- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Novel DRAQ5?/SYTOX? Blue Based Flow Cytometric Strategy to Identify and Characterize Stem Cells in Human Breast Milk
摘要： Human breast milk could be an important stem cell source for the development of newborn and preterm infants, but quantitative data on the stem cell content in breast milk at various gestational stages are needed to determine the clinical value of breast milk as a source of stem cells. Breast milk also contains milk fat globules, lipid droplets of different sizes, debris and dead cells and these components hamper flow cytometry analysis of human breast milk samples. Here, we originally used standard protocols for flow cytometry to characterize cell populations in human breast milk but failed to discriminate between cells and noncellular components. We then applied a centrifugation protocol to separate cream and skim milk from the cell-containing pellet and used a novel staining protocol with DRAQ5? and SYTOX? blue dye as well as antibodies to characterize cells within the pellet fraction. Flow cytometry analysis identified viable DRAQ5?+/SYTOX? Blue? cells and determined the content of CD11b+ monocytes and TRA-1-81+ putative stem cells in human breast milk samples. Hence, we developed a novel and reliable flow cytometry based-approach to quantify subpopulation of cells in human breast milk with a high content of milk fat globules, lipid droplets, and particles. This approach will improve the identification and quantification of breast milk cells and allow standardizing the flow cytometry-based evaluation of the stem cell content.
关键词： Nile red,viability,DRAQ5,flow cytometry,TRA-1-81,CD11b,SYTOX blue,human breast milk cells
更新于2025-09-10 09:29:36
-
A surface-enhanced Raman scattering-based lateral flow immunosensor for colistin in raw milk
摘要： A surface-enhanced Raman scattering (SERS)-based lateral flow immunosensor was created to identify colistin in milk. The Raman reporter 5,5-dithiobis-2-nitrobenzoic acid (DTNB) was used to label gold nanoparticles, and then anti-colistin monoclonal antibody (mAb) was attached. The size of the gold nanoparticles in the SERS nanoprobe was optimized, and the amount of DTNB and mAb, the change in hydrodynamic size, zeta potential, and the surface plasmon resonance band were also monitored in the preparation process. The SERS nanoprobe was then applied to a lateral flow strip followed by Raman signal readout for the quantitative determination of colistin with high sensitivity. The limits of detection of this assay were 0.10 ng/mL for colistin in milk, which was far below the previously reported value that was obtained with the ELISA method and the maximum residue limit set by the European Union. The spiking experiment showed high accuracy for this SERS-based immunosensing assay, with a recovery of 88.1% to 112.7% and satisfactory assay precision with a standard deviation below 15%. Furthermore, this assay also has the advantage of rapidity, with an assay time less than 20 min. Therefore, these results demonstrate that this SERS-based lateral flow immunosensor is promising for use in the rapid monitoring of colistin in milk.
关键词： Surface enhanced Raman scattering,Immunoassay,Sensor,Milk,Colistin
更新于2025-09-09 09:28:46
-
Paper-Based Fluorescent Immunoassay for Highly Sensitive and Selective Detection of Norfloxacin in Milk at Picogram Level
摘要： Norfloxacin (NOR) in milk may influence mammalian cell replication and bring about a decrease in the efficiency for treating infection in humans. However, current techniques for detecting NOR usually require expensive instruments and trained personnel. In this work, we have developed a low-cost and simple method via paper-based fluorescent immunoassay for highly sensitive and selective detection of NOR in milk at picogram level. The NOR monoclonal antibody labeled with quantum dots is used as a detection probe to recognize the corresponding NOR, which can quantitatively detect NOR on paper-based devices. The detection limits in aqueous solution and milk are 1 pg/mL and 10 pg/mL, respectively. The developed paper-based method provides a cheap, sensitive, eco-friendly, and rapid approach for quantitative detection of trace NOR in milk, which may find wide applications in food safety inspection. Noteworthy, the method is especially suitable for applications at resource-limited and on-site settings.
关键词： Fluorescent immunoassay,Paper-based devices,Quantum dots,Norfloxacin,Milk
更新于2025-09-09 09:28:46
-
Rapid immunofluorescence assay for staphylococcal enterotoxin A using magnetic nanoparticles
摘要： A competitive immunoassay for staphylococcal enterotoxin A (SEA) detection in milk was developed, using immobilised antibody onto magnetic nanoparticles (MNPs). MNPs were prepared and then modified to introduce amino groups on them. The morphology and size of the obtained both unmodified and modified MNPs were characterized using TEM analyses. Monoclonal anti-SEA antibody was immobilised onto the modified MNPs (MNP-Ab). Staphylococcal enterotoxin A was conjugated with fluorescent dye ATTO620NHS. The characteristics of fluorescence conjugate were examined. The amount of MNP-Ab and concentration of the fluorescent conjugate used for competitive immunoassay were optimized: 0.25 mg and 53 lg mL(cid:1)1, respectively. The detection limit of developed immunoassay was determined – 0.23 ng mL(cid:1)1 SEA in spiked milk samples. The immunoassay takes only 30 min, the magnetic separation is fast (<10 s) and the volume of the sample for analysis is very small (200 lL).
关键词： fluorescent conjugate,staphylococcal enterotoxin,milk,Antibody immobilisation,magnetic nanoparticles,immunofluorescence
更新于2025-09-09 09:28:46
-
Fluorescence-based analyser as a rapid tool for determining soluble protein content in dairy ingredients and infant milk formula
摘要： Milk protein, in particular native whey protein, is of interest to dairy manufacturers as a measure of functional and nutritional quality. However, quantification of soluble whey protein (SP) is time consuming; giving rise to the need to develop rapid, accurate, and portable at-line process analytical technology. In this study, the performance of a fluorescence-based analyser(F) (Amaltheys II, Spectralys Innovations, France) was evaluated for quantification of SPF and whey protein nitrogen index (WPNI)F in skim milk, whey protein concentrate and infant formula powders. Rehydration of powders prior to analysis was a key factor for ensuring repeatability and reproducibility. A comparison of the analyser with reference methods for SPF and WPNIF resulted in coefficient of determination (R2) > 0.993 for both SPKjeldahl method and WPNIGEA. The results show the fluorescence-based analyser to be rapid, compact, and accurate device, suited for providing reliable support to dairy ingredient and infant formula manufacturers.
关键词： Infant milk formula,Process analytical technology,Dairy ingredients,Whey protein nitrogen index,Soluble protein,fluorescence-based analyser
更新于2025-09-09 09:28:46
-
Investigation and Performance analysis of Solar Milk Pasteurisation system
摘要： The main aim of this research work is to test and evaluate the performance of solar milk pasteurisation system. To evaluate the performance of solar milk pasteurisation system, a solar hot water system, concentric tube type heat exchanger, the cooling tank has used. To test the solar milk pasteurisation system, three different mass flow rate of hot water like 2 litres/minute, 3 litres/minute and 5 litres/minute and cold milk 0.5 litres/minute, 0.7 litres/minute and 1.0 litre/minute have been used. After the pasteurisation, the obtained milk from the concentric tube type heat exchanger has been tested in the laboratory and achieved satisfactory results. From the series of experiments, it has been found that the hot water flow rate of 5 litres/minute and milk flow rate of 0.5 litres/minute found the optimum for the pasteurisation system.
关键词： concentric tube heat exchanger,Solar Pasteurization,Flat plate collector,Pasteurisation,Milk
更新于2025-09-04 15:30:14
-
Target-switched triplex nanotweezer and synergic fluorophore translocation for highly selective melamine assay
摘要： This paper describes a triplex DNA nanotweezer to specifically capture melamine (MEL). The triplex-forming oligonucleotide (TFO) arm can be switched from the open state to the closed state once MEL binds to the abasic site (AP site) in duplex via the bifacial hydrogen bonding with thymines. Following this nanotweezer operation, the AP site-bound fluorophore is translocated to the terminal triplet to subsequently light up the nanotweezer. The TFO arm is found to be pivotal for permitting the AP site binding. The synergic processes of target competition and fluorophore translocation support a high selectivity for the MEL assay even against the inherent adenosine and the MEL hydrolysis products. Chelerythrine is employed as the fluorescent probe. The detection limit of MEL was estimated to be about 140 nM assuming a signal-to-noise ratio of 3. It was applied to the determination of MEL in spiked milk samples without any separation procedure. Conceivably, this method opens a new avenue towards highly selective triplex-based sensors by making use of other commercially available DNA modifications for recognizing other analytes.
关键词： Milk,Chelerythrine,Switch,Fluorescence,Hydrogen bonding,DNA,Fluorometry,Abasic site
更新于2025-09-04 15:30:14
-
A novel on-chip solution enabling rapid analysis of melamine and chloramphenicol in milk by smartphones
摘要： Ubiquitous food security control is desirable. However, the analysis methods, such as those for milk, are highly based on manual analysis, leading to low efficiency. Thus, we report a multilayer paper-based microfluidic chip transforming chromatic readout to electric signals. First, colloidal gold immunochromatographic assays (GICA) are used to achieve the colorimetric occurrence. Secondly, the test (T) lines and control (C) lines are patterned to encode different EAN-8 barcode. Furthermore, accurate scanning is accomplished by the automatic threshold segmentation. These technologies make the digital determination of melamine (MEL) and chloramphenicol (CAP) by phone readily accessible. Results indicate that the accurate machine-scanning can be assured when MEL and CAP is above 30 ng/mL and 6 ng/mL in milk respectively. The detection time is under 8 min, and the stable storage life is over 90 days. Therefore, this simple chip allows rapid, machine-readable, electric-recordable diagnostic directly from chromatic assays with satisfying stability, specificity and accuracy.
关键词： rapid analysis,smartphone,milk,melamine,on-chip solution,chloramphenicol
更新于2025-09-04 15:30:14