Optical Detection Module Research Articles

Optical Spectroscopy Based Microfluidic Platform for Detecting Pathogens Using Immunomagnetic Separation

Rapid detection of pathogens is crucial for controlling pathogenic diseases and improving the quality of food industry. This paper presents a microfluidic platform integrated with optical detection module to rapidly detect Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli). The detection module comprises a microfluidic chip embedded with fiber optics connected to photosensors and a laser source. Initially, the immunomagnetic separation technique was applied to isolate specific pathogens out of testing sample using magnetic particles coated with antibodies. The separated sample containing magnetic beads was loaded into the chip and passed by the monochromatic light in the detection module. The scattered light signals from the passing magnetic beads were collected by the photosensors coupled with fiber optics. The acquired raw data were pre-processed by removing noise and distortions for further analysis. A new calibration model known as the Optical Transformer (OptiTr) structure was used for classification of acquired data. Convolution-based classical model (ResNeXt) was used as baseline comparison. The system provided higher classification results using the OptiTr model for classifying P. aeruginosa and E. coli, with accuracy values of 99.57% and 94.59%, respectively. The blank samples without P. aeruginosa and E. coli showed a classification accuracy of 94.73%. The microfluidic platform has the capability to identify P. aeruginosa and E. coli with a detection limit of 101 CFU/mL. The technique does not require complex sample preparation methods or complicated laboratory tools. The developed technique has a 15-minute detection time with a 40-minute sample preparation duration.

A-367 Development of a Novel Handheld Platform for Real-time Fluorescence-based Nucleic Acid Detection

Abstract Background Real-time fluorescent nucleic acid detection systems are usually large and complex to operate. In the past three years, the pandemic outbreak of COVID-19 has sparked a variety of point-of-care testing (POCT) nucleic acid detection platforms. However, most of these platforms need to be paired with specific reagents, and many detection reagents on the market cannot be applied to these POCT platforms. Methods In this research, a novel handheld real-time nucleic acid detection device was invented. The device uses a heating element to adjust the temperature in time with a sensor to ensure accuracy. The optical detection module is highly scalable and can be extended up to 6 fluorescence channels. The FAM and HEX fluorescence channels were utilized in this experiment. This platform is open and can adjust temperature for various types of isothermal nucleic acid detection, such as LAMP, RPA, and RCA. Results We used a commercial COVID-19 reagent kit with our device to get results in just 30 minutes, detecting SARS-CoV-2 virus as little as 500 copies/mL. Our system provides a reliable and efficient tool for COVID-19 testing in a variety of settings. Conclusion The handheld device was also used to test for flu A and mycobacterium tuberculosis, with good results. This device can be used not only for pathogen detection of human diseases, but also in pathogen detection for animals and plants, food safety, environmental monitoring, and other fields, thus expanding the application range of nucleic acid detection and making it simpler and more convenient to use.

Smallest dual-color qPCR device

The global outbreak of the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), necessitated the development of point-of-care (POC) systems for rapid and widespread population screening. Current POC systems, based on reverse transcription–quantitative polymerase chain reaction (RT-qPCR) methods, are unable to perform RNA target multiplexing, which is crucial for specific viral strain identification. This study presents a compact qPCR system capable of dual fluorescence channel gene multiplexing by simultaneously detecting two targets of the SARS-CoV-2 virus using 6-carboxyfluorescein (FAM)- and TxRed-labeled probes. The device measures (110 × 83 × 41) mm3 and weighs 210 gm. It features four virtual reaction chambers, a thermal cycle system, a real-time optical signal detection module, a USB interface, and a Bluetooth wireless data transmission module. Moreover, it can perform single fluorescent channel detection of PCR using intercalating dye, followed by a melting curve analysis and loop-mediated isothermal amplification. The proposed compact dual-color qPCR device significantly broadens its potential for POC applications, such as diagnostics or field testing, molecular biology, microfluidics, and virus detection.

Ultrafast Nucleic Acid Detection Equipment with Silicon-Based Microfluidic Chip

Recently, infectious diseases, such as COVID-19, monkeypox, and Ebola, are plaguing human beings. Rapid and accurate diagnosis methods are required to preclude the spread of diseases. In this paper, an ultrafast polymerase chain reaction (PCR) equipment is designed to detect virus. The equipment consists of a silicon-based PCR chip, a thermocycling module, an optical detection module, and a control module. Silicon-based chip, with its thermal and fluid design, is used to improve detection efficiency. A thermoelectric cooler (TEC), together with a computer-controlled proportional-integral-derivative (PID) controller, is applied to accelerate the thermal cycle. A maximum of four samples can be tested simultaneously on the chip. Two kinds of fluorescent molecules can be detected by optical detection module. The equipment can detect viruses with 40 PCR amplification cycles in 5 min. The equipment is portable, easily operated, and low equipment cost, which shows great potential in epidemic prevention.

Sophisticated and precise: design and implementation of a real-time optical detection system for ultra-fast PCR.

Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) has become indispensable in the realm of disease nucleic acid screening and diagnostics, owing to its remarkable precision and sensitivity, in which the real-time fluorescence detection system plays an extremely critical role. To solve the problems of long time and slow speed of traditional nucleic acid detection, PCR systems are evolving towards ultra-rapid configurations. Nonetheless, most extant ultra-rapid PCR systems either depend on endpoint detection for qualitative assessments due to inherent structural or heating constraints or circumvent the challenge of adapting optical systems to expeditious amplification systems, resulting in potential shortcomings in assay efficacy, volume, or expense. Consequently, this study proposed a design of a real-time fluorescence detection system for ultra-fast PCR, capable of executing six channels of real-time fluorescence detection. Through the meticulous calculation of the optical pathway within the optical detection module, effective regulation of system dimensions and the cost was accomplished. By devising an optical adaptation module, the signal-to-noise ratio was enhanced by approximately 307% without compromising the PCR temperature alteration rate. Ultimately, by employing a fluorescence model that accounted for the spatial attenuation effect of excitation light, as proposed herein, fluorescent dyes were arranged to evaluate the repeatability, channel interference, gradient linearity, and limit of detection of the system, which proved that the system had good optical detection performance. Finally, the real-time fluorescence detection of human cytomegalovirus (CMV) under 9 min ultra-fast amplification was achieved by a complete ultra-fast amplification experiment, which further validated the potential of the system to be applied to rapid clinical nucleic acid detection.

All-optical laser ultrasonic technique for imaging of subsurface defects in carbon fiber reinforced polymer (CFRP) using an optical microphone

Defects, such as delamination and debonding, are critical to the performance of carbon fiber-reinforced polymer (CFRP) composites. In recent years, non-destructive testing techniques have been improved for the inspection of these defects among CFRPs. In this study, an all-optical and non-destructive laser ultrasonic technique with an optical microphone detection module has been presented to detect the artificial subsurface defects among the CFRP composites. A finite element simulation based on the thermo-mechanical coupling model was used to study the process of nanosecond pulsed laser excitation of the CFRP laminate to produce ultrasound and the propagation behavior of ultrasound among the CFRP laminate. A series of non-contact laser ultrasonic testing experiments were carried out to study the flat bottom holes of different sizes via a laser ultrasonic detection system. The artificial subsurface defects were reliably identified by the presented all-optical laser ultrasonic system imbedded in the optical microphone using four feature images.

Development of Detection Equipment for a Polymerase Chain Reaction with a Loop-Mediated Isothermal Amplification Reaction

In this research, low-cost detection equipment intended to carry out a polymerase chain reaction (PCR) through a loop-mediated isothermal amplification (LAMP) reaction is presented. We designed the internal structure with SolidWorks and AutoCAD. The equipment comprised a Raspberry Pi development board, a temperature control module, and a fluorescent optical detection module. The main program, temperature control, florescent signal processing, signal analysis, and screen display were programmed with Java. We applied the digital temperature controller module to obtain precise temperature control of the equipment. The experimental results showed that the heating rate of the testing equipment could reach 65°C within 4 minutes and could be accurately controlled to within 1°C. The duration of the LAMP PCR experiment was found to be significantly shorter than that of the conventional PCR. The results also revealed that with LAMP PCR, the temperature could be accurately controlled within a specific range, and the designed heating tasks could be completed within 15 minutes to one hour, depending on the specimen. The equipment could also correctly read both the positive and negative reactions with fluorescent signals. Thus, the proposed LAMP PCR detection equipment is more sensitive, more stable, and more cost-effective than other conventional alternatives and can be used in numerous clinical applications.

Weak Radio-Frequency Signal Detection Based on Piezo-Opto-Electro-Mechanical System: Architecture Design and Sensitivity Prediction

We propose a novel radio-frequency (RF) receiving architecture based on the microelectromechanical system (MEMS) and optical coherent detection module. The architecture converts the received electrical signal into mechanical vibration through the piezoelectric effect and adopts an optical detection module to detect the mechanical vibration. We analyze the response function of the piezoelectric film to an RF signal, the noise-limited sensitivity of the optical detection module, and the system transfer function in the frequency domain. A simple on–off keying (OOK) modulation with carrier frequency 1 GHz is used to numerically evaluate the detection sensitivity. The result shows that considering the main noise sources in system, the signal detection sensitivity can reach around −116.6 dBm at bandwidth 5 MHz. Such sensitivity significantly outperforms that of the currently deployed long-term evolution (LTE) system. Finally, we conduct preliminary experiments based on an off-the-shelf aluminium nitride piezoelectric film, which shows that the vibration amplitude based on the theoretical prediction can be achieved.

Design and evaluation of a condensation particle counter with high performance for single-particle counting

A full-flow butanol-based condensation particle counter (CPC) with a concentration range from 0 to 2 × 105 particles/cm3 was developed to measure nanoparticles down to 4.5 nm. Good single-particle counting performance was achieved by developing a high-speed optical particle detection module. The pulse width of single particle was approximately 1.2 μs at a flow rate of 0.3 L/min. By establishing a heat and mass transfer model using the COMSOL simulation software, the effects of temperature and aerosol sampling flow on the condensation growth of nanoparticles were studied. The performance of developed condensation particle counter was evaluated through a series of experiments to determine the coincidence probability, concentration range, and detection efficiency (cutoff diameter). At concentrations of 1.5 × 104 particles/cm3 and 2 × 105 particles/cm3, the coincidence probabilities of the developed condensation particle counter were 9.5% and 55%, respectively. A 99.9% (R2) statistical correlation was obtained between the pulse-time corrected concentration of the developed condensation particle counter and the standard reference concentration. Finally, the experimental results showed that the developed condensation particle counter cutoff diameter, at which the detection efficiency was 50%, for sucrose aerosol particles was 4.5 nm.

A field amplification enhanced paper-based analytical device with a robust chemiluminescence detection module.

A sensitive detection method combined with an effective on-line concentration may improve the analytical performance of a paper-based analytical device (PAD), and its merits of low cost and portability in POCT are fully demonstrated. Here, a sensitive PAD system with chemiluminescence (CL) detection and electrokinetic preconcentration was introduced, and the performance was demonstrated by the detection of hemin. A commercially available low cost and miniaturized optical detection module was used for the CL detection. Firstly, hemin was stacked on a simple paper fluidic channel based on field amplified stacking (FAS), and then a CL reagent (luminol-H2O2) was loaded on the stacked band to initiate the CL reaction. The photons were directly detected using the detection module. With optimization of the background electrolyte (BGE), voltage and CL reagent, a limit of detection (LOD) of 0.58 nM for hemin was obtained with a linear range of 1-1000 nM (R2 = 0.995). With FAS, the signal intensity was about 13-fold enhanced. This PAD also exhibited satisfactory selectivity over possible interfering components at a 104 times higher concentration. The applicability of the PAD was demonstrated by the detection of hemin from iron supplements and human serum samples. With total manual operation, recovery rates of 84.8-115.6% were obtained with an RSD of less than 14.3%. With the introduction of the optical detection model, and together with FAS, both the LOD and dynamic range of this PAD were effectively improved.

A Microfluidic Chip for Detecting Cholangiocarcinoma Cells in Human Bile

Cholangiocarcinoma (CCA), a biliary tract malignancy, accounts for 20% of all liver cancers. There are several existing methods for diagnosis of CCA, though they are generally expensive, laborious, and suffer from low detection rates. Herein we first developed a means of partially purifying human bile for consequent injection into a microfluidic chip. Then, the novel microfluidic system, which featured 1) a cell capture module, 2) an immunofluorescence (IF) staining module featuring two CCA-specific biomarkers, and 3) an optical detection module for visualization of antibody probes bound to these CCA marker proteins, was used to detect bile duct cancer cells within partially purified bile samples. As a proof of concept, CCA cells were successfully captured and identified from CCA cell cultures, blood samples inoculated with CCA cells, and clinical bile specimens. In 7.5 ml of bile, this system could detect >2, 0, and 1 positive cells in advanced stage patients, healthy patients, and chemotherapy-treated patients, respectively. In conclusion, our microfluidic system could be a promising tool for detection of cancer cells in bile, even at the earliest stages of CCA when cancer cells are at low densities relative to the total population of epithelial cells.

Portable System for Rapid Field Test of CEA in Human Serum Based on Chemiluminescence Enzyme Immunoassay

Carcinoembryonic antigen (CEA) is one of the most widely used tumor markers worldwide. A portable system was designed for rapid field specific test of CEA based on immunomagnetic separation and chemiluminescence immunoassay, which consisted of chemiluminescent immunosensor and optical test instrument. The chemiluminescent immunosensor was based on immunomagnetic separation and chemiluminescence immunoassay, which utilized a immuno-sandwich scheme as-say with Horseradish peroxidase (HRP) labeled anti-CEA antibody and Immunomagnetic beads (IMBs). And the test instrument consisted of optical detection module and central processing and control system. The optical noise of this instrument was below 40 photons/s. The system could achieve a sample test in 30 minutes, and the detecting result showed a good liner relationship between the intensity of luminescence and concentration of CEA in the range from 1 to 1000ng/mL, with a correlation coefficient of 0.9858. Real human samples were also detected with this system in comparison with clinical results and a correlation coefficient of 0.9934 was obtained. The instrument is portable and easy to operate, which will provide potential application in cancer clinical test.

Automated determination of nitrite in aqueous samples with an improved integrated flow loop analyzer

A compact loop flow analyzer was developed for automated determination of nitrite in aqueous samples based on Griess reaction and spectrophotometric detection. The integrated system employed a customized single chip microcomputer based hardware and laboratory-programmed software written by LabVIEW to control the injection valve, pumps and optical detection module. Experimental parameters related to nitrite analysis, including the reagent volume, sample temperature and salinity were evaluated and optimized. This fully automated analyzer showed a limit of detection as low as 0.02μM with sample throughput of 15h−1. The calibration curves prepared in pure water and low nutrient seawater were consistent over the linear range of 0–10μM (R2=0.999), showing insignificant interference from the common ions in seawater. Different aqueous samples were successfully analyzed using both the present analyzer and the standard benchtop method, and the results from the two techniques showed no significant difference according to the statistical t-test (P=0.95). This compact automatic analyzer is simple, fully integrated, and user-friendly, making it highly suitable for field applications, such as on-line environmental monitoring and underway analysis.

Biochip technology applied to an automated ABO compatibility test at the patient bedside

In the field of blood transfusion, there is a need to improve the bedside pre-transfusion ABO compatibility test. In France, this test is mandatory for each red cell concentrates transfusion. It is performed manually and serious transfusion accidents still occur, principally due to human errors. Therefore, an automated ABO compatibility test is required. Works concerning objective interpretation of ABO compatibility test have been reported but the proposed techniques cannot be easily translated to the patient's bedside. We propose a prototype device which demonstrates the easy use of biochip technology to perform this test: it contains a fluidic system, biochips (two to test the patient and two to test the red cell concentrates) and an optical absorbance detection module. When blood is applied to the biochips, red blood cells are trapped onto the surface if antigens and antibodies are complementary (positive chips). If they are not complementary, very little red blood cells are adsorbed (negative chips). Percentages of surface covered with red blood cells in negative biochips are 2%±2 (red cell concentrates) and 1%±1 (whole blood). This proves that the fluidic configuration leads to an optimum control of fluids flows with little retention of red blood cells in the circuitry. These percentages increase to 96%±3 and 82%±8 for red cell concentrates and whole blood respectively. This demonstrates a strong and specific immunocapture of red blood cells on positive chips. Furthermore, optical detection proves to be efficient at critical red blood cells concentrations (108C/mL) and absorbance strongly correlates to the percentage of red blood cells captured by antibodies.

A microfluidic system integrated with buried optical fibers for detection of Phalaenopsis orchid pathogens

Orchids of the genus Phalaenopsis are some of the most economically important plants in Taiwan. Fast, accurate, and on-site detection of pathogens in these orchids is therefore of critical importance in order to prevent or suppress costly disease outbreaks. Traditional pathogen detection methods are time-consuming, require well-equipped laboratories with highly trained personnel, and cannot be conducted in situ. In this study, a microfluidic system integrated with buried optical fibers was developed to detect viral pathogens of Phalaenopsis spp. Briefly, virus-specific ribonucleic acid (RNA) purification was achieved by a pre-treatment incubation with magnetic beads, and reverse-transcription loop-mediated isothermal amplification (RT-LAMP) was used subsequently to amplify the viral RNA. Positive RT-LAMP reactions resulted in the precipitation of magnesium pyrophosphate, which caused a change in turbidity that could be seen by the naked eye. A buried optical fiber-based detection module and a micro-stirring device were then integrated into the microfluidic chip to detect the RT-LAMP reaction product directly on the chip itself by measuring the change in the optical signals caused by the turbidity change associated with a positive amplification. The limit of detection for this system was found to be 25fg, which is of similar sensitivity to existing, more laborious methods. Therefore, by using the integrated microfluidic system, a sensitive, rapid, accurate, and automatic diagnosis of viral pathogens in Phalaenopsis spp. orchids could be achieved within only 65min.

基于Cortex-M3的快速发光二极管光电参数测量系统

According to the demands of Light Emitting Diode(LED)separation equipment for the photoelectric parameter measurement system,this paper describes a self-designed fast LED photoelectric parameter measurement system based on Cortex-M3(hereinafter referred to as M3).The system consists of an optical parameter detection module(homemade spectrometer),an electrical test module and a display module.The optical parametric module uses the M3as the main processor to acquire the spectral data and then gets the actual chromatic parameters to pass to the same M3-based processor module of electrical parameters.It greatly improves the LED parameter measuring speed and performance.Finally,without control of LED sorting machenisms,the designed LED photoelectric parameter measurement system was realized experimetally,in which the electrical testing period is less than 31ms,optical testing period can be as small as 10ms,and the deviation in consistency of chromaticity coordinate is less than 0.002 5%.

Development and calibration of a single UV LED based bioaerosol monitor

A high-sensitivity bioaerosol monitor based on a single 365 nm LED is developed and a calibration approach is discussed for the first time. The fluorescence detection system, which is the core part of the monitor, contains an optical detection module and a fluorescence signal processor configured with a phase sensitive detector (PSD). B800 fluorescent microspheres and staphylococcus are used for performance evaluation of the monitor. B800 microspheres are appropriate as calibration material. The experimental results demonstrate the PSD plays a significant role in improving sensitivity and signal-to-noise ratio (SNR) of detection. Our monitor can detect staphylococcus concentration above 1800 cfu/L of air stably.

An integrated microfluidic platform for rapid detection and subtyping of influenza viruses from clinical samples

This study reports on the development of an integrated microfluidic system that performs sample pretreatment, nucleic acid amplification, and optical detection for molecular diagnosis of influenza viruses. The entire analysis protocol including virus lysis, extraction of ribonucleic acid, reverse transcription, polymerase chain reaction, and optical detection was successfully performed using the microfluidic system, which automatically performed the rapid diagnosis and subtyping of the influenza viruses. Signals obtained from an optical detection module could accurately differentiate influenza A/H1 (infA/H1), influenza A/H3 (infA/H3), influenza B (infB), and positive and negative control samples. More importantly, the entire process could be integrated and performed automatically with less human intervention. The experimental results demonstrated that this developed microfluidic system can successfully distinguish between infA/H1, infA/H3, and infB within 60 min. Furthermore, oral swabs from 92 patients were successfully tested using the developed microfluidic system. Thus, it may be a promising tool for rapid detection of novel and seasonal influenza strains in the near future.

A microfluidic immunomagnetic bead-based system for the rapid detection of influenza infections: from purified virus particles to clinical specimens

Seasonal and novel influenza infections have the potential to cause worldwide pandemics. In order to properly treat infected patients and to limit its spread, a rapid, accurate and automatic influenza diagnostic tool needs to be developed. This study therefore presents a new integrated microfluidic system for the rapid detection of influenza infections. It integrated a suction-type, pneumatic-driven microfluidic control module, a magnetic bead-based fluorescent immunoassay (FIA) and an end-point optical detection module. This new system can successfully distinguish between influenza A and B using a single chip test within 15 min automatically, which is faster than existing devices. By utilizing the micromixers to thoroughly wash out the sputum-like mucus, this microfluidic system could be used for the diagnosis of clinical specimens and reduced the required sample volume to 40 μL. Furthermore, the results of diagnostic assays from 86 patient specimens have demonstrated that this system has 84.8 % sensitivity and 75.0 % specificity. This developed system may provide a powerful platform for the fast screening of influenza infections.Electronic supplementary materialThe online version of this article (doi:10.1007/s10544-013-9753-0) contains supplementary material, which is available to authorized users.

An integrated microfluidic platform for rapid tumor cell isolation, counting and molecular diagnosis

Ovarian cancer is the second most common of the gynecological cancers in Taiwan. It is challenging to diagnose at an early stage when proper treatment is the most effective. It is well recognized that the detection of tumor cells (TCs) is critical for determining cancer growth stages and may provide important information for accurate diagnosis and even prognosis. In this study, a new microfluidic platform integrated with a moving-wall micro-incubator, a micro flow cytometer and a molecular diagnosis module performed automated identification of ovarian cancer cells. By efficiently mixing the cells and immunomagnetic beads coated with specific antibodies, the target TCs were successfully isolated from the clinical samples. Then counting of the target cells was achieved by a combination of the micro flow cytometer and an optical detection module and showed a counting accuracy as high as 92.5 %. Finally, cancer-associated genes were amplified and detected by the downstream molecular diagnosis module. The fluorescence intensity of specific genes (CD24 and HE4) associated with ovarian cancer was amplified by the molecular diagnosis module and the results were comparable to traditional slab-gel electrophoresis analysis, with a limit of detection around 10 TCs. This integrated microfluidic platform realized the concept of a "lab-on-a-chip" and had advantages which included automation, disposability, lower cost and rapid diagnosis and, therefore, may provide a promising approach for the fast and accurate detection of cancer cells.