Lab in a Pasteur pipette: low-cost, rapid and visual detection of Bacillus cereu using denaturation bubble-mediated strand exchange amplification

2019 ◽  
Vol 1080 ◽  
pp. 162-169 ◽  
Author(s):  
Shuai Liu ◽  
Manman Wei ◽  
Rui Liu ◽  
Shaoping Kuang ◽  
Chao Shi ◽  
...  
2017 ◽  
Vol 8 (2) ◽  
pp. 1200-1208 ◽  
Author(s):  
Muhit Rana ◽  
Mustafa Balcioglu ◽  
Neil M. Robertson ◽  
Mustafa Salih Hizir ◽  
Sumeyra Yumak ◽  
...  

A single gold nanoprobe can be programmed for low picomolar visual detection of inorganic mercury and/or silver in water, soil or urine samples.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
M. E. Ali ◽  
U. Hashim ◽  
S. Mustafa ◽  
Y. B. Che Man ◽  
Kh. N. Islam

We visually identify pork adulteration in beef and chicken meatball preparations using 20 nm gold nanoparticles (GNPs) as colorimetric sensors. Meatball is a popular food in certain Asian and European countries. Verification of pork adulteration in meatball is necessary to meet the Halal and Kosher food standards. Twenty nm GNPs change color from pinkish-red to gray-purple, and their absorption peak at 525 nm is red-shifted by 30–50 nm in 3 mM phosphate buffer saline (PBS). Adsorption of single-stranded DNA protects the particles against salt-induced aggregation. Mixing and annealing of a 25-nucleotide (nt) single-stranded (ss) DNA probe with denatured DNA of different meatballs differentiated well between perfectly matched and mismatch hybridization at a critical annealing temperature. The probes become available in nonpork DNA containing vials due to mismatches and interact with GNPs to protect them from salt-induced aggregation. Whereas, all the pork containing vials, either in pure and mixed forms, consumed the probes totally by perfect hybridization and turned into grey, indicating aggregation. This is clearly reflected by a well-defined red-shift of the absorption peak and significantly increased absorbance in 550–800 nm regimes. This label-free low-cost assay should find applications in food analysis, genetic screening, and homology studies.


2020 ◽  
Author(s):  
Xiong Ding ◽  
Kun Yin ◽  
Ziyue Li ◽  
Rajesh V. Lalla ◽  
Enrique Ballesteros ◽  
...  

Abstract The recent outbreak of novel Coronavirus (SARS-CoV-2), the causative agent of COVID-19 disease, has spread rapidly all over the world. Human immunodeficiency virus (HIV) is another deadly virus and causes acquired immunodeficiency syndrome (AIDS). Rapid and early detection of these viruses will facilitate early intervention and prevent disease spread. Here, we present an All-In-One Dual CRISPR-Cas12a (termed "AIOD-CRISPR") assay method for simple, rapid, ultrasensitive, specific, one-pot, and visual detection of coronavirus SARS-CoV- 2 and HIV-1 virus. In our AIOD-CRISPR assay, a pair of crRNAs was introduced to initiate dual CRISPR-Cas12a-based detection and improve both detection sensitivity and fluorescence signals. The AIOD-CRISPR assay method was utilized to detect nucleic acids (DNA and RNA) of the SARS-CoV-2 and HIV-1 with a sensitivity of few copies. We validated our AIOD-CRISPR method by using COVID-19 swab samples and obtained consistent results with that of RT-PCR method. More importantly, we successfully demonstrated to use a low- cost hand warmer (~$ 0.3) as an incubator of our AIOD-CRISPR assay and detect COVID-19 patient samples within 20 minutes, enabling an instrument-free, visual detection of COVID-19 at the point of care. Thus, our method has significant potential for developing next-generation point-of-care molecular diagnostics.


2019 ◽  
Vol 11 (45) ◽  
pp. 5826-5832
Author(s):  
Govindaraj Usha ◽  
Ramesh Prakash ◽  
Karuppasamy Karpagalakshmi ◽  
Sundaram Ramalakshmi ◽  
Lakshminarayanan Piramuthu ◽  
...  

A facile and low-cost detection method for the surfactants of ionic and non-ionic types was successfully demonstrated using rhodamine B-decorated graphene oxide, which also helped the visual detection of surfactants under a UV light source.


2018 ◽  
Vol 10 (48) ◽  
pp. 5749-5754 ◽  
Author(s):  
Tao Hu ◽  
Yi Ye ◽  
Ke Chen ◽  
Feifei Long ◽  
Wen Sang ◽  
...  

In this study, we demonstrated a new optical glucose microfluidic sensor based on quantum dots (QDs) aerogels and glucose oxidase (GOx) for rapid, low-cost and quantitative detection of glucose in human urine and serum.


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