“…The imaging system was isolated from both optical and electronic background noise in a special chamber, in which ambient light, temperature and humidity were strictly controlled. A detailed description of this controlled chamber can be found elsewhere ( Agranat et al, 2021 ).…”
Section: Methodsmentioning
confidence: 99%
“…The imaging system was isolated from both optical and electronic background noise in a special chamber, in which ambient light, temperature and humidity were strictly controlled. A detailed description of this controlled chamber can be found elsewhere (Agranat et al, 2021). A monolayer of beads was homogenously spread on triplicate 35 mm diameter targets, containing soil with different amounts of buried DNT, as well as DNT-free control targets.…”
Section: Exposure Of Alginate-immobilized Cells To Dnt Soil Surfacementioning
Detection of buried landmines is a dangerous and complicated task that consumes large financial resources and poses significant risks to the personnel involved. A potential alternative to conventional detection methodologies is the use of microbial bioreporters, capable of emitting an optical signal upon exposure to explosives, thus revealing to a remote detector the location of buried explosive devices. We have previously reported the design, construction, and optimization of an Escherichia coli-based bioreporter for the detection of 2,4,6-trinitrotoluene (TNT) and its accompanying impurity 2,4-dinitrotoluene (DNT). Here we describe the further enhancement of this bioreporter by the directed evolution of YhaJ, the transcriptional activator of the yqjF gene promoter, the sensing element of the bioreporter’s molecular circuit. This process resulted in a 37-fold reduction of the detection threshold, as well as significant enhancements to signal intensity and response time, rendering this sensor strain more suitable for detecting the minute concentrations of DNT in the soil above buried landmines. The capability of this enhanced bioreporter to detect DNT buried in sand is demonstrated.
“…The imaging system was isolated from both optical and electronic background noise in a special chamber, in which ambient light, temperature and humidity were strictly controlled. A detailed description of this controlled chamber can be found elsewhere ( Agranat et al, 2021 ).…”
Section: Methodsmentioning
confidence: 99%
“…The imaging system was isolated from both optical and electronic background noise in a special chamber, in which ambient light, temperature and humidity were strictly controlled. A detailed description of this controlled chamber can be found elsewhere (Agranat et al, 2021). A monolayer of beads was homogenously spread on triplicate 35 mm diameter targets, containing soil with different amounts of buried DNT, as well as DNT-free control targets.…”
Section: Exposure Of Alginate-immobilized Cells To Dnt Soil Surfacementioning
Detection of buried landmines is a dangerous and complicated task that consumes large financial resources and poses significant risks to the personnel involved. A potential alternative to conventional detection methodologies is the use of microbial bioreporters, capable of emitting an optical signal upon exposure to explosives, thus revealing to a remote detector the location of buried explosive devices. We have previously reported the design, construction, and optimization of an Escherichia coli-based bioreporter for the detection of 2,4,6-trinitrotoluene (TNT) and its accompanying impurity 2,4-dinitrotoluene (DNT). Here we describe the further enhancement of this bioreporter by the directed evolution of YhaJ, the transcriptional activator of the yqjF gene promoter, the sensing element of the bioreporter’s molecular circuit. This process resulted in a 37-fold reduction of the detection threshold, as well as significant enhancements to signal intensity and response time, rendering this sensor strain more suitable for detecting the minute concentrations of DNT in the soil above buried landmines. The capability of this enhanced bioreporter to detect DNT buried in sand is demonstrated.
“…They employed a network of six biosensors to find minuscule dinitrotoluene (DNT) quantities. These results demonstrated a DNT detection sensitivity of 0.25 mg DNT per kg sand [76].…”
Section: Development Of Luminescent Bacteria–based Biosensorsmentioning
confidence: 99%
“…(a) The biosensor module structure; (b) schematic design of the biological sensing‐reporting element; and (c) schematic illustration of the optoelectronic circuit, which consists of a differential amplifier (DA) with a feedback resistor (R 3 ), photodiodes (PD1 and PD2), transimpedance amplifiers (TIA1 and TIA2), and feedback resistors (R 1 and R 2 ). Source : Reproduced with permission [76]. Copyright 2021 Elsevier B.V.…”
Section: Development Of Luminescent Bacteria–based Biosensorsmentioning
Luminescent bacteria–based biosensors are widely used for fast and sensitive monitoring of food safety, water quality, and other environmental pollutions. Recent advancements in biomedical engineering technology have led to improved portability, integration, and intelligence of these biotoxicity assays. Moreover, genetic engineering has played a significant role in the development of recombinant luminescent bacterial biosensors, enhancing both detection accuracy and sensitivity. This review provides an overview of recent advances in the development and applications of novel luminescent bacteria–based biosensors, and future perspectives and challenges in the cutting‐edge research, market translation, and practical applications of luminescent bacterial biosensing are discussed.
“…Ellipsometric biosensors allow monitoring the changing polarization of light that has been reflected [149]. Moreover, improvements in genetic recombination techniques have led to the generation of bioluminescent molecules that are usually immobilized in optical fiber that emit an optical signal in response to the binding of the analyte of interest [150]. In recent years, optical biosensors have established a significant role in miRNA quantification, since their ability to reach a low detection limit and high sensitivity and specificity were confirmed.…”
Section: Optical Biosensors For Mirna Detectionmentioning
MicroRNA (miRNA) are constituted of approximately 22 nucleotides and play an important role in the regulation of many physiological functions and diseases. In the last 10 years, an increasing interest has been recorded in studying the expression profile of miRNAs in cancer. Real time-quantitative polymerase chain reaction (RT-qPCR), microarrays, and small RNA sequencing represent the gold standard techniques used in the last 30 years as detection methods. The advent of nanotechnology has allowed the fabrication of nanostructured biosensors which are widely exploited in the diagnostic field. Nanostructured biosensors offer many advantages: (i) their small size allows the construction of portable, wearable, and low-cost products; (ii) the large surface–volume ratio enables the loading of a great number of biorecognition elements (e.g., probes, receptors); and (iii) direct contact of the recognition element with the analyte increases the sensitivity and specificity inducing low limits of detection (LOD). In this review, the role of nanostructured biosensors in miRNA detection is explored, focusing on electrochemical and optical sensing. In particular, four types of nanomaterials (metallic nanoparticles, graphene oxide, quantum dots, and nanostructured polymers) are reported for both detection strategies with the aim to show their distinct properties and applications.
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