Dual-channel fluorescent probe for discriminative detection of H2S and N2H4: Exploring sensing mechanism and real-time applications.

A highly efficient system incorporates the real-time visualization of the two toxic molecules (H2S and N2H4) and the recognition of corresponding transforms using a fluorescent sensor. In this paper, a dual-responsive probe (QS-DNP) based on methylquinolinium-salicyaldehyde-2,4-dinitrophenyl was developed that can simultaneously detect H2S and N2H4 at two independent fluorescent channels without signal crosstalk. QS-DNP showed excellent anti-interference, high selectivity, outstanding water solubility, low LOD values (H2S: 51 nM; N2H4: 40 nM), low cytotoxicity, and mitochondrial localization properties. The 2,4-dinitrophenyl site was sensitive to H2S, and the CC bridge was reactive to N2H4, with strong fluorescence at 680 and 488 nm, respectively. The wavelength gap between these two channels is 192 nm; verify that there is no signal crosstalk throughout detection. By this means, the probe was used to simultaneously detect H2S and N2H4 in real soil samples, food samples, and living cells. The endogenous H2S and N2H4 were monitored in HeLa cells and investigated the mitochondria organelle of living cells with a positive charge on QS-DNP. Overall, all results emphasize that the QS-DNP probe is a powerful tool for the simultaneous detection of H2S and N2H4 and presents a potential new sensing approach.

Novel H2S sensing mechanism derived from the formation of oligomeric sulfide capping the surface of gold nanourchins.

A gold nanourchin (AuNU) probe with a novel sensing mechanism for monitoring H2S was developed as a feasible colorimetric sensor. In this study, AuNUs that are selectively responsive to H2S were fabricated in the presence of trisodium citrate and 1,4-hydroquinone using a seed-mediated approach. Upon exposure of the AuNU solution to H2S, the hydrosulfide ions (HS-) in the solution are converted into oligomeric sulfides by 1,4-hydroquinone used as a reducing agent during the synthesis of AuNUs. The oligomeric sulfides formed in the AuNU solution upon the addition of H2S were found to coat the surface of the AuNUs, introducing a blue shift in absorption accompanied by a color change in the solution from sky blue to light green. This colorimetric alteration by the capping of oligomeric sulfides on the surface of AuNUs is unique compared to well-known color change mechanisms, such as aggregation, etching, or growth of nanoparticles. The novel H2S sensing mechanism of the AuNUs was characterized using UV-Vis spectroscopy, high-resolution transmission microscopy, X-ray photoelectron spectroscopy, surface-enhanced Raman spectroscopy, secondary ion mass spectroscopy, liquid chromatography-tandem mass spectrometry, and atom probe tomography. H2S was reliably monitored with two calibration curves comprising two sections with different slopes according to the low (0.3-15 µM) and high (15.0-300 µM) concentration range using the optimized AuNU probe, and a detection limit of 0.29 µM was obtained in tap water.

High-sensitivity NH3 gas sensor using pristine graphene doped with CuO nanoparticles.

A highly sensitive and selective NH3 gas sensor was developed based on single-layer pristine graphene doped with copper(II) oxide (CuO) nanoparticles of a specific size. High-quality single-layer graphene was grown using chemical vapor deposition. Approximately 15 nm-sized CuO colloidal nanoparticles were fabricated by a microwave-assisted thermal method using copper acetate as the precursor, and dimethylformamide as the reducing and stabilizing agent. Pristine graphene was doped with an aqueous suspension of CuO nanoparticles at a coating speed of 1500 rpm using a simple spin coater. CuO nanoparticle doping induces changes in the electronic properties of graphene; in particular, p-type doping significantly altered graphene resistivity in the presence of NH3 gas. Upon exposure of the pristine graphene surface to NH3 gas, NH3 reacted with O2-/ O-/ O2- species on the graphene surface and released electrons into graphene. This caused a change in the concentration of charge carriers in the valence channel of graphene and an increase in graphene resistivity, facilitating real-time NH3 monitoring with quick response and rapid recovery at 25 ℃ and ~ 55% relative humidity. Our results indicated that graphene doped with ~ 15 nm-sized CuO nanoparticles can sense NH3 gas selectively with a resistivity response of ~ 83%. Moreover, the sensor exhibited good reusability, fast response (~ 19 s), and rapid recovery (~ 277 s) with a detection limit of 0.041 ppm and a relative standard deviation of 0.76%.

Surface Analysis of Fermented Wheat and Rice Starch Used for Coating Traditional Korean Textiles.

Wheat and rice starches, traditionally used to stiffen fabric, become less contaminated and more antiseptic after fermentation for several years, thus enhancing their functional activity. In the present study, analytical techniques using particle size analysis, a gloss meter and a colorimeter were used to measure the physical properties of wheat and rice starches that had been fermented for 5 and 7 years, respectively. Their chemical contents and composition were determined by nutrient measurements and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The ToF-SIMS spectra and ion images showed that fermented starch contained more carbohydrate and less lipid than fresh starch. The surface morphologies of the fermented starch granules and starch-coated textiles were examined by scanning electron microscopy and compared with the surface morphologies of fresh starch granules. The fermented wheat and rice starch granules were smaller and more rounded with a lower level of N-containing compounds (proteins) and exhibited more antiseptic properties than fresh starch granules. The results showed that physical measurements and chemical analysis were simple and complementary techniques for investigating traditional Korean starch materials and textiles.

A new recognition moiety diphenylborinate in the detection of pyruvate via Lewis acid/base sensing pathway and its bioimaging applications.

Developing new reaction based recognizing units can enhance the specificity of target analyte molecules in practical applications of real samples and biosystems. Therefore, introducing a recognizing moiety diphenylborinate was encountered for the detection of pyruvate biomolecule through Lewis acid-base reaction based sensing strategy. The construction of the Schiff-base back bone between quinoline and N-(diethylamino)salicylaldehyde-diphenylborinate (QSB) were expressed the red shift from blue emission of quinoline in to green as that of dative bond developed between Schiff base nitrogen and boron atoms. The new sensing approach was involved such a way that fluorophore QSB is a Lewis acid while pyruvate acts as Lewis base, where the elimination of Lewis pair produced a weak green fluorescence including the formation of quinoline, N-(diethylamino)salicylaldehyde (QS). The switching products were witnessed through 1H NMR titration, HR-MS and FT-IR studies. The good selectivity and interference ability were achieved in presence of 1000-fold excess of possible interferences with LOD of 16 nM. Moreover, the tracking ability of the probe was employed towards pyruvate in live HeLa cell imaging for evaluating an exogenous and endogenous signals producing ability and its mitochondria targeting property was investigated successfully. Further, the practical utility of the probe was tested with milk samples and obtained good recovery results.

Highly sensitive colorimetric determination of nitrite based on the selective etching of concave gold nanocubes.

Concave gold nanocubes are viable optical nanoprobes for the determination of nitrite ions. Herein, a novel approach was developed, based on the measurement of localized surface plasmon resonance absorption. The addition of nitrite ions selectively induced the etching of concave gold nanocubes, abrading the sharp vertices to spherical corners, which resulted in blue-shifted absorption accompanied by a color change from sapphire blue to light violet. The mechanism of selective etching of concave gold nanocube tips was elucidated by using X-ray photoelectron spectroscopy and atom probe tomography. The optimized detection of NO2- via the concave gold nanocube-based probe occurred at pH 3.0 and in 20 mM NaCl concentration at 40 °C. The absorption ratios (A550 nm/A640 nm) were proportional to the NO2- concentrations in the range 0.0-30 µM, with a detection limit of 38 nM (limit of quantitation of 0.12 µM and precision of 2.7%) in tap water. The highly selective and sensitive colorimetric assay has been successfully applied to monitor the nitrite ion concentrations in spiked tap water, pond water, commercial ham, and sausage samples.

Tetraphenylethene-based fluorescent probe with aggregation-induced emission behavior for Hg2+ detection and its application.

A tetraphenylethene (TPE) derivative was designed and synthesized upon conjugation with bis(thiophen-2-ylmethyl) amine (BTA) containing a mercury-binding moiety and further characterized by using Nuclear magnetic resonance (NMR), LC-MS, UV-Vis, and fluorescence spectroscopic methods. The resulting TPE-BTA exhibited comprehensive aggregation-induced emission while expressing a high quantum yield and emission intensity at 70% water fraction. The probe exhibited a good photochromic effect with a Stokes shift of 178 nm, and the emission intensity at 550 nm increased considerably with the color turning from dark green to bright green under a UV lamp upon the addition of 5 µM Hg2+. The lowest-energy conformation of the probe showed that two thiophene rings were perpendicular to the phenyl ring, while two BTA molecules were situated in a staggered form to each other. The sulfur and nitrogen atoms present in TPE-BTA were coordinated to the Hg2+ ion, and these binding sites were confirmed by the NMR parameters, X-ray photoelectron spectroscopy signals, and structural calculations. The binding of Hg2+ to TPE-BTA was believed to restrict the intramolecular motion of TPE-BTA, thus inducing it to shine brighter according to the unique aggregation-induced emission effect. The concentration of Hg2+ was determined based on the enhancement of the emission intensity, and the present probe showed an extremely high sensitivity with a limit of detection of 10.5 nM. Furthermore, TPE-BTA enabled selective detection of Hg2+ even in the presence of a 1000-fold excess of other interfering metal ions. The proposed method was successfully employed to determine Hg2+ in living HeLa cells and real water samples.

A dual colorimetric probe for rapid environmental monitoring of Hg2+ and As3+ using gold nanoparticles functionalized with d-penicillamine.

A highly sensitive and selective colorimetric assay for the dual detection of Hg2+ and As3+ using gold nanoparticles (AuNPs) conjugated with d-penicillamine (DPL) was developed. When Hg2+ and As3+ ions coordinate with AuNP-bound DPLs, the interparticle distance decreases, inducing aggregation; this results in a significant color change from wine red to dark midnight blue. The Hg4f and As3d signals in the X-ray photoelectron spectra of Hg2+ (As3+)-DPL-AuNPs presented binding energies indicative of Hg2+-N(O) and As3+-N(O) bonds, and the molecular fragment observed in time-of-flight secondary ion mass spectra confirmed that Hg2+ and As3+ coordinated with two oxygen and two nitrogen atoms in DPL. The detection of Hg2+ and As3+ can be accomplished by observing the color change with the naked eye or by photometric methods, and this was optimized to provide optimal probe sensitivity. The assay method can be applied for environmental monitoring by first selectively quantifying Hg2+ in water samples at pH 6, then estimating the As3+ concentration at pH 4.5. The efficiency of the DPL-AuNP probe was evaluated for the sequential quantification of Hg2+ and As3+ in tap, pond, waste, and river water samples, and absorbance ratios (A 730/A 525) were correlated with Hg2+ and As3+ concentrations in the linear range of 0-1.4 µM. The limits of detection in water samples were found to be 0.5 and 0.7 nM for Hg2+ and As3+, respectively. This novel probe can be utilized for the dual determination of Hg2+ and As3+, even in the presence of interfering substances in environmental samples.

Rapid-Response and Highly Sensitive Boronate Derivative-Based Fluorescence Probe for Detecting H2O2 in Living Cells.

Intracellular H2O2 monitoring is important and has driven researchers to pursue advancements for the rapid identification of H2O2, since H2O2 is short-lived in cell lines. An arylboronate derivative has been investigated as a chemospecific fluorescence recognition agent for H2O2. Triphenylimidazoleoxadiazolephenyl (TPIOP) boronate was contrived as a novel candidate for the rapid and sensitive recognition of H2O2. The probe was conjugated using the TPIOP functional group acting as an excellent fluorescent enhancer. The TPIOP group stimulated the polarization of C-B bond due to its extended π-conjugation, which included heteroatoms, and induced the production of rapid signal because of the highly polar C-B bond along with the corresponding boronate unit. While H2O2 reacts with TPIOP boronate, its nucleophilic addition to the boron generates a charged tetrahedral boronate complex, and then the C-B bond migrates toward one of the electrophilic peroxide oxygen atoms. The resulting boronate ester is then hydrolyzed by water into a phenol, which significantly enhances fluorescence through aggregation-induced emission. The TPIOP boronate probe responded to H2O2 rapidly, within 2 min, and exhibited high sensitivity with a limit of detection of 8 nM and a 1000-fold selectivity in the presence of other reactive oxygen species. Therefore, the developed TPIOP boronate chemodosimeter was successfully utilized to visualize and quantify intracellular H2O2 from human breast cancer (MCF-7) cells, as well as gaseous and aqueous H2O2 from environmental samples using Whatman paper strips coated with TPIOP boronate.

On-off-on relay fluorescence recognition of ferric and fluoride ions based on indicator displacement in living cells.

A new boronic acid derivative functionalized with a 4-(3-(4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl)-1,2,4-oxadiazol-5-yl)phenyl (IOP) moiety was synthesized for use as a sequential "on-off-on"-type relay fluorescence probe for Fe3+ ions and F- ions with high selectivity and sensitivity under physiological conditions. The introduction of Fe3+ to IOP boronic acid (IOPBA) formed an Fe3+IOPBA complex, which led to quenching of the blue fluorescence intensity at 458 nm. The lowest-energy conformation of IOPBA was theoretically predicted to adopt an extended structure, and the Fe3+ ion in the Fe3+IOPBA complex was coordinated to two phenyl groups to form a π-complex. Upon addition of F- to the Fe3+IOPBA complex, the original fluorescence was recovered due to formation of [FeF6]3‒, resulting in "on-off-on"-type sensor behavior. IOPBA showed high selectivity towards Fe3+ among other cations. Moreover, the Fe3+IOPBA complex showed specific selectivity towards F-, with other cations and anions not interfering with detection. Both sensing processes showed 1:1 stoichiometry with binding constants of 6.87 × 106 and 4.49 × 106 mol-1 L for Fe3+ with IOPBA and F- with Fe3+IOPBA, respectively. The limits of detection for Fe3+ and F- were 10 and 1 nM, respectively. The proposed method was successfully applied in real water samples. Furthermore, the probe had low cytotoxicity and was successfully used as a bioimaging reagent to detect intracellular Fe3+ and F- in living HeLa cells.

A Highly Sensitive and Selective Colorimetric Hg2+ Ion Probe Using Gold Nanoparticles Functionalized with Polyethyleneimine.

A highly sensitive and selective colorimetric assay for the detection of Hg2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N-Hg2+-N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio (A700/A514) was correlated with the Hg2+ concentration in the linear range of 0.003-5.0 µM. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg2+ ions can be applied to the analysis of water and biological samples.

Highly Sensitive Colorimetric Assay for Determining Fe3+ Based on Gold Nanoparticles Conjugated with Glycol Chitosan.

A highly sensitive and simple colorimetric assay for the detection of Fe3+ ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe3+ ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe3+-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe3+ was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe3+ in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe3+ were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio (A700/A510) linearly correlated to the Fe3+ concentration in the linear range of 0-180 µM. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe3+ ions can be applied to the analysis of drinking water and pharmaceutical samples.

TOF-SIMS Analysis of Red Color Inks of Writing and Printing Tools on Questioned Documents.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a well-established surface technique that provides both elemental and molecular information from several monolayers of a sample surface while also allowing depth profiling or image mapping to be performed. Static TOF-SIMS with improved performances has expanded the application of TOF-SIMS to the study of a variety of organic, polymeric, biological, archaeological, and forensic materials. In forensic investigation, the use of a minimal sample for the analysis is preferable. Although the TOF-SIMS technique is destructive, the probing beams have microsized diameters so that only small portion of the questioned sample is necessary for the analysis, leaving the rest available for other analyses. In this study, TOF-SIMS and attenuated total reflectance Fourier transform infrared (ATR-FTIR) were applied to the analysis of several different pen inks, red sealing inks, and printed patterns on paper. The overlapping areas of ballpoint pen writing, red seal stamping, and laser printing in a document were investigated to identify the sequence of recording. The sequence relations for various cases were determined from the TOF-SIMS mapping image and the depth profile. TOF-SIMS images were also used to investigate numbers or characters altered with two different red pens. TOF-SIMS was successfully used to determine the sequence of intersecting lines and the forged numbers on the paper.

A colorimetric probe to determine Pb(2+) using functionalized silver nanoparticles.

A simple and sensitive colorimetric method for the determination of Pb(2+) ions in aqueous samples was developed using 1-(2-mercaptoethyl)-1,3,5-triazinane-2,4,6-trione (MTT) functionalized silver nanoparticles (MTT-AgNPs). The Pb(2+) ion acted as the metal center of the coordination complex, which formed N-Pb(2+)-O coordination bonds with the MTT-AgNPs, shortening the interparticle distance, and inducing aggregation of the MTT-AgNPs. This aggregation resulted in a dramatic color change from yellow to dark blue. Using this methodology, the concentration of Pb(2+) ions in environmental samples could be quantitatively detected with the naked eye or by using UV-vis spectrometry. Also, we found that the selectivity and sensitivity of detection were noticeably improved in the pH range of 7-8, at which a more obvious color change was observed. The absorption ratios (A625/A395) of the modified AgNP solution exhibited a linear correlation with Pb(2+) ion concentrations within the linear range of 0.1-0.6 µg mL(-1), and the limits of detection in tap and pond water were 0.02 and 0.06 µg mL(-1), respectively. This cost-effective sensing system allows for the rapid and facile determination of Pb(2+) ions in aqueous samples.

Attenuated total reflectance Fourier transform infrared spectroscopy analysis of red seal inks on questioned document.

Seals are traditionally used in the Far East Asia to stamp an impression on a document in place of a signature. In this study, an accuser claimed that a personal contract regarding mining development rights acquired by a defendant was devolved to the accuser because the defendant stamped the devolvement contract in the presence of the accuser and a witness. The accuser further stated that the seal ink stamped on the devolvement contract was the same as that stamped on the development rights application document. To verify this, the seals used in two documents were analyzed using micro-attenuated total reflectance Fourier transform infrared spectroscopy and infrared spectra. The findings revealed that the seals originated from different manufacturers. Thus, the accuser's claim on the existence of a devolvement contract was proved to be false.

Sensitive and selective determination of NO(2)(-) ion in aqueous samples using modified gold nanoparticle as a colorimetric probe.

A sensitive and selective colorimetric method for determination of nitrite ion in aqueous samples was developed using 1-(2-mercaptoethyl)-1, 3, 5-triazinane-2, 4, 6-trione-functionalized gold nanoparticles (MTT-GNPs). The nitrite ion seems to be used as a "molecular bridge", which can form NH---N and NH---O hydrogen bonds with the MTT-GNPs, shorten the interparticle distance, and induce the aggregation of the MTT-GNPs. This aggregation results in a dramatic change from wine-red to purple-gray color. Therefore, the concentration of nitrite ion in environmental samples can be quantitatively detected using the MTT-GNPs sensor by the naked eyes or UV-vis spectrometer. Moreover, investigations have revealed the sensitivity of the detection could be clearly improved by modulating pH of the solution, which led to a more rapid color change in the optimized GNPs system. The absorption ratios (A790/A535) of the modified GNPs solution exhibited a linear correlation with nitrite ion concentrations and the limit of detection was 1 ppm. This cost effective sensing system allows for the rapid and facile determination of the concentration of [Formula: see text] ions in aqueous samples.

Modern scientific evidence pertaining to criminal investigations in the Chosun dynasty era (1392-1897 A.C.E.) in Korea.

A guidebook detailing the process of forensic investigation was written in 1440 A.C.E. It outlines the fundamentals and details of each element of criminal investigation during the era of the Chosun dynasty in Korea. Because this old guidebook was written in terms of personal experience rather than on scientific basis, it includes many fallacies from the perspective of modern forensic science. However, the book describes methods to form a scientific basis for the experiments performed. We demonstrate the modern scientific basis for ancient methods to monitor trace amounts of blood and detect lethal arsenic poisoning from a postmortem examination as described in this old forensic guidebook. Traces of blood and arsenic poisoning were detected according to the respective color changes of brownish red, due to the reaction of ferric ions in blood with acetic ions of vinegar, and dark blue, due to the reaction of silver with arsenic sulfide.

Application of micro-attenuated total reflectance Fourier transform infrared spectroscopy to ink examination in signatures written with ballpoint pen on questioned documents.

Questioned documents examined in a forensic laboratory sometimes contain signatures written with ballpoint pen inks; these signatures were examined to assess the feasibility of micro-attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy as a forensic tool. Micro-ATR FTIR spectra for signatures written with 63 ballpoint pens available commercially in Korea were obtained and used to construct an FTIR spectral database. A library-searching program was utilized to identify the manufacturer, blend, and model of each black ballpoint pen ink based upon their FTIR peak intensities, positions, and patterns in the spectral database. This FTIR technique was also successfully used in determining the sequence of homogeneous line intersections from the crossing lines of two ballpoint pen signatures. We have demonstrated with a set of sample documents that micro-ATR FTIR is a viable nondestructive analytical method that can be used to identify the origin of the ballpoint pen ink used to mark signatures.

LC-TOF/MS determination of phthalates in edible salts from food markets in Korea.

Residual quantities of 12 phthalates have been monitored in edible salts (raw salts, refined salts, refined salts with additives and baked salts) available in Korean food markets. Liquid-liquid extraction followed by liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) was used to analyse the samples. The method was validated and showed linear correlation (R² > 0.996) in the range 0.5-100 ng g⁻¹ for all target analytes. Recoveries were 85.9-108.4%, except for diethyl phthalate (DEP). Relative standard deviations (RSDs) were 2.7-6.0% and the limits of detection (LODs) were 1.2-2.8 ng g⁻¹. Although the contamination of phthalates in salt would be trivial in comparison to those of other main foods and below the reference dose of the Chronic Oral Exposure recommended by US-EPA, the availability of reference data could be valuable for food chemists and salt manufacturers.

Safflower seed extract inhibits osteoclast differentiation by suppression of the p38 mitogen-activated protein kinase and IκB kinase activity.

Safflower seed has been reported to have a protective effect against bone loss diseases. However, the precise molecular mechanisms underlying the inhibitory effect of safflower seed in osteoclast differentiation remain unclear. In this study, we investigated the inhibitory action of safflower seed extract (SSE) on the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in cultured mouse-derived bone marrow macrophages (BMMs). We found that SSE significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells in BMMs without cytotoxicity. The gene expressions of nuclear factor of activated T-cells (NFATc1) and TRAP, which are genetic markers of osteoclast differentiation, were substantially decreased by SSE in a dose-dependent manner. Also, SSE diminished RANKL-mediated intracellular reactive oxygen species (ROS) generation on osteoclastogenesis in a dose-dependent manner. The SSE thereafter suppressed RANKL-induced p38 mitogen-activated protein kinase and IκBα kinase signalling activities which were activated by ROS generation for osteoclastogenesis. Additionally, SSE was found to decrease RANKL-induced actin ring formation, which is required for bone resorption activity. Taken together, our results suggest that SSE acts as a RANKL-induced osteoclastogenesis inhibitor by suppression of ROS generation. This induces a remarkable suppression of the p38 and IκBα kinase pathways, thereby suppressing the gene expression of NFATc1 in osteoclast precursors.