Binding Ratio Research Articles

Evaluation of the interaction between new holmium(III) complex and DNA: A comprehensive study

In this research, we conducted a comprehensive investigation into the interactions between the holmium(III)-curcumin complex ([Ho(Cur)2]+) and DNA. To elucidate these interactions, we employed various analytical techniques including cyclic voltammetry (CV), UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), fluorescence spectrophotometry, thermal gravimetric analysis (TGA), and molecular docking calculations. Our findings revealed compelling evidence of strong binding between [Ho(Cur)2]+ and DNA, as indicated by hypochromic effects in absorbance and fluorescence quenching. The binding affinity of [Ho(Cur)2]+ to DNA was substantiated by the evaluation of maximum absorption of the [Ho(Cur)2]+ spectra at different DNA concentrations. Furthermore, fluorescence resonance energy transfer experiments demonstrated that the distance between the donor (DNA) and acceptor ([Ho(Cur)2]+) was favorable for energy transfer. The combination of experimental data and molecular docking results suggested that non-covalent binding likely played a significant role in the binding of [Ho(Cur)2]+ to DNA. FT-IR spectra and molecular docking analyses provided further insights, indicating specific binding primarily between [Ho(Cur)2]+ and the base pairs of DNA. Electrochemical measurements indicated a groove binding mode between [Ho(Cur)2]+ and DNA, with a binding ratio of 1:1. Notably, our results indicated that increasing the amount of DNA resulted in a significant reduction in the current intensity of [Ho(Cur)2]+ under optimal conditions.

A “Turn-Off” Pyrene-Based Ligand as a Fluorescent Sensor for the Detection of Cu2+ and Fe2+ Ions: Synthesis and Application in Real Water Samples, Logic Gate Construction, and Bio-Imaging

Herein, we report the synthesis and characterization of a novel Schiff base ligand, (Z)-5-((pyren-1-ylmethylene)amino)-2,4-dihydro-3H-pyrazol-3-one (PMDP). The characterization of ligand PMDP was carried out using ESI-MS, 1H NMR, and UV–Visible spectroscopic techniques. As a probe, PMDP displayed a detectable, colorimetric colour shift in the presence of Cu2+ and Fe2+ ions. The solution was seen to have a light brown colour and to exhibit a fluorometric “turn off” response when Cu2+ and Fe2+ ions were present in a DMSO solution (HEPES 0.01 M, pH = 7.4) at room temperature. Job’s plot revealed that the PMDP binding ratio to Cu2+ and Fe2+ ions was in 1:2 ratio. In contrast to the other metal ions (Cd2+, Mn2+, Co2+, Na+, Ni2+, Cu+, Fe3+, Hg2+, Mg2+, Zn2+, K+, and V5+), the synthesised probe showed exceptional sensitivity and selectivity for detecting Cu2+ and Fe2+ metal ions. The results indicate that the detection limits for Cu2+ and Fe2+ are 0.42 μM and 0.51 μM, respectively. Furthermore, PMDP was efficiently utilised for the quantitative analysis of Cu2+ and Fe2+ in real water samples, RGB colour values in smart phones, logic gate construction, and cell imaging in HeLa cells.

Novel azo- and bisazo-5-pyrazolone dyes and their application as a colorimetric chemosensor for naked eye recognition of Cu2+

In this study, novel azo- and bisazo-5-pyrazolones (1/2a, b, and 1/2c, d, respectively) were synthesized. The structures of the new compounds were characterized using FTIR, UV–Vis., 1H NMR, 13C NMR-APT, and HRMS spectroscopic methods. 1H-NMR study revealed that the compounds are in hydrazone- form in solution. Among fourteen metal nitrate salts, the azo-5-pyrazolones showed a colorimetric response only to the Cu2+ ion, whereas the new bisazo-5-pyrazolones did not cause a specific color change to only one cation. The produced ligand changed from orangey-yellow to very light yellow, making it possible to identify Cu2+ without the need for spectroscopic equipment. Compound 1b [4-((2,4-dimethylphenyl)diazenyl)-2-(naphthalene-1-yl)-5-phenyl-2,4-dihydro-3H-pyrazole-3-one)] was taken as a representative example of the new azo-5-pyrazolones for the chemosensor research. The Cu(1b)2 complex was also synthesized and characterized. The binding ratio between the 1b sensor and Cu2+ was found to be 2:1 (ligand:metal) from the structural characterization of Cu(1b)2 and using Job's plot method. The pH study showed that even if the pH changes, the Cu2+ ion can still bind to the 1b receptor. In the reversibility experiment, when EDTA was added to the (1b+Cu2+) solution, the spectrum returned to the 1b spectrum. The interference study showed the selectivity of 1b with Cu2+ even in the presence of other cations. A study of the detection limit (LOD) revealed considerable sensitivity towards Cu2+metal cation using absorption titration method and LOD value was found to be 4.31 μM. The association constant (Ka) of (1b+Cu2+) was determined to be 0.79×105M−1 using the Benesi-Hildebrand plot.

Study of the binding interaction between modified glycinin and d-galactose and functions of the resulting complexes via multi-spectroscopy and molecular dynamics simulation

This study evaluated the effects of d-galactose (DG) concentration on the functional characteristics, physicochemical properties, structure and non-covalent binding ability of pH shifting treated soybean glycinin (S–11S). Multispectral and microscopic imaging analysis showed that the pH shifting induced soybean glycinin self-assembly into more stable small particle size aggregates, and the functional properties of S–11S were significantly enhanced. The introduction of DG further enhances the functional properties of S–11S, and the solubility and emulsification activity of the composite system are inversely proportional to the concentration of DG. In order to clarify the reason for the change, multispectral analysis found that the tertiary structure of S–11S was de-folded and the disordered structure was increased, which induced S–11S and DG to form smaller and stable nanoparticles than S–11S through hydrophobic forces and hydrogen bonding, and the optimal binding ratio was 10.8:1. In addition, the simulation results of molecular dynamics and molecular docking are in agreement with the experimental results. Therefore, the addition of DG can stabilize the overly discrete S–11S conformation and improve its functional characteristics. These results provide a theoretical basis for the application of modified protein and monosaccharide composite products in food and materials.

Increased CSF DOPA Decarboxylase Correlates with Lower DaT-SPECT Binding: Analyses in Biopark and PPMI Cohorts.

Recent studies identified increased cerebrospinal fluid (CSF) DOPA decarboxylase (DDC) as a promising biomarker for parkinsonian disorders, suggesting a compensation to dying dopaminergic neurons. A correlation with 123I-FP-CIT-SPECT (DaT-SPECT) imaging could shed light on this link. The objective is to assess the relationship between CSF DDC levels and DaT-SPECT binding values. A total of 51 and 72 Parkinson's disease (PD) subjects with available DaT-SPECT and CSF DDC levels were selected from the PPMI and Biopark cohorts, respectively. DDC levels were analyzed using proximity extension assay and correlated with DaT-SPECT striatal binding ratios (SBR). All analyses were corrected for age and sex. CSF DDC levels in PD patients correlated negatively with DaT-SPECT SBR in both putamen and caudate nucleus. Additionally, SBR decreased with increased DDC levels over time in PD patients. CSF DDC levels negatively correlate with DaT-SPECT SBR in levodopa-treated PD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Infant Formula with 50% or More of Palmitic Acid Bound to the sn-2 Position of Triacylglycerols Eliminate the Association between Formula-Feeding and the Increase of Fecal Palmitic Acid Levels in Newborns: An Exploratory Study.

The binding ratio of palmitic acid (PA) at the sn-2 position of triacylglycerols in infant formulas is lower than that in breast milk, resulting in higher levels of fecal PA. Even if the ratio is increased to 40-50%, fecal PA levels in formula-fed infants remain higher than those in breast-fed infants. In Japan, infant formulas with 50% or more of PA bound to sn-2 (high sn-2 PA milk) are commercially available; however, their effects on PA excretion have not been investigated. Therefore, this observational study aimed to preliminarily evaluate whether the feeding volume of high sn-2 PA milk is significantly associated with fecal total/soaped PA levels in newborns. Infant formulas were classified as high (≥50% of PA bound to sn-2) or low sn-2 (<50%) PA milk. Associations between feeding volume of high or low sn-2 PA milk and fecal PA levels were evaluated using multiple regression analysis models. The results showed that the feeding volume of low sn-2 PA milk was positively associated with fecal total/soaped PA levels, while there was no significant association between those of high sn-2 PA milk and fecal total/soaped PA levels. Our preliminary study suggests that high sn-2 PA milk may reduce increased fecal PA levels in formula-fed newborns.

Bis-Schiff base for selective detection of Al(III) and citric acid: Real sample analysis, anticancer potential and docking study

A novel bis-Schiff base 4 has been synthesized in this manuscript, it is well characterised by different spectroscopic technique such as FT-IR, 1H &13C NMR spectroscopy and Mass spectrometry, TGA analysis has done to check the thermal stability of compound 4 and it complexes with Al(III) and citric acid. Under the UV–visible spectrophotometer, chemosensor 4 detects Al(III) and citric acid and then comprehensive analysis of real sample using aluminium foil and lemon juice solution toward compound 4 were carried out to enhance to support for sensing application. The limit of detection (LOD) and association constant (Ka) of synthesized chemosensor 4 towards Al(III) are found to be 9 × 10−6 M and 7 × 104 M whereas with citric acid are 2.6 × 10−6 M and 1.8 × 105 M respectively. The binding ratio of the compound 4 with Al(III) and citric acid are found to be 1:1 ratio. Anti-cancer activity of the chemosensor 4 has responded maximum reduction of cell viability up to 61.5 % to compare with untreated control cell, furthermore to assess anticancer activity computationally, molecular docking study of the compound 4 against protein 5hu9 has shown maximum binding energy (−11.41 kcal/mole).

Synthesis of Schiff‐Base Allied Silanes for the Photophysical Detection of Cr(III) Ion And In‐Silico Staphylococcus Aureus Inhibiting Activity

AbstractChromium is known to play an important role in various metabolic pathways; however, its excessive use can result in negative impact on mankind, this necessitates the development of sensors for Cr(III) ion. The current study has incorporated the synthesis of ether derived Schiff base allied silanes 4 a–4 d, which have been characterized using 1H NMR, 13C NMR and mass spectrometry. The spectroscopic technique of UV‐visible has been utilized to study the sensing behaviour of probe 4 a, resulting in a good sensing ability towards Cr(III) ion, yielding a detection limit of 4.2×10−7 M and an association constant value of 2.25×106 M−1. In order to study the stoichiometric binding between probe and metal ion, Job's plot method has been employed which shows 1 : 1 binding ratio. The mechanism of binding has been studied via 1H NMR, UV‐visible, FT‐IR spectroscopy and mass spectrometry. The binding has been further supported by DFT. The real sample analysis has been performed to validate the utility of the synthesized sensor in practical applications. The theoretical tool of molecular docking has been considered to study the protein‐ligand interaction between S. aureus bacterial protein and ligand 4 a, yielding a value of −7.63 kcal/mol for binding energy.

Reduction in presynaptic dopamine transporter may be associated with future problematic delusion

ObjectivesPsychosis, especially in delusions, greatly impairs the quality of life of patients with Parkinson’s disease (PD) and their caregivers. Few objective risk indicators of the association between psychosis and clinical features has been reported. It is unclear whether the reduction in DAT binding represents the underlying mechanism of delusion or its association. There are no long-term data on the objective prognostic value of DAT binding for delusions. We investigated whether DAT binding at baseline can be a prognostic risk factor for future development of PD delusions. Materials and methodsWe reviewed the detailed clinical chart of patients with PD without a history of psychosis who underwent [123I]FP-CIT SPECT during the disease. The endpoint was defined as when the delusions occurred during the 5 years after the examination of [123I]FP-CIT SPECT. Specific binding ratio (SBR) values were calculated. ResultsSixty-one patients with PD were included in the analysis, and 11 patients had delusions within 5 years of [123I] FP-CIT SPECT. The average (p = 0.004), minimum (p = 0.004), maximum (p = 0.001), right-sided (p = 0.002), and left-sided (p = 0.003) SBRs in the striatum were significantly smaller in patients with delusions than in patients without delusions. Each difference of each SBR was significantly smaller than those without delusions after adjusting after controlling for age, gender, disease severity, timing of [123I]FP-CIT SPECT, anti-parkinsonian medications, hospitalization, administering more or newly anti-parkinsonian drugs, and receiving DBS or LCIG. ConclusionsPD delusions is still problematic, and lowering DAT binding may be helpful for predicting future delusions, regardless of the timing of [123I]FP-CIT SPECT.

The chronic use of serotonin norepinephrine reuptake inhibitors facilitates dyskinesia priming in early Parkinson's disease.

Parkinson's disease (PD) patients are frequently exposed to antidepressant medications (ADMs). Norepinephrine (NE) and serotonin (5HT) systems have a role in levodopa-induced dyskinesias (LID) pathophysiology. We performed a longitudinal analysis on the PPMI cohort including drug-naïve PD patients, who are progressively exposed to dopamine replacement therapies (DRTs) to test the effect of ADM exposure on LID development by the 4th year of follow-up. LID prevalence (according to MDS UPDRS score 4.1 ≥ 1) was 16% (42/251); these patients were more likely women (p = 0.01), had higher motor (p < 0.001) and depression scores (p = 0.01) and lower putaminal DAT binding ratio (p = 0.01). LID were associated with the exposure time to L-DOPA (2.2 ± 1.07 vs 2.6 ± 0.9, p = 0.02) and to the exposure to ADMs, in particular to SNRI (4.8% vs 21.4%, p < 0.001). The latter persisted after correcting for significant covariates (e.g., disease duration, cognitive status, motor impairment, depression, dopaminergic denervation). A similar difference in LID prevalence in PD patients exposed vs non-exposed to SNRI was observed on matched data by the real-world TriNetX repository (22% vs 13%, p < 0.001). This study supports the presence of an effect of SNRI on LID priming in patients with early PD. Independent prospective cohort studies are warranted to further verify such association.

Enhanced subsurface chloride transport resistance of cement pastes via optimizing CO2 curing time

The chloride erosion of CO2 cured cementitious materials could be a concern for concrete structure application. This study aims to clarify the chloride transport and binding behavior by elucidating the alteration of free and bound chloride content from the outer towards the core (5 layers with 2 mm intervals). The carbonation depth and chloride binding ratio at the carbonation zone were also determined. The results showed that dense carbonated surface significantly reduced the penetration of chloride, especially in the carbonation zone, resulting in a decrease in total chloride content (48 %–83 %) and a slight increase in the chloride binding ratio (up to 22 %). It is found that the benefits of minimizing surface porosity to impede chloride penetration significantly outweigh the drawbacks associated with the consumption of AFm phase and C-S-H gel. However, as prolonged the CO2 curing time to 7 days, the surface areas with the highest carbonation degree exhibited more chloride content than the inward partially carbonated zone. This is because excessive carbonation at early age could increase the surface pore structures, resulting in the promotion of chloride transport. It was found that the content of chloride and CaCO3 are strongly correlated with CO2 curing time, and CO2 at first 24 h curing can achieve greater benefits in reducing chloride penetration. Moreover, amorphous calcium carbonate gradually transformed into crystalline calcium carbonate during the process of chloride attack, conducive to the further improvement of the compactness of the sample.

Identification of immune subsets with distinct lectin binding signatures using multi-parameter flow cytometry: correlations with disease activity in systemic lupus erythematosus.

Cell surface glycosylation can influence protein-protein interactions with particular relevance to changes in core fucosylation and terminal sialylation. Glycans are ligands for immune regulatory lectin families like galectins (Gals) or sialic acid immunoglobulin-like lectins (Siglecs). This study delves into the glycan alterations within immune subsets of systemic lupus erythematosus (SLE). Evaluation of binding affinities of Galectin-1, Galectin-3, Siglec-1, Aleuria aurantia lectin (AAL, recognizing core fucosylation), and Sambucus nigra agglutinin (SNA, specific for α-2,6-sialylation) was conducted on various immune subsets in peripheral blood mononuclear cells (PBMCs) from control and SLE subjects. Lectin binding was measured by multi-parameter flow cytometry in 18 manually gated subsets of T-cells, NK-cells, NKT-cells, B-cells, and monocytes in unstimulated resting state and also after 3-day activation. Stimulated pre-gated populations were subsequently clustered by FlowSOM algorithm based on lectin binding and activation markers, CD25 or HLA-DR. Elevated AAL, SNA and CD25+/CD25- SNA binding ratio in certain stimulated SLE T-cell subsets correlated with SLE Disease Activity Index 2000 (SLEDAI-2K) scores. The significantly increased frequencies of activated AALlow Siglec-1low NK metaclusters in SLE also correlated with SLEDAI-2K indices. In SLE, activated double negative NKTs displayed significantly lower core fucosylation and CD25+/CD25- Siglec-1 binding ratio, negatively correlating with disease activity. The significantly enhanced AAL binding in resting SLE plasmablasts positively correlated with SLEDAI-2K scores. Alterations in the glycosylation of immune cells in SLE correlate with disease severity, which might represent potential implications in the pathogenesis of SLE.

CT-guided spatial normalization of nuclear hybrid imaging adapted to enlarged ventricles: Impact on striatal uptake quantification

IntroductionSpatial normalization is a prerequisite step for the quantitative analysis of SPECT or PET brain images using volume-of-interest (VOI) template or voxel-based analysis. MRI-guided spatial normalization is the gold standard, but the wide use of PET/CT or SPECT/CT in routine clinical practice makes CT-guided spatial normalization a necessary alternative. Ventricular enlargement is observed with aging, and it hampers the spatial normalization of the lateral ventricles and striatal regions, limiting their analysis. The aim of the present study was to propose a robust spatial normalization method based on CT scans that takes into account features of the aging brain to reduce bias in the CT-guided striatal analysis of SPECT images. MethodsWe propose an enhanced CT-guided spatial normalization pipeline based on SPM12. Performance of the proposed pipeline was assessed on visually normal [123I]-FP-CIT SPECT/CT images. SPM12 default CT-guided spatial normalization was used as reference method. The metrics assessed were the overlap between the spatially normalized lateral ventricles and caudate/putamen VOIs, and the computation of caudate and putamen specific binding ratios (SBR). ResultsIn total 231 subjects (mean age ± SD = 61.9 ± 15.5 years) were included in the statistical analysis. The mean overlap between the spatially normalized lateral ventricles of subjects and the caudate VOI and the mean SBR of caudate were respectively 38.40 % (± SD = 19.48 %) of the VOI and 1.77 (± 0.79) when performing SPM12 default spatial normalization. The mean overlap decreased to 9.13 % (± SD = 1.41 %, P < 0.001) of the VOI and the SBR of caudate increased to 2.38 (± 0.51, P < 0.0001) when performing the proposed pipeline. Spatially normalized lateral ventricles did not overlap with putamen VOI using either method. The mean putamen SBR value derived from the proposed spatial normalization (2.75 ± 0.54) was not significantly different from that derived from the default SPM12 spatial normalization (2.83 ± 0.52, P > 0.05). ConclusionThe automatic CT-guided spatial normalization used herein led to a less biased spatial normalization of SPECT images, hence an improved semi-quantitative analysis. The proposed pipeline could be implemented in clinical routine to perform a more robust SBR computation using hybrid imaging.

Feature engineering-based analysis of DaTSCAN-SPECT imaging-derived features in the detection of SWEDD and Parkinson's disease

Scans without evidence of dopamine deficit (SWEDD) refer to patients with a normal dopamine transporter scan who have been clinically considered to have Parkinson's disease (PD). To prevent misdiagnosis between SWEDD and PD, it is imperative to identify the manifestations of SWEDD in the early stages. In this experiment, imaging-based striatum binding ratio (SBR) features of four striatum regions are utilized and obtained from the Parkinson's Progression Marker Initiative (PPMI). After that, by implementing feature engineering, six combinational pairs are created by taking two SBR features at a time using a mathematical-based combination (nCr)technique. Then, by evaluating the maximum and minimum values of features of each pair, the six new features are obtained from each combinational pair based on arithmetic operations. Finally, a total of thirty-six new features have been derived by using these existing four SBR features. These derived 36 features are further applied to various supervised and ensemble classifiers of machine learning for three binary classifications (PD vs SWEDD, PD vs healthy, and healthy vs SWEDD). From the consequences, it has been observed that the Naive Bayes classifier performed well across all classification probabilities and among other classifiers. To differentiate SWEDD from PD, the classifier achieved 98.03 % accuracy, 98.85 % recall, 96.29 % precision, 92.96 % Jaccard_score, 96.29 % F1-score, & 99.34 % AUC. Moreover, the comparison has been made between with and without implementing the feature engineering technique for all three classification probabilities for better interpretation. Thus, it is reasonable to hypothesize that the suggested method, which is based on feature engineering, may not only improve performance but also help medical professionals diagnose diseases at early stages.

A water-soluble colorimetric chemosensor for sequential probing of Cu2+ and S2− and its practical applications to test strips, reversible test, and water samples

A water-soluble colorimetric chemosensor NHOP ((E)-1-(2-(2-(2-hydroxy-5-nitrobenzylidene)hydrazineyl)-2-oxoethyl)pyridin-1-ium) chloride) was developed for the sequential probing of Cu2+ and S2−. NHOP underwent a color change from pale yellow to colorless in the presence of Cu2+ in pure water. The binding ratio between NHOP and Cu2+ was confirmed to be 1:1 by the Job plot and ESI-MS (electrospray ionization mass spectrometry). The detection limit of NHOP for Cu2+ was calculated as 0.15 μM, which was far below the EPA (Environmental Protection Agency) standard (20 μM). The NHOP-coated test strip was able to easily monitor Cu2+ in real-time. Meanwhile, the NHOP-Cu2+ complex reverted from colorless to pale yellow in the presence of S2− through the demetallation. The stoichiometric ratio between NHOP-Cu2+ and S2− was determined to be 1:1 by analyzing the Job plot and ESI-MS. The detection limit of NHOP-Cu2+ for S2− was calculated as 0.29 μM, which was very below the WHO (World Health Organization) guideline (14.7 μM). NHOP successfully achieved the quantification for Cu2+ and S2− in water samples. NHOP could work as a sequential probe for Cu2+ and S2− at the biological pH range (7.0–8.4). Moreover, NHOP could successively probe Cu2+ and S2− at least three cycles because of its reversible property. The detection mechanisms of NHOP for Cu2+ and NHOP-Cu2+ for S2− were demonstrated with Job plot, ESI-MS, and DFT (density functional theory) calculations. Therefore, NHOP could work as an efficient sequential probe for Cu2+ and S2− in environmental systems.

α-Naphtholbenzein based heterocyclic sensor for detection of Cu(II) ions

Present research work illustrates the ‘Click’ generation of 4-((1-((1-benzyl-1H-1,2,3-triazol-4-yl) methoxy) naphthalen-4-yl) (phenyl)methylene) naphthalen-1(4H)-one α-NBT, a heterocyclic compound analyzed as an optical chemosensor for the selective detection of Cu(II) ions. The molecule is synthesized by [3 + 2] cycloaddition reaction of α-naphtholbenzein based terminal alkyne 2 with 1-(azidomethyl) benzene 3 under Cu(I)-catalyzed conditions (CuAAC) and is further characterized for its structural components by various spectroscopic techniques like IR, NMR (1H, 13C) and Mass spectrometry. Being having significant absorption in UV–Visible region, the receptor molecule α-NBT is analyzed for its chemosensing characteristics by UV–Visible and fluorescence spectroscopy and found to be very selective towards Cu(II) ions among a range of metal ions including Na(I), K(I), Ba(II), Cr(III), Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), Zn(II), Cd(II), Hg(II), Pb(II), Th(IV) and Ce(III) in CH3CN:H2O (4:1, v/v) solvent system. From the recorded spectral responses with change in concentration of Cu(II) ions, the binding ratio of α-NBT:Cu(II) complexation is calculated as 2:1 with the limit of detection of Cu(II) ions as 3.12 µM and binding constant for ligand–metal interaction equal to 0.15 x 105 M−1.

Functional fluorescent probe based on amide condensation of coumarin and melatonin for the turn-on detection of calcium ion in vitro and living cell

Due to a physiological significant role of calcium ion, it is essential to develop ways of detecting and monitor the level of Ca2+ ions in living cell. Herein, we rationally designed and synthesized a functional blue fluorescent compound CM based on amide condensation of coumarin and melatonin. Interestingly, it could exhibit an “On-OFF” fluorescence response for Ca2+ in an aqueous environment with 80-fold enhancement in bright blue emission, which is also free from interference of other co-existing cations of high concentration. A detection limit of 0.28 ppm was obtained, and the binding ratio of CM and Ca2+ is further investigated by Job’s plot. After coordination of CM with calcium ion, a significant “Tyndall Effect” can be observed, and blue emissive nanowires induced by aggregation of complex of CM and Ca2+ were further investigated by Dynamic Light Scattering, analysis of Zeta potential, and confocal imaging. The molecular docking of CM with melatonin receptor 1A is also conducted. MTT assay reveals that CM ligand and the corresponding Ca2+ complex are non-cytotoxic. Moreover, CM shows good membrane permeability, and the relative cellular uptake mechanism is mainly dominated by an energy-dependent process. CM and its complex of Ca2+ can be further used as intracellular luminescent imaging probes and their localization in cell organelles is also revealed.

Long-term follow-up study of SWEDD patients with mild parkinsonian signs

BackgroundWhether scan without evidence of dopaminergic deficit (SWEDD) can be a reliable indication of a clinical entity of Parkinson’s disease (PD) is controversial.ObjectiveTo evaluate the proportion of SWEDD patients with...

Aggregation-induced emission enhancement (AIEE) active bispyrene-based fluorescent probe: “turn-off” fluorescence for the detection of nitroaromatics

The detection of nitroaromatic explosives in real samples is essential for environmental monitoring because of their strongly powerful nature and wide applications in industries. Aggregation-induced emission enhancement (AIEE) active fluorescent probe has been widely employed to detect nitroaromatic explosives. Hereby, a simple V-shaped bispyrene-based fluorescent probe (called py-o) with AIEE properties was designed and synthesized, which was fully charactered by 1D NMR, ESI, FTIR, and 2D NOESY spectra. The py-o displayed bright blue-green fluorescence excimer emission at 480 nm in DMF/H2O (v/v 1:1). It is observed that the fluorescence excimer emission of py-o at 480 nm was quenched by PA in solution with a quenching constant of 5.45 × 104 M–1, and the limit of detection was approximately 0.139 μM. The details of the sensing mechanism were explained using 1H NMR titrations, Job’s plot and Bensi-Hildebrand methods, which revealed a 1:1 binding ratio via the π-π interactions between PA and py-o. Meanwhile, it exhibited outstanding anti-interference ability in the detection of PA when interfering analytes were added under the same conditions. Furthermore, low-cost thin-layer chromatography (TLC) plates coated with py-o were developed as fluorescent tools for naked-eye detection of PA in the solid state. Therefore, this work provides a new method for constructing an AIEE fluorescent probe for the detection of nitroaromatic explosives to utilize in environmental monitoring.

Lantern-type G-quadruplex fluorescent sensors for detecting divalent metal ions

Three thioflavin T (ThT) derivatives, namely ThT/ethylenediaminetetraacetic acid conjugates (E1T, E2T, and E1T1P), were designed and synthesized as sensing components for divalent metal ion detection. Furthermore, these ThT derivatives were used to design lantern-type G-quadruplex (G4) fluorescent sensors. The fluorescence intensities of the ThT derivatives decreased by 1.2- to 5.6-folds in the presence of Ni2+ and Cu2+, respectively, regardless of the topology of the utilized G4. Conversely, when Mn2+ and Zn2+ coexisted in antiparallel G4, the fluorescence intensities of E2T increased to approximately 3.3- and 2.3-folds, respectively, depending on the concentration of the divalent metal ion, allowing for quantitative analyses. The Job plot analysis revealed that the binding ratio of G4 and E2T changed from 2:1 to 1:2 with the increasing concentration of the divalent metal ions. These results indicated that the basic principle of such a lantern-type G4 sensor can be applied to the detection of divalent metal ions and other types of targets, such as proteins, and small molecules via ThT derivatization.