Sensitive dual readout assays based on rolling circle amplification for fluorescent and colorimetric detection of Cronobacter spp. in powdered infant formula

Food Control ◽  
2021 ◽  
pp. 107840
Author(s):  
Ju Liu ◽  
Guoyang Xie ◽  
Qin Xiong ◽  
Taobo Liang ◽  
Hengyi Xu
RSC Advances ◽  
2015 ◽  
Vol 5 (35) ◽  
pp. 27571-27575 ◽  
Author(s):  
Dong Liang ◽  
Wei You ◽  
Yang Yu ◽  
Yao Geng ◽  
Feng Lv ◽  
...  

Schematic illustration of a colorimetric biosensor for breast cancer1 gene detection based on DNAzyme assistant DNA recycling and rolling circle amplification.


The Analyst ◽  
2015 ◽  
Vol 140 (13) ◽  
pp. 4515-4520 ◽  
Author(s):  
Chaohui Chen ◽  
Ming Luo ◽  
Tai Ye ◽  
Ningxing Li ◽  
Xinghu Ji ◽  
...  

A sensitive and selective colorimetric biosensor for the detection of protein, which combines gold nanoparticles and rolling circle amplification, is described.


Author(s):  
Mohammed Khalid Al-atrash

The present study was carried out to knowing effect different storage periods of the microbial quality for the Powdered Infant Formula (PIF) after opening the tin, and ensuring from the safety note (after opening, use within 3 weeks). Thirty (30) samples of (PIF) from category (1 – 6 months) in five different types are collected from pharmacies and local markets in Baquba city / Iraq, which are used as substitutes for breast milk during the first day of opening the tin powders such as Total viable count, Total coliform count, Salmonella count and Yeast and Molds count. These experiments repeated at each week of same samples within (5) weeks. Results were obtained at opening the tin, Total viable count (less than 0.05 1.0 x 103 ±1.5x10 CFU/g) were significantly higher than Total Coliform count (less than 0.05 ± 0.3 x 10 CFU/g) and Total Salmonella count (less than 0.05 0 x 10 CFU/g) and Yeasts and Molds (less than 0.05 ± 0.3 x 10 CFU/g). while results obtained at fifth week were (less than 0.05 8.8 x 103 ±5.5x102 CFU/g), (less than 0.05 0.9 x 102 ± 0.4x101 CFU/g), (less than 0.05 0 x 10 CFU/g), (less than 0.05 9.5 x 10 ± 1.2x101 CFU /g) respectively. All samples of (PIF) having non-significant difference. These results compared to Iraqi Quality Standards (IQS), all the results from the opening samples to fifth week were within the range of IQS and USA Environmental Protection Agency (USEPA) and as indicates the hygienic condition of (PIF) without risk level for human health. also observed increase in microbial contamination in each week because increase the moisture content for powdered milk. Can be used more than 3 weeks after opening if stored in good conditions with good hygienic practices during milk preparation.


2017 ◽  
Author(s):  
Bo Tian ◽  
Peter Svedlindh ◽  
Mattias Strömberg ◽  
Erik Wetterskog

In this work, we demonstrate for the first time, a ferromagnetic resonance (FMR) based homogeneous and volumetric biosensor for magnetic label detection. Two different isothermal amplification methods, <i>i.e.</i>, rolling circle amplification (RCA) and loop-mediated isothermal amplification (LAMP) are adopted and combined with a standard electron paramagnetic resonance (EPR) spectrometer for FMR biosensing. For RCA-based FMR biosensor, binding of RCA products of a synthetic Vibrio cholerae target DNA sequence gives rise to the formation of aggregates of magnetic nanoparticles. Immobilization of nanoparticles within the aggregates leads to a decrease of the net anisotropy of the system and a concomitant increase of the resonance field. A limit of detection of 1 pM is obtained with an average coefficient of variation of 0.16%, which is superior to the performance of other reported RCA-based magnetic biosensors. For LAMP-based sensing, a synthetic Zika virus target oligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by their co-precipitation with Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (a by-product of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement, high sensitivity and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate for designing future point-of-care devices.<br>


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