Multimode Luminesce Tailoring PMA4Na(In,Sb)Cl8 Organic-inorganic Hybrid Metal Halide via Rigid Benzene Ring Induced Local Lattice Distortion.

Low dimensional organic-inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity-forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow-emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low-dimensional OIMHs single crystal with a PLQY as high as 88% was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity-forbidden transition by strong spin-orbit (SO) coupling and Jahn-Teller (JT) interaction. The as-prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1 → 1S0 transitions of Sb3+ in [SbCl6]3- octahedral caused by JT deformation. Moreover, wide-range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3- octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti-thermal quenching from 8 to 400 K owing to the suppression of non-radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing,  low temperature anti-counterfeiting and WLED applications.

Selective Detection of Chromate and Permanganate Ions Using Gallic Acid Capped CaF2:Tb3+ Nanocrystals.

In this study, we have developed ligand-sensitized Ln3+-doped nanocrystals (NCs) for the selective sensing of Cr2O72- and MnO4- ions in nanomolar concentrations. This is accomplished with the gallic acid capped-CaF2:Tb3+ NCs. These NCs display bright green emission through an efficient energy transfer from surface functionalized gallic acid molecules to Tb3+ ions upon UV light excitation. The luminescence emissions from Tb3+ ions are selectively quenched by the addition of Cr2O72- and MnO4- anions. The reduction in the luminescence intensity is found to be quite selective, as the addition of other strong oxidizing species (I-, F-, Br-, Cl-, PO32-, SO42-, VO3-, WO42-, IO3-, ClO4-,) had minimal impact on the luminescence intensity of Tb3+ ions. The calculated limit of detection from the experimental results (for the 3/slope criterion) is 77 nM and 55 nM for K2Cr2O7 and KMnO4, respectively. The findings show that tuning the resonance energy transfer (RET) between analytes and Tb3+ inside the NCs serves as a tool for the detection of dichromate and permanganate ions selectively.

Photophysical Response of Propranolol in Biomimetic Micellar Media of Alkyltrimethylammonium Bromide Surfactants: Effect of pH and Alkyl Chain Length.

The photophysical behavior of a ß-blocker drug propranolol (PPL) in micellar environments, formed by alkyltrimethylammonium bromide surfactants viz.; Cetyltrimethylammonium bromide (CTAB), Tetradecyltrimethylammonium bromide (TTAB), and Dodecyltrimethylammonium bromide (DTAB), has been investigated through fluorescence and UV-visible spectroscopic techniques at pH levels of 3.5, 7.4, and 10.4. The impact of pH on the critical micelle concentration (cmc) and micropolarity of micelles were assessed using pyrene as a photophysical probe. The cmc values were found to be lower at pH 10.4 compared to pH 7.4 and pH 3.5. Fluorescence emission intensities of PPL at 323 nm, 338 nm, and 352 nm were significantly influenced by pH, hydrophobic alkyl chain length of surfactants, and their concentrations. Quenching experiments with Cetylpyridinium chloride (CpCl) indicated the localization of charged and uncharged forms of PPL within micelles, with quenching constant (Ksv) values dependent on alkyl chain length and pH. At pH < pKa, PPL is positioned near the Stern layer, whereas at pH 10.4, its naphthalene moiety resides near the hydrophobic micellar core. UV spectroscopy showed that the charged form of PPL interacted with micelles only above cmc, while the neutral form interacted even below the cmc. Density Functional Theory (DFT) reveals the HOMO of the surfactants to be localized on the hydrocarbon chains, and the LUMO localized around the quaternary ammonium unit. Upon complexation with PPL, both HOMO and LUMO shifted to the drug, thereby decreasing energy levels. The findings are explained based on weak noncovalent interactions, further supported and analyzed through Reduced Density Gradient (RDG) and Noncovalent Interaction (NCI) methods, confirming synergistic non-covalent interactions in surfactant-PPL complexes.

Assessing the complexation of dissolved organic matter with heavy metals (Cu2+, Pb2+) in leachate from an old Japanese landfill site using fluorescence quenching.

Dissolved organic matter (DOM) in landfill leachate impacts the toxicity, bioavailability, and migration of heavy metals. The present study investigated the complexation of heavy metals (Cu2+ and Pb2+) with DOM from two landfill leachate samples, representing an old landfill site containing incineration residues and incombustible waste. The logarithms of the stability constant (log KM) and percentage of complexed fluorophores were calculated using both the Ryan-Weber non-linear model and the modified Stern-Volmer model, yielding good agreement. The log KM values (at pH = 6.0 ± 0.1) calculated using both methods for the two sampling points were 5.02-5.13 and 4.85-5.11 for Cu2+-DOM complexation, and 5.01-5.13 and 4.46-4.87 for Pb2+-DOM complexation, respectively. Log KM was slightly higher for binding of DOM with Cu2+ than Pb2+, and the quenching degree was stronger for complexation with Cu2+ (28.5-30.6% and 38.0-45.9%) than Pb2+ (6.5-7.1% and 10.0-15.4%) in both leachate samples. While log KM values were similar, differences in the contributions of functional groups and molecular composition led to varying degrees of quenching. This study reveals the potential for heavy metal binding by DOM in landfill leachate with a unique solid waste composition and emphasizes variations in fluorescence quenching between Cu2+ and Pb2+ despite similar log KM levels. These findings may be useful for assessing heavy metal behavior in landfill leachate and its impacts on the surrounding environment.

Spectrofluorometric determination of ascorbic acid in the plasma matrix: exploring correlation with autism spectrum disorder.

Ascorbic acid (Vitamin C) is crucial for bodily functions, including collagen synthesis, immune system support and antioxidant defense. Despite autism spectrum disorder's multifactorial nature involving genetic, environmental and neurological factors, robust evidence exploring the association between ascorbic acid and this disorder is notably lacking. This study introduces an innovative spectrofluorometric method to quantify ascorbic acid in the plasma of healthy children and those with autism spectrum disorder. The method relies on the interaction of ascorbic acid with the fluorescent dye propidium iodide. In acidic conditions, propidium iodide undergoes protonation and selectively binds to the negatively charged ascorbic acid forming an ion-pair complex. This complex alters the molecular structure of propidium iodide inducing chemical fluorescence quenching, that can be utilized for ascorbic acid quantification. The developed method undergoes rigorous validation following ICH guidelines, demonstrating a linear relationship within a concentration range of 4-40 µg/mL, with high precision and accuracy metrics. Analysis of real plasma samples from autistic and healthy children reveals clinically and statistically elevated levels of ascorbic acid in those with autism spectrum disorder.

Separation and purification of bovine nasal cartilage-derived chondroitin sulfate and evaluation of its binding to bovine serum albumin.

This study employs an optimized and environmentally friendly method to extract and purify chondroitin sulfate (CS) from bovine nasal cartilage using enzymatic hydrolysis, ethanol precipitation, and DEAE Sepharose Fast Flow column chromatography. The extracted CS, representing 44.67 % ± 0.0016 of the cartilage, has a molecular weight of 7.62 kDa. Characterization through UV, FT-IR, NMR spectroscopy, and 2-aminoacridone derivatization HPLC revealed a high content of sulfated disaccharides, particularly ΔDi4S (73.59 %) and ΔDi6S (20.61 %). Interaction studies with bovine serum albumin (BSA) using fluorescence spectroscopy and molecular docking confirmed a high-affinity, static quenching interaction with a single binding site, primarily mediated by van der Waals forces and hydrogen bonding. The interaction did not significantly alter the polarity or hydrophobicity of BSA aromatic amino acids. These findings provide a strong foundation for exploring the application of CS in tissue engineering and drug delivery systems, leveraging its unique interaction with BSA for targeted delivery and enhanced efficacy.

Comparative role of calcium oxide nanoparticles and calcium bulk fertilizer to alleviate cadmium toxicity by modulating oxidative stress, photosynthetic performance and antioxidant-defense genes expression in alfalfa.

Cadmium (Cd) toxicity poses a significant threat to soil health and sustainable food production. Its bioaccumulation in plant tissues induces phytotoxicity by affecting physiological and biochemical attributes, leading to a reduction in plant biomass and production. Recently, nanotechnology has emerged as a promising approach for addressing heavy metal toxicity in an eco-friendly manner to enhance crop production. However, the comparative role of foliar applied calcium oxide nanoparticles (CaO-NPs) and bulk calcium fertilizer under Cd stress in alfalfa remains unexplored. Herein, we studied the ameliorative role of CaO-NPs and bulk calcium (50 and 100 mg L-1) to alleviate Cd stress (30 mg kg-1) in alfalfa seedlings. Plants exposed to Cd exhibited significant decreases in morpho-physiological traits, gas exchange attributes, and pigment contents as well as increase in Cd bioaccumulation in plant tissues. Notably, exogenous application of CaO-NPs ameliorates the toxic impact of Cd by enhancing plant biomass (45%), fluorescence efficiency and gaseous exchange attributes. The maximum dose of CaO-NPs induced Cd-tolerance response accompanied by a significant increase in antioxidative enzyme activities, such as superoxide dismutase (SOD; 29%), peroxidase (POD; 41%), catalase (CAT; 36%) and ascorbate peroxidase (APX; 49%), which play positive roles in ROS scavenging. TEM examination further revealed the protective role of these NPs in averting Cd-induced damage to leaf ultrastructure and mesophyll cells. Furthermore, CaO-NPs had a substantial influence on both Cd and Ca2+ accumulation in plant tissues, while qRT‒PCR analysis demonstrated higher expression of antioxidant defense genes viz. Cu/ZnSOD (0.38 fold change (FC)), MtPOD (0.51 FC), MtCAT (0.61 FC) and MtAPX (0.79 FC) under CaO-NPs application, over Cd control. Overall, our findings suggested that exogenous CaO-NPs could be effective in alleviating the adverse effects of Cd on alfalfa seedlings to ensure food safety and support sustainable agriculture.

Biological Fate Tracking of Nitric Oxide-Propelled Microneedle Delivery System Using an Aggregation-Caused Quenching Probe.

Nanoparticle-loaded dissolving microneedles (DMNs) have attracted increasing attention due to their ability to provide high drug loading, adjustable drug release behavior, and enhanced therapeutic efficiency. However, such delivery systems still face unsatisfied drug delivery efficiency due to insufficient driving force to promote nanoparticle penetration and the lack of in vivo fate studies to guide formulation design. Herein, an aggregation-caused quenching (ACQ) probe (P4) was encapsulated in l-arginine (l-Arg)-based nanomicelles, which was further formulated into nitric oxide (NO)-propelled nanomicelle-integrated DMNs (P4/l-Arg NMs@DMNs) to investigate their biological fate. The P4 probe could emit intense fluorescence signals in intact nanomicelles, while quenching with the dissociation of nanomicelles, providing a "distinguishable" method for tracking the fate of nanomicelles at a different status. l-Arg was demonstrated to self-generate NO under the tumor microenvironment with excessive reactive oxygen species (ROS), providing a pneumatic force to promote the penetration of nanomicelles in both three-dimensional (3D)-cultured tumor cells and melanoma-bearing mice. Compared with passive microneedles (P4 NMs@DMNs) without a NO propellant, the P4/l-Arg NMs@DMNs possessed a good NO production performance and higher nanoparticle penetration capacity. In conclusion, this study offered an ACQ probe-based biological fate tracking approach to demonstrate the potential of NO-propelled nanoparticle-loaded DMNs in penetration enhancement for topical tumor therapy.

Quantum dot-protein interface: Interaction of the CdS quantum dot with human hemoglobin for the study of the energy transfer process and binding mechanism along with detection of the unfolding of hemoglobin.

In this study, the interaction of the human hemoglobin with cost effective and chemically fabricated CdS quantum dots (QDs) (average sizes ≈3nm) has been investigated. The semiconductor QDs showed maximum visible absorption at 445 nm with excitonic formation and band gap of ≈ 2.88 eV along with hexagonal crystalline phase. The binding of QDs-Hb occurs through corona formation to the ground sate complex formation. The life time of the heme pocket binding and reorganization were found to be t1 = 43 min and t2 = 642 min, respectively. The emission quenching of the Hb has been indicated large energy transfer between CdS QDs and Hb with tertiary deformation of Hb. The binding thermodynamics showed highly exothermic nature. The ultrafast decay during corona formation was studied from TCSPC. The results showed that the energy transfer efficiency increases with the increase of the QDs concentration and maximum ≈71.5 % energy transfer occurs and average ultrafast lifetime varies from 5.45 ns to1.51 ns. The deformation and unfolding of the secondary structure of Hb with changes of the α-helix (≈74 % to ≈51.07 %) and ß-sheets (≈8.63 % to ≈10.25 %) have been observed from circular dichroism spectrum. The SAXS spectrum showed that the radius of gyration of CdS QDs-Hb bioconjugate increased (up to 23 ± 0.45 nm) with the increase of the concentration of QDs compare with pure Hb (11 ± 0.23 nm) and Hb becoming more unfolded.

Optimization Design of Quenching and Tempering Parameters for Crankshaft Based on Response Surface Methodology.

Existing optimization research on the crankshaft heat treatment process is mostly based on one-sided considerations, and less consideration is given to the matching of multiple process parameters, leading to irrational designs of heat treatment. To address this problem, this work investigates the influence mechanisms of cooling speed, tempering temperature, and holding time on the performance evaluation indexes of the straightness, residual stress, and martensite content of a crankshaft based on the response surface method. The results showed that the order of influence of these three different process parameters on the performance evaluation index was cooling speed > holding time > tempering temperature, and the order of influence on the performance evaluation indexes under multifactorial process parameters was cooling speed-holding time > cooling speed-tempering temperature > holding time-tempering temperature. The optimal process parameters were a cooling speed of 1.4 times the cooling oil, a tempering temperature of 555 °C, and a holding time of 6 h, with the straightness of the crankshaft reduced by 9.9%, the surface stress increased by 6.7%, and the martensitic content increased by 7.2% after the process optimization. This work can provide new clues for optimizing the heat treatment process parameters of crankshafts.

Role of Quenching Temperature Selection in the Improvement of the Abrasive (Al2O3) Wear Resistance of Hybrid Multi-Component Cast Irons.

In this paper, enhancing the tribological characteristics of novel cast metallic materials-hybrid multi-component cast irons-by applying a strengthening heat treatment is described. The experimental materials were the cast alloys of a nominal composition (5 wt.% W, 5 wt.% Mo, 5 wt.% V, 10 wt.% Cr, 2.5 wt.% Ti, Fe is a balance) supplemented with 0.3-1.1 wt.% C and 1.5-2.5 wt.% B (total of nine alloys). The heat treatment was oil-quenching followed by 200 °C tempering. The quench temperature (QT) varied in the range of 900-1200 °C, with a step of 50 °C (with a 2-h holding at QT). The correlation of the QT with microstructure and properties was estimated using microstructure/worn surface characterization, differential scanning calorimetry, hardness measurement, and three-body-abrasive wear testing (using Al2O3 particles). The as-cast alloys had a multi-phase structure consisting of primary and/or eutectic borocarbide M2(B,C)5, carboborides M(C,B), M7(C,B)3, M3(C,B), and the matrix (ferrite, martensite, pearlite/bainite) in different combinations and volume fractions. Generally, the increase in the quenching temperature resulted in a gradual increase in hardness (maximally to 66-67 HRC) and a decrease in the wear rate in most alloys. This was due to the change in the phase-structure state of the alloys under quenching, namely, the secondary carboboride precipitation, and replacing ferrite and pearlite/bainite with martensite. The wear rate was found to be inversely proportional to bulk hardness. The maximum wear resistance was attributed to QT = 1150-1200 °C, when the wear rate of the alloys was lowered by three to six times as compared to the as-cast state. With the QT increase, the difference in the wear rate of the alloys decreased by three times. The highest abrasive resistance was attributed to the alloys with 1.1 wt.% C, which had a 2.36-3.20 times lower wear rate as compared with that of the reference alloy (13 wt.% Cr cast iron, hardness of 66 HRC). The effects of carbon and boron on hardness and wear behavior are analyzed using the regression models developed according to the factorial design procedure. The wear mechanisms are discussed based on worn surface characterization.

Quorum Sensing Inhibitors: An Alternative Strategy to Win the Battle against Multidrug-Resistant (MDR) Bacteria.

Antibiotic resistance is a major problem and a major global health concern. In total, there are 16 million deaths yearly from infectious diseases, and at least 65% of infectious diseases are caused by microbial communities that proliferate through the formation of biofilms. Antibiotic overuse has resulted in the evolution of multidrug-resistant (MDR) microbial strains. As a result, there is now much more interest in non-antibiotic therapies for bacterial infections. Among these revolutionary, non-traditional medications is quorum sensing inhibitors (QSIs). Bacterial cell-to-cell communication is known as quorum sensing (QS), and it is mediated by tiny diffusible signaling molecules known as autoinducers (AIs). QS is dependent on the density of the bacterial population. QS is used by Gram-negative and Gram-positive bacteria to control a wide range of processes; in both scenarios, QS entails the synthesis, identification, and reaction to signaling chemicals, also known as auto-inducers. Since the usual processes regulated by QS are the expression of virulence factors and the creation of biofilms, QS is being investigated as an alternative solution to antibiotic resistance. Consequently, the use of QS-inhibiting agents, such as QSIs and quorum quenching (QQ) enzymes, to interfere with QS seems like a good strategy to prevent bacterial infections. This review sheds light on QS inhibition strategy and mechanisms and discusses how using this approach can aid in winning the battle against resistant bacteria.

Nonphotochemical quenching kinetics GWAS in sorghum identifies genes that may play conserved roles in maize and Arabidopsis thaliana photoprotection.

Photosynthetic organisms must cope with rapid fluctuations in light intensity. Nonphotochemical quenching (NPQ) enables the dissipation of excess light energy as heat under high light conditions, whereas its relaxation under low light maximizes photosynthetic productivity. We quantified variation in NPQ kinetics across a large sorghum (Sorghum bicolor) association panel in four environments, uncovering significant genetic control for NPQ. A genome-wide association study (GWAS) confidently identified three unique regions in the sorghum genome associated with NPQ and suggestive associations in an additional 61 regions. We detected strong signals from the sorghum ortholog of Arabidopsis thaliana Suppressor Of Variegation 3 (SVR3) involved in plastid-nucleus signaling. By integrating GWAS results for NPQ across maize (Zea mays) and sorghum-association panels, we identified a second gene, Non-yellowing 1 (NYE1), originally studied by Gregor Mendel in pea (Pisum sativum) and involved in the degradation of photosynthetic pigments in light-harvesting complexes. Analysis of nye1 insertion alleles in A. thaliana confirmed the effect of this gene on NPQ kinetics in eudicots. We extended our comparative genomics GWAS framework across the entire maize and sorghum genomes, identifying four additional loci involved in NPQ kinetics. These results provide a baseline for increasing the accuracy and speed of candidate gene identification for GWAS in species with high linkage disequilibrium.

Singlet-Oxygen-Mediated Regulation of Photosynthesis-Specific Genes: A Role for Reactive Electrophiles in Signal Transduction.

During photosynthesis, reactive oxygen species (ROS) are formed, including hydrogen peroxide (H2O2) and singlet oxygen (1O2), which have putative roles in signalling, but their involvement in photosynthetic acclimation is unclear. Due to extreme reactivity and a short lifetime, 1O2 signalling occurs via its reaction products, such as oxidised poly-unsaturated fatty acids in thylakoid membranes. The resulting lipid peroxides decay to various aldehydes and reactive electrophile species (RES). Here, we investigated the role of ROS in the signal transduction of high light (HL), focusing on GreenCut2 genes unique to photosynthetic organisms. Using RNA seq. data, the transcriptional responses of Chlamydomonas reinhardtii to 2 h HL were compared with responses under low light to exogenous RES (acrolein; 4-hydroxynonenal), ß-cyclocitral, a ß-carotene oxidation product, as well as Rose Bengal, a 1O2-producing photosensitiser, and H2O2. HL induced significant (p < 0.05) up- and down-regulation of 108 and 23 GreenCut2 genes, respectively. Of all HL up-regulated genes, over half were also up-regulated by RES, including RBCS1 (ribulose bisphosphate carboxylase small subunit), NPQ-related PSBS1 and LHCSR1. Furthermore, 96% of the genes down-regulated by HL were also down-regulated by 1O2 or RES, including CAO1 (chlorophyllide-a oxygnease), MDH2 (NADP-malate dehydrogenase) and PGM4 (phosphoglycerate mutase) for glycolysis. In comparison, only 0-4% of HL-affected GreenCut2 genes were similarly affected by H2O2 or ß-cyclocitral. Overall, 1O2 plays a significant role in signalling during the initial acclimation of C. reinhardtii to HL by up-regulating photo-protection and carbon assimilation and down-regulating specific primary metabolic pathways. Our data support that this pathway involves RES.

Microwave Synthesis of Fluorescent Carbon Quantum dots from Araucaria Heterophylla Gum: Application in Drug Detection.

This study employed a green microwave synthesis technique to produce carbon quantum dots (CQDs) from araucaria heterophylla gum extract. The produced CQDs emit a distinct blue fluorescent light, contributing a remarkable quantum yield of 14.69%. Their average particle size measures at 1.62 ± 0.39 nm. Furthermore, these CQDs demonstrate excellent water solubility and maintain high fluorescence stability despite ionic strength, pH and time variations. Moreover, we present here for the first time that the synthesized CQDs demonstrate a rapid, exceptionally sensitive, and discerning fluorescence quenching phenomenon (IFE) concerning Cefprozil (CPR). The fluorescent probe was sensitive and specific with good linear relationships for CPR in the 0-18 µM range. The limit of detection for relationships for CPR was 2.51 µM. This study provides novel opportunities for producing high-quality luminescent CQDs that meet the requirements for various biological and environmental applications.

Macrocyclic porphyrin photocatalysts without metal chelation: A novel pathway for complete degradation of tough halophenols with longwave visible LED light source.

Halophenols are toxic and persistent pollutants in water environments which poses harm to various organisms. Due to their high stability and long residence time, ultraviolet radiation, heavy metals and oxidizing agents have been largely adopted on treating these compounds. However, these treatment methods could pose toxicity or hazardous risks to the marine environment and plant operators. In this study, a water-soluble porphyrin photocatalyst was synthesized and introduced for halophenol treatment using UV-free LED white light. The porphyrin catalyst is a macrocyclic ring consisting of pyrroles linked with methine bridges, the highly conjugated ring provided the superior functionality of visible light absorption. Surprisingly, over 99 % degradation of halophenols and over 90 % dehalogenation have been achieved without metal chelation, even higher than those of transition metal porphyrins with inclusion of Fe3+, Zn2+, Cu2+, Co2+, Ni2+, and Mn2+. Ring-opening reactions were confirmed with the formation of carboxylic acids; dicarboxylic acids like acrylic acid, and malonic acid; while fumaric acid was the main product. Total organic carbon results indicated no CO2 produced during the reaction. Triplet absorbance and scavenger studies also indicated that singlet oxygen and conduction band electrons are the main radical species for halophenol degradation. The 100-fold singlet emission quenching over triplet absorption quenching indicated that the excited electrons tend to be transferred via singlet state. This concept brings along new approaches detoxifying halophenol-related wastewater without UV, metals and other additives, which is more environmentally-friendly and sheds light to the conversion of toxic materials into useful chemical precursors.

Correlation between local instantaneous dose rate and oxygen pressure reduction during proton pencil beam scanning irradiation.

Background and purpose: Oxygen dynamics may be important for the tissue-sparing effect observed at ultra-high dose rates (FLASH sparing effect). This study investigated the correlation between local instantaneous dose rate and radiation-induced oxygen pressure reduction during proton pencil beam scanning (PBS) irradiations of a sample and quantified the oxygen consumption g-value. Materials and methods: A 0.2 ml phosphorescent sample (1 µM PtG4 Oxyphor probe in saline) was irradiated with a 244 MeV proton PBS beam. Four irradiations were performed with variations of a PBS spot pattern with 5 × 7 spots. During irradiation, the partial oxygen pressure (pO2) was measured with 4.5 Hz temporal resolution with a phosphorometer (Oxyled) that optically excited the probe and recorded the subsequently emitted light. A calibration was performed to calculate the pO2 level from the measured phosphorescence lifetime. A fiber-coupled scintillator simultaneously measured the instantaneous dose rate in the sample with 50 kHz sampling rate. The oxygen consumption g-value was determined on a spot-by-spot level and using the total pO2 change for full spot pattern irradiation. Results: A high correlation was found between the local instantaneous dose rate and pO2 reduction rate, with a correlation coefficient of 0.96-0.99. The g-vales were 0.18 ± 0.01 mmHg/Gy on a spot-by-spot level and 0.17 ± 0.01 mmHg/Gy for full spot pattern irradiation. Conclusions: The pO2 reduction rate was directly related to the local instantaneous dose rate per delivered spot in PBS deliveries. The methodology presented here can be applied to irradiation at ultra-high dose rates with modifications in the experimental setup.

A Nano-Aggregatable Acedan Derivative for Clathrin-Mediated Cellular Uptake and Two-Photon Imaging of Diabetes-Associated Lipid Droplets.

Lipid droplets (LDs), the essential cytosolic fat storage organelles, have emerged as pivotal regulators of cellular metabolism and are implicated in various diseases. The noninvasive monitoring of LDs necessitates fluorescent probes with precise organelle selectivity and biocompatibility. Addressing this need, we have engineered a probe by strategically modifying the structure of a conventional two-photon-absorbing dipolar dye, acedan. This innovative approach induces nanoaggregate formation in aqueous environments, leading to aggregation-induced fluorescence quenching. Upon cellular uptake via clathrin-mediated endocytosis, the probe selectively illuminates within LDs through a disassembly process, effectively distinguishing LDs from the cytosol with exceptional specificity. This breakthrough enables the high-fidelity imaging of LDs in both cellular and tissue environments. In a pioneering investigation, we probed LDs in a diabetes model induced by streptozotocin, unveiling significantly heightened LD accumulation in cardiac tissues compared to other organs, as evidenced by TP imaging. Furthermore, our exploration of a lipopolysaccharide-mediated cardiomyopathy model revealed an LD accumulation during heart injury. Thus, our developed probe holds immense potential for elucidating LD-associated diseases and advancing related research endeavors.

High throughput method for simultaneous screening of membrane permeability and toxicity for discovery of new cryoprotective agents.

Vitrification is the most promising method for cryopreservation of complex structures such as organs and tissue constructs. However, this method requires multimolar concentrations of cell-permeant cryoprotective agents (CPAs), which can be toxic at such elevated levels. The selection of CPAs for organ vitrification has been limited to a few chemicals; however, there are numerous chemicals with properties similar to commonly used CPAs. In this study, we developed a high-throughput method that significantly increases the speed of cell membrane permeability measurement, enabling ~100 times faster permeability measurement than previous methods. The method also allows assessment of CPA toxicity using the same 96-well plate. We tested five commonly used CPAs and 22 less common ones at both 4 °C and room temperature, with 23 of them passing the screening process based on their favorable toxicity and permeability properties. Considering its advantages such as high throughput measurement of membrane permeability along with simultaneous toxicity assessment, the presented method holds promise as an effective initial screening tool to identify new CPAs for cryopreservation.

Sensing features, on-site detection and bio-imaging application of a tripodal tris(hydroxycoumarin) based probe towards Cu2+/His.

A new tripodal tris(hydroxycoumarin) based Schiff base, HCTN was synthesized and characterized by FT-IR, 1H NMR, 13C NMR and ESI-HRMS. The probe, HCTN exhibits cyan emission in DMSO/HEPES buffer (9:1, v/v) which selectively detects Cu2+ ion via turn-off fluorescence. The quenching of the fluorescence was due to the binding of the probe, HCTN towards paramagnetic Cu2+ ion resulting in chelation enhanced quenching effect (CHEQ). From the spectroscopic results, the limit of detection of Cu2+ ion was obtained as very low as 0.40 × 10-9 M. The complexation of the metal ion, Cu2+ towards the probe HCTN was confirmed by the ESI-HRMS and Job's plot analysis which supports 1:1 binding stochiometric ratio. In order to validate the affinity of Cu2+ ion towards histidine, the HCTN+Cu2+ system was utilized for the detection of histidine via turn-on mode by the metal displacement approach. The detection limit of His was found to be 7.31 × 10-10 M. In addition to the above, the probe was utilized for various detection applications such as paper strips, cotton swabs, logic gates and thin film applications. The probe, HCTN extends its application to the confocal bioimaging to sense the Cu2+ and Histidine intracellularly.