Effects of Plant-Derived Polyphenols on the Antioxidant Activity and Aroma of Sulfur-Dioxide-Free Red Wine.

Significant efforts have been made in recent years to produce healthier wines, with the primary goal of reducing the use of sulfur dioxide (SO2), which poses health risks. This study aimed to assess the effectiveness of three plant-derived polyphenols (dihydromyricetin, resveratrol, and catechins) as alternatives to SO2 in wine. After a three-month aging process, the wines were evaluated using analytical techniques such as high-performance liquid chromatography, colorimetry, gas chromatography-olfactometry-mass spectrometry, as well as electronic nose and electronic tongue analyses, with the purpose to assess parameters including antioxidant activity, color, contents of volatile aroma compounds, and sensory characteristics. The results demonstrated various degrees of improvement in the antioxidant activity, aromatic intensity, and sensory characteristics of wines using polyphenols. Notably, dihydromyricetin (200 mg/L) exhibited the strongest antioxidant activity, with increases of 18.84%, 23.28%, and 20.87% in 2,2-diphenyl-1-picrylhydrazyl, 2,2'azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric-ion-reducing antioxidant power assays, respectively. Resveratrol (200 mg/L) made the most significant contribution to volatile aroma compounds, with an 8.89% increase in the total content of alcohol esters. In E-nose analysis, catechins (200 mg/L) showed the highest response to aromatic compounds and the lowest response to volatile sulfur compounds, while also exhibiting the best sensory characteristics. Therefore, the three plant-derived polyphenols investigated here exhibited the potential to enhance wine quality as alternatives to SO2. However, it is important to consider the specific impact of different polyphenols on wine; hence, suitable antioxidants should be selected in wine production according to specific requirements.

The association between serum albumin and depression in chronic liver disease may differ by liver histology.

BACKGROUND: There are conflicting results regarding the association between chronic liver disease (CLD) and depression and the underlying biological mechanisms are lack of investigation. To address the impact of depression and its effects on the management of CLD, its biological marker is critical to be identified. The present study explored the association between serum albumin and depression in CLD patients and whether the association varied in different liver histological stages. METHODS: Based on the United States National Health and Nutrition Examination Survey 2017-2018, the data of serum albumin and depressive symptoms from 627 participants with CLD were used. Depression symptoms were assessed with the nine-item Patient Health Questionnaire (PHQ-9). We used multivariate linear regression to evaluate the association between serum albumin and PHQ-9 scores. Stratified analysis was performed according to the liver histology examined by vibration controlled transient elastography. RESULTS: Serum albumin level was inversely associated with PHQ-9 scores in the multivariate regression model after adjusting for mainly potential confounders (ß = - 1.113, 95% CI: - 2.065 to - 0.162, P = 0.0221). In the subgroup analysis stratified by gender, controlled attenuation parameter (CAP) and liver stiffness measurement (LSM), the inverse association remained significant in female (ß = - 2.002, 95% CI: - 3.515 to - 0.489, P = 0.0100), patients with CAP < 274 dB/m (ß = - 2.215, 95% CI: - 3.621 to - 0.808, P = 0.0023) and patients with LSM ≥8.2 kPa (ß = - 4.074, 95% CI: - 6.237 to - 1.911, P = 0.0003). Moreover, the association was much stronger when the serum albumin was higher than 3.4 g/dL among patients with LSM ≥8.2 kPa (ß = - 4.835, 95% CI: - 7.137 to - 2.533, P < 0.0001). CONCLUSION: Our study revealed an inverse association between serum albumin and depression in CLD patients and this association differed according to liver histological changes. Serum albumin could be a warning marker for depressive symptoms in CLD patients. It is essential for taking corresponding intervention strategies.

Regional Alteration within the Cerebellum and the Reorganization of the Cerebrocerebellar System following Poststroke Aphasia.

Recently, an increasing number of studies have highlighted the role of the cerebellum in language processing. However, the role of neural reorganization within the cerebellum as well as within the cerebrocerebellar system caused by poststroke aphasia remains unknown. To solve this problem, in the present study, we investigated regional alterations of the cerebellum as well as the functional reorganization of the cerebrocerebellar circuit by combining structural and resting-state functional magnetic resonance imaging (fMRI) techniques. Twenty patients diagnosed with aphasia following left-hemispheric stroke and 20 age-matched healthy controls (HCs) were recruited in this study. The Western Aphasia Battery (WAB) test was used to assess the participants' language ability. Gray matter volume, spontaneous brain activity, functional connectivity, and effective connectivity were examined in each participant. We discovered that gray matter volumes in right cerebellar lobule VI and right Crus I were significantly lower in the patient group, and the brain activity within these regions was significantly correlated with WAB scores. We also discovered decreased functional connectivity within the crossed cerebrocerebellar circuit, which was significantly correlated with WAB scores. Moreover, altered information flow between the cerebellum and the contralateral cerebrum was found. Together, our findings provide evidence for regional alterations within the cerebellum and the reorganization of the cerebrocerebellar system following poststroke aphasia and highlight the important role of the cerebellum in language processing within aphasic individuals after stroke.

Phenosafranin-Based Colorimetric-Sensing Platform for Nitrite Detection Enabled by Griess Assay.

A facile and effective colorimetric-sensing platform based on the diazotization of phenosafranin for the detection of NO 2 - under acidic conditions using the Griess assay is presented. Diazotization of commercial phenosafranin produces a color change from purplish to blue, which enables colorimetric quantitative detection of NO 2 - . Optimal detection conditions were obtained at a phenosafranin concentration of 0.25 mM, HCl concentration of 0.4 M, and reaction time of 20 min. Under the optimized detection conditions, an excellent linearity range from 0 to 20 µM was obtained with a detection limit of 0.22 µM. Favorable reproducibility and selectivity of the colorimetric sensing platform toward NO 2 - were also verified. In addition, testing spiked ham sausage, bacon, and sprouts samples demonstrated its excellent practicability. The presented colorimetric sensing platform is a promising candidate for the detection of NO 2 - in real applications.

A visual sensor array based on an indicator displacement assay for the detection of carboxylic acids.

Carboxylic acids (CAs) have been reported as potential biomarkers of specific diseases or human body odors. A visual sensor array is described here that is based on indicator displacement assays (IDAs). The arrays were prepared by spotting solutions of the following metal complexes: Murexide-Ni(II), murexide-Cu(II), zincon-Zn(II) and xylenol orange-Cu(II), with the capability of discrimination of 15 carboxylic acids (CAs) and the quantitation of pyruvic acid (PA). Clear differences can be observed through distinctive difference maps obtained within 5 min by subtraction of red, green and blue (RGB) values of digital images after and before exposure to analytes. After an analysis of multidimensional data by pattern recognition algorithms including HCA, PCA and LDA, excellent classification specificity, and accuracy of >96% were obtained for all samples. The IDA array exhibited a linear range from 10 to 1500 µM with a theoretical detection limit of 3.5 µM towards PA. Recoveries of real samples varied from 84.8% to 114.3%. As-fabricated IDA sensor array showed an excellent selectivity among other organic interfering substances and a good batch to batch reproducibility, demonstrating its robustness. All these observations suggested that the IDA sensor array is one of the most promising paths for the discrimination of CAs. Graphical abstract Schematic diagram of indicator displacement assay (a), the procedure for acquisition of difference maps (b), and pattern recognitions for CAs (c). The method uses hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA).

Highly Sensitive Fluorescent Sensor for Cartap Based on Fluorescence Resonance Energy Transfer Between Gold Nanoparticles and Rhodamine B.

Cartap residue poses a great threat to human health and its derivatives would remain in soils, natural waters and other environmental domains for a long time. Herein, a simple, rapid and ultrasensitive analytical method for the determination of cartap based on fluorescence resonance energy transfer (FRET) between Au nanoparticles (AuNPs) and rhodamine B (RB) is first described. With the presence of citrate-stabilized AuNPs, the fluorescence of RB was remarkably quenched by AuNPs via FRET. The fluorescence of the AuNPs-RB system was recovered upon addition of cartap, cartap can be adsorbed on the surface of AuNPs due to its amino group that has good affinity with gold, which could induce the aggregation of AuNPs accompanying color change from red to blue. Thus, the FRET between AuNPs and RB was weakened and the PL intensity of RB was recovered accordingly. A good linear correlation for detection of RB was exhibited from 1 nM to 180 nM, and the detection limit reached 0.88 nM, which was much lower than the safety limit required by USA, UK and China. To the best of our knowledge, it has been the lowest detection ever without the aid of costly instrumentation. This method was successfully carried out for the assessment of cartap in real samples with satisfactory results, which revealed many advantages such as high sensitivity, low cost and non-time-consuming compared with traditional methods.

Preparation of Quasi-Three-Dimensional Porous Ag and Ag-NiO Nanofibrous Mats for SERS Application.

In this study, two new quasi-three-dimensional Surface Enhanced Raman Scattering (SERS) substrates, namely porous Ag and Ag-NiO nanofibrous mats, were prepared using a simple, electrospinning-calcination, two-step synthetic process. AgNO3/polyvinyl pyrrolidone (PVP) and AgNO3/Ni(NO3)2/PVP composites serving as precursors were electrospun to form corresponding precursory nanofibers. Porous Ag and Ag-NiO nanofibers were successfully obtained after a 3-h calcination at 500 °C under air atmosphere, and analyzed using various material characterization techniques. Synthesized, quasi-three-dimensional porous Ag and Ag-NiO nanofibrous mats were applied as SERS substrates, to measure the model compound Rhodamine 6G (R6G), and investigate the corresponding signal enhancement. Furthermore, porous Ag and Ag-NiO nanofibrous mats were employed as SERS substrates for melamine and methyl parathion respectively. Sensitive detection of melamine and methyl parathion was achieved, indicating their feasibility as an active SERS sensing platform, and potential for food safety and environmental monitoring. All the results suggest that the electrospinning-calcination, two-step method offers a new, low cost, high performance solution in the preparation of SERS substrates.

Digital, Rapid, Accurate, and Label-Free Enumeration of Viable Microorganisms Enabled by Custom-Built On-Glass-Slide Culturing Device and Microscopic Scanning.

Accurately measuring the number of viable microorganisms plays an essential role in microbiological studies. Since the conventional agar method of enumerating visible colonies is time-consuming and not accurate, efforts have been made towards overcoming these limitations by counting the invisible micro-colonies. However, none of studies on micro-colony counting was able to save significant time or provide accurate results. Herein, we developed an on-glass-slide cell culture device that enables rapid formation of micro-colonies on a 0.38 mm-thick gel film without suffering from nutrient and oxygen deprivation during bacteria culturing. Employing a phase contrast imaging setup, we achieved rapid microscopic scanning of micro-colonies within a large sample area on the thin film without the need of fluorescent staining. Using Escherichia coli (E. coli) as a demonstration, our technique was able to shorten the culturing time to within 5 h and automatically enumerate the micro-colonies from the phase contrast images. Moreover, this method delivered more accurate counts than the conventional visible colony counting methods. Due to these advantages, this imaging-based micro-colony enumeration technique provides a new platform for the quantification of viable microorganisms.

Synthesis of maltodextrin-grafted-cinnamic acid and evaluation on its ability to stabilize anthocyanins via microencapsulation.

In this work, maltodextrin-grafted-cinnamic acid (MD-g-CA) was synthesised and used as wall material to improve the stability of purple sweet potato anthocyanins (PSPa) via microencapsualtion. MD-g-CA was prepared through esterification in a two-step convenient synthesis procedure and characterised using infra-red (IR) spectroscopy. The IR data indicated the typical ester carbonyl stretching at around 1721 cm-1. Moreover, MD-g-CA could give about 40% inhibition of DPPH radical and present excellent UV-absorption, which were notably better than that of native MD. Maltodextrin (MD) and MD-g-CA were used to prepare PSPa microcapsules by spray drying. The stability of PSPa was evaluated by UV-Vis analysis. The microcapsules produced by MD-g-CA showed a spheres-like appearance with some cracks. Storage tests revealed that the degradation rate of PSPa embedded by MD-g-CA was much lower than that of free PSPa under the same condition. Thus, MD-g-CA could be used as an effective wall material to improve stability of anthocyanins.

Synthesis, Characterization, and Antifungal Activity of Benzimidazole-Grafted Chitosan against Aspergillus flavus.

Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H and 13C NMR). Then, the efficiency of BAC against A. flavus ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of A. flavus. Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.

Tea polyphenols mediated biogenic synthesis of chitosan-coated cerium oxide (CS/CeO2) nanocomposites and their potent antimicrobial capabilities.

In the present study, we hypothesized that novel nanocomposites of chitosan-coated cerium oxide (CS/CeO2 NCs) derived from aqueous extracts of tea polyphenols would be stabilized and reduced by using green chemistry. The UV-visible spectrum of the synthesized material revealed an SPR peak at 279 nm, and the morphological characteristics of nanoparticles (NPs) as a uniformly distributed spherical shape with a size range of 20 nm were confirmed by field emission scanning electron microscopy (FESEM). The Fourier transform infrared spectroscopy (FTIR) spectrum illustrated the amino groups of chitosan-coated with CeO2 NPs on the surface. While, the hydrodynamic size (376 nm) and surface charge (+ 25.0 mV) of particles were assessed by dynamic light scattering (DLS), and the existence of oxidation state elements Ce 3d, O 1 s, and C 1 s was identified by employing X-ray photoelectron spectroscopy (XPS). A cubic fluorite polycrystalline structure with a crystallite size of (5.24 nm) NPs was determined using an X-ray Diffractometer (XRD). The developed CS/CeO2 NCs demonstrated excellent antibacterial and antifungal efficacy against foodborne pathogens such as Escherichia coli, Staphylococcus aureus, and Botrytis cinerea with zone of inhibition of 13.5 ± 0.2 and 11.7 ± 0.2 mm, respectively. The results elucidated the potential of biosynthesized CS/CeO2 NCs could be utilized as potent antimicrobial agents in the food and agriculture industries.

Preparation, antioxidant and antibacterial activities of cryptate copper(II)/sulfonate chitosan complexes.

In this work, we synthesized cryptate copper(II) followed by complexed with sulfonate chitosan (SCS). After characterization, the evaluation of the antioxidant properties of resulting complexes were carried out by 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH•), hydroxyl radical (•OH), and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•+), while the antibacterial and biofilm inhibitory activity against Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) were also investigated. According to the results, cryptate copper(II) exhibited the best antioxidant activity followed by cryptate copper(II)/SCS complexes, and SCS. Significant antibacterial activity of cryptate copper(II) against P. aeruginosa PAO1 was observed with the minimum inhibitory concentration of MIC value 12.50 µg/mL and minimum bactericidal concentration of MBC value 100.00 µg/mL, followed by cryptate copper(II)/SCS complexes and SCS. Cryptate copper(II) and cryptate copper(II)/SCS exhibited antibacterial activity which copper ions might enter the interior of cells, and the intracellular ions made the killed bacteria serve as an antibacterial agent showing a zombie effect. The copper ions complexed with cryptate and SCS rendering potential unlimited biological activities, might become one of the most popular research areas because of their unique coordination chemistry and their long-term biological activities.

Reconstruction of spinel Co3O4 by inert Zn2+ towards enhanced oxygen catalytic activity.

ZnxCo3-xO4 (0 ≤ x≤ 1) coupled with nitrogen-doped hollow porous carbon spheres exhibits a superior oxygen catalytic activity. A Zn-air battery using Zn0.6Co2.4O4/NHCS as a cathodic catalyst affords a high-power density (130 mW cm-2) and excellent stability. The effect of reconstruction of catalytically active Co ions induced by Zn is well-investigated.

The sensitivity and specificity of the modified volume-viscosity swallow test for dysphagia screening among neurological patients.

Oropharyngeal dysphagia (OD) is a highly prevalent condition after stroke and other neurological diseases. The volume-viscosity swallow test (V-VST) is a screening tool for OD. Considering that the recommendations of volume and thickeners in the original V-VST limited the popularization and application of the test in the Chinese population, we provide the modified V-VST to detect OD among neurological patients. In addition, the accuracy of the modified V-VST to screen OD needs to be verified. We included 101 patients with neurological diseases. OD was evaluated by a modified V-VST and a videofluoroscopy swallowing study (VFSS) using 3 volumes (i.e., 3, 5, and 10 ml) and 4 viscosities (i.e., water, mildly thick, moderately thick, and extremely thick). In this study, to compare with the original V-VST results, a volume of 20 ml was also included. The discriminating ability of modified V-VST in detecting OD was assessed by the sensitivity and specificity values of clinical signs of impaired efficiency (impaired labial seal, piecemeal deglutition, and residue) and impaired safety of swallowing (cough, voice changes, and oxygen desaturation ≥3%) in comparison to the results of VFSS. The modified V-VST showed 96.6% sensitivity and 83.3% specificity for OD, 85.2% sensitivity and 70% specificity for impaired safety, and 90.9% sensitivity and 76.9% specificity for impaired efficacy. Our study suggests that the modified V-VST offers a high discriminating ability in detecting OD among neurological patients.

Co-Cr mixed spinel oxide nanodots anchored on nitrogen-doped carbon nanotubes as catalytic electrode for hydrogen peroxide sensing.

Hydrogen peroxide (H2O2) is a significant biomarker in physiological processes. Abnormal levels of H2O2 are considered to be closely related to some acute diseases. Therefore, it is important to monitor the H2O2 levels in bio-samples. Herein, we present a novel non-enzymatic electrochemical H2O2 sensor based on the excellent electrocatalytic performance of a composite comprising Zn-Cr-Co ternary spinel metal oxide nanodots (ZnCrCoO4) anchored on the surface of nitrogen-doped carbon nanotubes (NCNTs), denoted as ZnCrCoO4/NCNTs, toward H2O2 reduction. ZnCrCoO4/NCNTs were synthesized using a facile one-pot hydrothermal strategy. The enhanced electrocatalytic performance of ZnCrCoO4 is resulted from the partial substitution of Co in spinel zinc cobaltate (ZnCo2O4) with Cr, which modifies the CoO electronic structure and enhances electroconductivity. The ZnCrCoO4/NCNTs-based H2O2 sensor exhibited a wide quantitative detection range from 1 to 7330 µM with a detection limit of 1 µM. The sensor showed excellent reproducibility and selectivity for H2O2 sensing. In addition, remarkable recoveries were obtained for H2O2-spiked fish serum samples. These results demonstrated that the as-developed sensor has a great potential in monitoring H2O2 levels in practical applications.

Fluorescent and colorimetric dual-readout sensor based on Griess assay for nitrite detection.

In this work, we presented a sensitive and selective colorimetric and fluorescent dual-readout sensor based on Griess assay for nitrite (NO2-) detection under acidic condition. The sensor system was constituted of acid-resistant carbon quantum dots (CQDs) and 3-aminophenol (3-Aph) with acidic condition regulated using HCl. During the sensing procedure, reaction of 3-Aph and NO2- under acidic condition can yield a yellow-colored azoic compound (AZO), which gives the colorimetric readout; meanwhile, the fluorescence of CQDs (fluorescence reporter) quenched due to the strong absorption of AZO, leading to fluorescent readout. Wherein, CQDs were synthesized via hydrothermal method through using polyacrylamide as precursor and characterized by AFM, XRD and XPS. Under the optimized condition, the sensor exhibit broad linear relationships towards NO2- in the range of 10 to 100 nM and 2.5 to 100 µM, with practical detection limits of 10 nM and 2.5 µM for the fluorescent and colorimetric readout, respectively. And the sensor displayed excellent capability of selectivity according to interferences study. Furthermore, testing of sprouts, bacon and ham sausage real samples demonstrated good recoveries and reproducibility of the sensor system. All these results suggested the presented colorimetric and fluorescent dual-readout sensor can be a promising candidate for the NO2- detection in real applications.

Rapid and fingerprinted monitoring of pesticide methyl parathion on the surface of fruits/leaves as well as in surface water enabled by gold nanorods based casting-and-sensing SERS platform.

An effective, simple and portable gold nanorod (Au NR) based casting-and-sensing surface enhanced Raman scattering (SERS) platform was developed for rapid and fingerprinted detection of pesticide methyl parathion. Monodispersed Au NRs with an average length of 60 nm and an aspect ratio of ca. 3 were synthesized through a seed mediated method and then systematically characterized. After a proof-of-concept detection for methyl parathion in DI water and on solid surface, the sensing platform was further applied to real samples (lake water, orange, apple and plant leave) contaminated with methyl parathion. The results show that the sensitivity of the SERS sensor for methyl parathion was satisfactory for real application, with detection limits of 1 µM in spiked lake water and 110-440 ng/cm2 on the surface of various fruits and plant leaves. This study indicates that the developed casting-and-sensing SERS sensor shows great promise to secure agricultural, food and environmental safety.

Psychometric properties of the Chinese-version Stroke and Aphasia Quality of Life Scale 39-generic version (SAQOL-39g).

BACKGROUND AND PURPOSE: Aphasia is a common outcome of stroke affecting one-third of the post-stroke population in China. While the quality of life (QOL) may be affected, care is often inadequately guided due to lack of validated measure for Chinese population with stroke-induced aphasia. This study aimed to develop a Chinese-version of the Stroke and Aphasia Quality of Life-39 generic version (SAQOL-39g) and evaluate its feasibility, reliability, and validity in Chinese patients with stroke-induced aphasia. METHODS: The process of translation and adaptation suggested by WHO was used to develop the Chinese-version of SAQOL-39. We evaluated the feasibility, reliability, and validity of the scale in 84 aphasia patients and their proxies by assessing the internal consistency of the test items, test-retest consistency, and the structural validity of data. RESULTS: The self-report and the proxy-report form were completed within 21.4 and 13.3 min on average, respectively. Physical, communication, and psychological subdomains were extracted as three common factors. The Cronbach's alpha coefficients of overall domain and subdomains for both forms ranged from 0.879 to 0.950, indicating high internal consistency. The intraclass correlation coefficients ranged from 0.804 to 0.987 for overall domain and subdomains of the forms. No significant difference was found between two forms. CONCLUSIONS: The Chinese-version SAQOL-39g has excellent reliability, validity, and feasibility for measuring the QOL of Chinese post-stroke aphasia patients. The consistency between self-report and proxy-report forms was good, implying that the proxy-report form can be used to assess the QOL of post-stroke aphasia patients.

Dual functional rhodium oxide nanocorals enabled sensor for both non-enzymatic glucose and solid-state pH sensing.

Both pH-sensitive and glucose-responsive rhodium oxide nanocorals (Rh2O3 NCs) were synthesized through electrospinning followed by high-temperature calcination. The as-prepared Rh2O3 NCs were systematically characterized using various advanced techniques including scanning electron microscopy, X-ray powder diffraction and Raman spectroscopy, and then employed as a dual functional nanomaterial to fabricate a dual sensor for both non-enzymatic glucose sensing and solid-state pH monitoring. The sensing performance of the Rh2O3 NCs based dual sensor toward pH and glucose was evaluated using open circuit potential, cyclic voltammetry and amperometric techniques, respectively. The results show that the as-prepared Rh2O3 NCs not only maintain accurate and reversible pH sensitivity of Rh2O3, but also demonstrate a good electrocatalytic activity toward glucose oxidation in alkaline medium with a sensitivity of 11.46 µA mM-1 cm-2, a limit of detection of 3.1 µM (S/N = 3), and a reasonable selectivity against various interferents in non-enzymatic glucose detection. Its accuracy in determining glucose in human serum samples was further demonstrated. These features indicate that the as-prepared Rh2O3 NCs hold great promise as a dual-functional sensing material in the development of a high-performance sensor forManjakkal both solid-state pH and non-enzymatic glucose sensing.

A Simple SERS-Based Trace Sensing Platform Enabled by AuNPs-Analyte/AuNPs Double-Decker Structure on Wax-Coated Hydrophobic Surface.

In this work, a simple and versatile SERS sensing platform enabled by AuNPs-analyte/AuNPs double-decker structure on wax-coated hydrophobic surface was developed using a portable Raman spectrometer. Wax-coated silicon wafer served as a hydrophobic surface to induce both aggregation and concentration of aqueous phase AuNPs mixed with analyte of interest. After drying, another layer of AuNPs was drop-cast onto the layer of AuNPs-analyte on the substrate to form double-decker structure, thus introducing more "hot spots" to further enhance the Raman signal. To validate the sensing platform, methyl parathion (pesticide), and melamine (a nitrogen-enrich compound illegally added to food products to increase their apparent protein content) were employed as two model compounds for trace sensing demonstration. The as-fabricated sensor showed high reproducibility and sensitivity toward both methyl parathion and melamine detection with the limit of detection at the nanomolar and sub-nanomolar concentration level, respectively. In addition, remarkable recoveries for methyl parathion spiked into lake water samples were obtained, while reasonably good recoveries for melamine spiked into milk samples were achieved. These results demonstrate that the as-developed SERS sensing platform holds great promise in detecting trace amount of hazardous chemicals for food safety and environment protection.