Simple Detection System Research Articles

Detection of the SARS-CoV-2 spike protein in saliva with Shrinky-Dink© electrodes

Using the children's toy, Shrinky-Dink©, we present an aptamer-based electrochemical (E-AB) assay that recognizes the spike protein of SARS-CoV-2 in saliva for viral infection detection. The low-cost electrodes are implementable at population scale and demonstrate detection down to 1 ag mL-1 of the S1 subunit of the spike protein.

Development of a novel polymerase spiral reaction (PSR) assay for rapid and visual detection of Clostridium perfringens in meat

C. perfringens is a widespread foodborne pathogen and one of the major concerns in the meat industry. There is a need for a simple, rapid and equipment free detection system for C. perfringens as conventional anaerobic culture method is labour and resource intensive. Here, we applied a novel polymerase spiral reaction phenomenon to develop and evaluate an assay for effortless and visual detection of C. perfringens in meat foods employing pork as a representative model. Specificity of the assay was determined using 51 C perfringens and 20 non- C. perfringens strains. Analytical sensitivity of the developed test was 80 fg DNA per tube indicating 100 times more sensitivity than end-point PCR assay. The detection limits were 980 CFU/g and 9.8 × 104 CFU/g of pork for PSR and PCR assays, respectively. The operation time of the PSR assay including DNA extraction was 120 min. The developed PSR assay was accurate and effective in comparison to culture method, in detecting C. perfringens in 38 of 74 pork samples. Therefore the specificity, sensitivity, negative predictive value, positive predictive value and accuracy rate of the developed PSR assay were 100%. The developed PSR assay is easy to perform, rapid, affordable, permitting sophisticated-equipment free amplification and naked eye interpretation. This is the initial report in which the PSR assay was optimized for the detection of C. perfringens.

Rapid and simple single-chamber nucleic acid detection system prepared through nature-inspired surface engineering.

Background: Nucleic acid (NA)-based diagnostics enable a rapid response to various diseases, but current techniques often require multiple labor-intensive steps, which is a major obstacle to successful translation to a clinical setting.Methods: We report on a surface-engineered single-chamber device for NA extraction and in situ amplification without sample transfer. Our system has two reaction sites: a NA extraction chamber whose surface is patterned with micropillars and a reaction chamber filled with reagents for in situ polymerase-based NA amplification. These two sites are integrated in a single microfluidic device; we applied plastic injection molding for cost-effective, mass-production of the designed device. The micropillars were chemically activated via a nature-inspired silica coating to possess a specific affinity to NA.Results: As a proof-of-concept, a colorimetric pH indicator was coupled to the on-chip analysis of NA for the rapid and convenient detection of pathogens. The NA enrichment efficiency was dependent on the lysate incubation time, as diffusion controls the NA contact with the engineered surface. We could detect down to 1×103 CFU by the naked eye within one hour of the total assay time.Conclusion: We anticipate that the surface engineering technique for NA enrichment could be easily integrated as a part of various types of microfluidic chips for rapid and convenient nucleic acid-based diagnostics.

Implementation of an Available Parking Space Detection System in Hectic Parking Lots

Parking automation has been developed for locating available parking spaces inside a parking lot with new technologies, such as automatic collection, capacity, or empty spaces’ detection; to both reduce search time and avoid crowds of vehicles waiting to park in it. A simple detection system of available spaces, within the Faculty and Staff parking lot of the Engineering and Chemistry Departments at the Autonomous University of Chihuahua, Mexico (UACH), was set up. First, an analysis of vehicle capacity was carried out to establish the peak hours of vehicles’ entrances and compare it to the parking lots’ capacity. For one working week (6 days), it was determined that Tuesdays have the highest vehicle occupancy, and Saturdays are the days with the least traffic. Second, the geometric design of the parking lot (divided into two areas because of the terrain topography: upper and bottom levels), its dimensions and location of parking spots and marks on the pavement for traffic directions, were obtained from its blueprint, to visualize how the surveillance cameras can be oriented to cover the area. A detection system prototype was created for a specific area of the parking lot, using an artificial vision technique to perform the video extraction, while the digital image processing was developed in MATLAB. To complement and achieve the objective, Object- Oriented Programming (OOP) was used to obtain the count analysis as well as the availability/occupancy of each of the parking areas. This information is shown on a web page, with a simple driver-friendly design, since it has each parking space number and its availability in blue with the word “Available” or, in the opposite case, the word “Taken” in pink.

Electrodes Based on a Titanium Dioxide Nanotube-Spherical Silver Nanoparticle Composite for Sensing of Proteins.

The aim of the research was to provide electrochemical, chemical, phase, and microscopic characteristics of electrodes based on titanium dioxide nanotubes (TNTs) containing uniformly deposited, nonagglomerated spherical silver nanoparticles (AgNPs). The nanoparticles were produced with the use of electrodeposition and sputter deposition methods. This paper presents the results of research of these platforms with the use of the following techniques: electrochemical impedance spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy. Evaluation of the adsorption of proteins-bovine serum albumin (BSA)-was carried out to establish the possibility of the use of the electrodes in a low-cost, simple detection system without surface functionalization. The research proved that the AgNP deposition facilitated the electron transfer increasing their conductivity properties as well as promoting the protein adsorption. The AgNPs/TNT electrodes showed a high selectivity to the BSA-anti-BSA complex. Half an hour of immobilization was enough to completely saturate the TNT electrodes, whereas for AgNPs/TNTs, 1 h of immobilization seemed to be not enough. The impedance parameter changes for electrodes with the AgNPs reached even about 300%. The biggest changes were noted for the platform obtained using cyclic voltammetry, so it is the best detection platform for biosensing.

Scanning single-molecule counting system for Eprobe with highly simple and effective approach.

Here, we report a rapid and ultra-sensitive detection technique for fluorescent molecules called scanning single molecular counting (SSMC). The method uses a fluorescence-based digital measurement system to count single molecules in a solution. In this technique, noise is reduced by conforming the signal shape to the intensity distribution of the excitation light via a circular scan of the confocal region. This simple technique allows the fluorescent molecules to freely diffuse into the solution through the confocal region and be counted one by one and does not require statistical analysis. Using this technique, 28 to 62 aM fluorescent dye was detected through measurement for 600 s. Furthermore, we achieved a good signal-to-noise ratio (S/N = 2326) under the condition of 100 pM target nucleic acid by only mixing a hybridization-sensitive fluorescent probe, called Eprobe, into the target oligonucleotide solution. Combination of SSMC and Eprobe provides a simple, rapid, amplification-free, and high-sensitive target nucleic acid detection system. This method is promising for future applications to detect particularly difficult to design primers for amplification as miRNAs and other short oligo nucleotide biomarkers by only hybridization with high sensitivity.

Kaleidoscopic fluorescent arrays for machine-learning-based point-of-care chemical sensing

Multiplexed analysis allows simultaneous measurements of multiple targets, improving the detection sensitivity and accuracy. However, highly multiplexed analysis has been challenging for point-of-care (POC) sensing, which requires a simple, portable, robust, and affordable detection system. In this work, we developed paper-based POC sensing arrays consisting of kaleidoscopic fluorescent compounds. Using an indolizine structure as a fluorescent core skeleton, named Kaleidolizine (KIz), a library of 75 different fluorescent KIz derivatives were designed and synthesized. These KIz derivatives are simultaneously excited by a single ultraviolet (UV) light source and emit diverse fluorescence colors and intensities. For multiplexed POC sensing system, fluorescent compounds array on cellulose paper was prepared and the pattern of fluorescence changes of KIz on array were specific to target chemicals adsorbed on that paper. Furthermore, we developed a machine-learning algorithm for automated, rapid analysis of color and intensity changes of individual sensing arrays. We showed that the paper sensor arrays could differentiate 35 different volatile organic compounds using a smartphone-based handheld detection system. Powered by the custom-developed machine-learning algorithm, we achieved the detection accuracy of 97 % in the VOC detection. The highly multiplexed paper sensor could have favorable applications for monitoring a broad-range of environmental toxins, heavy metals, explosives, pathogens.

An Overview on Prediction of Plant Leaves Disease using Image Processing Techniques

In the Indian Economy, agriculture plays a main role, therefore prior detection of plant diseases will aid in maximizing the productivity of the crops thereby adding to the economy’s augmentation. To predict the plant diseases, manual identification is used earlier but it requires vast manpower and wide knowledge about plants. Multi disease models and pest prediction can be automated using image processing techniques. This paper shows an overview of various image processing techniques to obtain and organize diseases in the plant. Developing contamination, supplement lack, dry season, and so on are the reasons in light of which plants are inclined to the various sicknesses. Illnesses can be found on the root, stem, branches, leaves, blossoms, and organic products. Diseases in plants are the main production and financial losses also decrease in agricultural product quality and quantity. To propose a proper solution for relating illness, recognizable proof, and arrangement of infections is significant. We reviewed a simple plat leaf disease detection system that would ease progressions in agriculture. The survey on various classification techniques presented in this paper for plant leaf diseases. An Automatic finding of plant diseases is significant to regularly find out the disease signs as soon as they emerge on the mounting phase.

Face Detection By some Methods based on MATLAB

Over the past few years, technology has begun to discover things rapidly growing, as this technology has come to dominate the vision of computers, which have taken an important role in monitoring cars and their safety.
 In this work, the face detection and tracking process was highlighted,[6], and two algorithms were created to clarify the role of the MATLAB program in creating a simple system for facial tracking and detection where the first example shows the application of Algorithm1 using the CAMShift method where the face was tracked where the results were weak due to sufficient contrast between Face and background area, the algorithm1 was created to implement the method, [2].
 Example2 is using the method Kanade Lucas Tomasi (KLT), which is a simple system where it is able to detect the face and track it where the system is able to detect the face when the head moves and tilts, with Estim Geometric Transform (EGT) function and Duration Geometric Transform (DGT), The algorithm 2 was created to implement the method.
 The examples in this work show the implementation and efficiency of the mentioned algorithms

The Performance Comparison of a Dual-Ridge Horn Antenna and a Planar Monopole Antenna in the Microwave Breast Cancer Detection

Detection of the breast cancer tumors at an early stage is very crucial to be successful in the treatment. Microwave measurement systems have gained much attention for this aim over last decades. The main principle of these systems is based on the significant difference in the dielectric properties of the malignant tumor and normal breast tissue in the microwave frequencies. In this paper, firstly several breast cancer detection techniques are mentioned. Then the advantages of the using microwaves in the detection systems are given. After that, some simulation and experimental studies of the radar-based ultra-wideband microwave measurement system are presented to detect tumor. The main purposes of these measurements are comparing the performance of a previously designed planar monopole antenna (PMA) with a dual-ridge horn (DRH) antenna and demonstrating a simple microwave breast cancer detection system. In the system, a planar breast phantom which is consisted of low dielectric constant material to represent the healthy tissue and high dielectric constant material to represent the tumor is used. Firstly, the measurements are made without tumor in the phantom. Then, the tumor-mimicking object is located to the phantom. In the measurements, both the PMA and DRH antennas are used respectively. These antennas are ultra-wideband and directional. They have narrow beamwidth and stable directional pattern at the interval of 3-10 GHz. According to the return loss results, the reflected energy increases when the antenna gets close to the tumor. Therefore, it can be said that the scattering parameters give important information about the tumor. According to the obtained results in this study, it can be said that the performance of the compact-sized PMA is better than the DRH antenna having larger size.

On the detection of defects on smooth free metallic paint surfaces

In view of the difficulty of automatic detection of defects on smooth free metallic paint surfaces, a simple and effective automatic detection system based on deflection principle is proposed in this paper. This system consists of cameras and a set of striped lights. A series of images can be acquired at a certain frequency by camera. And the detection algorithm is divided into three steps. In the first step, the square-difference fusion method and minimum fusion method are used to fuse a group of the standard images to obtain two fusion images, which are used to extract the ROI and partial template. In the second step, partial template is used to perform template matching and correction on the fusion images. In the last step, extraction of mask, extraction of defects, and screening of defects are performed on the corrected fusion image to extract defects. To detect complex metallic paint surfaces of the car, the experimental results demonstrate that the defects detection accuracy can reach 85% and the defect recognition size can reach 0.1mm.

Novel 1D/2D KWO/Ti3C2Tx Nanocomposite-Based Acetone Sensor for Diabetes Prevention and Monitoring

The acetone content in the exhaled breath of individuals as a biomarker of diabetes has become widely studied as a non-invasive means of quantifying blood glucose levels. This calls for development of sensors for the quantitative analysis of trace concentration of acetone, which is presents in the human exhaled breath. Traditional gas detection systems, such as the Gas Chromatography/Mass Spectrometry and several types of chemiresistive sensors are currently being used for this purpose. However, these systems are known to have limitations of size, cost, response time, operating conditions, and consistent accuracy. An ideal breath acetone sensor should provide solutions to overcome the above limitations and provide good stability and reliability. It should be a simple and portable detection system of good sensitivity, selectivity that is low in terms of both cost and power consumption. To achieve this goal, in this paper, we report a new sensing nanomaterial made by nanocomposite, 1D KWO (K2W7O22) nanorods/2D Ti3C2Tx nanosheets, as the key component to design an acetone sensor. The preliminary result exhibits that the new nanocomposite has an improved response to acetone, with 10 times higher sensitivity comparing to KWO-based sensor, much better tolerance of humidity interference and enhanced stability for multiple months. By comparing with other nanomaterials: Ti3C2, KWO, and KWO/Ti3C2Tx nanocomposites with variable ratio of KWO and Ti3C2Tx from 1:1, 1:2, 1:5, 2:1, 4:1, and 9:1, the initial results confirm the potential of the novel KWO/Ti3C2 (2:1) nanocomposite to be an excellent sensing material for application in sensitive and selective detection of breath acetone for diabetics health care and prevention.

Elevating Chemistry Research with a Modern Electronics Toolkit

With the rapid development of high technology, chemical science is not as it used to be a century ago. Many chemists acquire and utilize skills that are well beyond the traditional definition of chemistry. The digital age has transformed chemistry laboratories. One aspect of this transformation is the progressing implementation of electronics and computer science in chemistry research. In the past decade, numerous chemistry-oriented studies have benefited from the implementation of electronic modules, including microcontroller boards (MCBs), single-board computers (SBCs), professional grade control and data acquisition systems, as well as field-programmable gate arrays (FPGAs). In particular, MCBs and SBCs provide good value for money. The application areas for electronic modules in chemistry research include construction of simple detection systems based on spectrophotometry and spectrofluorometry principles, customizing laboratory devices for automation of common laboratory practices, control of reaction systems (batch- and flow-based), extraction systems, chromatographic and electrophoretic systems, microfluidic systems (classical and nonclassical), custom-built polymerase chain reaction devices, gas-phase analyte detection systems, chemical robots and drones, construction of FPGA-based imaging systems, and the Internet-of-Chemical-Things. The technology is easy to handle, and many chemists have managed to train themselves in its implementation. The only major obstacle in its implementation is probably one's imagination.

A simple on-line detection system based on fiber-optic sensing for the realtime monitoring of fixed bed adsorption processes of molecularly imprinted polymers

Fixed bed adsorption is widely used for separations and purifications of active components in medicine, and for wastewater treatment. At present, fixed bed adsorption breakthrough curve is generally obtained by manual sampling and off-line detection. In this study, we proposed a method for on-line monitoring of fixed bed adsorption process using a self-assembled fiber-optic sensing (FOS) system. The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) on the fixed bed packed with molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs) were studied. The reproducibility and precision of the system was investigated. The relative standard deviation (RSD) of the system was less than 1.54%, which indicates that the system has a good reproducibility. The effects of initial concentration, flow rate, adsorbent mass and particle size on the breakthrough curves were investigated. Through screening, it was found that adsorption kinetics of the polymer materials fit to Thomas and Yoon-Nelson models. The MIPs showed high binding capacity, good selectivity, fast adsorption rate, indicating a great potential for the treatment of 2,4-D contaminated water. Moreover, this study has identified that the detection method has the advantages of being on-line, realtime, simple, and accurate. The on-line method can facilitate the study of fixed bed adsorption processes and accelerate the understanding of adsorption kinetics.

Design and Analysis for Fall Detection System Simplification.

This paper presents a methodology based on multimodal sensors to configure a simple, comfortable and fast fall detection and human activity recognition system that can be easily implemented and adopted. The methodology is based on the configuration of specific types of sensors, machine-learning methods and procedures. The protocol is divided into four phases: (1) database creation (2) data analysis (3) system simplification and (4) evaluation. Using this methodology, we created a multimodal database for fall detection and human activity recognition, namely UP-Fall Detection. It comprises data samples from 17 subjects that perform 5 types of falls and 6 different simple activities, during 3 trials. All information was gathered using 5 wearable sensors (tri-axis accelerometer, gyroscope and light intensity), 1 electroencephalograph helmet, 6 infrared sensors as ambient sensors, and 2 cameras in lateral and front viewpoints. The proposed novel methodology adds some important stages to perform a deep analysis of the following design issues in order to simplify a fall detection system: a) select which sensors or combination of sensors are to be used in a simple fall detection system, b) determine the best placement of the sources of information, and c) select the most suitable machine learning classification method for fall and human activity detection and recognition. Even though some multimodal approaches reported in literature only focus on one or two of the above-mentioned issues, our methodology allows simultaneously solving these three design problems related to a human fall and activity detection and recognition system.

A highly integrated system with rapid DNA extraction, recombinase polymerase amplification, and lateral flow biosensor for on-site detection of genetically modified crops

With the large-scale planting of genetically modified (GM) crops, the development of a rapid and convenient method for on-site monitoring GM crops is needed. In this study, a duplex recombinase polymerase amplification (DRPA)-based, quick and simple detection system is presented for on-site detection of GM crops. In this system, a rapid DNA extraction method, a DRPA, and a lateral flow biosensor (LFB) are integrated to allow for rapid DNA extraction and amplification, and fast visualization of the detection results. Using the rapid DNA extraction method, high-quality DNA suitable for RPA and polymerase chain reaction (PCR) was quickly isolated from various crops within 5 min. Utilizing the optimal DRPA assay, the universal screening sequences (Cauliflower mosaic virus 35S promoter [35S] and Agrobacterium tumefaciens NOS terminator [NOS]) were rapidly and simultaneously amplified with high selectivity and sensitivity. The sensitivity threshold of the DRPA assay was ∼10 copies for GM soybean genomic DNA and 100 ng DNA of 0.1% GM soybean. In combination with the LFB in an enclosed cassette, the entire detection process was performed in approximately 20–30 min and eliminated the carryover contamination. No special or expensive equipment was needed for the detection process. The system was successfully applied and validated for on-site detection of GM rice, demonstrating its suitability for on-site testing of GM crops and high potential for application to other fields, especially in low-resource regions that require rapid detection of DNA targets.

Fast Detection of Myricetin With the Use of Dedicated Microdroplets

A 4-cyano-4’-pentylbiphenyl(5CB) microdroplet-based sensing method for myricetin (MY) detection, which is produced by a syringe pump connected tapered capillary microtube and functionalized by dodecyltrimethylammonium bromide (DTAB) and deoxyribonucleic acid (DNA) at the aqueous/liquid crystal (LC) interface is proposed and demonstrated. As the concentration of MY increases, the 5CB microdroplet exhibits a structural transition from a bipolar configuration to a radial configuration. We also exploit the 5CB microdroplet to act as an optical microcavity of the whispering gallery mode (WGM) and obtain typical WGM lasing spectra under a pulsed laser pump. The WGM spectrum, which is related to the orientation of LC molecules at the aqueous/LC interface, presents a spectral blue shift with the increase of the MY addition. The sensitivity within the detection range is 0.04 nm/ $\mu \text{M}$ . The experimental results demonstrate the feasibility of this simple and small size system for MY detection.

Au-Hg/rGO with enhanced peroxidase-like activity for sensitive colorimetric determination of H2O2.

The Au-Hg amalgam anchored on the surface of reduced graphene oxide nanosheets (Au-Hg/rGO) has been synthesized successfully and characterized by various techniques such as transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The Au-Hg/rGO nanocomposites were found to possess excellent peroxidase-like catalytic activity and can quickly catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxTMB in the presence of H2O2. The obvious color change offered accurate determination of the H2O2 concentration by recording the absorbance at 652 nm using a UV-vis spectrophotometer. The linear response range for H2O2 was from 5 μM to 100 μM and the detection limit was 3.25 μM (S/N = 3). Furthermore, a kinetic study indicated that the catalytic behavior of Au-Hg/rGO nanocomposites followed the typical Michaelis-Menten theory and Au-Hg/rGO nanocomposites showed good affinity for H2O2. We envision that the simple and sensitive colorimetric detection system holds great promising applications in clinical diagnostics and food and environment monitoring.

Detection of Nonylphenol with a Gold-Nanoparticle-Based Small-Molecule Sensing System Using an ssDNA Aptamer.

Endocrine-disrupting chemicals (EDCs) threaten many kinds of life throughout the world. These compounds function the same as sexual hormones, inducing precocious puberty, gynecomastia, etc., in the human body. To prevent excess exposure to nonylphenol (NP), a simple and rapid detection system is needed. In this study, we develop a nonylphenol-specific aptamer from a random single-stranded DNA library and test a rapid sensor system based on the aptamer and gold nanoparticles (AuNPs). The aptamer was screened by a methodology involving reduced graphene oxide (rGO). As a result of screening and sequencing, a DNA aptamer was developed that recognizes the target with high binding affinity (Kd = 194.2 ± 65.9 nM) and specificity. The sensor system developed using the aptamer and gold nanoparticles is sensitive (LOD = 2.239 nM). Circular dichroism (CD) spectrometry results show that the free aptamer binds to the target molecule. The aptamer was characterized using gold nanoparticles to measure UV absorbance. Our results suggest that the sensor system developed using this aptamer is useful for field diagnosis of small molecules.

Fluorescence Polarization-Based Rapid Detection System for Salivary Biomarkers Using Modified DNA Aptamers Containing Base-Appended Bases.

The field of care testing toward the analysis of blood and saliva lacks nowadays simple test techniques for biomarkers. In this study, we have developed a novel nucleobase analog, Ugu, which is a uracil derivative bearing a guanine base at the 5-position. Moreover, we attempted the development of aptamers that can bind to secretory immunoglobulin A (SIgA), which has been examined as a stress marker in human saliva. It was observed that the acquired aptamer binds strongly and selectively to the SIgA dimer (Kd = 13.6 nM) without binding to the IgG and IgA monomers of human serum. Reduction of the aptamer length (41 mer) successfully improved 4-fold the binding affinity (Kd = 3.7 nM), compared to the original, longer aptamer (78 mer). Furthermore, the development of a simple detection system for human saliva samples by fluorescence polarization was investigated, using the reported human salivary α-amylase (sAA) and the SIgA-binding aptamer. Comparison of the present method with conventional enzyme-linked immunosorbent assay techniques highlighted a significant Pearson's correlation of 0.94 and 0.83 when targeting sAA and SIgA, respectively. It is thus strongly suggested that a new simple test of stress markers in human saliva can be quantified quickly without bound/free (B/F) separation.