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In this study, polyvinyl alcohol (PVA)-based ratiometric fluorescence nanofiber films with salicylamide (SA) as the response signal, rhodamine B (RhB) as the internal reference were prepared using electrospinning technique, and reducing their water solubility by glutaraldehyde (G) crosslinked. The RhB and SA were successfully immobilized in the PVA substrate. Moreover, RhB and SA improved the water resistance, water vapor barrier, and mechanical strength of the nanofiber films, among the PVA nanofiber films containing RhB and 400 mg SA (PVA/RhB/4SA-G) showed the best packaging performance. Meanwhile, it exhibited high sensitivity to ammonia (limit of detection was 0.97 ppm), and could effectively distinguish the freshness states of shrimp stored at 4 and 25 °C by displaying a distinct shift from light pink to bright purple fluorescence. Moreover, the migration studies confirmed the safety of PVA/RhB/4SA-G. Therefore, the fabricated PVA/RhB/4SA-G can be utilized as a promising intelligent packaging for monitoring seafood freshness in real-time., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Ochratoxin A (OTA) is toxic secondary metabolites produced by fungi and can pose a serious threat to food safety and human health. Due to the high stability and toxicity, OTA contamination in agricultural products is of great concern. Therefore, the development of a highly sensitive and reliable OTA detection method is crucial to ensure food safety. Although fluorescent sensors have been widely used for OTA detection, they still face challenges such as false positives and insufficient sensitivity, thus further improvement of the detection performance is necessary., Results: Herein, a ratiometric biosensor based on DNA-gated Fe₃O₄@Uio-66-NH₂ nanocomposites and Nucleic Acid Exonuclease I (Exo I)-assisted signal amplification was constructed for the sensitive detection of OTA. This functional nanocomposite combines magnetic, porous and fluorescent properties. Fe₃O₄ of the core enables efficient magnetic separation, while the porous structure of Uio-66-NH₂ encapsulates the fluorescent dye rhodamine 6G (Rho 6G). In addition, a label-free DNA gating strategy was introduced to control the release of Rho 6G. The sensor performs OTA detection by the fluorescence signal ratio of Fe 3 O 4 @Uio-66-NH 2 and Rho 6G, which effectively avoids false positives of the sensor. Accelerated release of Rho 6G using Exo I greatly improves the sensitivity of the sensor. The sensor has a low LOD (0.308 ng mL -1 ) and the recoveries for OTA detection in real samples were 92.4%-116.0 %., Significance: The development of this ratiometric fluorescent aptasensor highlights its potential for highly sensitive OTA detection, offering significant advantages in selectivity and accuracy due to its unique DNA-gated mechanism and the dual fluorescence signal ratio strategy. Additionally, the use of Fe₃O₄@Uio-66-NH₂ enables effective magnetic separation, while the Exo I-assisted signal amplification enhances sensitivity, making this sensor a powerful tool for detecting OTA in complex sample matrices with high reliability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Hypothesis: The small size of the nanoparticles used to obtain high surface area photocatalysts makes their removal from solution difficult. Producing photocatalysts on substrates would alleviate this limitation. Adding heterojunctions to photocatalysts, for example, TiO 2 /Ag, could improve photocatalytic performance due to Schottky junction formation and introduce antibacterial properties., Experiments: TiO 2 nanorod arrays were synthesised on a substrate via a hydrothermal approach, on which Ag nanoparticles were deposited using an electroless plating technique with varied deposition times and metal precursor concentrations. Photocatalytic performance was evaluated by monitoring Rhodamine B (RhB) degradation under ultraviolet light and antibacterial properties of the films tested using Methicillin-resistant Staphylococcus aureus., Findings: The Ag nanoparticle content was controlled by the Ag deposition process. The TiO 2 /Ag nanorod array containing 6.6 atomic% Ag as nanoparticles of ∼ 25 nm in diameter degraded 88 % of the RhB in 6 h compared to 54 % degradation for bare TiO 2 nanorods under the same reaction conditions. Decreased photoluminescence with heterojunction formation would indicate electron transfer from the TiO 2 into the Ag nanoparticles, thereby reducing charge carrier recombination. The antibacterial test conducted in the dark revealed enhanced performance for the TiO 2 /Ag sample compared to TiO 2 nanorods against Methicillin-resistant Staphylococcus aureus after 16 h exposure with a death rate of 84 %., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Rachel Caruso reports financial support was provided by Australian Research Council. Aaron Elbourne reports financial support was provided by Australian Research Council. Louisa Huang reports financial support was provided by AINSE Ltd. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

During stressful conditions, the human body synthesizes catecholamine neurotransmitters such as dopamine and adrenaline, and cortisol. The monitoring of these three molecules levels is crucial for stress management and holds significant medical applications. Here we developed an analytical device that incorporates a biomimetic (tongue-mimic) associated with an optical physico-chemical transducer, able to detect simultaneously cortisol, dopamine and adrenaline in human saliva without pre-treatments, using an array sensor based on fluorescent chemical receptors (BODIPY, Rhodamine, and Naphthylamides) able to interact by non-covalent interaction with cortisol, adrenaline and dopamine, leading to a change of the emission. Calibration, recovery and selectivity have been performed to validate the device. In particular, the linear responses of the array to concentration range of 1 pM-1 mM of the three analytes were demonstrated by PLS analysis, as well as the high selectivity by PLS-DA analysis performed with artificial saliva samples. Analyses in real human saliva samples, compared to the validated analytical methods, demonstrated that our prototype represents the first point-of-care device able to quantify these three analytes in human saliva with one single analysis in a wider concentration range respect to the other standard methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Design of a sensitive, cost-effective SERS substrate is critical for probing analyte in trace concentration in real field environment. Present work reports the fabrication of an oxygen (O 2 ) plasma treated bimetallic nanofibers as a sensitive SERS platform. In contrast to the conventional nanofiber-based SERS platform, the proposed plasma-treated bimetallic nanofibers-based SERS platform offers high sensitivity and reproducibility characteristics. On top, the use of bimetallic nanoparticles provides a synergistic effect, contributing to both electromagnetic and chemical enhancement to SERS performance and the plasma treatment contributes to the controlled exposure of the embedded nanoparticles (NPs) to the analyte thereby enhancing the overall sensitivity of the proposed technique. With standard Raman active probe molecules - 1,2-bis(4-pyridyl) ethylene (BPE) and rhodamine-6G (R6G) the limit of detection (LOD) and the limit of quantification (LOQ) of the proposed sensing platform are estimated to be 3.8 nM and 11.6 nM respectively. The enhancement factor (EF) of the designed sensing platform is calculated to be ∼10 8 with a maximum signal variations of 5 %. The applicability of the designed SERS substrate has been realized through detection of two antibiotics - fluconazole (FLU) and lincomycin (LIN) widely used in poultry farms. Furthermore, a deep learning model - artificial neural network (ANN) has been implemented for effective classification of the analyte molecules from a mixed sample., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Backgroud: Biomimetic nanoplatforms based on membrane coating strategies have received increasing attention in the field of medical research. However, it cannot perform biomedical imaging screening, which is essential for real-time identification. As a rich source of new drug discovery, traditional Chinese medicine (TCM) has made important contributions to the treatment of many diseases., Resullt: Therefore, a magnetic fluorescent bifunctional nanomaterial was developed for screening the active ingredients in Fuzi. The magnetic fluorescence nanoparticles Fe 3 O 4 @GO@RhB synthesized by one-step synthesis showed low toxicity, excellent fluorescence properties and fast magnetic separation. After coating the magnetic nanoparticle with cell membrane, the screening procedure was optimized with positive drug verapamil hydrochloride. Under the optimal conditions, the active ingredients in aconite were screened, and the three active ingredients were identified as benzoyl-mesaconine, benzoyl-aconine and benzoyl-hypacoitine by UPLC-MS/MS. In addition, in situ imaging technique was used to further verify the proliferative activity of the screened active ingredients., Significance: The magnetic fluorescence bifunctional nanoplatform for cell membrane bionic screening combined with in situ imaging technology established in this paper not only can rapidly and effectively target screening and separation of active ingredients in TCM, but also provides a new platform for bioimaging screening., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Regarding the coexistence of heavy metals and organic pollutants, many studies have achieved synergistic removal of Cr(VI) and organic pollutants under acidic conditions. However, the role of Cr(VI) in the removal of organic pollutants under neutral conditions may have been overlooked. Here, the catalytic effect of Cr(VI) in promoting the photoelectrocatalytic degradation of organic pollutants was investigated using a ternary system, which was a combination of photocatalysis, electrocatalysis and Cr(VI) catalysis. A fabricated TiO 2 /SnO 2 /BiVO 4 composite was used as an anode for degradation experiments. We found that the degradation efficiency and final removal of rhodamine B (RhB), ofloxacin (OFL), and tetracycline (TC) were improved by increasing the Cr(VI) concentration within the range of 10-20 mg L -1 . And the addition of Cr(VI) sharply improved the removal of the three organic pollutants under the optimal conditions (from 65% to 96% for RhB, from 34% to 81% for OFL, and from 43% to 100% for TC). According to the results of different processing methods and quenching experiments, we proposed a new catalytic mechanism that, Cr(VI) promotes PEC degradation by acting as an electron transfer carrier between TiO 2 /SnO 2 /BiVO 4 and O 2 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The photocatalytic degradation of rhodamine B (RhB), a cationic dye, and bromocresol green (BCG), an anionic dye, was investigated using oxygen vacancy-enriched ZnO as the catalyst. These dyes were selected due to their differing charges and molecular structures, allowing for a deeper exploration of how these characteristics impact the degradation process. The catalyst was prepared by reducing ZnO with 10% H 2 /Ar gas at 500 °C, and the introduction of oxygen vacancies was confirmed using various characterization techniques. A detailed kinetic model was developed to track dye degradation, accounting for adsorption and photocatalytic degradation simultaneously, both in solution and on the catalyst surface. The model incorporated the effect of pH on adsorption by considering the dissociation behavior of the dyes and their respective pK a values. The study revealed that degradation primarily occurs on the catalyst surface at acidic pH, while at basic pH, degradation is more pronounced in the solution. DFT calculations supported these findings, showing that the electrostatic potential of the dyes shifts depending on pH, influencing their interaction with hydroxyl radicals or the catalyst surface. Quantum yield calculations indicate peak values of 6.32 10 -5 molecules per photon for RhB at pH 11, and 4.20 10 -5 for BCG at pH 3., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier Ltd. All rights reserved.)

Tungsten oxide (WO 3 ) nanoparticles (WO 3 NPs) were prepared using beetroot (Beta vulgaris) extract. The synthesis was optimized by evaluating the effect of pH during the reduction of the WO 3 precursor and sintering temperature. Physicochemical characterization of the formed nanoparticles was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance UV-visible spectroscopy. Furthermore, the prepared WO 3 NPs were employed as photocatalyst for rhodamine B removal over the photocatalytic oxidation mechanism. Synthesis optimization revealed that a single phase of WO 3 NPs obtained by reduction at pH 4 and a sintering temperature of 550 °C. XRD and XPS measurements revealed that the single-phase WO 3 NPs was obtained with a crystallite size of 26.4 nm. SEM and transmission electron microscopy (TEM) indicated polymorphic forms, predominantly as nanorods, with a mean particle size of 24 nm. The WO 3 NPs have a band gap energy of 2.9 eV, supporting their performance as a photocatalyst. Evaluation of the photocatalytic activities of WO 3 NPs represents high activity and reusability of the material. A removal efficiency of 99.67% was achieved during 30 min of treatment under UV light illumination. A study on the effect of scavengers revealed the important role of hydroxy radicals in the photocatalysis mechanism. WO 3 NPs can be recycled and reused for photocatalysis, maintaining photoactivity for five cycles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A ratiometric fluorescent nanoprobe (CDs-Rho), synthesized through the simple covalent amide linkage between carbon dots (CDs) and pH-sensitive rhodamine dye (Rho), was designed for the precise sensing and imaging of extremely alkaline environments. The sensing mechanism involves the opposite pH-dependent fluorescence changes in CDs and Rho, respectively, coupled with pH-regulated FRET efficiency from CDs to Rho. The nanoprobe features a wide pH response window from pH 7.0 to 12.0 with a pK a value of 11.3 and shows high sensitivity, robust anti-interference capability, and high reversibility. Moreover, the significant shifts in emission wavelength following the pH fluctuations result in two well-separated emission signals, thus ensuring the visualization of reversible and distinct color changes (from green to red) during in vivo fluorescence imaging. This work furnished a facile protocol that contributes to the advancement of a novel method for the accurate sensing and imaging of extreme alkaline environments., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

A stable dual-emission fluorescent system, R6G/Eu-MOF, was obtained by simple mixing Eu-MOF with fluorescent rhodamine 6G (R6G). This system not only achieved robust dual luminescence performance at 430 nm (Eu-MOF) and 555 nm (R6G) under single-wavelength excitation, but also endowed it with significantly improved fluorescence stability. Orientin (OT), a bioactive traditional Chinese medicine (TCM) component, was found to efficiently quench the dual fluorescent emissions via the synergistic effect of dynamic quenching, photo-induced electron transfer and molecular interactions. Therefore, a rapid fluorescent assay for OT was developed based on the variations in fluorescence signals at 430 nm and 555 nm, as well as the alterations in the ratio between these two signals. This method can achieve highly sensitive determination of OT in the linear range of 1.1-220 μM, with a LOD of 0.26 μM at 430 nm and 0.16 μM at 555 nm (3 σ / N ). The R6G/Eu-MOF hybrid exhibits significantly lower detection limits and a broader linear range for OT than either R6G or Eu-MOF alone. This work presents a simple strategy to improve the water stability of Eu-MOF and also provides a rapid analysis of small molecule drugs using a fluorescence approach based on a dual-emission MOF hybrid system.

This study presents an efficient and environmentally sustainable synthesis of ZnO nanoparticles using a starch-mediated sol-gel approach. This method yields crystalline mesoporous ZnO NPs with a hexagonal wurtzite structure. The synthesized nanoparticles demonstrated remarkable multifunctionality across three critical applications. In photocatalysis, the ZnO NPs exhibited exceptional efficiency, achieving complete degradation of methylene blue within 15 min at pH 11, significantly surpassing the performance of commercial ZnO. Under neutral pH conditions, the nanoparticles effectively degraded various organic dyes, including methylene blue, rhodamine B, and methyl orange, following pseudo-first-order kinetics. The methylene blue degradation process was aligned with the Langmuir-Hinshelwood model, emphasizing their advanced catalytic properties. For supercapacitor applications, the ZnO NPs attained a high specific capacitance of 550 F/g at 1 A/g, underscoring their potential as energy storage solutions. Additionally, the nanoparticles demonstrated strong UV-induced antiradical activity, with an EC 50 of 32.2 μg/mL in DPPH assays. Notably, the cytotoxicity evaluation revealed an LC 50 of 1648 μg/mL, indicating excellent biocompatibility. This study highlights a sustainable approach for the synthesis of multifunctional ZnO NPs that offers effective solutions for environmental remediation, energy storage, and biomedical applications.

This paper presents the development of near-infrared (NIR) fluorescent probes, A and B , engineered from hemicyanine dyes with 1,8-naphthalic and rhodamine derivatives for optimized photophysical properties and precise mitochondrial targeting. Probes A and B exhibit absorption peaks at 737 nm and low fluorescence in phosphate-buffered saline (PBS) buffer. Notably, their fluorescence intensities, peaking at 684 ( A ) and 702 nm ( B ), increase significantly with viscosity, as demonstrated through glycerol-to-PBS ratio experiments. This increase is attributed to restricted rotational freedom in the fluorophore and its linkages to rhodamine or 1,8-naphthalic groups. Theoretical modeling suggests nonplanar configurations for both probes, with primary absorptions in the rhodamine and hemicyanine cores ( A : 543; B : 536 nm), and additional transitions to 1,8-naphthalic ( A : 478 nm) and rhodamine ( B : 626 nm) groups. Probe A is also responsive to human serum albumin (HSA), a key biomarker, with fluorescence increasing in HeLa cells as HSA concentrations rise. In contrast, probe B shows no response to HSA, likely due to steric hindrance from its bulky rhodamine group, illustrating a selectivity difference between the probes. Probe B , however, excels in mitochondrial imaging, confirmed through cellular and in vivo studies. In HeLa cells, it tracked viscosity changes following treatment with monensin, nystatin, and lipopolysaccharide (LPS), with fluorescence increasing in a dose-dependent manner. In fruit flies, probe B effectively detected monensin-induced viscosity changes, demonstrating its stability and in vivo applicability. These findings highlight the versatility and sensitivity of probes A and B as tools in biological research, with potential applications in monitoring mitochondrial health, detecting biomarkers like HSA, and investigating mitochondrial dynamics in disease.

Four rhodamine 6G-PAH probes with pyrene (R6G-Pyr), anthracene (R6G-Ant), acenaphthene (R6G-Acp) or phenanthrene (R6G-PA) as fluorophore were designed and synthesized for Hg(II) detection. Probe R6G-PA, which had the lowest detection limit of 0.84 nmol/L, displayed the best fluorescence performance as compared to the other three probes. This type of probe had good anti-interference properties against most common metal ions except Cu(II). Metal Cu(II) had a certain quenching effect on the fluorescence generated by Hg(II), with a minimum detection limit of 0.31 nmol/L (for R6G-Acp), indicating its potential practicability for Cu(II) detection. The structure-fluorescence relationship was discussed based on density functional theory (DFT) calculations, and R6G-PA + Hg(II), which had the minimum dihedral angle between polycyclic aromatic rings and rhodamine spiro ring, produced the strongest π-π accumulation and provided the brightest fluorescence. Probe R6G-PA was successfully employed for fluorescence detection of Hg(II) in biological samples. Its solid-phase sensor PS@R6G-PA was developed by immobilizing R6G-PA on PS microspheres for the determination of Hg(II) in water and food samples, with excellent reproducibility and fluorescence "on/off" response. The relative error of the spiked recovery rate was less than 10 %., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tracing copper ions levels in the environment and subcellular microenvironment is crucial due to the key role copper ions play in physiological and pathological processes. Herein, a novel naphthalimide-fused rhodamine probe Rh-Naph-Cu was prepared through modification with phenylhydrazine to produce a closed and non-fluorescent spirolactam. Based on the copper-induced spirolactam ring-opening and hydrolysis process, Rh-Naph-Cu can be employed as a fluorescence off-on probe for copper ions with high selectivity, high sensitivity (limit of detection: 33.0 nM), broad pH-response range (pH: 5.0-10.0), and color change visible with the naked eye. Rh-Nap-Cu could be made into test strips for the in-situ chromogenic detection of Cu 2+ . Significantly, Rh-Naph-Cu can be utilized for the detection of copper ions in living HeLa cells and zebrafish, and exhibits excellent lysosomal-targeting ability with high Pearson's correlation coefficient (PCC) of 0.96., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this project, a sensitive fluorescent aptasensor was fabricated to detect lead ions (Pb 2+ ) by applying hollow gold nanoparticles (HGNPs) as a nano-carrier and rhodamine B (RDB) fluorescent dye as the signal agent. In the aptasensor that was created, the specific attachment of the aptamers to Pb 2+ ions led to the release of aptamer from the chitosan (CTS) coated-HGNPs loaded with RDB, causing an increase in fluorescence intensity due to the leakage of RDB. The method demonstrated specific detection of the target analyte, achieving a detection limit (LOD) of 1 ppb and a broad linear dynamic range spanning from 2 to 1000 ppb. The aptasensor was able to accurately measure the concentration of Pb 2+ in human serum, low-fat milk, and mineral water samples. The suggested biosensor, which offers the benefits of simplicity, user-friendliness, affordability, and high sensitivity, is well-suited for use with complex samples such as environmental and clinical samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

A switchable ratiometric fluorescent smartphone-assisted sensing platform based on nitrogen-doped carbon dots (N-CDs) and Rhodamine B was fabricated for the determination of the ascorbic acid (AA) content in fruits by quenching the fluorescence of N-CDs with Hg 2+ (turn-off) and recovering with AA (turn-on). The blue-emission N-CDs was synthesized by liquid dielectric barrier discharge microplasma with an average size of 3.65 nm and an absolute quantum yield of 18 % (excited at 345 nm). In addition, the fluorescence color was converted to RGB values, enabling visual and quantitative determination of AA. Under optimal parameters, the linear ranges for detecting AA were found to be 3-170 μM and 5-170 μM for fluorescence spectrometer and smartphone sensing platform. The detection limits were 0.98 μM and 2.90 μM, respectively. Furthermore, the satisfactory recoveries in fruits were obtained by RF probe and smartphone platform. This smartphone-assisted platform will facilitate sensitive and visual determination for AA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Fe, Ni, and Cu doped ceria nanoparticles (CeNPs) were prepared with a simple and one-pot hydrothermal synthesis method. We investigated the chemiluminescence (CL) interaction between these NPs and rhodamine B (Rh B) and found that the highest CL intensity was related to the Rh B- Cu doped CeNPs. We assigned that to the higher catalytic property of Cu doped NPs compared to the others. Cu doped CeNPs have been applied for the first time as a catalyst in chemiluminescence reactions. Rh B- Cu doped CeNPs reaction was introduced as a novel CL system, and its mechanism was studied. Considering the sensitivity, simplicity, portability, and rapidness of the CL methods, we applied the introduced reaction to the development of a CL sensor for nitrite monitoring. In the presence of nitrite, the CL intensity of the system decreased, and there was a linear relationship between the CL intensity and nitrite concentration in the range 0.5-100 µM. Based on this fact, a sensitive and selective CL sensor with the detection limit of 0.2 µM was established for nitrite detection in various food and water samples., Competing Interests: Declarations. Ethical approval: Not applicable. Conflict of interest: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Lysosomes are acidic membrane-bound organelles that aid digestion, excretion, and cell renewal. The lysosomal membranes are essential for maintaining lysosomal functions and cellular homeostasis. In this work, we developed a molecular "NOR" logic gate, SIATFluor-580L , by introducing malachite green into the spirocyclic rhodamine. SIATFluor-580L requires restriction of molecular rotation of the malachite green motif ( Input 1 , tight membrane structure) and a large amount of H + ions to convert the spirocyclic rhodamine into the zwitterionic form ( Input 2 , acidic environment) to produce a fluorescent product ( Output ), providing a fluorogenic probe to visualize the lysosomal membrane dynamics in living cells with subdiffraction resolution by using HyVolution (also known as Lightning), an unconventional and inexpensive super-resolution imaging approach based on a basic confocal optical system.

A series of HaloTag ligands that incorporate near-infrared (NIR)-emissive phospha-rhodamine (POR) dyes have been developed. The PORs that contain dealkylated amino groups exhibit a hypsochromic shift in their absorption and emission wavelengths. Subsequent refinement of the POR spirocyclization equilibrium significantly enhanced membrane permeability, thereby leading to a substantial reduction in the time necessary for labelling. Consequently, target organelles could even be labeled at low POR dye concentrations in the tens of nM range.

8-Oxo-7,8-dihydro-2'-deoxyguanosine (dOG), the dominant oxidative product of 2'-deoxyguanosine (dG) under high levels of reactive oxygen species, usually serves as a biomarker for oxidative stress and a risk assessment factor for various diseases. Due to the extremely low abundance of dOG and the susceptibility of dOG detection to the interference of spurious oxidation, research on related biological processes is limited by insufficient sensitivity and specificity. In this work, an ultrasensitive and reliable approach for genome-wide dOG quantification was developed through chemical labeling-assisted high-performance liquid chromatography-tandem mass spectrometry with the introduction of glycosylase pretreatment. Upon derivatization by a novel labeling reagent rhodamine B ethylenediamine, the detection sensitivity of dOG was enhanced by 100-fold, and the detection limit was as low as 25 amol, which was superior to those of reported mass spectrometry-based methods. Potassium ferricyanide, as a single-electron oxidant, was shown to possess strong selectivity for dOG versus dG, improving the labeling specificity and reducing the interference from dG. The spurious oxidation during sample pretreatment was systematically explored and minimized, and a control assay of glycosylase pretreatment was proposed to further improve the quantitative accuracy of dOG. Precise quantification of endogenous dOG in different cells was achieved with less than 500 ng of genomic DNA. This method was successfully applied to the assessment of the overall level of oxidative damage under the treatment of glycosylase inhibitors, potentially contributing to the exploration of the complex role of dOG in physiological status and disease phenotype.

Ischaemic stroke and glioma, as leading causes of mortality and long-term disability, pose critical challenges to healthcare systems, necessitating innovative approaches to enable early and cost-effective diagnosis for timely intervention. Glial fibrillary acidic protein (GFAP), an astrocyte-produced protein, is highly responsive to both ischaemic stroke and glioblastoma multiforme, with its levels correlating to the extent of brain damage. In this study, we present the development of an immunoassay probe for the ratiometric fluorescent detection of glial fibrillary acidic protein (GFAP), employing a monoclonal GFAP antibody-conjugated silicon quantum dots (Ab@SiQDs) and rhodamine B dye (RhB)-based immunoprobe. The developed probe exhibited a fluorescence emission shift from 580 nm to 530 nm in response to GFAP, demonstrating a linear detection range from 31.15 pg mL -1 to 243 pg mL -1 , with a limit of detection of 0.7 pg mL -1 . Additionally, the immunoprobe showed high selectivity for GFAP, effectively discriminating it from other potential interfering biomolecules and ions. The probe was also capable of detecting GFAP in spiked serum samples, achieving a recovery rate ranging from 83% to 111%. Notably, a cost-effective paper strip assay was developed, offering significant potential for the visual detection of GFAP under ultraviolet illumination.

Most of the existing SERS systems failed to achieve satisfactory results in early diagnosis of Alzheimer's disease owing to a lack of effective signal transduction. Herein, we developed a dual signal amplification strategy for SERS detection of amyloid-β oligomers based on proximity hybridization-triggered catalyzed hairpin assembly (CHA) and hybridization chain reaction (HCR). In the presence of the target protein and two DNA-labeled antibodies, a proximate complex formed in a homogeneous solution. Each of the AβO-DNA complexes served as a catalyst to trigger and accelerate numerous hybridization processes between MB1 and MB2. Subsequently, the single-strand fragment on the electrode surface initiated HCR, resulting in the hybridization reaction to form double-strand DNA concatemers on the substrate surface. The surface became negatively charged and allowed the absorption of silver ions on the DNA skeleton. After chemical reduction by hydroquinone, the formed silver nanoparticles could be further grown with a silver enhancement step to amplify the detectable SERS signal by absorbing rhodamine 6G as a SERS reporter on the silver nanoparticle surface. This biosensing platform had potential applications in molecular diagnostics of AD serum samples.

In this study, a new method was used to evaluate the levels of four organochlorine pesticides in edible samples. In this method, a density tunable dispersive solid phase extraction procedure was coupled with gas chromatography-mass spectrometry. Rhodamine B was used as a sorbent, which was distributed throughout the oil matrix with the aid of evaporation of methanol. This process enabled the possibility of effective extraction and preconcentration of the target analytes. To achieve this goal, several factors affecting the extraction efficiency, including the type and volume of diluent, the amount of rhodamine B, the volume of methanol, and the temperature of the ultrasonic bath were carefully evaluated. This method provided low detection limits (from 0.21 to 0.36 ng g -1 ), wide linear range (1.1-100 ng g -1 ) and acceptable extraction recoveries (64-72%) and enrichment factors (102-115). The precision of the method was evaluated by calculating the relative standard deviation, which ranged from 3.6 to 6.8% for intra- and 3.1 to 8.8% for inter-day precisions. The investigated method reduced the interference of the matrix and provided the possibility of quantitative determination of the studied organochlorine pesticides in various oil samples (canola, corn, sunflower, and olive). This method introduced a reliable analytical tool for the monitoring of the pesticide residues in different oil samples by providing capabilities such as simplicity, sensitivity, and compatibility with the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The revolutionary impact of photoredox catalytic processes has ignited novel avenues for exploration, empowering us to delve into nature in unprecedented ways and to pioneer innovative biotechnologies for therapy and diagnosis. However, integrating artificial photoredox catalysis into living systems presents significant challenges, primarily due to concerns over low targetability, low compatibility with complex biological environments, and the safety risks associated with photocatalyst toxicity. To address these challenges, herein, we present a novel bioorthogonally activatable photoredox catalysis approach. In this approach, potent photocatalyst selection via atom replacement of the rhodamine core yielded the bioorthogonally activatable photocatalyst ( PC-Tz ). The introduction of 1,2,4,5-tetrazine quenched its photocatalytic properties, which were restored upon an intracellular inverse electron-demand Diels-Alder (iEDDA) reaction with trans -cyclooctene (TCO) localized in mitochondria. This reaction led to remarkable photocatalytic oxidation of nicotinamide adenine dinucleotide (NADH), effectively manipulating the mitochondrial electron transport chain (ETC) under hypoxic conditions in cancer cells. Additionally, photocatalytic pyroptotic cell death was observed through a caspase-3/gasdermin E (GSDME) pathway, achieving notable antitumor efficacy and adenosine triphosphate (ATP) reduction in tumor cells. To the best of our knowledge, this represents the first example of bioorthogonally activatable photoredox catalysis, opening new avenues for chemists to spatiotemporally control activity in specific cell organelles without disrupting other native biological processes.

This study reports on the facile development of star-shaped gold nanoparticles via seed-mediated growth protocol. Gold nanostars (AuNSTs) demonstrated average particle size of 48 nm using transmission electron microscopy (TEM). Chemical composition of AuNSTs was verifired using energy dispersive X-ray spectroscopy (EDX) mapping. AuNSTs demonstrated high optical response under visible spectrum, with maximum absorption at 685 nm, using UV-Vis spectroscopy. Therefore AuNSTs could be involoved into photocatalytic reaction under visible spectrum. AuNSTs demonstrated superior performance in degradation of rhodamine B dye (RB), and disinfection of some pathogenic bacteria. AuNSTs offered enhanced removal efficiency against rhodamine B dye (82.0 ± 0.35% in 135 min) under visible irradiation. Remarkably, under proper conditions of pH = 9, approximately 94 ± 0.55% of a 10 ppm RB solution was effectively photodegraded after 135 min; this could be ascribed to the strong electrostatic attraction between negatively charged AuNSTs surface and positive RB contaminant. This superior photocatalytic activity of AuNSTs could be correlated to high interfacial charge transfer efficiency for Au, and enhanced charge pair separation under visible spectrum. Additionally, AuNSTs exhibited potential antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). AuNSTs demonstrated substantial antibacterial activity via disk diffusion and microbroth dilution tests with zones of inhibition and minimum inhibitory concentrations (MIC) for E. coli (20.0 ± 0.54 mm, 1.25 µg/ml) and S. aureus (23.0 ± 0.35 mm, 0.625 µg/ml), respectively. In conclusion, AuNSTs demonstrated efficient dye removal capabilities along with significant antimicrobial activity against gram-positive and gram-negative bacterial strains., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

The shortwave infrared (SWIR) region is an ideal spectral window for next-generation bioimaging to harness improved penetration and reduced phototoxicity. SWIR spectral activity may also be accessed via supramolecular dye aggregation. Unfortunately, development of dye aggregation remains challenging. We propose a crystal-aided aggregate synthesis (CAASH) approach to introduce a layer of rationality for the development of J-aggregate and the successful development of a water-soluble SWIR JV-aggregate with a bisbenzannulated silicon rhodamine scaffold (ESi5). The resulting SWIR-aggregates exhibit excellent stabilities toward organic solvents, pH, sonication, photobleaching, thiols, and endogenous oxidative species. Notably, the aggregates have a high structure-dependent melting temperature of ca. 330-335 K. In fact, the heating/annealing process can be exploited to reduce aggregation disorder. The aggregates are biocompatible and have broad potential in in vivo fluorescence and photoacoustic imaging and more., Competing Interests: Competing interests: A Chinese patent application (2024115961715) with Y.Y., X.Q., X.L., and C.Y. listed as inventors is filed for the structures, preparation, and potential applications of the aggregates described in this manuscript. Y.Y., X.Q., X.L., and C.Y. declare no other competing interests. Other authors declare no competing interests., (© 2024. The Author(s).)

Dissolved copper and iron ions are regarded as friendly and economic catalysts for peroxymonosulfate (PMS) activation, however, neither Cu(II) nor Fe(III) shows efficient catalytic performance because of the slow rates of Cu(II)/Cu(I) and Fe(III)/Fe(II) cycles. Innovatively, we observed a significant enhancement on the degradation of organic contaminants when Cu(II) and Fe(III) were coupled to activate PMS in borate (BA) buffer. The degradation efficiency of Rhodamine B (RhB, 20 µmol/L) reached up to 96.3% within 10 min, which was higher than the sum of individual Cu(II)- and Fe(III)- activated PMS process. Sulfate radical, hydroxyl radical and high-valent metal ions (i.e., Cu(III) and Fe(IV)) were identified as the working reactive species for RhB removal in Cu(II)/Fe(III)/PMS/BA system, while the last played a predominated role. The presence of BA dramatically facilitated the reduction of Cu(II) to Cu(I) via chelating with Cu(II) followed by Fe(III) reduction by Cu(I), resulting in enhanced PMS activation by Cu(I) and Fe(II) as well as accelerated generation of reactive species. Additionally, the strong buffering capacity of BA to stabilize the solution pH was satisfying for the pollutants degradation since a slightly alkaline environment favored the PMS activation by coupling Cu(II) and Fe(III). In a word, this work provides a brand-new insight into the outstanding PMS activation by homogeneous bimetals and an expanded application of iron-based advanced oxidation processes in alkaline conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

In order to improve the low specific surface area and high recombinant light generation carriers of BiOBr, loading BiOBr onto suitable Metal Organic Frameworks (MOFs) is an effective strategy to unleash its efficient visible light response and intrinsic catalytic activity. In this study, using classic MOF CAU-17 as a precursor, using a straightforward co-precipitation technique, four BiOBr/CAU-17 composites with distinct MOF contents values BCAU-1, BCAU-2, BC, AU-3, and BCAU-4 were created, and their photo-catalytic characteristics were examined. The BCAU-2 composite exhibited much higher photo-catalytic degradation efficiency for Rhodamine B (RhB) and Tetracycline (TC) than the pristine materials, counter compositions, and early reported materials. XRD, SEM, TEM, XPS, and EDX results revealed the strong synergistic photo-catalytic effect of BiOBr and CAU-17. The photocatalytic degradation of TC was significantly enhanced by the BiOBr bimetal modification, with the 2 wt.% BiOBr/CAU-17 nanocomposite achieving an 87.2 % degradation of TC and 82 % Total Organic Carbon (TOC) removal within 60 min. The high photo-degradation efficiency of BCAU-2 composite should be attributed to the efficient transfer of photo-generated carriers at interfaces and the synergistic effect between BiOBr/CAU-17. Furthermore, the experiments on the capture of the active species proved that the main active free radicals involved in the degradation of RhB and TC are attributed to the photo-induced holes h + and ⋅ O 2 - under visible light. The catalyst's efficacy is corroborated by the outcomes of photoluminescence spectroscopy and photo current response. This study offers a new understanding for the design of green synthesis schemes for photo-catalytic dye degradation and removal of certain antibiotics from the aquatic environment., (© 2024 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

The advancement of an efficient photocatalyst via a straightforward process is critical for environmental remediation and energy conversion. In this study, a series of multifunctional nitrogen-doped graphene/BiOCl (NGBOC) Schottky heterojunction photocatalysts were successfully prepared by hydrothermal method. The systematic characterization and analysis results showed that the addition of NG guided the formation and growth of BiOCl to thinner and smaller nanosheets, during which, under the strong interaction between both, more abundant oxygen vacancies were introduced into BiOCl and a small amount of N element was doped in lattices, ultimately BiOCl and NG with excellent electron transport form Schottky heterojunction. This series of favorable effects not only improve the adsorption capacity of BiOCl to pollutants, but also accelerate the separation and migration rate of photogenerated carriers. Under visible light, the 3NGBOC with optimal content of NG exhibits the highest photocatalytic activity for the degradation of Rhodamine B (RhB) and tetracycline (TC), which is more than four times higher than that of the reference BiOCl. Meanwhile, The NGBOC photocatalysts is highly reusable and has the potential to be recycled five times. Besides, under simulated sunlight, the conversion rate of CO 2 to CO over 3NGBOC was about twice that of a single BiOCl. In addition, capture experiments and room temperature electron paramagnetic resonance (EPR) strongly support the dominant role of hydroxyl radicals and superoxide radicals in photocatalytic reactions. This study reveals the design and preparation of multifunctional BiOCl-based Schottky heterojunction photocatalyst, provides a green economic strategy and promising scheme for promoting environmental remediation and energy conversion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A huge amount of polyvinyl alcohol (PVA) fabric is abandoned from nuclear power plants every year, the traditional treatment process will occupy land resources and pollute the environment; therefore, a lot of research has been carried out on the chemical treatment of PVA fabric. Herein, the performance of degradation of polyvinyl alcohol under high-pressure and high-temperature conditions is investigated. The effects of the initial pH value, reaction temperature, molar ratio of H 2 O 2 /Fe 2+ , and H 2 O 2 dosage on PVA degradation were evaluated. In the tested ranges in this work, the degradation of PVA fabric via high-pressure and high-temperature method was optimum at the initial pH value of 4, reaction temperature of 300℃, molar ratio of H 2 O 2 /Fe 2+ as 10, and H 2 O 2 dosage of 13 g/L. The PVA removal rate and TOC removal rate were 99.99% and 97.36%, respectively. Meanwhile, the high-pressure and high-temperature methods also had a great effect on the removal of Rhodamine-B and Reactive Red X-3B, the removal rates of Rhodamine-B and Reactive Red X-3B were 99.83% and 99.76%, respectively. The reaction mechanism of high-pressure and high-temperature methods was also discussed in this study.

This study was aimed at evaluating the removal of different cationic dyes onto phosphoric acid-activated coconut shell carbon. The activated carbon was characterized for surface functional groups, thermal decomposition profiles, surface morphology, and textural properties. The specific area was recorded as 1,221 m 2 /g with 100% mesoporosity. On molecular basis, the activated carbon adsorbs malachite green, methylene blue, and rhodamine B at maximum capacities of 1.52 mmol/g, 0.80 mmol/g, and 0.58 mmol/g, respectively. It indirectly implies the selectivity of activated carbon toward malachite green, and behaves differently due to steric hindrance of dye molecules. All equilibrium data obeyed Langmuir model, while the kinetic data are closely fitted to pseudo-second order model as concentration increases. To conclude, coconut shell activated carbon is more effective to remove malachite green compared to methylene blue and rhodamine B.

The proton electrochemical gradient generated by the respiratory chain activity accounts for over 90% of the available respiratory energy and, as such, its evaluation and accurate measurement regarding total values and fluctuations are an invaluable component of the understanding of mitochondrial function. Consequently, alterations in electric potential across the inner mitochondrial membrane generated by differential protonic accumulation and transport are known as the mitochondrial membrane potential, or Δψ, and are reflective of the functional metabolic status of mitochondria. There are several experimental approaches to measure Δψ, ranging from fluorometric evaluations to electrochemical probes. In this chapter, we describe how Δψ may be evaluated in isolated mitochondria and live cells using electrochemical and fluorescent methods, such as tetraphenylphosphonium (TPP+) and tetramethylrhodamine methyl ester (TMRM), respectively. These methods are dependent on the accumulation of cationic probes within mitochondria, which are assessed by using a TPP + -selective electrode or instruments that measure fluorescence (microplate reader and flow cytometer)., (© 2025. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Mitochondrial morphology and membrane potential (Δψ) are important readouts of mitochondrial function. Integrated analysis of these parameters in living cells can be performed using fluorescent lipophilic cations, which enter cells and accumulate in the mitochondrial matrix in a Δψ-dependent manner. Here, we describe the use of tetramethylrhodamine methyl ester (TMRM) and Mitotracker Green FM (MG) for mitochondrial morphology and semiquantitative Δψ analysis in living primary human skin fibroblasts (PHSFs). Practically, we present an integrated protocol to quantify mitochondrial morphology parameters and signal intensity using epifluorescence microscopy of PHSFs co-stained with TMRM and MG. This approach performs best using large flat cells like PHSFs, which display a high mitochondria-specific fluorescence signal and are imaged at a relatively high (x40) magnification., (© 2025. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

A one-stone-for-three-bird strategy comprising lignocellulose waste management, photocatalytic toxic organic dye degradation, and anti-bacterial activity has been demonstrated using waste coconut coir derived carbon-supported NiO/PdO (NiO/PdO@C) nanocomposite. The formation of interconnected fibrous morphology with intact formation of face-centered cubic NiO and tetragonal PdO within the graphitic carbon shell in NiO/PdO@C was identified from various structural and morphological analyses. Additionally, the elemental mapping and high magnification transmission electron microscopy analyses observed the homogeneous distribution of bimetallic oxides and their complete coverage by multilayered carbon shell. After systematic structural and morphological analyses, the prepared materials were exploited as photocatalysts for the degradation of rhodamine 6G dye. The importance of NiO and PdO heterostructure formation toward overall photocatalytic activity was analyzed by performing catalytic efficiency of individual NiO@C and PdO@C nanostructures and achieving the dye removal efficiencies of 44 % and 34 %, respectively. By integrating NiO and PdO, the electron-hole charge separation was greatly increased while the electron-hole recombination was decreased, and thereby NiO/PdO@C-equipped catalysis degraded 94 % of rhodamine 6G dye within 20 min. Furthermore, similar to photocatalytic activity, the NiO/PdO@C also exhibited exceptional anti-bacterial activity against Klebsiella pneumonia (K. pneumonia), Pseudomonas aeruginosa (P. aeruginosa), and Staphylococcus aureus (S. aureus) bacteria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Environmentally friendly natural polymer-based room temperature phosphorescence (RTP) materials exhibit promising applications in anti-counterfeiting and information encryption. However, the construction of natural polymer-based RTP materials with multicolor long afterglow and even persistent near-infrared (NIR) luminescence remains a tough challenge. Here, starch (S)-based ultralong RTP materials with wide color-tunability, persistent NIR luminescence are conveniently prepared through Förster resonance energy transfer (FRET) strategies. The binary doping system S-4-carboxyphenylboric acid with an ultralong phosphorescence lifetime of up to 449 ms is used as energy donor, and commercial dyes fluorescein, rhodamine 6G and lissamine rhodamine B (LRB) are selected as energy acceptors. By adjusting the weight ratio of energy donor and acceptor, tunable multicolor long afterglow from blue to yellow-green, purple, red and even nearly white (0.32, 0.33) can be successfully achieved through the triplet-to-singlet FRET process. The quaternary doping system displays persistent NIR luminescence band from 650 to 800 nm along with the longest phosphorescence lifetime of up to 131 ms via the stepwise FRET process using LRB as the intermediate energy acceptor and NIR dye Nile blue A as the energy acceptor. Satisfactorily, the prepared S-based RTP materials with wide-range color-tunable long afterglow demonstrate potential applications in multimode information encryption and anti-counterfeiting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

To efficiently treat rhodamine B (RhB) and tetracycline (TC) in wastewater, MIL-101(Cr) was prepared by hydrothermal method and encapsulated with phosphotungstic acid (H 3 PW 12 O 40 , abbreviated as PTA) to form an S-scheme heterojunction PTA@MIL-101(Cr)-x (P@M-x, x = 50, 100, 150, 200). The experimental results showed that after 180 min under visible light at pH 7, the degradation rates of RhB and TC were 97.81% and 99.9%, respectively. Meanwhile, the cycling experiments have showed that the P@M-100 S-scheme heterojunction exhibits good stability. Density Functional Theory (DFT) calculations theoretically verified the experimental results and elucidated the electrons migrate to MIL-101(Cr) and hole enrichment on the PTA surface. It was also revealed that the P@M-x photocatalyst belongs to the S-scheme heterojunction. Moreover, •O 2 - and h + had been identified as the main active constituents during the photocatalytic degradation process. The synergistic effect of MIL-101(Cr) and PTA enhances the visible light absorption of P@M-x S-scheme heterojunction, resulting in more efficient electron transfer ability and faster photoreaction rate, thereby improved its photocatalytic performance. This study provides a potential solution for addressing aromatic pollutants in water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Immobilization of nanometer-scale photocatalysts on a 3D polymeric substrate could play several complementary roles in photocatalysis, such as providing mechanical stability, facilitating easy recycling after usage, enhancing adsorption capability, and improving light harvesting properties through multiple reflections. To achieve stable and efficient photocatalysis under weak light conditions, 3D cellulose micro-rolls were introduced into the photocatalytic composites. Here, the formation of micro-rolls is attributed to the presence of titania nanoparticles, which generate uneven shrinkage stress in cellulose during the freeze-drying process, thereby inducing the cellulose to curl up. The dramatic structural transformation of the 3D micro-rolls increased the Brunauer-Emmett-Teller (BET) surface area of the sample. The 3D micro-roll structure is more favorable for photocatalysis due to its efficient mass transfer and exposed reactive sites, laying the foundation for enhanced adsorption capacity and photocatalytic reactions. The adsorption experiments suggested that the inner space of the micro-rolls provides a sufficient reaction zone, enabling fast mass transfer of molecules and easy access to the active sites. The samples could stand a high strain of 80 % and retain 96 % of the original maximum stress after 200 cyclic compressions, indicating excellent long-term stability. In addition, the photocatalytic tests show that with the help of micro-rolls, TiO 2 can convert and utilize weak light that would otherwise be unused, and the catalysate exhibits almost no toxicity towards Escherichia coli., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A novel semiconductor photocatalyst was developed using bamboo cellulose fibers (BCFs) embedded with nano-AgBr (AgBr@BCFs) via a simple and rapid method. BCFs prevented the agglomeration of AgBr and provided numerous active reaction sites as a dispersant and structural support. The photocatalytic activity of AgBr@BCFs in removing organic pollutants was investigated and the endogenous factors leading to the high activity were analyzed through a combination of a series of experiments, characterizations and theoretical calculations. We propose that the efficient photocatalytic performance of AgBr@BCFs was attributed to the interface integration facilitated by hydrogen bonds and robust electronic interactions. The interface demonstrated a significantly negative reduction potential (-0.57 eV), enhancing carrier transport efficiency and inhibiting the recombination of photogenerated electron-hole pairs. Compared to the intrinsic activity of AgBr, AgBr@BCFs exhibits 7.2 times higher performance for Rhodamine B and 8.6 times greater intensity for tetracycline (TC). Additionally, the applicability of the photocatalyst across various pH ranges, photocorrosion resistance, and recyclability were evaluated. The mechanism of the photocatalytic process revealed that the synergistic bifunctionality of high adsorption rate and strong degradation activity is the primary reason for the high activity. BCFs-based semiconductor material can be recycled efficiently, which is a promising photocatalyst for the purification of organic sewage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biogenic amines (BAs), produced in fish and seafood due to microbial contamination, pose significant health risks. This study introduces a novel ratiometric fluorescent probe, synthesized by integrating rhodamine 6G(R6G) and gold nanoparticles (AuNCs), for the sensitive and specific detection of BAs. The probe operates on the principle of BAs hydrolysis, catalyzed by diamine oxidase, to produce hydrogen peroxide (H 2 O 2 ), which selectively quenches the fluorescence of AuNCs at 620 nm, while the fluorescence of R6Gat 533 nm remains unaffected. The ratio of I 620 /I 553 demonstrated excellent linearity with a wide dynamic range (1-1000 μM) and a low detection limit of 0.1 μM. Validation using grass carp samples showed high recovery rates (97.57% to 104.29%), confirming the probe's efficacy and potential for practical application in food safety monitoring.

Potassium ion (K + ) is the most abundant metal ion in cells and plays an indispensable role in practically all biological systems. Although there have been reports of both synthetic and genetically encoded fluorescent K + indicators, there remains a need for an indicator that is genetically targetable, has high specificity for K + versus Na + , and has a high fluorescent response in the red to far-red wavelength range. Here, we introduce a series of chemigenetic K + indicators, designated as the HaloKbp1 series, based on the bacterial K + -binding protein (Kbp) inserted into HaloTag7 self-labeled with environmentally sensitive rhodamine derivatives. This series of high-performance indicators features high brightness in the red to far-red region, large intensiometric fluorescence changes, and a range of K d values. We demonstrate that they are suitable for the detection of physiologically relevant K + concentration changes such as those that result from the Ca 2+ -dependent activation of the BK potassium channel.

This study represents a pioneering investigation into using microfluidic technology for manufacturing PLA and PLGA nanocarriers (NCs) loaded with tracer molecules or metals through a co-precipitation protocol that involves saturating the water phase. The effects of total flow rate (TFR), flow rate ratio (FRR), surfactant amount, and polymer concentration on particle sizes and distributions were examined. The average size of PLA-NCs varied from 349 ± 175 nm to 170 ± 64 nm, with surface charges ranging from -13 to -6 mV. In contrast, PLGA-NCs had an average size between 192 ± 46 nm and 100 ± 34 nm, with surface charges from -23 mV to -53 mV. Increasing the TFR from 6 to 10 mL/min with a fixed FRR of 1:1 and reducing polymer concentrations in the organic phase from 20 to 5 mg/mL generally resulted in smaller NC sizes and distributions (monodispersed), with PLGA-NCs consistently exhibiting smaller dimensions. Under these specific conditions, Rhodamine B (Rhod) and gold (Au) were successfully loaded, achieving encapsulation efficiencies exceeding 50 %. Electron microscopy analysis confirmed that the nanocarriers exhibited a consistent spherical shape with smooth surface morphology. X-ray energy-dispersive spectroscopy (EDX) revealed a uniform distribution of gold within the polymer matrix. PLA-NCs were effectively internalized by various cell types, including human Peripheral Blood Mononuclear Cells (PBMCs), HT-29 colon cancer cells, and C6 glioma cells. Uptake occurred in a dose-dependent manner for PLA-NCs sized at 260 ± 51 nm, with only 30 % internalization at 2 mg/mL concentration after 24 to 48 h. Notably, smaller PLA-NCs with a mean size of 170 ± 64 nm achieved nearly 100 % uptake across all tested cell types after 48 h, indicating that particle size significantly influenced cellular uptake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Photosensitizing compounds are eco-friendly promising organic dyes for managing insect pests without facing the risk of resistance. The photodynamic efficacy of four Photosensitizing compounds (rose Bengal, rhodamine B, methylene blue and methyl violet) was monitored against the third larval instar of Spodoptera littoralis (Boisduval), after exposure to sunlight. The LC 50 values of the four compounds; rose Bengal, rhodamine B, methylene blue and methyl violet recorded 0.029 × 10 -5 , 0.24 × 10 -5 , 14.69 × 10 -5 and 15.59 × 10 -5 M, respectively. Therefore, rose Bengal was the most effective compound followed by rhodamine B, Methylene blue and methyl violet. Compared to similar previously documented photosensitizer compounds, these four tested compounds recorded higher mortality percentage. The effect of those compounds on the larval biochemical components was assessed by measuring larval spectral and thermal reflectance. Larvae fed on photosensitizing compounds showed distinct spectral reflectance patterns. Treated larvae had same reflectance manner; which were higher than that of control samples. Along the whole spectrum, the highest reflectance was after 60 min of exposure to sunlight in case of rose Bengal, rhodamine B and methylene blue. Methyl violet reflected sunlight mostly at zero time then the reflectance decreased after 30 min then increased again after 60 min. There was a noticeable absorption of IR wavelengths at ~ 1900, 1400, 1200 and 950 nm in all treated samples. Thermal imaging indicated abnormal larval warmth after treatment. Differences in reflectance were monitored immediately after feeding, confirming the speed and mode of action of those compounds., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval: This research was approved by the Research Ethics Committee of Faculty of Science, Ain Shams University, Cairo, Egypt (Approval Code: ASU-SCI/ENTO/2023/4/2)., (© 2024. The Author(s).)

A novel near-infrared fluorescent probe TM2 based on a rhodamine-bearing framework was disclosed with a large Stokes shift (100 nm). TM2 exhibits highly selective recognition for Cu 2+ in EtOH/H 2 O (1 : 1, v/v) solution with a low detection limit (2.3 μM) and a wide detection range (0-50 μM). Detection of Cu 2+ is undisturbed at physiological pH levels of 5-9. This recognition mechanism is attributed to the formation of a 1 : 1 complex between TM2 and Cu 2+ , validated by Job's plot, 1 H NMR titration, and LC-MS experiments. Moreover, the successful fluorescence imaging of Cu 2+ both in vitro and in vivo was also accomplished.

Waterborne infections caused by pathogenic microorganisms represent serious health risks for humans. Ternary zinc-tin oxide nanoparticles have great potential as a cost-effective, environmentally friendly, and efficient candidate for waterborne infections; however, their photocatalytic and antibacterial effects are quite limited due to insufficient visible light absorption and rapid electron-hole recombination. Herein, barium-doped zinc stannate (Ba@ZTO) nanoparticles were synthesized by the hydrothermal method and used for the first time not only as antibacterial agents to prevent the spread of the harmful bacteria S. aureus and E. coli but also as photocatalysts to degrade the organic pollutant rhodamine B. Unexpectedly, Ba 2+ ions exhibited compressive stress behavior instead of the predicted tensile stress when inserted into the ZTO crystal lattice, playing an active role in increasing oxygen vacancies within the crystal lattice and in the formation of hydroxyl radicals in the bulk solution and hydrogen peroxide (H 2 O 2 ) radicals, significantly improving the photocatalytic and antibacterial properties. Strain-induced defects created by the insertion of larger barium ions into the ZTO lattice promote the increase of shallow traps for boosting photocatalytic/disinfection properties while suppressing deep-level traps that encourage nonradiative recombination. In essence, defect and strain engineering opens a promising route to achieve high disinfection efficiency by inducing larger cation ions under visible light in oxide-based materials.

Methamphetamine (METH) is the second abused drug which affects abusers' health and induces social crimes, developing novel methods with high sensitivity and selectivity for METH detecting is still challenging. In this paper, a colorimetric and fluorescent dual-channel sensor for METH has been constructed. We combine the enzyme-mimic catalytic activity of gold nanoparticles (GNPs) with high target specificity of METH aptamer to create a nanosensor (Apt-GNP), in the presence of METH, the absorption of 3,3',5,5'-tetramethylbenzidine (OxTMB) at 650 nm enhanced with METH concentration increasing, while the absorption characteristic peak of GNPs at 530 nm remained almost unchanged. The ratio of A 650nm /A 530nm and METH concentration had a good linear relationship when METH concentration was in the range of 5-50 μM, and the corresponding linear equation is A 650nm /A 530nm  = 0.00727C METH (μM) + 0.783 with R 2  = 0.997 and LOD = 0.40 μM (LOD = 3σ/s, n = 11). Interestingly, the fluorescence emission of Rhodamine B (RB) overlaps with the absorption spectrum of OxTMB which represents the content of METH and the fluorescence signal of RB can be quenched through internal filtering effect (IEF). Hence, when RB was doped to the detection system, the decay of RB fluorescence can reflect the concentrations change of METH. Accordingly, the linear equation is F/F R  = -0.00751C METH (μM) + 0.895 with R 2  = 0.993 and LOD = 0.40 μM, where F was the fluorescence of the analytical solution at 580 nm with METH and F R was fluorescence of RB control solution. The dual-channel sensor can measure METH in serum and artificial urine successfully which is potential to be applied in drug-using crime sites and provide direct evidence to law enforcement officials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mercury, one of the various harmful metals, is particularly significant in affecting aquatic organisms, currently gaining more attentions and sparking discussions. In response to the limitations of traditional detections, fluorescent probes have emerged as a promising solution with some advantages, such as weaker background interference, shorter processing time, higher accuracy. Thus, a novel fluorescent probe, FS-Hg-1, has been developed for assessing mercury ion (Hg 2+ ) concentrations in aquatic products. This probe displays specific recognition of mercury ions in fluorescence spectra. Notably, FS-Hg-1 exhibits a distinct color change to pink when combined with Hg 2+ (with a 948-fold increase in absorption at 568 nm) and a substantial fluorescence change towards Hg 2+ (361-fold increase, excitation at 562 nm, emission at 594 nm) in N, N-dimethylformamide. The probe boasts a detection limit of 0.14 μM and rapid reaction with Hg 2+ within 10 s, showing an excellent linear correlation with [Hg 2+ ] in the range of 0 to 10 μM. Through thorough analysis using FS-Hg-1, the results align with those from the standard method (P > 0.05), with spiked recovery rates ranging from 108.4% to 113.2%. With its precise recognition, low detection limit, and remarkable sensitivity, this fluorescent assay proves effective in mercury concentration determination in aquatic samples without interference. The potential of FS-Hg-1 is promising for speedy detection of residual Hg 2+ and holds significance in ensuring food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This research introduces a pioneering biogenic deposition-precipitation method for synthesis of Ag@g-C 3 N 4 nanocomposites (NCs) employing fennel seed extract (FSE). This technique involves the reduction and capping of silver nanoparticles (AgNPs) onto g-C 3 N 4 , employing polyphenolic content of FSE, consequently establishing a strong Schottky junction. The, NCs were characterized through various spectroscopic and microscopic techniques, confirming successful biogenic deposition of AgNPs and purity of prepared nanomaterials. Further, the synthesized NCs were utilized for photocatalytic degradation of various hazardous pollutants viz. Rhodamine-B (Rh-B) dye, Tetracycline (TCy) antibiotic, Imidacloprid (IMD) insecticide and deactivation of E. coli microbes. Amongst the synthesized NCs, 3 wt% Ag@g-C 3 N 4 NCs exhibited superior photocatalytic mitigation of Rh-B (99.26%, k = 90.4 × 10 -3 min -1 ), TCy (96.86%, k = 40.2 × 10 -3 min -1 ), IMD (95.7%, k = 34.96 × 10 -3 min -1 ) and E. coli deactivation (99.5%, k = 49.19 × 10 -3 min -1 ). Moreover, the rate constants revealed many-fold increase in photocatalytic degradation of pollutants, contrary to pristine g-C 3 N 4 (k = 11.8 × 10 -3 min -1 ). This investigation also unveils an intricate photocatalytic mitigation pathway for the aforementioned-contaminants, elucidating key role of superoxide radical anions in photocatalytic mitigation. One of the significant highlights of this research is the sustainable and cost-effective synthesis methodology involving fennel seeds, which not only ensures the wide availability of resources but also guarantees environmental safety, in alignment with green principles., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, a type-I heterojunction was synthesized based on eggshell waste doped mixed metal oxide (ES@ZnAl MMO) for the degradation of RhB dye under visible light irradiation. The ES@ZnAl MMO core-shell was synthesized using waste eggshell and layered double hydroxide (LDH) as primary precursors. After their mechanochemical assembly and thermal treatment, CaCO 3 was formed in both calcite and vaterite forms, alongside mixed metal oxides derived from the LDH (ZnO and Al 2 O 3 ). The formation of a heterojunction between the semiconductors results in an improved activation of sites, a decrease in bandgap energy from 5.72 to 3.44 eV, and an increase in degradation capacity. The elemental composition, morphology, structural, and optical properties of the ES@ZnAl MMO nanocomposite were analyzed using various techniques. The optimal ES@ZnAl MMO photocatalyst demonstrated superior performance, reaching over 98% of RhB dye degradation under optimal conditions, outperforming pure ZnAl LDH, ZnAl MMO, and ES. After five run cycles, the ES@ZnAl MMO heterojunction still maintained a high photocatalytic performance for RhB dye (99%). Furthermore, it displayed high performance in degrading various other pollutants, including OG, IC, MB, and 2.4-DP, with degradation efficiencies of 97%, 99%, 99%, and 87%, respectively. This economically advantageous heterojunction showed its importance in environmental remediation, presenting a promising solution for addressing diverse pollution challenges., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The objective of this study was to compare the properties of core-shell nanoparticles with a PLGA core and shells composed of different types of polymers, focusing on their structural integrity. The core PLGA nanoparticles were prepared either through a high-pressure homogenization-solvent evaporation technique or nanoprecipitation, using poloxamer 188 (P188), a copolymer of divinyl ether with maleic anhydride (DIVEMA), and human serum albumin (HSA) as the shell-forming polymers. The shells were formed through adsorption, interfacial embedding, or conjugation. For dual fluorescent labeling, the core- and shell-forming polymers were conjugated with Cyanine5, Cyanine3, and rhodamine B. The nanoparticles had negative zeta potentials and sizes ranging from 100 to 250 nm (measured using DLS) depending on the shell structure and preparation technique. The core-shell structure was confirmed using TEM and fluorescence spectroscopy, with the appearance of FRET phenomena due to the donor-acceptor properties of the labels. All of the shells enhanced the cellular uptake of the nanoparticles in Gl261 murine glioma cells. The integrity of the core-shell structures upon their incubation with the cells was evidenced by intracellular colocalization of the fluorescent labels according to the Manders' colocalization coefficients. This comprehensive approach may be useful for the selection of the optimal preparation method even at the early stages of the core-shell nanoparticle development.