Development of chip-compatible sample preparation for diagnosis of infectious diseases

Ritzi-Lehnert, Marion

doi:10.1586/erm.11.98

Cited by 49 publications

(31 citation statements)

References 116 publications

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“…Products such as InstaGene Matrix (Bio-Rad) also remove PCR inhibitors from patient samples but dilute the DNA instead of concentrating it. Self-contained microfluidic devices embedded with silica beads or posts have been developed for one-step nucleic acid extractions [15]. However, the small diameter of microfluidic channels restricts the silica surface area available for biomarker adsorption as well as the maximum sample volume that can be flowed through the channels (typically <500 µL) [14].…”

Section: Introductionmentioning

confidence: 99%

A Magnetic Bead-Based Method for Concentrating DNA from Human Urine for Downstream Detection

et al. 2013

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Due to the presence of PCR inhibitors, PCR cannot be used directly on most clinical samples, including human urine, without pre-treatment. A magnetic bead-based strategy is one potential method to collect biomarkers from urine samples and separate the biomarkers from PCR inhibitors. In this report, a 1 mL urine sample was mixed within the bulb of a transfer pipette containing lyophilized nucleic acid-silica adsorption buffer and silica-coated magnetic beads. After mixing, the sample was transferred from the pipette bulb to a small diameter tube, and captured biomarkers were concentrated using magnetic entrainment of beads through pre-arrayed wash solutions separated by small air gaps. Feasibility was tested using synthetic segments of the 140 bp tuberculosis IS6110 DNA sequence spiked into pooled human urine samples. DNA recovery was evaluated by qPCR. Despite the presence of spiked DNA, no DNA was detectable in unextracted urine samples, presumably due to the presence of PCR inhibitors. However, following extraction with the magnetic bead-based method, we found that ∼50% of spiked TB DNA was recovered from human urine containing roughly 5×103 to 5×108 copies of IS6110 DNA. In addition, the DNA was concentrated approximately ten-fold into water. The final concentration of DNA in the eluate was 5×106, 14×106, and 8×106 copies/µL for 1, 3, and 5 mL urine samples, respectively. Lyophilized and freshly prepared reagents within the transfer pipette produced similar results, suggesting that long-term storage without refrigeration is possible. DNA recovery increased with the length of the spiked DNA segments from 10±0.9% for a 75 bp DNA sequence to 42±4% for a 100 bp segment and 58±9% for a 140 bp segment. The estimated LOD was 77 copies of DNA/µL of urine. The strategy presented here provides a simple means to achieve high nucleic acid recovery from easily obtained urine samples, which does not contain inhibitors of PCR.

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Section: Introductionmentioning

confidence: 99%

A Magnetic Bead-Based Method for Concentrating DNA from Human Urine for Downstream Detection

et al. 2013

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“…The system should be able to detect pathogens and host biomarkers (proteins and nucleic acids) simultaneously. Sample preparation remains the largest bottleneck in miniaturised diagnostics: 134 large volumes (several millilitres of blood) need to be reduced to small amounts (in the order of microlitres); the microbial load in the sample can vary a lot and be very low; the target should remain intact, but many complex specimens contain nucleases or inhibitors of nucleic acid amplifi cations. Therefore, most sample preparations of available miniaturised molecular systems rely on many operations, and need several liquid additions and washing steps.…”

Section: Huge Technical Challengesmentioning

confidence: 99%

Antibiotic resistance—the need for global solutions

2014

Br Dent J

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The causes of antibiotic resistance are complex and include human behaviour at many levels of society; the consequences aff ect everybody in the world. Similarities with climate change are evident. Many eff orts have been made to describe the many diff erent facets of antibiotic resistance and the interventions needed to meet the challenge. However, coordinated action is largely absent, especially at the political level, both nationally and internationally. Antibiotics paved the way for unprecedented medical and societal developments, and are today indispensible in all health systems. Achievements in modern medicine, such as major surgery, organ transplantation, treatment of preterm babies, and cancer chemotherapy, which we today take for granted, would not be possible without access to eff ective treatment for bacterial infections. Within just a few years, we might be faced with dire setbacks, medically, socially, and economically, unless real and unprecedented global coordinated actions are immediately taken. Here, we describe the global situation of antibiotic resistance, its major causes and consequences, and identify key areas in which action is urgently needed.

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“…The strengths of such systems include a reduced requirement for samples and reagents, fast and high-throughput results, low power consumption, a reduced contamination risk and a high degree of parallelization [1,3]. These designs take advantage of the great developments occurring in microfabrication techniques.…”

Section: Lab-on-a-chip (Loc)mentioning

confidence: 99%

“…New diagnostic tools are needed to meet the increasing demand for fast, reliable and cost-effective diagnostic devices. These new tools would replace currently available tests that can only be conducted in fully equipped diagnostics laboratories [1]. Many research groups have proposed models for POC systems that are implemented in microfluidic-based platforms, based on a wide range of available technologies.…”

Section: Introductionmentioning

confidence: 99%

Microarray Dot Electrodes Utilizing Dielectrophoresis for Cell Characterization

Yafouz

Kadri

Ibrahim

2013

Sensors

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During the last three decades; dielectrophoresis (DEP) has become a vital tool for cell manipulation and characterization due to its non-invasiveness. It is very useful in the trend towards point-of-care systems. Currently, most efforts are focused on using DEP in biomedical applications, such as the spatial manipulation of cells, the selective separation or enrichment of target cells, high-throughput molecular screening, biosensors and immunoassays. A significant amount of research on DEP has produced a wide range of microelectrode configurations. In this paper; we describe the microarray dot electrode, a promising electrode geometry to characterize and manipulate cells via DEP. The advantages offered by this type of microelectrode are also reviewed. The protocol for fabricating planar microelectrodes using photolithography is documented to demonstrate the fast and cost-effective fabrication process. Additionally; different state-of-the-art Lab-on-a-Chip (LOC) devices that have been proposed for DEP applications in the literature are reviewed. We also present our recently designed LOC device, which uses an improved microarray dot electrode configuration to address the challenges facing other devices. This type of LOC system has the capability to boost the implementation of DEP technology in practical settings such as clinical cell sorting, infection diagnosis, and enrichment of particle populations for drug development.

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Development of chip-compatible sample preparation for diagnosis of infectious diseases

Cited by 49 publications

References 116 publications

A Magnetic Bead-Based Method for Concentrating DNA from Human Urine for Downstream Detection

A Magnetic Bead-Based Method for Concentrating DNA from Human Urine for Downstream Detection

Antibiotic resistance—the need for global solutions

Microarray Dot Electrodes Utilizing Dielectrophoresis for Cell Characterization

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