共查询到20条相似文献,搜索用时 15 毫秒
1.
Edwards KA Curtis KL Sailor JL Baeumner AJ 《Analytical and bioanalytical chemistry》2008,391(5):1689-1702
Dye-encapsulating liposomes can serve as signaling reagents in biosensors and biochemical assays in place of enzymes or fluorophores.
Detailed here is the use and preparation of streptavidin-coupled liposomes which offer a universal approach to biotinylated
target detection. The universal approach provides two advantages, i.e. only one type of liposome is necessary despite varying
target and probe sequences and the hybridization event can take place in the absence of potential steric hindrance occurring
from liposomes directly conjugated to probes. One objective of this work was to optimize the one-step conjugation of SRB-encapsulating
liposomes to streptavidin using EDC. Liposome, EDC, streptavidin concentrations, and reaction times were varied. The optimal
coupling conditions were found to be an EDC:carboxylated lipid:streptavidin molar ratio of 600:120:1 and a reaction time of
15 min. The second goal was to utilize these liposomes in sandwich hybridization microtiter plate-based assays using biotinylated
reported probes as biorecognition elements. The assay was optimized in terms of probe spacer length, probe concentration,
liposome concentration, and streptavidin coverage. Subsequently, the optimized protocol was applied to the detection of DNA
and RNA sequences. A detection limit of 1.7 pmol L−1 and an assay range spanning four orders of magnitude (5 pmol L−1−50 nmol L−1) with a coefficient of variation ≤5.8% was found for synthetic DNA. For synthetic RNA the LOQ was half that of synthetic
DNA. A comparison was made to alkaline phosphatase-conjugated streptavidin for detection which yielded a limit of quantitation
approximately 80 times higher than that for liposomes in the same system. Thus, liposomes and the optimized sandwich hybridization
method are well suited for detecting single-stranded nucleic acid sequences and compares favorably to other sandwich hybridization
schemes recently described in the literature. The assay was then used successfully for the clear detection of mRNA amplified
by nucleic acid sequence-based amplification (NASBA) isolated from as little as one Cryptosporidium parvum oocyst. The detection of mRNA from oocysts isolated from various water sample types using immunomagnetic separation was also
assessed. Finally, to prove the wider applicability and sensitivity of this universal method, RNA amplified from the atxA gene of Bacillus anthracis was detected when the input to the preceding NASBA reaction was as low as 1.2 pg. This highly sensitive liposome-based microtiter
plate assay is therefore a platform technology allowing for high throughput and wide availability for routine clinical and
environmental laboratory applications. 相似文献
2.
Elizabeth Diesel Madeline Schreiber Jan Roelof van der Meer 《Analytical and bioanalytical chemistry》2009,394(3):687-693
Arsenic contamination of natural waters is a worldwide concern, as the drinking water supplies for large populations can have
high concentrations of arsenic. Traditional techniques to detect arsenic in natural water samples can be costly and time-consuming;
therefore, robust and inexpensive methods to detect arsenic in water are highly desirable. Additionally, methods for detecting
arsenic in the field have been greatly sought after. This article focuses on the use of bacteria-based assays as an emerging
method that is both robust and inexpensive for the detection of arsenic in groundwater both in the field and in the laboratory.
The arsenic detection elements in bacteria-based bioassays are biosensor–reporter strains; genetically modified strains of,
e.g., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Rhodopseudomonas palustris. In response to the presence of arsenic, such bacteria produce a reporter protein, the amount or activity of which is measured
in the bioassay. Some of these bacterial biosensor–reporters have been successfully utilized for comparative in-field analyses
through the use of simple solution-based assays, but future methods may concentrate on miniaturization using fiberoptics or
microfluidics platforms. Additionally, there are other potential emerging bioassays for the detection of arsenic in natural
waters including nematodes and clams. 相似文献
3.
A quantitative and highly sensitive, yet simple and rapid, biosensor system was developed for the detection of nucleic acid sequences that can also be adapted to the detection of antigens. A dipstick-type biosensor with liposome amplification, based on a sandwich assay format with optical detection, was combined with a simple coupling reaction that allows the transformation of the generic biosensor components to target specific ones by a mere incubation step. This biosensor platform system was developed and optimized, and its principle was proven using DNA oligonucleotides that provided a nucleic acid biosensor for the specific detection of RNA and DNA sequences. However, the coupling reaction principle chosen can also be used for the immobilization of antibodies or receptor molecules, and therefore for the development of immunosensors and receptor-based biosensors. The generic biosensor consists of liposomes entrapping sulforhodamine B that are coated with streptavidin on the outside, and polyethersulfone membranes with anti-fluorescein antibodies immobilized in the detection zone. In order to transform the generic biosensor into a specific DNA/RNA biosensor, two oligonucleotides that are able to hybridize to the target sequence were labeled with a biotin and a fluorescein molecule, respectively. By simultaneously incubating the liposomes, both oligonucleotides, and the target sequence in a hybridization buffer for 20–30 min at 42 °C, a sandwich complex was formed. The mixture was applied to the polyethersulfone membrane. The complex was captured in the detection zone and quantified using a handheld reflectometer. The system was tested using RNA sequences from B. anthracis, C. parvum and E. coli. Quantitation of concentrations between 10 fmol and 1000 fmol (10–1000 nM) was possible without altering any biosensor assay conditions. In addition, no changes to hybridization conditions were required when using authentic nucleic acid sequence-based amplified RNA sequences, and the generic biosensor compared favorably with those previously developed specifically for the RNA sequences. Therefore, the universal biosensor described is an excellent tool, for use in laboratories or at test sites, for rapidly investigating and quantifying any nucleic acid sequence of interest, as well as potentially any antigen of interest that can be bound by two antibodies simultaneously. 相似文献
4.
F. Ceyda Dudak İsmail H. Boyacı Agnese Jurkevica Mahmud Hossain Zoraida Aquilar H. Brian Halsall Carl J. Seliskar William R. Heineman 《Analytical and bioanalytical chemistry》2009,393(3):949-956
A rapid and convenient assay system was developed to detect viable Escherichia coli in water. The target bacteria were recovered from solution by immunomagnetic separation and incubated in tryptic soy broth
with isopropyl-β-d-thiogalactopyranoside, which induces formation of β-galactosidase in viable bacteria. Lysozyme was used to lyse E. coli cells and release the β-galactosidase. β-Galactosidase converted 4-methylumbelliferyl-β-d-galactoside to 4-methylumbelliferone (4-MU), which was measured by fluorescence spectrophotometry using excitation and emission
wavelengths of 355 and 460 nm, respectively. Calibration graphs of 4-MU fluorescence intensity versus E. coli concentration showed a detection range between 8 × 104 and 1.6 × 107 cfu mL−1, with a total analysis time of less than 3 h. The advantage of this method is that it detects viable cells because it is
based on the activity of the enzyme intrinsic to live E. coli. 相似文献
5.
Baeumner AJ Leonard B McElwee J Montagna RA 《Analytical and bioanalytical chemistry》2004,380(1):15-23
A simple membrane-strip-based biosensor assay has been combined with a nucleic acid sequence-based amplification (NASBA) reaction for rapid (4 h) detection of a small number (ten) of viable B. anthracis spores. The biosensor is based on identification of a unique mRNA sequence from one of the anthrax toxin genes, the protective antigen (pag), encoded on the toxin plasmid, pXO1, and thus provides high specificity toward B. anthracis. Previously, the anthrax toxins activator (atxA) mRNA had been used in our laboratory for the development of a biosensor for the detection of a single B. anthracis spore within 12 h. Changing the target sequence to the pag mRNA provided the ability to shorten the overall assay time significantly. The vaccine strain of B. anthracis (Sterne strain) was used in all experiments. A 500-L sample containing as few as ten spores was mixed with 500 L growth medium and incubated for 30 min for spore germination and mRNA production. Thus, only spores that are viable were detected. Subsequently, RNA was extracted from lysed cells, selectively amplified using NASBA, and rapidly identified by the biosensor. While the biosensor assay requires only 15 min assay time, the overall process takes 4 h for detection of ten viable B. anthracis spores, and is shortened significantly if more spores are present. The biosensor is based on an oligonucleotide sandwich-hybridization assay format. It uses a membrane flow-through system with an immobilized DNA probe that hybridizes with the target sequence. Signal amplification is provided when the target sequence hybridizes to a second DNA probe that has been coupled to liposomes encapsulating the dye sulforhodamine B. The amount of liposomes captured in the detection zone can be read visually or quantified with a hand-held reflectometer. The biosensor can detect as little as 1 fmol target mRNA (1 nmol L–1). Specificity analysis revealed no cross-reactivity with 11 organisms tested, among them closely related species such as B. cereus, B. megaterium, B. subtilis, B. thuringiensis, Lactococcus lactis, Lactobacillus plantarum, and Chlostridium butyricum. Also, no false positive signals were obtained from nonviable spores. We suggest that this inexpensive biosensor is a viable option for rapid, on-site analysis providing highly specific data on the presence of viable B. anthracis spores. 相似文献
6.
Stratis-Cullum DN Griffin GD Mobley J Vo-Dinh T 《Analytical and bioanalytical chemistry》2008,391(5):1655-1660
This paper reports the first intensified biochip system for chemiluminescence detection and the feasibility of using this
system for the analysis of biological warfare agents is demonstrated. An enzyme-linked immunosorbent assay targeting Bacillus globigii spores, a surrogate species for Bacillus anthracis, using a chemiluminescent alkaline phosphatase substrate is combined with a compact intensified biochip detection system.
The enzymatic amplification was found to be an attractive method for detection of low spore concentrations when combined with
the intensified biochip device. This system was capable of detecting approximately 1 × 105
Bacillus globigii spores. Moreover, the chemiluminescence method, combined with the self-contained biochip design, allows for a simple, compact
system that does not require laser excitation and is readily adaptable to field use.
Figure Schematic diagram of the miniature biochip detection system 相似文献
7.
A flow injection method is described for the determination of iron in fresh water based on potassium permanganate chemiluminescence
detection via oxidation of formaldehyde in aqueous hydrochloric acid. Total iron concentrations are determined after reducing
Fe(III) to Fe(II) using hydroxylamine hydrochloride. The detection limit (three standard deviations of blank) is 1.0 nM, with
a sample throughput of 120 h−1. The calibration graph was linear over the range (2–10) × 10−7 M (r
2 = 0.9985) with relative standard deviations (n = 5) in the range 1.0–2.3%. The effect of interfering cations (Ca(II), Mg(II), Zn(II), Ni(II), Co(II), Fe(III), Mn(II), Pb(II),
and Cu(II)) and common anions (Cl−, SO
4
2−
, PO
4
3−
, NO
3
−
, NO
2
−
, I−, F−, and SO
3
2−
) was studied at their maximum admissible concentrations in fresh water. The method was applied to fresh-water samples from
the Quetta Valley, and the results obtained (0.04 ± 0.001–0.11 ± 0.01 mg/L Fe(II)) were in reasonable agreement with those
obtained using the spectrophotometric reference method (0.05 ± 0.01–0.12 ± 0.02 mg/L Fe(II)).
The text was submitted by the authors in English. 相似文献
8.
Kristl J Veber M Krajnicic B Oresnik K Slekovec M 《Analytical and bioanalytical chemistry》2005,383(5):886-893
A new method is described for the determination of endogenous jasmonic acid (JA) in Lemna minor plant extracts using liquid chromatography (LC) with fluorescence detection. Plant tissues were extracted and derivatised
using 9-anthryldiazomethane (ADAM reagent) prepared in situ. Accuracy and precision were improved by using the internal standard
dihydrojasmonic acid (dh-JA) for the correction of JA losses during sample preparation steps. Liquid chromatography–mass spectrometry
(LC/MS) analysis of ADAM derivatives of JA and dh-JA confirmed that a single molecule of JA and dh-JA was coupled with one
molecule of reagent. Derivatives of JA and dh-JA were separated with gradient elution on a C18 reversed-phase column using acetonitrile/water as a mobile phase and detected by a fluorescence detector at excitation and
emission wavelengths of 254 and 412 nm, respectively. The detection limits of JA and dh-JA were 2.9 ng mL−1 and 3.7 ng mL−1 per 50-μL injection. The method is reproducible and selective and yields single peaks for each compound regardless of isomer.
The specificity and accuracy of the proposed LC/FD method was confirmed by liquid chromatography–TurboIon Spray tandem mass
spectrometric (LC/MS/MS) analysis of free JA in Lemna minor samples under multiple reaction monitoring conditions. 相似文献
9.
Summary The main triterpene glycosides ofCimicifuga racemosa were separated by reversed phase HPLC, using a C-18 column, Evaporative Light Scattering (ELS) detection and a grient system
consisting of water, acetonitrile and reagent alcohol. Within 35 min three main glycosides could be separated and quantified
in the methanolic root extract with detection limits of 10.5, 15.6 and 31.6 μg·mL−1 respectively. The method was successfully used, to analyzed differentCimicifuga racemosa market products, as well as to distinguish between otherCimicifuga samples from China. 相似文献
10.
Harshanie Abeywardena Aaron R. Jex Simon M. Firestone Sandra McPhee Nicole Driessen Anson V. Koehler Shane R. Haydon Georg von Samson‐Himmelstjerna Melita A. Stevens Robin B. Gasser 《Electrophoresis》2013,34(15):2259-2267
In the present study, we undertook a molecular epidemiological survey of Cryptosporidium and Giardia in calves on three dairy and two beef farms within an open drinking water catchment area (Melbourne, Australia). Faecal samples (n = 474) were collected from calves at two time points (5 months apart) and tested using a PCR‐based mutation scanning‐targeted sequencing phylogenetic approach, employing regions within the genes of small subunit (SSU) of ribosomal RNA (designated partial SSU), 60 kDa glycoprotein (pgp60) and triose phosphate isomerase (ptpi) as genetic markers. Using partial SSU, the C. bovis, C. parvum, C. ryanae and a new genotype of Cryptosporidium were characterised from totals of 74 (15.6%), 35 (7.3%), 37 (7.8%) and 9 (1.9%) samples, respectively. Using pgp60, C. parvum genotype IIa subgenotype A18G3R1 was detected in 29 samples. Using ptpi, G. duodenalis assemblages A and E were detected in totals of 10 (2.1%) and 130 (27.4%) samples, respectively. The present study showed that a considerable proportion of dairy and beef calves in this open water catchment region excreted Cryptosporidium (i.e. subgenotype IIaA18G3R1) and Giardia (e.g. assemblage A) that are consistent with those infecting humans, inferring that they are of zoonotic importance. Future work should focus on exploring, in a temporal and spatial way, whether these parasites occur in the environment and water of the catchment reservoir. 相似文献
11.
Fumonisins B1 (FB1) and fumonisin B2 (FB2) are the main members of a family of mycotoxins produced by Fusarium verticillioides, Fusarium proliferatum, and other fungi species of the section Liseola. The present work shows the results of comparative studies using two different procedures for the analysis of fumonisins
in maize and maize-based samples. The studied analytical methods involve extraction with methanol/water, dilution with PBS,
and clean-up through immunoaffinity columns. Two reagents (o-phthaldialdehyde and naphthalene-2,3-dicarboxaldehyde) were studied for formation of fluorescent derivatives. The separation
and identification were carried out by high-performance liquid chromatography with fluorescence detection. The optimized method
for analysis of fumonisins in maize involved extraction with methanol/water (80:20), clean-up with an immunoaffinity column,
and derivatization with naphthalene-2,3-dicarboxaldehyde (NDA). The limit of detection was 20 μg kg−1 for FB1 and 15 μg kg−1 for FB2. Recoveries of FB1 and FB2 ranged from 79% to 99.6% for maize fortified at 150 μg kg−1 and 200 μg kg−1, respectively, with within-day RSDs of 3.0 and 2.7%. The proposed method was applied to 31 samples, and the presence of fumonisins
was found in 14 samples at concentrations ranging from 113 to 2,026 μg kg−1. The estimated daily intake of fumonisins was 0.14 μg kg−1 body weight per day. 相似文献
12.
Nakamura S Wada M Crabtree BL Reeves PM Montgomery JH Byrd HJ Harada S Kuroda N Nakashima K 《Analytical and bioanalytical chemistry》2007,387(6):1983-1990
A sensitive semi-micro column HPLC method with peroxyoxalate chemiluminescence (POCL) detection and column switching has been
developed for simultaneous determination of 3,4-methylenedioxymethamphetamine (MDMA) and related compounds, for example 3,4-methylenedioxyamphetamine,
methamphetamine, and amphetamine, in hair. After digestion of the hair with 1 mol L−1 sodium hydroxide the compounds were extracted with n-heptane and derivatized with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. A mixture of hydrogen peroxide and bis(2,4,5-trichloro-6-carbopentoxyphenyl)oxalate
in acetonitrile was used as post-column CL reagent. Calibration plots showed linearity was good (r = 0.999); detection limits were 0.02–0.16 ng mg−1 hair at a signal-to-noise ratio of 3. The precision of the method, as RSD (n = 5), in intra-day and inter-day assays was better than 5.0 and 6.9%, respectively. The proposed method was sufficiently
sensitive to detect low ng mg−1 levels of MDMA and related compounds in hair, and could be used for quantification of the compounds in hair samples from
patients treated in a chemical dependency unit. 相似文献
13.
Fanjul-Bolado P González-García MB Costa-García A 《Analytical and bioanalytical chemistry》2006,385(7):1202-1208
p-Nitrophenyl phosphate is one of the most widely used substrates for alkaline phosphatase in ELISAs because its yellow, water-soluble
product, p-nitrophenol, absorbs strongly at 405 nm. p-Nitrophenol is also electroactive; an oxidative peak at 0.97 V (vs. an Ag pseudoreference electrode) is obtained when a bare
screen-printed carbon electrode is used. When an amperometric detector was coupled to a flow-injection analysis system the
detection limit achieved for p-nitrophenol was 2×10−8 mol L−1, almost two orders of magnitude lower than that obtained by measuring the absorbance of the compound. By use of this electrochemical
detection method, measurement of 7×10−14 mol L−1 alkaline phosphatase was achieved after incubation for 20 min. The feasibility of coupling immunoassay to screen-printed
carbon electrode amperometric detection has been demonstrated by performing an ELISA for detection of pneumolysin, a toxin
produced by Streptococcus pneumoniae, which causes respiratory infections. The method is simple, reproducible, and much more sensitive than traditional spectrophotometry. 相似文献
14.
Simultaneous detection of A and B trichothecenes by gas chromatography with flame ionization or mass selective detection 总被引:3,自引:0,他引:3
A clean-up cartridge consisting of ammonium sulfate, celite, alumina, charcoal and C18 was developed for the simultaneous detection of A and B type trichothecenes, namely 4,15-diacetoxy-scirpenol, T2-toxin, deoxynivalenol (DON) and nivalenol (NIV). After derivatization with N,N-dimethyl-trimethylsilyl-carbamate, the purified extracts were analyzed by gas chromatography with flame ionization (GC-FID) or mass selective detection (GC-MSD). Using this cartridge, no further sample clean-up steps are required that makes the developed method time and cost effective. The method is easy to implement; no special experience or instrumentation is required. The limits of detection in semolina and corn grits ranged from 0.30 to 0.47 mg kg−1 for GC-FID and from 0.05 to 0.35 mg kg−1 for GC-MSD. Corn gluten feed (CGF) samples were analyzed as well, for 4,15-diacetoxy-scirpenol and T2 toxin, with a limit of detection of 0.23 and 0.14 mg kg−1, respectively. 相似文献
15.
Dupard-Julien CL Kandlakunta B Uppu RM 《Analytical and bioanalytical chemistry》2007,387(3):1027-1032
A reversed-phase, high-performance liquid chromatography (RP-HPLC) method that allows quantitation of low levels of epoxides
has been described. The method involved derivatization of epoxides using 100- to 1,000-fold excess N,N-diethyldithiocarbamate (DTC) at 60 °C for 20 min at neutral pH. The unreacted DTC was then decomposed to CS2 and diethyl amine by acidification of the reaction mixture to pH 2 using orthophosphoric acid. The first two steps could
be performed in the same reaction vessel by sequential addition of reagents. In the final step, an aliquot (20 μL) of the
derivatized sample was analyzed for the presence of stable esters of DTC by RP-HPLC using a Supelcosil LC-18-S (150 × 4.6-mm)
column and a mobile phase consisting of 40% (v/v) acetonitrile in water at a flow of 1 mL min−1. Using UV detection at 278 nm, the epoxides gave linear responses in the concentration range of 0.25 to 50 μM. The method
is robust, and as low as 5 pmol of the analyte could be successfully detected and quantified with recoveries of ≥94%. Following
a minimal pretreatment such as ultrafiltration (molecular weight cutoff 5,000 Da), the method is suitable for analysis of
epoxides in complex physiological fluids (e.g., fetal bovine serum). The method has been rigorously evaluated and adapted
in our laboratory for routine analysis and determination of stability of epoxides of 1,3-butadiene and other alkenes added
to cell cultures. 相似文献
16.
Pól J Varadová Ostrá E Karásek P Roth M Benesová K Kotlaríková P Cáslavský J 《Analytical and bioanalytical chemistry》2007,388(8):1847-1857
Pressurised fluid extraction using water or methanol was employed for the extraction of stevioside from Stevia rebaudiana Bertoni. The extraction method was optimised in terms of temperature and duration of the static or the dynamic step. Extracts
were analysed by liquid chromatography followed by UV and mass-spectrometric (MS) detections. Thermal degradation of stevioside
was the same in both solvents within the range 70–160 °C. Methanol showed better extraction ability for isolation of stevioside
from Stevia rebaudiana leaves than water within the range 110–160 °C. However, water represents the green alternative to methanol. The limit of
detection of stevioside in the extract analysed was 30 ng for UV detection and 2 ng for MS detection. 相似文献
17.
Contamination by Brettanomyces is a frequent problem in many wineries that has a dramatic effect on wine aroma and hence its quality. The yeast Brettanomyces/Dekkera is involved in the formation of three important volatile ethylphenols—4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol—that
transmit an unpleasant aroma to wine that has often been described as ‘medicinal’, ‘stable’ or ‘leather’. This study proposes
an in situ derivatisation and headspace solid-phase microextraction– gas chromatography coupled to mass spectrometry method
to determine the three ethylphenols in red Brettanomyces-tainted wines. The most important variables involved in the derivatisation (acetic anhydride and base concentration) and
the extraction (extraction temperature and salt addition) processes were optimised by experimental design. The optimal conditions
using 4 mL of wine in 20-mL sealed vials were 35 μL of acetic anhydride per millilitre of wine, 1 mL of 5.5% potassium carbonate
solution and 0.9 g of sodium chloride and the extraction was performed with a divinylbenzene–carboxen–poly(dimethylsiloxane)
fibre at 70 °C for 70 min. Then, the performance characteristics were established using wine samples spiked with the ethylphenols.
For all compounds, the detection limits were below the odour threshold reported in the literature and they were between 2
and 17 μg L−1 for 4-ethylguaiacol and 4-ethylphenol, respectively. Intermediate precision (as relative standard deviation) was acceptable,
with values ranging from 0.3 to 12.1%. Finally, the method was applied in the analysis of aged Brettanomyces-tainted wines. 相似文献
18.
Summary A novel method is described for the determination of paracetamol (acetaminophen;N-acetyl-4-aminophenol) in urine. After reversed-phase HPLC separation, paracetamol is oxidized by H2O2 with horseradish peroxidase catalysis. Detection is performed fluorimetrically at an excitation wavelength of 329 nm and
an emission wavelength of 435 nm. Urine samples were spiked with paracetamol, diluted, and injected directly without further
pretreatment. Under these conditions, the limit of detection was 2×10−8 molL−1, and the limit of quantification was 7×10−8 molL−1. The method was validated by two different approaches based on HPLC with UV-Vis detection. 相似文献
19.
O. Isildak 《Journal of Analytical Chemistry》2009,64(12):1242-1246
A simple method for determination of common inorganic anions in mushroom samples has been developed by using suppressed ion
chromatography with a pH detection unit. The detection unit which was constructed in such a way that practically no additional
dispersion occurred consisted of a flow-through quinhydrone pH sensor and a small reference electrode. Chromatographic separation
was performed in the order F−, Cl−, NO2−, Br−, PO43−, ClO3−, NO3−, and SO42−, at room temperature by using Ion Pac AS 9-HC anion exchange column. Anion extracts from dried mushroom samples at room temperature
were homogenized and filtered before injection. Under optimized analytical conditions, the detection limits of the method
were between 2 × 10−6 and 3 × 10−4 M, depending on the anion studied. The results showed that the concentrations of fluoride and bromide in all mushroom samples
were below their limit of detection. Nitrite was found to be the lowest abundant ion, while the most abundant ion was sulfate
in all the mushroom samples studied. 相似文献
20.
《中国化学快报》2023,34(2):107360
Screening of foodborne pathogens is important to prevent contaminated foods from their supply chains. In this study, a portable detection device was developed for rapid, sensitive and simple detection of viable Salmonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide (PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic extraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera and analyzed using a self-developed smartphone App to quantitatively determine the bacterial concentration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 102 CFU/mL to 1.3 × 107 CFU/mL in 2 h with a lower detection limit of 130 CFU/mL, and has shown its potential for on-site detection of foodborne pathogens. 相似文献