scholarly journals Pre-Degassed Microfluidic Chamber-Based Digital PCR Device for Meat Authentication Applications

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 694
Author(s):  
Hezhi Hu ◽  
Jingmeng Cheng ◽  
Chunyang Wei ◽  
Shanshan Li ◽  
Chengzhuang Yu ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Dna Amplification ◽  
Digital Pcr ◽  
Copy Numbers ◽  
Microfluidic Chamber ◽  
Skilled Personnel ◽  
Amplification Process ◽  
Dna Template ◽  
Pilot Channel ◽  
Digital Polymerase Chain Reaction

Droplet digital polymerase chain reaction (ddPCR) suffers from the need for specific equipment and skilled personnel; thus, we here present a chamber-based digital PCR microfluidic device that is compatible with fluorescence image read-out systems and removes bubbles by a pre-degassed microfluidic device that consists of a pilot channel and micro chamber arrays. Digitalized PCR reagents are introduced into micro chambers, and thermocycles are taken to perform a DNA amplification process. Then, fluorescence images of a micro chamber array are read out and analyzed to obtain the total number of positive chambers. Thereby, the copy numbers of target DNA are calculated for quantitative detections. As a validation, this device is evaluated by the application of meat authentication. We performed dPCR tests using DNA templates extracted from a pure mutton DNA template with different dilutions. Then, the dPCR chip was used to identify the meat authentication using mutton–chicken mixtures with different mass ratios, showing its performance in real biotechnical applications.

scholarly journals A Self-Priming Microfluidic Chip with Cushion Chambers for Easy Digital PCR

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 158
Author(s):  
Gangwei Xu ◽  
Huaqing Si ◽  
Fengxiang Jing ◽  
Peng Sun ◽  
Dongping Wu
Keyword(s):  
Microfluidic Chip ◽  
Low Cost ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Quantitative Detection ◽  
Pdms Layer ◽  
Resource Limited ◽  
Dna Template ◽  
Digital Polymerase Chain Reaction ◽  
Easy Operation

A polydimethylsiloxane (PDMS)-based self-priming microfluidic chip with cushion chambers is presented in this study for robust and easy-operation digital polymerase chain reaction (dPCR). The chip has only one inlet and can partition samples autonomously through negative pressure, provided by a de-gassed PDMS layer with a multi-level vertical branching microchannel design. Meanwhile, cushion chambers make the chip capable of very robust use for sample partitioning. Finally, the proposed microfluidic chip showed excellent performance in the absolute quantification of a target gene by performing quantitative detection of a 10-fold serial dilution DNA template. Owing to its characteristics of easy operation, low cost, and high robustness, the proposed dPCR chip is expected to further promote the extensive application of digital PCR, especially in resource-limited settings.

scholarly journals Droplet Digital PCR (ddPCR) Analysis for the Detection and Quantification of Cow DNA in Buffalo Mozzarella Cheese

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1270
Author(s):  
Anna Cutarelli ◽  
Andrea Fulgione ◽  
Pasquale Fraulo ◽  
Francesco Paolo Serpe ◽  
Pasquale Gallo ◽  
...  
Keyword(s):  
Digital Pcr ◽  
Buffalo Milk ◽  
Cow Milk ◽  
Mozzarella Cheese ◽  
Chain Reaction ◽  
New Methods ◽  
Protected Designation Of Origin ◽  
Commission Regulation ◽  
Polymerase Chain ◽  
Digital Polymerase Chain Reaction

Buffalo mozzarella cheese is one of the most appreciated traditional Italian products and it is certified as a Protected Designation of Origin (PDO) product under the European Commission Regulation No. 1151/2012. It is obtained exclusively from buffalo milk. If made from cow milk, or a mixture of buffalo and cow milk, buffalo mozzarella cheese does not qualify as a PDO product. In order to maximize their profits, some producers market buffalo mozzarella that also contains cow milk as a PDO product, thus defrauding consumers. New methods for revealing this fraud are therefore needed. One such method is the droplet digital Polymerase Chain Reaction (ddPCR). Thanks to its high precision and sensitivity, the ddPCR could prove an efficacious means for detecting the presence of cow milk in buffalo mozzarella cheese that is marketed as a PDO product. ddPCR has proved able to detect the DNA of cow and/or buffalo milk in 33 buffalo mozzarella cheeses labelled as PDO products, and experimental evidence could support its application in routine analyses.

Abstract P613: Absolute Gene Quantification Of Intrarenal Renin-angiotensin System Components Using Droplet Digital PCR Analysis

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Ryousuke Satou ◽  
Akemi Katsurada ◽  
Kayoko Miyata ◽  
Andrei Derbenev ◽  
Andrea Zsombok
Keyword(s):  
Copy Number ◽  
System Analysis ◽  
Renin Angiotensin System ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Gene Copy ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Copy Numbers ◽  
Intrarenal Ras

The intrarenal renin-angiotensin system (RAS) has been shown to play crucial roles in the development of hypertension and RAS associated kidney injury including diabetic nephropathy. Although some circulating RAS components are filtered into kidneys and contribute to the regulation of intrarenal RAS activity, evaluating expression levels of RAS components in the kidney is important to elucidate the mechanisms underlying intrarenal RAS activation. Digital PCR is a new technique that has been established to quantify absolute target gene levels, which allows for comparisons of different gene levels. Thus, this study was performed to establish profiles of absolute gene copy numbers for intrarenal RAS components in wild-type (WT) rats, WT and streptozotocin (STZ)-induced diabetic mice. Male Sprague-Dawley rats (N=5) and male C57BL/6J mice were used in this study. The mice were subjected to either control (N=5) or STZ (200 mg/kg, N=4) injection. Seven days after STZ injection, copy numbers of renal cortical angiotensinogen (AGT), angiotensin-converting enzyme (ACE), ACE2, angiotensin type 1 receptor a (AT1a), and AT2 mRNA were determined by a droplet digital PCR. Since (pro)renin proteins produced by juxtaglomerular cells are secreted to circulating system, analysis of renin mRNA was excluded from this evaluation. In the renal cortex of WT rats, the copy number of AGT was higher than other measured RAS components (AGT: 719.2±46.6, ACE: 116.0±14.9, ACE2: 183.6±21.5, AT1a: 196.0±25.2 copies in 1 ng total RNA). AT2 levels were lower than other components (0.068±0.01 copies). In WT mice, ACE exhibited the highest copy number in the components (AGT: 447.2±29.0, ACE: 1662.4±61.2, ACE2: 676.8±41.5, AT1a: 867.0±16.8, AT2: 0.049±0.01 copies). Although STZ-induced diabetes did not change ACE2 and AT1a, ACE levels were reduced (765.5±98.1 copies) and AT2 levels were augmented (0.10±0.01 copies) as previously demonstrated. Accordingly, the absolute quantification by digital PCR established precise gene profiles of intrarenal RAS components, which will provide rationales for targeting the each component in future studies. Furthermore, the results indicate that the high sensitive assay accurately quantifies rare target genes including intrarenal AT2.

scholarly journals Copy Number and Prevalence of Porcine Endogenous Retroviruses (PERVs) in German Wild Boars

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 419
Author(s):  
Luise Krüger ◽  
Milena Stillfried ◽  
Carolin Prinz ◽  
Vanessa Schröder ◽  
Lena Katharina Neubert ◽  
...  
Keyword(s):  
Wild Boar ◽  
Copy Number ◽  
Digital Pcr ◽  
Endogenous Retroviruses ◽  
Wild Boars ◽  
Domestic Pigs ◽  
Copy Numbers ◽  
Cellular Genes ◽  
Porcine Endogenous Retroviruses ◽  
Different Populations

Porcine endogenous retroviruses (PERVs) are integrated in the genome of pigs and are transmitted like cellular genes from parents to the offspring. Whereas PERV-A and PERV-B are present in all pigs, PERV-C was found to be in many, but not all pigs. When PERV-C is present, recombination with PERV-A may happen and the PERV-A/C recombinants are characterized by a high replication rate. Until now, nothing has been known about the copy number of PERVs in wild boars and little is known about the prevalence of the phylogenetically youngest PERV-C in ancient wild boars. Here we investigated for the first time the copy number of PERVs in different populations of wild boars in and around Berlin using droplet digital PCR. Copy numbers between 3 and 69 per genome have been measured. A lower number but a higher variability was found compared to domestic pigs, including minipigs reported earlier (Fiebig et al., Xenotransplantation, 2018). The wild boar populations differed genetically and had been isolated during the existence of the Berlin wall. Despite this, the variations in copy number were larger in a single population compared to the differences between the populations. PERV-C was found in all 92 analyzed animals. Differences in the copy number of PERV in different organs of a single wild boar indicate that PERVs are also active in wild boars, replicating and infecting new cells as has been shown in domestic pigs.

scholarly journals Covalent chemistry on nanostructured substrates enables noninvasive quantification of gene rearrangements in circulating tumor cells

2019 ◽  
Vol 5 (7) ◽  
pp. eaav9186 ◽  
Author(s):  
Jiantong Dong ◽  
Yu Jen Jan ◽  
Ju Cheng ◽  
Ryan Y. Zhang ◽  
Meng Meng ◽  
...  
Keyword(s):  
Disease Progression ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Chain Reaction ◽  
Biopsy Specimens ◽  
Copy Numbers ◽  
Polymerase Chain ◽  
Treatment Responses ◽  
Rapid Purification ◽  
Digital Polymerase Chain Reaction

Well-preserved mRNA in circulating tumor cells (CTCs) offers an ideal material for conducting molecular profiling of tumors, thereby providing a noninvasive diagnostic solution for guiding treatment intervention and monitoring disease progression. However, it is technically challenging to purify CTCs while retaining high-quality mRNA.Here, we demonstrate a covalent chemistry–based nanostructured silicon substrate (“Click Chip”) for CTC purification that leverages bioorthogonal ligation–mediated CTC capture and disulfide cleavage–driven CTC release. This platform is ideal for CTC mRNA assays because of its efficient, specific, and rapid purification of pooled CTCs, enabling downstream molecular quantification using reverse transcription Droplet Digital polymerase chain reaction. Rearrangements of ALK/ROS1 were quantified using CTC mRNA and matched with those identified in biopsy specimens from 12 patients with late-stage non–small cell lung cancer. Moreover, CTC counts and copy numbers of ALK/ROS1 rearrangements could be used together for evaluating treatment responses and disease progression.

scholarly journals Clarity Plus™ digital PCR: A novel platform for absolute quantification of SARS-CoV-2

2021 ◽  
Author(s):  
Shawn Yi Han Tan ◽  
Milton Sheng Yi Kwek ◽  
Huiyu Low ◽  
Yan Ling Joy Pang
Keyword(s):  
Dynamic Range ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Viral Loads ◽  
Nucleic Acid Analysis ◽  
Polymerase Chain ◽  
The Absolute ◽  
Assay Precision ◽  
Digital Polymerase Chain Reaction ◽  
Higher Sensitivity

In recent years, the usage of digital polymerase chain reaction (dPCR) for various clinical applications has increased exponentially. Considering the growing demand for improved dPCR technology, the Clarity Plus™ dPCR system which features enhanced multiplexing capability and a wider dynamic range for nucleic acid analysis was recently launched. In this study, a dPCR assay optimized for use on Clarity Plus™ was evaluated for the absolute quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent responsible for the global coronavirus disease 2019 (COVID-19) outbreak. The assay demonstrated good inter- and intra- assay precision, accuracy, as well as excellent linearity across a range of over 6 orders of magnitude for target gene quantification. In addition, comparison of the assay on both dPCR and qPCR platforms revealed that dPCR exhibited a slightly higher sensitivity compared to its qPCR counterpart when quantifying SARS-CoV-2 at a lower concentration. Overall, the results showed that the dPCR assay is a reliable and effective approach for the absolute quantification of SARS-CoV-2 and can potentially be adopted as a molecular tool in applications such as detecting low viral loads in patients as well as in wastewater surveillance of COVID-19.

scholarly journals First Characterization of a Biphasic, Switch-like DNA Amplification

2017 ◽  
Author(s):  
Burcu Özay ◽  
Cara M Robertus ◽  
Jackson L Negri ◽  
Stephanie E McCalla
Keyword(s):  
Dna Amplification ◽  
High Gain ◽  
Clinical Diagnostics ◽  
Second Phase ◽  
Binding Domains ◽  
Trigger Loop ◽  
Reaction Acceleration ◽  
Biphasic Reaction ◽  
Dna Template ◽  
Amplification Reaction

ABSTRACTWe report the first DNA amplification chemistry with switch-like characteristics: the chemistry is biphasic, with an expected initial phase followed by an unprecedented high gain burst of product oligonucleotide in a second phase. The first and second phases are separated by a temporary plateau, with the second phase producing 10 to 100 times more product than the first. The reaction is initiated when an oligonucleotide binds and opens a palindromic looped DNA template with two binding domains. Upon loop opening, the oligonucleotide trigger is rapidly amplified through cyclic extension and nicking of the bound trigger. Loop opening and DNA association drive the amplification reaction, such that reaction acceleration in the second phase is correlated with DNA association thermodynamics. Without a palindromic sequence, the chemistry resembles the exponential amplification reaction (EXPAR). EXPAR terminates at the initial plateau, revealing a previously unknown phenomenon that causes early reaction cessation in this popular oligonucleotide amplification reaction. Here we present two distinct types of this biphasic reaction chemistry and propose dominant reaction pathways for each type based on thermodynamic arguments. These reactions create an endogenous switch-like output that reacts to approximately 1pM oligonucleotide trigger. The chemistry is isothermal and can be adapted to respond to a broad range of input target molecules such as proteins, genomic bacterial DNA, viral DNA, and microRNA. This rapid DNA amplification reaction could potentially impact a variety of disciplines such as synthetic biology, biosensors, DNA computing, and clinical diagnostics.

scholarly journals Komparasi Metode Isolasi DNA Patogen Antraknosa dan Bulai untuk Deteksi PCR

2016 ◽  
Vol 12 (4) ◽  
pp. 124
Author(s):  
Ade Syahputra ◽  
Kikin Hamzah Mutaqin ◽  
Tri Asmira Damayanti
Keyword(s):  
Pure Culture ◽  
Dna Isolation ◽  
Total Yield ◽  
Dna Amplification ◽  
Colletotrichum Acutatum ◽  
Isolation Method ◽  
Peronosclerospora Sorghi ◽  
Dna Purity ◽  
Dna Template ◽  
Commercial Kit

Polymerase chain reaction (PCR) is an important tool for detection, identification and monitoring of quarantine pests in Indonesia. DNA isolation method from target organism is an important step to provide adequate DNA template for performing PCR. Objective of the research was to compare conventional, commercial kit, FTA-card and its modification methods of DNA isolation to be used in PCR detection for Colletotrichum acutatum and Peronosclerospora sorghi from chili and maize, respectively. DNA obtained from various isolation methods were measured using UV-vis nanodrop-spectrophotometry.  DNA amplification was performed using DNA concentration of 15 ng µL-1 from each isolation method with gradual primer concentrations of 0.4; 0.6; 0.8; and 1.0 mM. The highest concentration of DNA was achieved with conventional methods for C. acutatum from pure culture and P. sorghi from maize leaf. Best DNA purity was obtained from isolation method using commercial kit for C. acutatum from infected fruit (1.94) and from conventional method for C. acutatum from pure culture (1.91). The highest total yield of isolated DNA was achieved by modified FTA-card for C. acutatum from pure culture. In general DNA amplification using various primer concentration gave positive results although DNA bands intensity was varied from faint to very bright.  Furthermore PCR optimization using the best primer concentration from previous reaction showed that all DNA templates resulted in thick and bright DNA bands.

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