Rapid detection of foodborne pathogens at an early stage is imperative for preventing the outbreak of foodborne diseases, known as serious threats to human health. Conventional bacterial culturing ...methods for foodborne pathogen detection are time consuming, laborious, and with poor pathogen diagnosis competences. This has prompted researchers to call the current status of detection approaches into question and leverage new technologies for superior pathogen sensing outcomes. Novel strategies mainly rely on incorporating all the steps from sample preparation to detection in miniaturized devices for online monitoring of pathogens with high accuracy and sensitivity in a time-saving and cost effective manner. Lab on chip is a blooming area in diagnosis, which exploits different mechanical and biological techniques to detect very low concentrations of pathogens in food samples. This is achieved through streamlining the sample handling and concentrating procedures, which will subsequently reduce human errors and enhance the accuracy of the sensing methods. Integration of sample preparation techniques into these devices can effectively minimize the impact of complex food matrix on pathogen diagnosis and improve the limit of detections. Integration of pathogen capturing bio-receptors on microfluidic devices is a crucial step, which can facilitate recognition abilities in harsh chemical and physical conditions, offering a great commercial benefit to the food-manufacturing sector. This article reviews recent advances in current state-of-the-art of sample preparation and concentration from food matrices with focus on bacterial capturing methods and sensing technologies, along with their advantages and limitations when integrated into microfluidic devices for online rapid detection of pathogens in foods and food production line.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In this paper, we present, to the best of our knowledge, for the first time, in-depth theoretical analysis and experimental results for the optimisation of supercritical angle fluorescence (SAF) ...structures in polymer microfluidic chips fabricated from a combination of micro-milling and polymer injection-moulding techniques for their application in the highly-sensitive detection of pathogens. In particular, we address experimentally and theoretically the relationship between the supercritical angle and the heights of the SAF structures embedded in the microfluidic chips to obtain optimised results where the highest fluorescence intensity is collected, and hence determining the optimised limit of detection (LOD). Together with theoretical modelling, we experimentally fabricate microarrays of SAF structures with different heights varying from zero to the order of 300 μm in cyclic olefin copolymer (COC) microfluidic chips. The results show that for fluorophores at the interface of air and COC, the highest fluorescence intensities are obtained at SAF structures with a 163 μm height for a milling tool with a 97.4 μm diameter, which is in excellent agreement with our modelling. A fluorescence LOD of 5.42 × 10
molecules is achieved when using such SAF structures. The solid-phase polymerase chain reaction (SP-PCR) on these SAF structures permits sensitive pathogen detection (3.37 × 10
copies of the E. coli genome per μL) on-chip. These results especially are of interest for applications in hypersensitive pathogen detection as well as in assisting the design of devices for point-of-care applications. Findings on the height optimization of SAF structures also advance our understanding of SAF detection techniques and provide insights into the development of fluorescence microscopy.
Five new dibenzocyclooctadiene lignans, named kadsuindutains A–E (1–5), and three known ones schizanrin F (6), schizanrin O (7), and schisantherin J (8) were isolated from the stems of Kadsura induta .... Their structures were determined by analyses of HR-ESI-MS, NMR, and ECD spectra. Compounds 1–5 contain a 2′,4′-dioxygenated-2′,3′-dimethylbutyryl moiety which is rarely reported for dibenzocyclooctadiene lignans. Molecular docking predicted that compounds 1–8 displayed good binding affinity to the active site of iNOS and TNF-α proteins but unstable binding to the active site of COX-2 protein. Additionally, in vitro experiments showed that compounds 1–8 inhibited NO production in LPS-activated RAW264.7 cells with IC 50 values from 10.7 μM to 34.0 μM, compared to the positive control L-NMMA (IC 50 = 31.2 μM).
Full text
Available for:
IJS, KILJ, NUK, UL, UM, UPUK
The volume of point of care (POC) testing continues to grow steadily due to the increased availability of easy-to-use devices, thus making it possible to deliver less costly care closer to the ...patient site in a shorter time relative to the central laboratory services. A novel class of molecules called microRNAs have recently gained attention in healthcare management for their potential as biomarkers for human diseases. The increasing interest of miRNAs in clinical practice has led to an unmet need for assays that can rapidly and accurately measure miRNAs at the POC. However, the most widely used methods for analyzing miRNAs, including Northern blot-based platforms, in situ hybridization, reverse transcription qPCR, microarray, and next-generation sequencing, are still far from being used as ideal POC diagnostic tools, due to considerable time, expertize required for sample preparation, and in terms of miniaturizations making them suitable platforms for centralized labs. In this review, we highlight various existing and upcoming technologies for miRNA amplification and detection with a particular emphasis on the POC testing industries. The review summarizes different miRNA targets and signals amplification-based assays, from conventional methods to alternative technologies, such as isothermal amplification, paper-based, oligonucleotide-templated reaction, nanobead-based, electrochemical signaling- based, and microfluidic chip-based strategies. Based on critical analysis of these technologies, the possibilities and feasibilities for further development of POC testing for miRNA diagnostics are addressed and discussed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
LAMP has received great interest and is widely utilized in life sciences for nucleic acid analysis. To monitor a real-time LAMP assay, a fluorescence DNA dye is an indispensable component and ...therefore the selection of a suitable dye for real-time LAMP is a need. To aid this selection, we investigated the inhibition effects of twenty-three DNA dyes on real-time LAMP. Threshold time (T
t
) values of each real-time LAMP were determined and used as an indicator of the inhibition effect. Based on the inhibition effects, the dyes were classified into four groups: (1) non-inhibition effect, (2) medium inhibition effect, (3) high inhibition effect, and (4) very high inhibition effect. The signal to noise ratio (SNR) and the limit of detection (LOD) of the dyes in groups 1, 2, and 3 were further investigated, and possible inhibition mechanisms of the DNA dyes on the real-time LAMP are suggested and discussed. Furthermore, a comparison of SYTO 9 in different LAMP reactions and different systems is presented. Of the 23 dyes tested, SYTO 9, SYTO 82, SYTO 16, SYTO 13, and Miami Yellow were the best dyes with no inhibitory effect, low LOD and high SNR in the real-time LAMP reactions. The present classification of the dyes will simplify the selection of fluorescence dye for real-time LAMP assays in point of care setting.
Five undescribed (four guaianolide sesquiterpenes and a benzoate ester derivative) and seven known compounds were isolated from the aerial parts of S. orientalis L. Their chemical structures were ...determined by extensive analysis of HR-ESI-MS and NMR spectroscopic methods. Absolute configurations were elucidated by experimental and TD-DFT calculated ECD spectra. Twelve isolated compounds exhibited potential xanthine oxidase inhibitory activity with IC50 values ranging from 0.76 ± 0.17 μM to 31.80 ± 0.97 μM. Molecular docking studies predicted that the binding energies of all isolated compounds with xanthine oxidase were lower than that of the positive control allopurinol. Benzyl 2-hydroxy-6-O-β-D-glucopyranosylbenzoate and benzyl 2-methoxy-6-O-β-D-glucopyranosylbenzoate displayed not only the best docking score but also the highest in vitro xanthine oxidase inhibitory activity with IC50 values of 0.76 ± 0.17 μM and 0.98 ± 0.26 μM, respectively.
Five undescribed (four guaianolide sesquiterpenes and a benzoate ester derivative) and seven known compounds were isolated from the aerial parts of Siegesbeckia orientalis L. Twelve isolated compounds exhibited xanthine oxidase inhibitory activity with IC50 values in the range 0.76–31.80 μM. Display omitted
•Five undescribed compounds were isolated from Siegesbeckia orientalis.•Their structures were established by spectroscopic methods.•Isolated compounds exhibited potential xanthine oxidase inhibitory activity.•Docking scores predicted better than that of allopurinol.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Five new triterpenoid glycosides, named campetelosides A–E (1–5), together with three known compounds, chikusetsusaponin IVa (6), umbellatoside B (7), and silvioside E (8) were isolated from the ...leaves of Camellia petelotii (Merr.) Sealy. Their chemical structures were determined by interpretations of HR‐ESI‐MS and NMR spectra. In addition, compounds 1–8 were evaluated for their α‐glucosidase inhibitory effects. Compounds 1–3 significantly showed α‐glucosidase inhibitory activity with IC50 values of 166.7±6.0, 45.9±2.6, and 395.3±10.5 μM, respectively, compared to that of the positive control, acarbose, with an IC50 value of 200.4±10.5 μM.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
From the methanol extract of the Cryptolepis buchananii fruits, four undescribed pentacyclic triterpenene glycosides (1–4) and five known pentacyclic triterpenenes (5–9) were isolated. Their ...structures were determined to be uncargenin C 28‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐glucopyranosyl ester (1), 3‐O‐β‐D‐glucopyranosyluncargenin C 28‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐glucopyranosyl ester (2), 3‐O‐β‐D‐glucopyranosyl‐(1→6)‐β‐D‐glucopyranosyl‐6β,23‐dihydroxyursolic acid 28‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐glucopyranosyl ester (3), 3‐O‐β‐D‐glucopyranosyl‐(1→2)‐β‐D‐glucopyranosylasiatic acid 28‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐glucopyranosyl ester (4), asiatic acid (5), 2α,3β,23‐trihydroxyoleana‐11,13(18)‐dien‐28‐oic acid (6), arjunolic acid (7), 6β‐hydroxyarjunolic acid (8), and actinidic acid (9) based on analyses of their HR‐ESI‐MS, 1D and 2D NMR spectra. All the isolates showed significantly NO production inhibition in LPS‐activated RAW264.7 cells with the IC50 values ranging from 18.79 to 37.57 μM, compared to that of the positive control compound, dexamethasone, which showed IC50 value of 14.05 μM.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A new megastigmane glycoside, (3S,4R,7E)-megastigma-5,7-diene-9-one-3,4-diol 3-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (1) and a new cyanogenic glycosyl derivative, ...(S)-2-(6′-O-R-rosmarinoyl-β-D-glucopyranosyloxy)-phenylacetonitrile (2) were isolated from the methanol extract of the Elsholtzia ciliata together with twelve known compounds, 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene (3), citrusin C (4), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (5), manglieside B (6), 4-allyl-2-hydroxyphenyl 1-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (7), (-)-isolariciresinol 3α-β-D-glucopyranoside (8), 7R,8R-threo-4,7,9-trihydroxy-3,3′-dimethoxy-8-O-4′-neolignan-9′-O-β-D-glucopyranoside (9), 7R,8R-threo-4,7,9,9′-tetrahydroxy-3-methoxy-8-O-4′-neolignan-9′-O-β-D-glucopyranoside (10), cedrusin-4-O-β-D-glucopyranoside (11), icariside E
3
(12), everlastoside L (13) and rosmarinic acid (14). Their chemical structures were elucidated on the basic of extensive 1D and 2D-NMR experiments, as well as their mass spectroscopic data. The absolute configurations of the compounds 1 and 2 were successfully indicated by both theoretical and calculated CD spectra. Compounds 3-7, 9 and 10 potential inhibited NO production in LPS-activated RAW264.7 cells with IC
50
values of 6.71, 8.97, 12.38, 14.27, 16.13, 13.54, 16.27 µM, respectively, compared to that of the positive control of N
G
-monomethyl-L-arginine acetate (L-NMMA), IC
50
= 32.51 µM.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Gnetum latifolium var. funiculare Markgr. is a medicinal plant and widely distributed in mountainous areas of Vietnam. Phytochemical investigation on the trunks of this plant afforded eight stilbene ...derivatives (1–8) including for new compounds (1–4). Their structures were determined based on extensive analyses of HR‐ESI‐MS, 1D and 2D NMR spectra. Among the isolates, compounds 1–3 showed moderate NO production inhibition in LPS‐activated RAW264.7 cells with the IC50 values ranging from 46.81 to 68.10 μM, compounds 4 and 6 showed weak effects with the IC50 values of 96.57 and 79.46 μM, respectively, compared to that of the positive control compound, dexamethasone (IC50 14.20 μM).
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
