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
Digital microfluidic (DMF) has emerged as one of the most popular microfluidic platforms for sample-preparation in biochemical analysis and lab-on-a-chip applications. Operated with electrowetting on dielectric (EWOD) mechanism, DMF conventionally requires an external power source to provide the actuation voltage, which limited its portability and broader applications in point-of-care testing (POCT) environment. Herein, a DMF device, self-powered by triboelectric nanogenerator (TENG) is presented. TENG possesses a number of unique characteristics, and is very attractive to be integrated with DMF. It only requires a simple configuration with low-cost fabrication that can improve the DMF portability, but it also provides high voltage, low current output characteristics that are consistent with the EWOD actuation requirements. Basic droplet manipulations, including transportation, split, merge, dispense, and even elongate to follow the electrode patterns of alphabets, on a DMF device powered with manually-rotated Disk-TENG are demonstrated for the first time. Further, droplets containing samples and reagents are transported and mixed on the programmed electrode patterns on the chip to conduct chemical reactions, including nucleic acid amplification and phenol red test, showing that Disk-TENG can serve as the power source for DMF chips in POCT applications. © 2023 Elsevier Ltd
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
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
Extracellular vesicles (EVs) are a group of communication organelles enclosed by a phospholipid bilayer, secreted by all types of cells. The size of these vesicles ranges from 30 to 1000 nm, and they contain a myriad of compounds such as RNA, DNA, proteins, and lipids from their origin cells, offering a good source of biomarkers. Exosomes (30 to 100 nm) are a subset of EVs, and their importance in future medicine is beyond any doubt. However, the lack of efficient isolation and detection techniques hinders their practical applications as biomarkers. Versatile and cutting-edge platforms are required to detect and isolate exosomes selectively for further clinical analysis. This review paper focuses on lab-on-chip devices for capturing, detecting, and isolating extracellular vesicles. The first part of the paper discusses the main characteristics of different cell-derived vesicles, EV functions, and their clinical applications. In the second part, various microfluidic platforms suitable for the isolation and detection of exosomes are described, and their performance in terms of yield, sensitivity, and time of analysis is discussed.