This research introduces a homemade high throughput surface plasmon resonance imaging electrochemical system which can detect more than 50 spots simultaneously. The SPRI system was constructed in the Kretschmann configuration and the SPR sensor chip served as the working electrode in the EC module. K3Fe(CN)6 solution were tested by the cyclic voltammetry (CV) method and the SPRI method recording more than 50 spot signals simultaneously. The multiple sensing spots were unanimous due to the ununiformity of incident light and sensor surface. In order to eliminate ununiformity of different spots, glycerol gradient solution was tested, and a calibration and normalization method was applied.
The survival rate of lung cancer can be significantly improved by monitoring biomarkers in exhaled air that indicate diseases in early stage, so it is very important to develop micro analytical systems which can offer a fast, on-site, real-time detecting biomarkers in exhaled air. In this paper, a mini-gas chromatography (GC)-photo-ionization detector (PID) system integrated with a micro GC column and a micro pre-concentrator was developed for forming an inexpensive, fast, and non-invasive diagnostic tool for lung cancer. This system has very strong concentrate ability owing to its integrated micro pre-concentrator, which make the detection of trace components in exhaled air very easy. In addition, the integrated micro GC column can separate complex mixtures, which overcome low resolution and poor anti-interference ability of other instruments. The results indicated that the mini-GC-PID system can effectively separate and detect the biomarkers at parts-per-billion (ppb) level.
Polymerase chain reaction (PCR) is the gold standard for nucleic acid amplification in molecular diagnostics. The PCR includes multiple reaction stages (denaturation, annealing, and extension), and a complicated thermalcycler is required to repetitively provide different temperatures for different stages for 30-40 cycles within at least 1-2 hours. Due to the complicated devices and the long amplification time, it is difficult to adopt conventional PCR in point-of-care testing (POCT). Comparing to conventional PCR, isothermal amplification is able to provide a much faster and more convenient nucleic acid detection because of highly efficient amplification at a constant reaction temperature provided by a simple heating device. When isothermal amplification is combined with microfluidics, a more competent platform for POCT can be established. For example, various diagnosis devices based on isothermal amplification have been used to rapidly and conveniently detect SARS-CoV-2 viruses. This review summarized the recent development and applications of the microfluidics-based isothermal amplification. First, different typical isothermal amplification methods and related detection methods have been introduced. Subsequently, different types of microfluidic systems with isothermal amplification were discussed based on their characteristics, for example, functionality, system structure, flow control, and operation principles. Furthermore, detection of pathogens (e.g. SARS-CoV-2 viruses) based on isothermal amplification was introduced. Finally, the combination of isothermal amplification with other new technologies, e.g. CRISPR, has been introduced as well.
Abstract In this paper, a low-cost multi-parameter surface plasmon resonance (SPR) instrument is designed for the detection of nucleic acids with a functional biosensor. The photodiode array is used as the photodetector of the sensing system, which is cooperated with the linear light source, prism, and mechanical transmission system to form an integrated opto-mechatronic system. An adaptive threshold correction algorithm is proposed to solve the problem of inconsistent responsivity of each pixel of the photodiode array. The sensitivity of the instrument is 6.75×10 -6 refractive index unit, measured with various concentrations of glycerol solution. Multiplex nucleic acid hybridization takes 30 minutes, and the biosensor can be regenerated over 50 times, with low-performance loss and good repeatability and specificity. The instrument has a limit of detection (LODs) of 50nM for target oligonucleotides, and the smallest detectable absolute amount of the sample is about 4 pmol. It provides a simple and efficient POCT detection platform for the detection of small molecules such as DNA and miRNA.
Bioretention cells are an important facility to solve the hydrological and non-point pollution problems in urban areas, especially phosphorus. In this paper, ceramsite composite was made from coal ash and modified by nano-iron through coprecipitation and reduction, which was used to remove the phosphorus in the water. The results of the characteristics of the ceramsite composite using scanning electron microscope showed that the surface of the ceramsite loaded with nano-iron became rougher and the iron nanoparticles were uniformly distributed on the surface, and there was no obvious agglomeration of nano-iron particles. The loading effect was good and the activity of the ceramsite was greatly improved. The results from the static and dynamic continuous experiments indicated that the modified ceramsite with nano-iron had a good removal effect on phosphorus, and the removal rate reached over 99%. The results of this study can provide a new way for the resource utilization of coal ash, and also inspires a new idea for the improvement of filler in bioretention facilities.
Most medical diagnostic tests are expensive, involve slow turnaround times from centralized laboratories and require highly specialized equipment with seasoned technicians to carry out the assay. To facilitate realization of precision medicine at the point of care, we have developed a mixed-scale nanosensor chip featuring high surface area pillar arrays where solid-phase reactions can be performed to detect and identify nucleic acid targets found in diseased patients. Products formed can be identified and detected using a polymer nanofluidic channel. To guide delivery of this platform, we discuss the operation of various components of the device and simulations (COMSOL) used to guide the design by investigating parameters such as pillar array loading, and hydrodynamic and electrokinetic flows. The fabrication of the nanosensor is discussed, which was performed using a silicon (Si) master patterned with a combination of focused ion beam milling and photolithography with deep reactive ion etching. The mixed-scale patterns were transferred into a thermoplastic via thermal nanoimprint lithography, which facilitated fabrication of the nanosensor chip making it appropriate for in vitro diagnostics. The results from COMSOL were experimentally verified for hydrodynamic flow using Rhodamine B as a fluorescent tracer and electrokinetic flow using single fluorescently labelled oligonucleotides (single-stranded DNAs, ssDNAs).
A real-time fluorescence detection biomedical miniaturized system with a disposable microfluidic chip was developed for loop-mediated isothermal amplification (LAMP) reactions.The miniaturized system was developed consisting of a mini heating plate, a temperature sensor, a temperature controller and an adjustable mechanical stage.Based on experimental result, the temperature of the heating plate is evenly distributed, and the error of the temperature is less than 1.3%.The microfluidic chip was designed and fabricated by MEMS technology and thin-casting method.The volume of the LAMP reaction was changed from 25 μL to 2 μL.The volume of the LAMP reaction was optimized.The nucleic acid of Zika viruses was amplified and detected in real-time mode with our miniatureized system by using above microfluidic chip.From the experiment results, the detection range was from 100 copies to 10 6 copies.This biomedical system has the potential for point-of-care diagnostics (POCT) with the many advantages, such as not high cost, short analysis and detection time, not much reagent and sample consumption and so on.
GRSA (GNSS Remote Sensing ASIC) is a new generation space-borne and radiation-hardened GNSS remote sensing ASIC of NSSC (National Space Science Center, CAS). In comparison to the previous generation space-borne GNSS ASIC of NSSC named GOPA (GNSS Occultation Processing ASIC), GRSA adds new functionalities and possesses improved performance. It will be used in multiple space missions for POD (Precise Orbit Determination), GNSS-RO (Radio Occultation), and GNSS-R (Reflectometry). GRSA is now in program transformation phase in which program is being transferred into ASIC, after architecture design and VHDL (Very high speed integrated circuit Hardware Description Language) implementation. GRSA is capable of processing civil signals from all GNSS satellite constellations and integrates an on-chip processor to provide enough computing power so that complicated on-board applications can be carried out. It will take approximate one year to tape out.
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