Gascoyne 2004 Microfluidic approaches to malaria detection (original) (raw)
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ACS Nano, 2012
We present an attractive new system for the specific and sensitive detection of the malaria-causing Plasmodium parasites. The system relies on isothermal conversion of single DNA cleavageÀligation events catalyzed specifically by the Plasmodium enzyme topoisomerase I to micrometer-sized products detectable at the single-molecule level. Combined with a droplet microfluidics labon-a-chip platform, this design allowed for sensitive, specific, and quantitative detection of all human-malaria-causing Plasmodium species in single drops of unprocessed blood with a detection limit of less than one parasite/μL. Moreover, the setup allowed for detection of Plasmodium parasites in noninvasive saliva samples from infected patients. During recent years malaria transmission has declined worldwide, and with this the number of patients with low-parasite density has increased.
12th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2008, 2008
A novel, point-of-care immunoassay format is demonstrated for malarial diagnosis. The assay system consists of a disposable card with integrated dry reagent storage and an external reader that conducts fluidic actuation and assay quantification. Reagents flow through a porous membrane encased in the card's polymeric laminates to conduct a colorimetric sandwich assay on the membrane's surface. The system produces quantitative results with detection limits on the order of ELISA in under 9 minutes.
Microsystem Technologies, 2020
Digital Microfluidics (DMF) has potentially been a favorable platform for point-of-care molecular diagnostics. However, its fabrication process normally relies heavily on expensive microfabrication facilities and equipment. In this work, we developed a portable, small footprint DMF device that requires minimal microfabrication work (only a small clean bench and a DIY spin coater were required) but is still capable of performing nucleic acid amplification tests. The DMF system implemented in this work could perform successfully the Loop-mediated isothermal Amplification (LAMP) reaction with samples containing extracted DNA of Plasmodium falciparum that causes Malaria in human. The LAMP reaction was conducted at the optimal temperature of 65°C in 45 min with the total reaction volume of 1.5 lL. The results of LAMP were designed to be observable to naked eyes via the color change from pink to yellowish orange, which simplifies the readout step and eliminates the necessity for external and bulky result-reading equipment.
Development of a film-based immunochromatographic microfluidic device for malaria diagnosis
Biomedical Microdevices, 2019
In this study, a novel film-based immunochromatographic microfluidic device (IMD) has been developed for malaria diagnosis. A microfluidic channel was patterned on a polyethylene terephthalate (PET) double-sided adhesive film using a plotting cutter and was assembled with a polycarbonate (PC) film. The PC film used for the probe immobilization layer was activated using oxygen plasma treatment to modify the film surface with avidin-biotin linker to immobilize a capture antibody. A fluorescent labeled Pan type mAb conjugate was prepared for signal indicator after undergoing a sandwich enzyme-linked immunosorbent assay (ELISA). Target antigens include Plasmodium falciparum (P. falciparum) lactate dehydrogenase (LDH) and Plasmodium vivax (P. vivax) LDH which were injected into the sample inlet. Target antigens combined with the conjugate and then flowed to the detection chamber where two test dots and a control dot (Ctrl) exist. In the presence of P. falciparum LDH, three detection dots including test dot 1 (T1), test dot 2 (T2) and Ctrl revealed fluorescence signals where P. falciparum mAb, Pan type pLDH mAb and goat anti-mouse IgG were immobilized, respectively. When P. vivax LDH was present, T2 and Ctrl dots showed fluorescence signals while no signal was detected with the negative control. P. falciparum LDH and P. vivax LDH were successfully detected on the IMD with a detection limit of 50 ng/mL and 100 ng/mL, respectively. The IMD provides a point-of-care diagnosis platform which is able to analyze pathogenic bacteria and viruses that can be applied in the field of clinical diagnosis and food safety testing.
Malaria detection using inertial microfluidics
Diagnosis of malaria at the early stage of infection is challenging due to the difficulty in detecting low abundance parasites from blood. Molecular methods such as real-time polymerase chain reaction (qPCR) can be especially useful for detecting low parasitemia levels due to their high sensitivity and their ability to recognize different malarial species and strains. Unfortunately, the accuracy of qPCR-based malaria detection can be compromised by many factors, including the limited specificity of primers, presence of PCR inhibitors in blood serum and DNA contamination from nucleated blood cells. Here, we use a label-free, shear-modulated inertial microfluidic system to enrich malaria parasites from blood so as to facilitate a more reliable and specific PCR-based malaria detection. This technique capitalizes on cell focusing behaviors in high aspect ratio microchannels coupled with pinched flow dynamics to isolate ring-stage malaria parasites from lysed blood containing white blood cells (WBCs). In this high aspect ratio (ratio of the channel height to the width) platform, the high shear rate along the channel width causes the dispersed WBCs at the inlet to migrate and align into two streams near the channel sidewalls while the malaria parasites remain unfocused. Sensitive detection of parasites at spiked densities ranging from 10 3 to 10 4 Plasmodium falciparum parasites per mL (~2-10 per μL) has been demonstrated; they have also been quantified in whole blood using qPCR. This is approximately 100-fold more sensitive than the gold standard conventional microscopy analysis of thick blood smears. The simplicity of this device makes it ideal for integration with an automatic system for ultra-fast and accurate detection despite low levels of parasitemia. It can also help in malaria screening and elimination efforts.
A lab-on-chip for malaria diagnosis and surveillance
Malaria Journal, 2014
Background: Access to timely and accurate diagnostic tests has a significant impact in the management of diseases of global concern such as malaria. While molecular diagnostics satisfy this need effectively in developed countries, barriers in technology, reagent storage, cost and expertise have hampered the introduction of these methods in developing countries. In this study a simple, lab-on-chip PCR diagnostic was created for malaria that overcomes these challenges.
Journal of Pharmaceutical Research International, 2021
Objective: The objective of the study is to compare three techniques, routinely used rapid diagnostic tests (lateral flow immune chromatography) versus nucleic acid amplification test (NAT) versus Paper-based microfluidics for DNA diagnostics of Malaria, in terms of their sensitivity and specificity as diagnostic tests in detecting malarial infection among febrile illnesses, suspected of malaria, as well as to compare their cost-effectiveness. Methodology: Three seventy febrile cases suspected of malaria with negative results with RDT will be screened by real-time PCR and DNA microfluidics techniques, sensitivity and specificity of these as screening tests will be compared. The number of extra positive cases detected by NAT gives us the yield. Cost-effectiveness analysis will be done by calculating the incremental cost-effectiveness ratio (ICER) and average cost-effectiveness ratio (ACER) for the tests. Statistical Analysis: Statistical analysis will be done using SPSS version 21. ...
A Lab‐On‐chip Tool for Rapid, Quantitative, and Stage‐selective Diagnosis of Malaria
Advanced Science, 2021
Malaria remains the most important mosquito-borne infectious disease worldwide, with 229 million new cases and 409.000 deaths in 2019. The infection is caused by a protozoan parasite which attacks red blood cells by feeding on hemoglobin and transforming it into hemozoin. Despite the WHO recommendation of prompt malaria diagnosis, the quality of microscopy-based diagnosis is frequently inadequate while rapid diagnostic tests based on antigens are not quantitative and still affected by non-negligible false negative/positive results. PCR-based methods are highly performant but still not widely used in endemic areas. Here, a diagnostic tool (TMek), based on the paramagnetic properties of hemozoin nanocrystals in infected red blood cells (i-RBCs), is reported on. Exploiting the competition between gravity and magnetic forces, i-RBCs in a whole blood specimen are sorted and electrically detected in a microchip. The amplitude and time evolution of the electrical signal allow for the quantification of i-RBCs (in the range 10-10 5 i-RBC µL −1) and the distinction of the infection stage. A preliminary validation study on 75 patients with clinical suspect of malaria shows on-field operability, without false negative and a few false positive results. These findings indicate the potential of TMek as a quantitative, stage-selective, rapid test for malaria.
On-Chip Integration of Lysis and Nucleic Acid Preparation of Malaria-Infected Blood
2011
We present a device and technique for integrating on-chip lysing and extraction of DNA from P. falciparum-infected human blood. The device combines microfluidic channels and reservoirs fabricated in photoresist with surface-mounted electronics of a printed circuit board (PCB). Blood is lysed on-chip above a surface-mounted resistive heater. On-chip electrodes initiate isotachophoresis, which extracts nucleic acids into the channel. This process uses microliter blood volumes. Lysis is achieved in 4 min and nucleic acids are extracted through a 2.5 cm long channel over 5 min. We show that the extracted nucleic acids are compatible with off-chip polymerase chain reaction (PCR).