+] and Cu[2+], it shows noticeable colour changes, the colour changes from mild yellow to sea blue for Cu[2+] and in presence of Co[2+] ions colour changes to baby pink along with strong fluorescence quenching, but it is insensitive to other competing metal ions. Excellent linearity and high sensitivity are demonstrated by UV-visible and fluorescence titration tests, with nanomolar limits of detection of 45 nM for Co[2+] and 68 nM for Cu[2+]. The sensor exhibits reversible acidochromic behaviour toward volatile acid vapours and functions well across a broad pH range. Polymer-embedded films and paper-strip devices were developed to convert molecular sensing into useful platforms. These allowed for quick, portable, on-site detection with distinct visual responses under both visible and UV light. TDC2 is positioned as a reliable and application-focused sensor for real-time monitoring of Co[2+] and Cu[2+] ions due to its combination solution-state performance, solid-state device integration, and theoretical validation.

Organosilicon fluorescent materials have emerged as a remarkable innovation in the rapidly evolving field of material science, serving as a bridge between fundamental chemistry and cutting-edge applications. This review explores the transformative potential of these materials across various domains, highlighting their unique fluorescence properties and synthesis techniques. Their impact spans optoelectronics, medical diagnostics, and beyond, from enhancing biological imaging accuracy to advancing chemical sensing technologies. Additionally, key challenges such as stability, durability, and biocompatibility are examined in the context of industrial applications. We also explore their promising roles in advanced materials research, offering insights into future directions that may shape the next frontier of organosilicon fluorescence. By providing this comprehensive overview, we aim to deepen understanding and broaden the application of these extraordinary materials, facilitating their continued success in technological innovation.

Accurate determination of cysteine (Cys) remains challenging because of the structural similarity and comparable nucleophilicity of biological thiols. Herein, a red-emissive turn-on fluorescent probe, TCF-C1, was developed for selective Cys detection by coupling an acrylate recognition unit with a thiophene-extended TCF fluorophore. Reaction with Cys triggered a conjugate addition-cyclization process, resulting in the release of highly fluorescent TCF-OH and a pronounced fluorescence enhancement at 664 nm, accompanied by a visible color change from pink to purple. TCF-C1 exhibited a rapid response within 10 min and high selectivity for Cys over homocysteine, glutathione, amino acids, and common inorganic ions, together with a large Stokes shift of approximately 160 nm. The fluorescence intensity showed a linear dependence on Cys concentration from 0 to 35 µM, with a detection limit of 32.91 nM. The proposed sensing mechanism was supported by ESI-MS analysis and theoretical calculations. In addition, TCF-C1 exhibited low cytotoxicity and enabled fluorescence imaging of endogenous and exogenous Cys in living cells. Its analytical applicability was further demonstrated by the determination of Cys in samples of spinach, broccoli, snap beans, and carrots. These results establish TCF-C1 as a simple and sensitive fluorescent probe for Cys determination in food samples and for cellular imaging.

An integrated experimental and computational approach, including UV-Vis absorption, fluorescence quenching, circular dichroism (CD) spectroscopy, viscosity measurements, agarose gel electrophoresis, thermodynamic analysis, molecular docking, and Molecular Electrostatic Potential (MEP) mapping, was used to study the DNA-binding behavior of a nitro-substituted Schiff base Cu (II) complex. With a binding constant of approximately 1.7 × 10[5] M[-1], spectroscopic analyses verified an efficient interaction with fish salmon DNA (FS-DNA). Thermodynamic characteristics revealed a spontaneous process supported mainly by hydrogen bonding and van der Waals interactions, while fluorescence data suggested a static quenching mechanism and approximately 1:1 binding stoichiometry. The molecular docking results, together with the absence of any significant change in DNA viscosity and the negligible DNA-cleavage activity, suggest that groove binding is more likely than classical intercalation. The electron withdrawing nitro substituent really changes how the complex's electrons are spread out, creating clear electrophilic and nucleophilic zones. These regions facilitate interaction through the groove, while also reducing the electron density that would be required for the classical π-π stacking, as indicated by the MEP analysis. Overall, these findings suggest the nitro group governs the DNA binding preference, providing valuable insights for the design of metal complexes aimed at nucleic acids in future applications.

The emergence of super-resolution microscopy (SRM) has had a significant impact on the research field of diffraction-limited optical fluorescence microscopy, which has a span of applications from fundamental biophotonics to advanced materials science. SRM is a powerful technique capable of producing ultra-high-resolution images of organic, semiconductor materials and live cells by overcoming the conventional diffraction limit. In this manuscript, we discuss various strategies for improving the spatial and temporal resolution of SRM techniques without causing photodamage to the sample, which is a common issue when samples are exposed to high-intensity depletion beams. The problem of background noise is also a major limitation of all SRM techniques. In order to address these limitations, we propose various strategies to improve optical design, optical alignments, tuning of wavelengths of excitation and depletion laser beams, fluorescent probes, and microscopy modalities. Moreover, SRM techniques are reviewed and compared with each other as well as with conventional microscopy techniques in terms of imaging properties, spatiotemporal resolution, and fluorescent labels for cancer pathology applications. The continued integration of advanced probe design, adaptive optics, and AI-driven image reconstruction can serve as a future road-map to revolutionize SRM, enabling real-time, non-invasive, and ultra-high-resolution imaging across complex biological and material systems.

Peroxidase nanozymes and fluorophores have attracted considerable attention in catalysis and luminescence-based sensing applications. In this study, novel class of iron-, nitrogen-, and sulfur-functionalized carbon dots (Fe/N/S-CDs) featuring with inherent fluorescence and peroxidase-like activity were developed successfully via a facile hydrothermal approach. The Fe/N/S-CDs displayed strong blue fluorescence under UV irradiation with a high quantum yield of 44.5%. The incorporation of Fe active centers within the carbon framework and surface structure endowed Fe/N/S-CDs with efficient peroxidase-like activity toward hydrogen peroxide (H2O2) through a Fenton-like reaction, producing hydroxyl radicals (•OH). The generated •OH radicals induced surface oxidation of Fe/N/S-CDs, resulting in fluorescence quenching and enabling a selective "on-off" sensing mechanism. Structural and spectroscopic analyses confirmed H2O2-induced surface oxidation of Fe/N/S-CDs, accompanied by increased oxygen-containing functional groups, altered electronic structure, and sustained Fe[2+]/Fe[3+] redox cycling. Based on this strategy, a dual-mode sensing platform integrating fluorometric detection and smartphone-assisted colorimetric analysis was developed for H2O2 monitoring. The proposed sensor achieved low detection limits of 3.55 µM and 8.99 µM for fluorometric and smartphone-based colorimetric detection, respectively. Wide linear ranges of 4-5000 µM for fluorometric analysis and 30-1000 µM for smartphone-based detection were obtained. The practical applicability of the sensing platform was evaluated using commercial and medical H2O2 samples, demonstrating excellent recovery values ranging from 98.9% to 104.8% with low RSDs. The integration of functionalized Fe/N/S-CD nanozymes with smartphone-based analysis establishes a robust dual-mode sensing platform that paves the way for accessible, reliable, and real-time chemical sensing in environmental, biomedical, and food safety applications.

Biogenic amines are important indicators of food spoilage and freshness. In this study, four 3,4-Ethylenedioxythiophene (EDOT) derivatives, EDOT-EN1, EDOT-EN2, EDOT-EN3, and EDOT-EN4, were synthesized as fluorescent probes for the detection of biogenic amines. The four fluorescent probes were prepared by introducing different substituents based on 3,4-ethylenedioxythiophene. Comparison of their photophysical properties showed that EDOT-EN1 exhibited the most favorable photophysical and sensing performance among the four probes. EDOT-EN3 and EDOT-EN4 exhibited substantially weaker fluorescence than EDOT-EN1 and EDOT-EN2, resulting in insufficient signal contrast for quantitative sensing. Therefore, subsequent optimization focused on EDOT-EN1 and EDOT-EN2. EDOT-EN2 showed a response time comparable to that of EDOT-EN1. However, during the titration process, the concentration-dependent fluorescence response was less regular and less sensitive, making it less suitable for quantitative analysis, and its titration upper limit was approximately 1.5 times higher than that of EDOT-EN1. Therefore, EDOT-EN1 was selected for further investigation. The probe enables the detection of 1,5-pentanediamine (Cad) due to the aza-Michael addition reaction between EDOT-EN1 and Cad, resulting in Schiff-base products. Furthermore, EDOT-EN1 was immobilized on filter paper to fabricate portable fluorescent test strips for monitoring the freshness of shrimp and fish. Additionally, an electrospun film doped with EDOT-EN1 was prepared, which can selectively detect Cad vapor.

Reactive oxygen species generate a family of oxidized guanine species that serve as important biomarkers of oxidative damage. Here, we report the development of a fluorogenic RNA switch that selectively recognizes oxidized guanine species. We first systematically characterized an oxidized guanine RNA aptamer, defining its minimum functional binding domain and molecular recognition profile. Structural minimization produced a compact aptamer with higher affinity than the full-length sequence that retained broad recognition of structurally diverse oxidized guanine species while discriminating against their unmodified counterparts. We subsequently incorporated the optimized aptamer into fluorogenic RNA switch architectures, revealing that fluorescence activation required iterative optimization of aptamer topology, scaffold architecture, and communication-linker design. The resulting fluorogenic RNA switch exhibited target-dependent fluorescence activation while retaining the aptamer's molecular recognition profile. This work establishes a fluorogenic RNA switch for oxidized guanine species and highlights the importance of systematic aptamer characterization and optimization in fluorogenic RNA switch development.

The development of blue-green emitting organic chromophores with excellent optoelectronic properties remains an important issue. In this context, the newly synthesized oxadiazole-based blue-green emitting chromophore, 2-(4-(2-(anthracen-10-yl)vinyl)phenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (AVBO), was accomplished via the donor-π-acceptor (D- π-A) strategy using a Wittig reaction. The integration of aryl-heteroaryl groups and the oxadiazole group was utilized to obtain efficient blue-green emission with excellent optical properties. AVBO exhibited stable and efficient PL in the range of 485-510 nm across diverse solvent environments. Solvatochromic analysis using multiple correlations (Lippert-Mataga, Bakhshiev, Kawski-Chamma-Viallet, and Reichardt) revealed a significantly higher excited-state dipole moment compared to the ground state ([Formula: see text]>[Formula: see text]), with a parallel orientation ([Formula: see text]). The values calculated using these empirical equations were compared with those calculated computationally. Kamlet-Taft and Catalán MLR analyses further identified dominant non-specific solvent interactions ([Formula: see text]) alongside specific hydrogen-bonding donor contributions. To explore its potential in optoelectronic applications, AVBO was integrated into hybrid systems with ZnSe/ZnS core-shell quantum dots (7-8 nm). This assembly functioned as an efficient FRET mechanism, reaching an efficiency of 88% with Förster radii of 6.14-6.16 nm. The quenching kinetics, validated by Stern-Volmer plots, showed both static and dynamic components with super-diffusion-limited rate constants (kq ≈ 10[14] /MS). Time-resolved photoluminescence (TRPL) confirmed energy transfer via dipole-dipole interactions. These findings highlight the AVBO-QDs hybrid as a promising, cadmium-free, and tunable emitter for light harvesting, photosensitization, and bio-sensing applications.

The detection of hazardous analytes such as CN[-], N2H4, and ClO[-] is of great importance due to their potential risks to human health and the environment. Although numerous fluorescent sensors have been developed for the determination of these species, most studies have focused on individual analytes; conversely, the simultaneous evaluation of CN[-], N2H4, and ClO[-] considering them as potential interfering species has received relatively limited attention. Therefore, in this study, a dicyanovinyl-substituted D-π-A type organic material (TPA-Th-DCV) was developed as a fluorescent sensor exhibiting a rapid response, high selectivity, and excellent sensitivity toward cyanide ions (CN[-]) even in the presence of other anions (N2H4, ClO[-] and etc.). The photophysical behavior of TPA-Th-DCV was significantly altered by the nucleophilic addition of CN[-] to its vinyl group, which disrupted the intramolecular charge transfer (ICT) process. Fluorescence measurements revealed a remarkably low limit of detection (LOD) of 48 nM. The sensing mechanism of TPA-Th-DCV toward CN[-] was elucidated through NMR spectroscopy, mass spectrometry, and DFT/TDDFT calculations. Moreover, the turn-on fluorescence response of TPA-Th-DCV enabled the successful detection of cyanide in common food samples, demonstrating its strong potential for real-world environmental and food safety monitoring applications.

The electronic structure, Mg adsorption behavior, and optical response of M2B2 MBene quantum dots (M = Cr, Fe, Mn, Sc, Ti, and V) were systematically investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to evaluate their potential as anode materials for magnesium-ion batteries. The calculated adsorption energies demonstrate that the transition metal species strongly influences Mg binding, with V2B2 and Fe2B2 exhibiting the most favourable adsorption energies of - 1.44 and - 1.31 eV, respectively, accompanied by open-circuit voltages of 0.72 and 0.65 V. Among the investigated systems, V2B2 delivers the highest theoretical specific capacity of 780.93 mAh g[-1] while maintaining stable Mg adsorption energies ranging from - 0.94 to - 1.09 eV during successive Mg loading, indicating favorable electrochemical reversibility. Frontier molecular orbital, density of states, and charge-transfer analyses reveal pronounced Mg-V orbital hybridization and reduced HOMO-LUMO energy gaps upon Mg adsorption, leading to enhanced electronic conductivity. Furthermore, TD-DFT calculations predict tunable optical absorption extending from the near-infrared to the mid-infrared region with progressive red shifts as the Mg concentration increases. These findings provide molecular-level insight into the structure-property relationships governing Mg storage in MBene quantum dots and identify V2B2 as a promising candidate for next-generation magnesium-ion battery anodes.