ABSTRACT
A 3D printed (3DP) microfluidic polymerase chain reaction (PCR) device was demonstrated by detecting synthetic SARSCoV-2 at 106 copies/μL. The microfluidic device was fabricated using stereolithography 3DP and had a reaction volume of ~22 nL. The microdevice showed PCR amplification with 85 base synthetic ssDNA targets and primers designed for a SARS-CoV-2-specific region. The device was 2.5 times faster compared to a qPCR instrument with >60,000 times smaller reagent volume. The 3DP microdevice is a promising technology to significantly reduce the manufacturing costs of microfluidic devices that could be used towards point-of-care applications. © 2023 SPIE.
ABSTRACT
A portable, inexpensive, and easy-to-manufacture microfluidic device is developed for the detection of SARS-CoV-2 dsDNA fragments. In this device, four reaction chambers separated by carbon fiber rods are pre-loaded with isothermal amplification and CRISPR-Cas12a reagents. The reaction is carried out by simply pulling the rods, without the need for manual pipetting. To facilitate power-free pathogen detection, the entire detection is designed to be heated with a disposable hand warmer. After the CRISPR reaction, the fluorescence signal generated by positive samples is identified by naked eye, using an inexpensive flashlight. This simple and sensitive device will serve as a new model for the next-generation viral diagnostics in either hospital or resource-limited settings. © 2023 SPIE.
ABSTRACT
In this work, applications of microfluidic devices in the field of biomedical engineering will be described, with special focus on point-of-care tools (POC). These are devices offering rapid and easy-to-read diagnostic assays of various diseases or physiological conditions (COVID-19, allergies, cardiovascular diseases, tumours, pregnancy, etc.) that often can be applied by non-medically trained persons. Microfluidic devices play an important role in the development of POC tools. Recent advances in novel fabrication methods and multi-technology approaches allow to overcome common limitations, such as high cost, complex fluidic controls and pumping systems, or requiring specialized labour equipment and well-trained operators. Hence, these devices can be made available for a broad range of patients that might not have sufficient medical facilities. The influence of point-of-care tools on society, medical practice and early diagnosis will be discussed. Copyright © 2022 The Authors.
ABSTRACT
In many microfluidic applications, unwanted bubbles can be formed in the microfluidic device and adversely affect device operation. In this work, a novel membrane-based debubbler is developed to remove bubbles in the microfluidic device quickly and efficiently. Our experiments show that this new debubbler can perform well at a flow rate of up to 500 µl/min, and have a very small dead volume of less than 0.35µl. Besides, it has also been verified to be workable on a PCR assay for the SARS-CoV-2 test. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
The need to develop high-throughput diagnostic platforms for infectious diseases has never been more evident than with the emergence of SARS-CoV-2 and the ensued COVID-19 pandemic. Microfluidics, in tandem with its multiplexing capabilities, high sensitivity, and potential for automation, provides a unique advantage towards the development of high-throughput serological diagnostic platforms. Here, we present a microfluidic device that detects IgG or IgM raised against four SARS-CoV-2 antigens (spike, S;S1 subunit, S1;the receptor-binding domain, RBD;and nucleocapsid, N) from 50 serum samples in parallel. We validated the platform with a cross-sectional cohort of 66 samples from confirmed COVID-19 patients and a pre-pandemic control of 34 serum samples collected in 2018. The analysis of both antibodies against all four viral antigens provided a sensitivity of 90.4% and a specificity of 94.1%, with both parameters increasing to 100% in late-stage samples (21-30 days after symptoms onset). We expect our device to open the door to massive serological testing, impacting diagnostics, vaccine development, and epidemiological understanding of COVID-19. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
Rapid, sensitive, quantitative and patient-friendly diagnostic tools have yet to be developed for COVID-19 continued monitoring at the point-of-care. Here, we present an instrument-free capillary microfluidic chip coupled to a lateral flow module that is compatible with a smartphone application for quantitative detection of SARS-CoV-2 from saliva samples. The microfluidic chip is fully autonomous, and performs aliquoting, sample metering, and sequential delivery of reagents. The limit of detection is 0.07 ng/mL for recombinant nucleocapsid protein in saliva. This rapid antigen test provides results in less than 1 hour, without sacrificing analytical sensitivity. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
The SARS-CoV-2 pandemic has elevated the development of novel diagnostic solutions, including rapid nucleic acid amplification tests (NAATs), to a global priority to meet the high demand for accurate, timely viral detection and diagnosis. However, ubiquitously implemented NAATs, such as polymerase chain reaction (PCR), consume hours of testing. We report a field-forward instrument capable of ultra-fast real-time PCR for amplification-based nucleic acid detection in a custom-designed microfluidic chip. Prudent selection and unconventional positioning of thermal cyclers relative to the microfluidic chip and a fluorescent detector permit ultra-fast simultaneous amplification and detection, with 40 cycles complete in under 10 minutes. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
This paper presents a newly developed microfluidic flow control theory for autonomous sample dispensing into an array of reaction microchambers. The theoretical predictions for the possible dispensing number and maximum flow rate were validated by comparison to experimental results. Moreover, we successfully demonstrated the rapid genetic detection of multiple infectious viruses including SARS-CoV-2 in fabricated polydimethylsiloxane (PDMS)-based microfluidic devices based on the loop-mediated isothermal amplification (LAMP) method. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
Massive PCR testing during the COVID-19 pandemic was difficult due to the insufficiency of instruments and reagents. We developed a portable thermocycler for RT-qPCR that combines thermal control and fluorescence detection into a highly integrated hybrid module. Our thermocycler, named HybOT Cycler, is Bluetooth-controlled from an Android tablet. We also developed a bubble-free microfluidic device to run the PCR assays. The acrylic mold for the replication of the microfluidic device and the instrument were fabricated with 3D printed parts or micromilling. Concentrations as low as 1000 copies/µL of the SARS-CoV-2 N1 gene were detected, similar to a benchtop thermocycler. Finally, we analyzed 20 samples tested positive for SAR-CoV-2 and 10 controls, obtaining a sensibility of 95% and specificity of 100%. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
The analysis of dielectric properties in Novel Coronavirus (COVID-19) has become an important research branch since the outbreak of the epidemic in 2019. In order to detect the dielectric properties of microfluidics like virus with higher sensitivity, a radio frequency sensor model is proposed in this paper. First, based on the excellent characteristics of the microstrip meander-line such as more concentrated electric field distribution, the microstrip meander-line is introduced into the design of traditional cancellation sensor, which is called the meander sensor. Then, the relationship between transmission coefficients of the system and dielectric properties of microfluidics is given in this paper. The simulation results verify the ultra-sensitivity of the meander sensor. Even though the relative permittivity of microfluidics is changed in the order of magnitude 10-2, the measurement results of the meander sensor also change significantly. However, the straight sensor can only measure changes of relative permittivity in the order of magnitude 10-1. What's more, there is a more concentrated measurement range for the meander sensor. This will be more practical for measuring weak changes of dielectric properties caused by the microfluidics itself and its interactions. © 2021 IEEE.