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Temperature measurement. a The portable PCR platform. b The IR camera images showing portable heater system powered by lithium batteries. c IR camera images showing the top and the side views of a 3D spiral PVC microreactor placed on a heater band
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A self-contained polymerase chain reaction (PCR) platform with miniaturized power-system is introduced. It is powered by portable lithium batteries and integrated continuous-flow PCR amplification platform. Generally speaking, traditional commercial thermal cyclers rely on external electric supply and thus they are too big in instrument size. This...
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The polymerase chain reaction (PCR) has unique advantages of sensitivity, specificity and rapidity in pathogen detection, which makes it at the forefront of academia and application in molecular biology diagnosis. In this study, we proposed a hand-held real-time fluorescence qPCR system, which can be used for the quantitative analysis of nucleic ac...
Citations
... The major symptoms of infected patients include neurological and respiratory diseases, such as fever, pain in the muscles and tiredness, cough and shortness of breath [25,26,27]. Unfortunately, these symptoms are not specific for the diagnosis of the infection [28]. ...
... Generally, traditional PCR instruments are practical obstacles for wide use in POCT scenarios due to the reason that they are more expensive and bigger in size [28]. They rely heavily on external electric powers to realize quick increase or decrease of the temperature. ...
... Shi et al. reported a miniaturized, portable and battery-powered heater with functions of thermo-cycled control and passive continuous-flow control as the platform for PCR reactions (Figure 3b). Integrated with a 3D microreactor, the system can be used for multiplexed detection of clinical-level DNA targets with more convenience [28]. Microfluidic systems are also well suited for highly automated processes. ...
Corona Virus Disease 2019 (COVID-19) has developed into a global pandemic in the last two years, causing significant impacts on our daily life in many countries. Rapid and accurate detection of COVID-19 is of great importance to both treatments and pandemic management. Till now, a variety of point-of-care testing (POCT) approaches devices, including nucleic acid-based test and immunological detection, have been developed and some of them has been rapidly ruled out for clinical diagnosis of COVID-19 due to the requirement of mass testing. In this review, we provide a summary and commentary on the methods and biomedical devices innovated or renovated for the quick and early diagnosis of COVID-19. In particular, some of micro and nano devices with miniaturized structures, showing outstanding analytical performances such as ultra-sensitivity, rapidness, accuracy and low cost, are discussed in this paper. We also provide our insights on the further implementation of biomedical devices using advanced micro and nano technologies to meet the demand of point-of-care diagnosis and home testing to facilitate pandemic management. In general, our paper provides a comprehensive overview of the latest advances on the POCT device for diagnosis of COVID-19, which may provide insightful knowledge for researcher to further develop novel diagnostic technologies for rapid and on-site detection of pathogens including SARS-CoV-2.
... Several genetic studies with a quantitative diagnostic focus on the polymerase chain reaction (PCR) technique have amplified trace amounts of DNA through repeated thermal cycling of the sample [1][2][3][4][5][6]. The PCR thermal cycling process is composed of three constant-temperature steps (denaturation, annealing, and extension) at the completion of which millions of target DNA copies are generated [1,4,7]. ...
... A microfluidic PCR device with a continuous-flow system increases portability and analysis response while reducing fabrication and operation costs [1,4,8,10]. However, this PCR system requires several miniaturized elements, such as pumping systems [6,12]. The major drawback of microfluidic PCR is air bubble formation, especially in the denaturation zone, due to the evaporation of the small volume of reagent [5,6,10,13]. ...
... However, this PCR system requires several miniaturized elements, such as pumping systems [6,12]. The major drawback of microfluidic PCR is air bubble formation, especially in the denaturation zone, due to the evaporation of the small volume of reagent [5,6,10,13]. Microfluidic channel design and fabrication over the substrate are essential to avoid such bubble formation [5,6,10,12]. ...
A microfluidic device based on the polymerase chain reaction (PCR) technique for genetic diagnostics was designed and fabricated. The continuous-flow microfluidic PCR system was integrated with two heating blocks to increase the temperature in each zone (denaturation, annealing, and extension). To maintain a constant temperature, heat transfer was controlled by a temperature controller system while receiving real-time feedback of a thermocouple attached to the microchannel. The DNA amplification was evaluated by fluorescence imaging through agarose gel electrophoresis. The developed continuous-flow microfluidic PCR chip provides reliable amplification of the target DNA with a real-time system controller while maintaining the temperature.
... As they are usually expensive, only large hospitals or laboratories can afford them. However, nowadays it is very important to quickly and accurately diagnose viruses for infectious diseases, requiring a PCR device capable of point-of-care test (POCT) [1,2]. For POCT devices, miniaturization and cost reduction are essential, which is what most PCR chips aim for [1][2][3][4]. ...
... However, nowadays it is very important to quickly and accurately diagnose viruses for infectious diseases, requiring a PCR device capable of point-of-care test (POCT) [1,2]. For POCT devices, miniaturization and cost reduction are essential, which is what most PCR chips aim for [1][2][3][4]. ...
This paper proposes a cost-effective real-time multiplexed polymerase chain reaction (PCR) chip system for point-of-care (POC) testing. In the proposed system, nucleic acid amplification is performed in a reaction chamber built on a printed-circuit-board (PCB) substrate with a PCB pattern heater and a thermistor. Fluorescence can be detected through the transparent plastic on the other side of the substrate. Open platform cameras were used for miniaturization and cost-effectiveness. We also used simple and cost-effective oblique lighting to stimulate fluorescence. Response performance was investigated by observing the change in the average brightness of the chamber images with various reference dye concentrations. In addition, we investigated the interference properties between different colors by measuring the fluorescence response for each dye concentration mixed with the maximum concentration of the different dyes. Quantitative performance was validated using standard DNA solutions. Experimental results show that the proposed system is suitable for POC real-time multi-PCR systems.
... In recent years, it is more and more important to use PCR technology to realize POCT application in outfield, such as disaster rescue [14]- [16], quarantine [10], [17] and plant disease monitoring [18], [19]. Our team has recently successfully developed a portable PCR platform with low energy consumption, light weight and small size, which can be applied to the accurate analysis of a variety of nucleic acids, to achieve the characteristics of small-scale portability, simple operation, and instant report [20]. However, the sample used in the analysis is not the intact bacteria obtained from field sampling, but the sample after DNA extraction. ...
Polymerase chain reaction (PCR) technology is an essential technology for point-of-care testing (POCT) application. To realize the simple, portable and fast detection of bacteria has always been an important technology. In this paper, we developed a pipeline-based oil-bath PCR method, to achieve the PCR amplification and detection for bacteria. We assembled a small-sized system with a uniform temperature environment and a stable heating module. By comparing the PCR performance with the other two existing pipeline-based methods on the reactions of both DNA fragment of H7N9 avian influenza and Escherichia Coli, the results show that the pipeline-based oil-bath PCR method is fully capable of the amplification and detection of both DNA fragment and bacteria. At the meanwhile, we performed two sets of tests, the experiment of pipeline diameter change and bacterial concentration gradient, to verify the sensitivity and universality of this method. The results show that the pipeline-based oil-bath PCR method developed by us not only gets rid of the complicated preparations, offers advantages of simple operation, low-cost and user-friendly, but also provides a stable and portable foundation for our later work.
... Polymerase chain reaction requires a denaturation temperature of 95 • C to uncoil the double-stranded DNA, which is very close to the boiling point of water. This causes bubbles to form in the microfluidic chips and the reaction to fail [25,26]. It is the main problem to be solved by microfluidic engineers. ...
Real-time polymerase chain reaction (PCR) is the standard for nucleic acid detection and plays an important role in many fields. A new chip design is proposed in this study to avoid the use of expensive instruments for hydrophobic treatment of the surface, and a new injection method solves the issue of bubbles formed during the temperature cycle. We built a battery-powered real-time PCR device to follow polymerase chain reaction using fluorescence detection and developed an independently designed electromechanical control system and a fluorescence analysis software to control the temperature cycle, the photoelectric detection coupling, and the automatic analysis of the experimental data. The microchips and the temperature cycling system cost USD 100. All the elements of the device are available through open access, and there are no technical barriers. The simple structure and manipulation allows beginners to build instruments and perform PCR tests after only a short tutorial. The device is used for analysis of the amplification curve and the melting curve of multiple target genes to demonstrate that our instrument has the same accuracy and stability as a commercial instrument.
... They developed a double-stereo PCR microfluidic chip, which allowed the PCR reagents to flow from the 54°C region directly to the 95°C region to begin the next cycle, increasing PCR amplification efficiency. Shi et al. [76] developed a self-contained polymerase chain reaction (PCR) platform for thermo-cycled amplifications of multiplexed DNA targets. This platform was powered by portable lithium batteries that allowing real-time and field testing during PCR diagnosis. ...
Lab-on-a-chip has evolved into a powerful analytical tool that combines multiple disciplines for biomedical research. The microfluidic reactor in lab-on-a-chip is regarded as a critical functional device and has a direct impact on the performance of the entire lab-on-a-chip system. The rich and flexible design allows the microfluidic reactor to be used for reactions in a micromixing channel or inside the common microchannel/chamber at a microscale. Moreover, a variety of microfluidic reactors could be utilized in the field of biomedical analysis with a high reaction rate and less reagent consumption. This paper reviewed the delicate design principle of microfluidic reactors (mixing and ordinary reactors). The biomedical applications of mixing reactor (reaction kinetics research and preparation of nanoparticle drug carriers) and the mature applications of other types of microreactor (on-chip polymerase chain reaction, enzyme-linked immunosorbent assay, and nucleic acid hybridization) were introduced in detail. Commonly utilized detection technologies (laser-induced fluorescence, light absorption measurement, and electrochemical) and low-cost on-chip detection strategies were summarized in detail. This review may shed light on the design and application of microfluidic reactor in the biomedical area.
The lack of portability and high cost of multiplex real-time PCR systems limits the device to be used in POC. To overcome this issue, this paper proposes a compact and cost-effective fluorescence detection system that can be integrated to a multiplex real-time PCR equipment. An open platform camera with embedded lens was used instead of photodiodes or an industrial camera. A compact filter wheel using a sliding tape is integrated, and the excitation LEDs are fixed at a 45° angle near the PCR chip, eliminating the need of additional filter wheels. The results show precise positioning of the filter wheel with an error less than 20 μm. Fluorescence detection results using a reference dye and standard DNA amplification showed comparable performance to that of the photodiode system.
This paper proposes a cloud-based software architecture for fully automated point-of-care molecular diagnostic devices. The target system operates a cartridge consisting of an extraction body for DNA extraction and a PCR chip for amplification and fluorescence detection. To facilitate control and monitoring via the cloud, a socket server was employed for fundamental molecular diagnostic functions such as DNA extraction, amplification, and fluorescence detection. The user interface for experimental control and monitoring was constructed with the RESTful application programming interface, allowing access from the terminal device, edge, and cloud. Furthermore, it can also be accessed through any web-based user interface on smart computing devices such as smart phones or tablets. An emulator with the proposed software architecture was fabricated to validate successful operation.
High efficient and stable droplets preparation is an essential technology in digital PCR (dPCR) and other analytical fields. In this paper, a microfluidic device called vertical step emulsification (VSE) device to produce emulsion droplets rapidly off‐chip is developed. VSE device prepares droplets by perfluoroalkoxy (PFA) capillary and microcentrifuge tube, when the continuous water phase in PFA capillary jets into the static oil phase in the microcentrifuge tube at a certain speed, the continuous water phase is emulsified into stable droplets due to the sudden change of surface tension. In order to control the droplet size accurately, a general screw mechanism to control the gap between the PFA capillary outlet and the bottom of the inner wall of microcentrifuge tube is used. Meanwhile, dPCR tests with high dynamic range throughput droplets from VSE device are performed. The results show that the off‐chip droplet preparation device developed by the authors not only gets rid of the complicated control structure, has the advantages of low cost, easy operation, and user‐friendly, but also provides a sustainable development scheme for the preparation of high‐throughput and stable droplets in a short time. In this paper, an off‐chip droplets preparation device based on step emulsification can be applied on droplet digital polymer chain reaction, in which step height and nozzles size can be freely adjusted, the droplet diameter is in the range of 30–120 µm, and the coefficient of variation is less than 5%.
The polymerase chain reaction (PCR) has unique advantages of sensitivity, specificity and rapidity in pathogen detection, which makes it at the forefront of academia and application in molecular biology diagnosis. In this study, we proposed a hand-held real-time fluorescence qPCR system, which can be used for the quantitative analysis of nucleic acid molecules. For the first time, we use a PVC microreactor which improved the transmittance of the microreactor and the ease to collect the fluorescence signal. In order to make it portable, the system adopted the passive syringe for sample injection and integrated temperature control and detection with a lithium battery for power supply. What’s more, the fluorescence signal was captured by a smartphone through an external automatic robotic arm. This real-time qPCR system can detect genomic DNA of the H7N9 avian influenza with over four orders of magnitude concentration from 107 to 104 copies per μL. In addition, it verified that the fluorescence images obtained by this system were clearer than those obtained by traditional system (using PTFE spatial PCR microreactor) with two typical dyes and a probe tested——EvaGreen, SYBR Green and FAM.
