Microgravity-like Crystallization of Paramagnetic Species in Strong Magnetic Fields.

The crystallization of paramagnetic species in a magnetic field gradient under microgravity-like conditions is an area of interest for both fundamental and applied science. In this paper, a setup for the crystallization of paramagnetic species in the magnetic field up to 7 T generated by a superconducting magnet is described. The research includes calculations of the conditions necessary to compensate for the gravitational force for several types of paramagnetic substances using the magnetic field of superconducting magnets (4.7 T, 7 T, 9.4 T, and 16.4 T). Additionally, for the first time, the crystallization of copper sulfate and cobalt sulfate, as well as a mixture of copper sulfate and cobalt sulfate under gravitational force compensation in a superconducting magnet, was performed. This paper experimentally demonstrates the feasibility of growing paramagnetic crystals within the volume of a test tube on the example of copper and cobalt sulfate crystals. A comparison of crystals grown from the solution of a mixture of copper and cobalt sulfates under the same conditions, with and without the presence of a magnetic field, showed changes in both the number and size of crystals.

NIR-activated quercetin-based nanogels embedded with CuS nanoclusters for the treatment of drug-resistant biofilms and accelerated chronic wound healing.

We have developed multifunctional nanogels with antimicrobial, antioxidant, and anti-inflammatory properties, facilitating rapid wound healing. To prepare the multifunctional nanogels, we utilized quercetin (Qu) and a mild carbonization process to form carbonized nanogels (CNGs). These CNGs possess excellent antioxidative and bacterial targeting properties. Subsequently, we utilized the Qu-CNGs as templates to prepare nanogels incorporating copper sulfide (CuS) nanoclusters, further enhancing their functionality. Notably, the CuS/Qu-CNGs nanocomposites demonstrated an exceptional minimum inhibitory concentration against tested bacteria, approximately 125-fold lower than monomeric Qu or Qu-CNGs. This enhanced antimicrobial effect was achieved by leveraging near-infrared II (NIR-II) light irradiation. Additionally, the CuS/Qu-CNGs exhibited efficient penetration into the extracellular biofilm matrix, eradicating methicillin-resistant Staphylococcus aureus-associated biofilms in diabetic mice wounds. Furthermore, the nanocomposites were found to suppress proinflammatory cytokines, such as IL-1ß, at the wound sites while regulating the expression of anti-inflammatory factors, including IL-10 and TGF-ß1, throughout the recovery process. The presence of CuS/Qu-CNGs promoted angiogenesis, epithelialization, and collagen synthesis, thereby accelerating wound healing. Our developed CuS/Qu-CNGs nanocomposites have great potential in addressing the challenges associated with delayed wound healing caused by microbial pathogenesis.

Photothermal and Acid-Responsive Fucoidan-CuS Bubble Pump Microneedles for Combined CDT/PTT/CT Treatment of Melanoma.

Transdermal cancer therapy faces great challenges in clinical practice due to the low drug transdermal efficiency and the unsatisfactory effect of monotherapy. Herein, we develop a novel bubble pump microneedle system (BPMN-CuS/DOX) by embedding sodium bicarbonate (NaHCO3) into hyaluronic acid microneedles (MNs) loaded with fucoidan-based copper sulfide nanoparticles (Fuc-CuS NPs) and doxorubicin (DOX). BPMN-CuS/DOX can generate CO2 bubbles triggered by an acidic tumor microenvironment for deep and rapid intradermal drug delivery. Fuc-CuS NPs exhibit excellent photothermal effect and Fenton-like catalytic activity, producing more reactive oxygen species (ROS) by photothermal therapy (PTT) and chemodynamic therapy (CDT), which enhances the antitumor efficacy of DOX and reduces the dosage of its chemotherapy (CT). Simultaneously, DOX increases intracellular hydrogen peroxide (H2O2) supplementation and promotes the sustained production of ROS. BPMN-CuS/DOX significantly inhibits melanoma both in vitro and in vivo by the combination of CDT, PTT, and CT. In short, our study significantly enhances the effectiveness of transdermal drug delivery by constructing BPMNs and provides a promising novel strategy for transdermal cancer treatment with multiple therapies.

Trace identification of cysteine enantiomers based on an electrochemical sensor assembled from CuxS@SOD zeolite.

The nonchiral sensor concept based on a sodalite (SOD) zeolite loaded CuxS (CuxS@SOD) catalyst is proposed as a sensing platform for chiral cysteine (Cys) determination. Chiral Cys is analyzed by the difference of binding capacity between CuxS catalysts. The observed current in amperometric i-t curve (A i-t C) is always positive for the L-cysteine (L-Cys), while it is negative for the D-cysteine (D-Cys). Under differential pulse voltammetry (DPV) method, the characteristic current peak for the CuxS@SOD moves to right (positive potential position) with the addition of L-Cys while it moves to left (negative potential direction) with the addition of D-Cys, respectively. Cyclic voltammetry (CV) is consistent with DPV and discusses the diffusion control mechanism. In this work, the ultra-trace determination of cysteine enantiomers reaches the limit of detection (LOD) of 0.70 fM and 0.60 fM by the highly efficient CuxS catalyst restrained in the nanosized SOD zeolite cages of the opening window pores, respectively. The sensor opens up a novel potential prospect for achiral composite in the field of chiral recognition through electrochemical methods with extra-low concentration.

Antibacterial functionalization of cotton and cotton/polyester fabrics applying hybrid coating of copper/chitosan nanocomposites loaded polymer blends via gamma irradiation.

In the present work, copper/chitosan nanocomposites (Cu/CS) were prepared in an aqueous solution in the presence of CS as stabilizer and CuSO4·5H2O precursor. The Cu/CS NPs formation was proved through transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier Transform infrared (FT-IR) spectroscopy and XRD diffraction. Cotton and cotton/polyester fabrics were gamma-radiation grafted by padding to pickup of 100%, in nanocomposites based on Cu/CS NPs loaded in polymer blends of poly(vinyl alcohol) (PVA) and plasticized starch (PLST). The grafted fabrics were characterized in terms of tensile mechanical, crease recovery and water absorption properties. The results showed that cotton fabrics displayed higher water absorption (%) than cotton/polyester fabrics for all PVA/PLST compositions and water absorption was found to decrease with increasing the ratio of PVA in the PVA/PLST blends. Cotton/polyester fabrics displays crease recovery angle (CRA) value of 147.6 upon treated with PVA/PLST (80/20%) and gamma irradiated to 30 kGy compared to CRA value of 125.0 for cotton fabrics treated under the same conditions. For cotton fabrics, the tensile strength was largely depends on the irradiation dose, in which the tensile strength of the treated fabric with the different formulations is higher than the untreated fabric. The antimicrobial activity of the fabrics against gram-positive bacteria (Staphylococcus aurous) and gram-negative bacteria (Escherichia coli) was investigated. In case of gram-positive bacteria cotton fabric showed the highest impact, for both 50/50 and 20/80 PVA/PLST of 14 and 14.5 mm inhibition zone, whilst, cotton/polyester fabric recorded 6 and 5 mm inhibition zone against gram-negative bacteria for 50/50 and 20/80 PVA/PLST, respectively.

Engineering Cu2-xS-conjugated upconverting nanocomposites for NIR-II light-induced enhanced chemodynamic/photothermal therapy of cancer.

The integration of chemodynamic therapy (CDT) and photothermal therapy (PTT) has played a huge role in improved anticancer treatments. Here, a novel multifunctional nanoplatform based on Cu2-xS conjugated NaYF4:Yb/Er@NaYF4:Yb upconversion nanoparticles (UCNPs) was proposed and designed. In the UCNPs-Cu2-xS nanocomposites, UCNPs with excellent luminescent properties and a high X-ray attenuation coefficient can serve as an upconversion luminescence (UCL) and computer tomography (CT) imaging contrast agent; meanwhile, Cu(II) in the Cu2-xS nanodots enables the nanocomposites to have a magnetic resonance imaging (MRI) ability owing to the presence of unpaired electrons. Moreover, the Cu2-xS nanodots with a strong absorbance in the NIR II biowindow not only could be employed as a stable photothermal agent under NIR laser irradiation, but also could be used as a photothermal-enhanced Fenton nanocatalyst to respond to over-expressed H2O2 in the tumor microenvironment (TME) and generate toxic hydroxyl radicals (˙OH) to effectively kill cancer cells. Furthermore, the UCNPs-Cu2-xS nanocomposites possess negligible cytotoxicity and a high photothermal conversion efficiency (43.8%) in the NIR-II biowindow (1064 nm), indicating that they possess great potential for the UCL/CT/MR multi-modal imaging guided synergistic enhanced CDT/PTT of cancer.

Influence of calcium and EDTA on copper ion bioavailability in copper nanoparticle toxicity tests improves understanding of nano-specific effects.

Metal-based nanoparticles (NPs) can release metal ions that are toxic to aquatic organisms; however, whether the toxicity is from metal ions rather than unique "nano-scale" effects of the NPs is unresolved. The present study aimed to compare the toxicity of Cu2+ and Cu-NPs in larval zebrafish (Danio rerio) to clarify whether toxic effects are attributable to release of Cu ions and to determine the effect of the chelating agent ethylenediaminetetraacetic acid (EDTA) and calcium hardness (as CaCO3) on the Cu toxicity. First, the acute toxicity (96-h lethality) of Cu-NPs was determined in comparison to aqueous Cu in larvae exposed to CuSO4, and subsequently, sublethal tests with Cu-NPs and CuSO4 were conducted with additions of EDTA or calcium ions to evaluate alterations in expression of metallothionein-2 (MT2) gene transcripts (quantitative real-time polymerase chain reaction). Acute toxicity of Cu in larvae exposed to CuSO4 was greater (LC50 = 226 µg Cu/L) than for larvae exposed to Cu-NPs (LC50 = 648 µg Cu/L). The expression of MT2 increased with Cu concentration (p < 0.05), and the slope of the linear regression was significantly greater in fish exposed to CuSO4 (slope = 0.090) compared to Cu-NPs (slope = 0.011). Cu2+ was 2.9-fold more toxic than Cu-NPs. The presence of 5 mg/L EDTA and 220 mg/L CaCO3 significantly reduced the expression of MT2 (1.8-fold for EDTA, 2.3-fold for CaCO3) in larvae exposed to CuSO4. For larvae exposed to Cu-NPs, the presence of EDTA reduced the expression of MT2 (1.7-fold) relative to Cu-NP concentration. While Cu-NPs induced MT2 expression, the differences in concentration relationships of MT2 expression between Cu-NPs and CuSO4 indicated that factors other than release of Cu ions from Cu-NPs influenced acute toxicity of Cu-NPs. The conclusion drawn from this ecotoxicological risk assessment was that EDTA and calcium significantly decreased Cu toxicity in freshwater fish.

Guided screen for synergistic three-drug combinations.

Combinations of three or more drugs are routinely used in various medical fields such as clinical oncology and infectious diseases to prevent resistance or to achieve synergistic therapeutic benefits. The very large number of possible high-order drug combinations presents a formidable challenge for discovering synergistic drug combinations. Here, we establish a guided screen to discover synergistic three-drug combinations. Using traditional checkerboard and recently developed diagonal methods, we experimentally measured all pairwise interactions among eight compounds in Erwinia amylovora, the causative agent of fire blight. Showing that synergy measurements of these two methods agree, we predicted synergy/antagonism scores for all possible three-drug combinations by averaging the synergy scores of pairwise interactions. We validated these predictions by experimentally measuring 35 three-drug interactions. Therefore, our guided screen for discovering three-drug synergies is (i) experimental screen of all pairwise interactions using diagonal method, (ii) averaging pairwise scores among components to predict three-drug interaction scores, (iii) experimental testing of top predictions. In our study, this strategy resulted in a five-fold reduction in screen size to find the most synergistic three-drug combinations.

Bimetallic CuCo2 S4 Nanozymes with Enhanced Peroxidase Activity at Neutral pH for Combating Burn Infections.

Peroxidase-mimicking nanozymes that can generate toxic hydroxyl radicals (. OH) hold great promise as antibacterial alternatives. However, most of them display optimal performance under strongly acidic conditions (pH 3-4), and are thus not feasible for many medical uses, including burn infections with a wound pH close to neutral. Herein, we report a copper-based nanozyme (CuCo2 S4 ) that exhibits intrinsic peroxidase-like activity and can convert H2 O2 into . OH at neutral pH. In particular, bimetallic CuCo2 S4 nanoparticles (NPs) exhibited enhanced peroxidase-like activity and antibacterial capacity, superior to that of the corresponding monometallic CuS and CoS NPs. The CuCo2 S4 nanozymes possessed excellent ability to kill various bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, this CuCo2 S4 nanozymes could effectively disrupt MRSA biofilms in vitro and accelerate MRSA-infected burn healing in vivo. This work provides a new peroxidase mimic to combat bacteria in neutral pH milieu and this CuCo2 S4 nanozyme could be a promising antibacterial agent for the treatment of burn infections.

Clearable Black Phosphorus Nanoconjugate for Targeted Cancer Phototheranostics.

Therapeutic efficacy of synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) is limited by complex conjugation chemistry, absorption wavelength mismatch, and inadequate biodegradability of the PDT-PTT agents. Herein, we designed biocompatible copper sulfide nanodot anchored folic acid-modified black phosphorus nanosheets (BP-CuS-FA) to overcome these limitations, consequently enhancing the therapeutic efficiency of PDT-PTT. In vitro and in vivo assays reveal good biocompatibility and commendable tumor inhibition efficacy of the BP-CuS-FA nanoconjugate because of the synergistic PTT-PDT mediated by near-infrared laser irradiation. Importantly, folic acid unit could target folate receptor overexpressed cancer cells, leading to enhanced cellular uptake of BP-CuS-FA. BP-CuS-FA also exhibits significant contrast effect for photoacoustic imaging, permitting its in vivo tracking. The photodegradable character of BP-CuS-FA is associated with better renal clearance after the antitumor therapy in vivo. The present research may facilitate further development on straightforward approaches for targeted and imaging-guided synergistic PDT-PTT of cancer.

Quantitation of copper chlorophylls in green table olives by ultra-high-performance liquid chromatography with inductively coupled plasma isotope dilution mass spectrometry.

Table olives, a widely consumed delicacy, are often selected by consumers based on the shade of their green color. The appealing coloration of fresh olives fades to brown or pale yellow during the industrial processing necessary for commercialization and storage, as a result of the degradation of chlorophyll a and b to their corresponding pheophytins and other chlorophyll degradation products (CDP). The re-greening of table olives may be achieved by complexation of CDP with Cu2+, to form stable bright green copper CDP (Cu-CDP) complexes. To study this phenomenon, we developed a novel method to separately extract lipophilic and hydrophilic Cu-CDP and quantify Cu-CDP by UHPLC combined with inductively coupled plasma isotope dilution mass spectrometry (UHPLC-ICP-ID-MS) using post-column isotopic dilution with 65Cu. This technique does not require species-specific calibration standards and was applied to survey the Cu-CDP composition of the various types of table olives sold in the US market. The CDP and Cu-CDP extracted from table olives were identified by high resolution full-scan mass spectrometry. Total elemental Cu in table olives was measured by microwave digestion followed by ICP-MS detection and correlated with the content of Cu-CDP. Pale yellow olives contained <1 mg/kg lipophilic Cu-CDP and <3.5 mg/kg total elemental Cu. Bright green table olives contained 4-22 mg/kg lipophilic Cu-CDP and 14.4-161 mg/kg total elemental Cu in contrast to <6 mg/kg reported for natural abundance, indicating the formation of Cu-CDP was achieved by addition of copper salts. A dark green sample with 2.5 mg/kg of total copper and 0.267 mg/kg lipophilic Cu-CDP may have been processed by addition of sodium copper chlorophyllin (SCC); the higher content of Cu isochlorin e4 compared to Cu 152-Me-chlorin e6 supports this conclusion.

CuSO4-Catalyzed dual annulation to synthesize O, S or N-containing tetracyclic heteroacenes.

In this work, CuSO4 is utilized as a practical redox catalyst for tandem dual annulation in the synthesis of indole-fused tetracyclic heteroacenes, which are important skeletons in both medicinal chemistry and materials chemistry. The preparation of such skeletons in a convenient and efficient manner is in high demand. This method realizes the modular synthesis of benzofuro-, benzothieno-, and indoloindoles from abundant feedstocks such as 2-halobenzyl halides and nitrile derivatives in up to 99% yields, providing a rapid access to diverse indole-fused heteroacenes with biological or optoelectronic properties.

Seed selection and storage with nano-silver and copper as potential antibacterial agents for the seagrass Zostera marina: implications for habitat restoration.

Globally, seagrass meadows are extremely important marine ecosystems that are disappearing at an alarming rate. Therefore, research into seagrass restoration has become increasingly important. Various strategies have been used in Zostera marina L. (eelgrass) restoration, including planting seeds. To improve the efficiency of restoration by planting seeds, it is necessary to select high-quality seeds. In addition, a suitable antibacterial agent is necessary for wet storage of desiccation sensitive seeds to reduce or inhibit microorganism infection and seed decay. In the present study, an efficient method for selecting for high-quality eelgrass seeds using different specific gravities of salt water was developed, and potential antibacterial agents (nano-silver and copper sulfate) for seed storage were assessed. The results showed that the highest proportion of intact seeds (72.91 ± 0.50%) was recorded at specific gravities greater than 1.20. Therefore, specific gravities greater than 1.20 can be used for selecting high-quality eelgrass seeds. During seed storage at 0 °C, the proportion of intact seeds after storage with nano-silver agent was over 90%, and also higher than 80% with copper sulfate agent, which was significantly higher than control treatments. The findings revealed a potential selection method for high-quality seeds and long-term seed storage conditions for Z. marina, which could facilitate conservation and habitat restoration.

Employing Laccase-Producing Aspergillus sydowii NYKA 510 as a Cathodic Biocatalyst in Self-Sufficient Lighting Microbial Fuel Cell.

In the present work, we isolated and identified Aspergillus sydowii NYKA 510 as the most potent laccase producer. Its medium constituents were optimized to produce the highest possible amount of laccase, which was after 7 days at 31°C and pH 5.2. Banana peel and peptone excelled in inducing laccase production at concentrations of 15.1 and 2.60 g/l, respectively. Addition of copper sulfate elevated enzyme yield to 145%. The fungus was employed in a microbial fuel cell (MFC). The best performance was obtained at 2000 Ω achieving 0.76 V, 380 mAm-2, 160 mWm-2, and 0.4 W. A project to design a self-sufficient lighting unit was implemented by employing a system of 2 sets of 4 MFCs each, connected in series, for electricity generation. A scanning electron microscopy image of A. sydowii NYKA 510 was utilized in algorithmic form generation equations for the design. The mixed patterning and patterned customized mass approach were developed by the authors and chosen for application in the design.

DNA-Compatible Diazo-Transfer Reaction in Aqueous Media Suitable for DNA-Encoded Chemical Library Synthesis.

DNA-encoded chemical libraries (DECLs) are increasingly employed in hit discovery toward proteins of pharmaceutical interest. Protected amino acids are the most commonly used building blocks for the construction of DECLs; therefore, the expansion of reaction scope with the subsequent free amine is highly desired. Here, we developed a robust DNA-compatible diazo-transfer reaction using imidazole-1-sulfonyl azide tetrafluoroborate salt converting a wide range of primary amines into their corresponding azides in good to excellent yields.

Novel fabrication of gelatin-encapsulated copper nanoparticles using Aspergillus versicolor and their application in controlling of rotting plant pathogens.

The fabrication of copper nanoparticles (CuNPs) with smallest size and more stability, with potential effects in plant disease management, may need a modified protocol for green synthesis. In this study, we could biosynthesize stable CuNPs extracellularly by an eco-friendly route using A. versicolor. The biosynthesis of nanoparticles was confirmed by UV-visible spectroscopy, Fourier transform infrared (FTIR), transmission electron microscope (TEM) and dynamic light scattering (DLS) techniques. CuNPs have a size range of 23-82 nm with round to polygonal shape. Antifungal study showed that CuNPs have potential antifungal activity against rotting plant pathogens, where 3.2 and 2.8 µg ml-1 of nanoparticle solution totally inhibited the growth of both Fusarium oxysporum and Phytophthora parasitica, respectively. Damaged hyphae with limited deformed spores were detected through scanning electron microscope (SEM) analysis after the treatment of both pathogens with CuNPs. Between all tested polymers, gelatin-encapsulated nanoparticles were characterized 'by their smallest size, 7-33 nm, and regular spherical shape at all experimental conditions. After 6 months of storage, gelatin-CuNPs maintained full nanoscale and antifungal properties compared with uncoated particles which lost these properties after only 1 month. It is concluded that CuNPs can be biosynthesized by an eco-friendly cheap method using A. versicolor and can be preserved stably for a long time with the smallest size and full antifungal activity by their encapsulation with gelatin as a natural polymer. These nanoparticles can be used safely in the management of plant rotting fungi.

Oxylipin profile of human low-density lipoprotein is dependent on its extent of oxidation.

BACKGROUND AND AIMS: Atherosclerosis is usually the underlying cause of heart attacks, strokes and peripheral vascular diseases - collectively known as cardiovascular diseases. Oxidation of low density lipoprotein (LDL) and its lipid content has an important role in the formation of lipid-laden atherosclerotic plaques. Not much is known about the impact of oxidative stress on bioactive oxylipin molecules present in LDL. The aim of this study is to understand the changes in oxylipin molecules present in LDL characterized by varying degrees of LDL oxidation. METHODS: LDL was isolated from the pooled plasma of healthy normolipidemic volunteers and was subjected to in vitro copper-catalyzed oxidation for varying time intervals (0 h, 6 h, 12 h, 24 h and 30 h). At each time interval, oxylipins were isolated through solid phase extraction and quantified using a targeted LC/-MS/MS approach employing stable isotope dilution method. RESULTS: Our results demonstrate that different forms of oxidized LDL (OxLDL) are characterized by specific oxylipin distribution and concentration. Compared to non-oxidized LDL, there is a significant increase in oxylipin generation (p ≤ 0.05) in OxLDL subjected to 12 h and 24 h of oxidation. Though linoleate derived oxylipins are the most abundant in OxLDL extracts, the concentration of particular oxylipin species differed with different degrees of oxidation. Specifically, two pro-inflammatory linoleate-derived triols, namely 9,10,13-triHOME and 9,12,13-triHOME, exhibited a concentration increase of ~25 fold in 12h-OxLDL compared to non-oxidized LDL. Moreover, Partial least squares Discriminant Analysis (PLS-DA) identified 10 oxylipins, primarily prostaglandins, which could serve as additional biomarkers for oxidative stress or cardiovascular risk assessment. CONCLUSIONS: Our data suggests that oxidative stress induces profound changes in the oxylipin content of LDL and the pattern of change is based on the extent of oxidation.

Synthesis of DNA-templated copper nanoparticles with enhanced fluorescence stability for cellular imaging.

Fluorescence of DNA-templated copper nanoparticles (DNA-CuNPs) is not stable over time which limits applications in cellular imaging. This is due to the presence of oxygen during synthesis which oxidizes Cu(0) to Cu(II) and also produces the free hydroxyl radical. The authors have prepared DNA-CuNPs with enhanced temporal stability of fluorescence by optimizing the reaction conditions so as to minimize the deleterious effects of oxygen. The operational lifetime of DNA-CuNPs was increased from 25 min to 200 min. Fluorescence spectra of DNA-CuNPs in optimized condition show an emission peak at 650 nm when excited at 340 nm. DNA-CuNPs synthesized in this manner were used for cell imaging. As a proof of concept, the nucleus of a human colon cell line (HCT116) was stained. The method does not involve any chemicals other that copper sulfate and ascorbate. This new approach for generating DNA-CuNPs improves imaging of biological processes and provides a basis for developing other types of DNA-templated nanomaterials. Graphical abstract Schematic presentation of the formation of fluorescent DNA-templated copper nanoparticles (DNA-CuNPs). A large amount of ascorbate provides long operational lifetime for cellular imaging under the condition exposed to oxygen. *Asc- and **DHA stand for ascorbate and dehydroascorbic acid.

Label free aptasensor for ultrasensitive detection of tobramycin residue in pasteurized cow's milk based on resonance scattering spectra and nanogold catalytic amplification.

TOB aptamer can be adsorbed on the AuNPs surface to form AuNPs-aptamer complexation to prevent AuNPs aggregation in high salt solution. When TOB was added to the AuNPs solution, the aptamer would bind with TOB and depart from the AuNPs surface. The amount of the AuNPs-aptamer complexation depends on the TOB concentration. Different concentration of AuNPs-aptamer can catalyze the reduction reaction of CuSO4 to produce different size Cu2O particle. The resonance scattering peak intensities are correlated with the Cu2O size. Large size Cu2O particle as a resonance scattering spectroscopy probe can remarkable improve the TOB detection sensitivity. We have succeeded to detect the trace TOB in aqueous solutions. The linear range and limit of detection were 0.50-17 nM and 0.19 nM, respectively. This simple and inexpensive method exhibited high sensitivity and selectivity, which was successfully used to detect TOB in milk. The results indicated the accuracy and precision were satisfied.