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Semi-automatic fluidics system for BSC: (A) schematic of the system and (B) the actual photo of the BSC LOC system. The system consists of: computer (I), analog to digital/digital to analog converter (II), signal amplifier (IIa), BSC chip (III), digital multimeter (IV), pump (V) and six-way valve (VI) with the valves marked as A, B, C, D, E and F.
Source publication
We describe a new lab-on-a-chip (LOC) which utilizes a biological semiconductor (BSC) transducer for label free analysis of Staphylococcal Enterotoxin B (SEB) (or other biological interactions) directly and electronically. BSCs are new transducers based on electrical percolation through a multi-layer carbon nanotube-antibody network. In BSCs the pa...
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... enable point-of-care label free immunoassay analysis of SEB with a biological semiconductor, a LOC was developed for applying electrical percolation based transducer. The overall system for real-time electrical percolation biosensing ( Fig. 1A) includes three main elements: (1) LOC chip, (2) electronics and computer control system, and (3) fluid delivery system. The modular system (Fig. 1B) was designed to deliver fluid to the LOC chip (input) and to record the LOC data ...
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... analysis of SEB with a biological semiconductor, a LOC was developed for applying electrical percolation based transducer. The overall system for real-time electrical percolation biosensing ( Fig. 1A) includes three main elements: (1) LOC chip, (2) electronics and computer control system, and (3) fluid delivery system. The modular system (Fig. 1B) was designed to deliver fluid to the LOC chip (input) and to record the LOC data ...
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... #III: this core layer is made from PMMA, which provides rigidity to the assembly, an engraved surface for the electrode assembly (Fig. 3C, 1 and 5), as well as high volume for the SWNT-antibody gate fabrication and for the sample flow through (Fig. 3C-3). In addition this layer provides an outlet for the sample (Fig. 3C-2) and serves as an anchor point for electrical connectors. This layer carries adhesive on the ...
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... the LOC performs the actual measurements, a support system is needed for fluid delivery to the LOC, electronic measurements, control and data analysis. Fig. 1A shows the schematic of the system and Fig. 1B shows the actual ...
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... the LOC performs the actual measurements, a support system is needed for fluid delivery to the LOC, electronic measurements, control and data analysis. Fig. 1A shows the schematic of the system and Fig. 1B shows the actual ...
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... configuration shown in Fig. 1 is capable of automatic delivery for up to six different fluids to the LOC. The multimeter is connected to the LOC by two electrodes for measuring resis- tance and is connected to the computer via USB port for data transmission and for the operation of the device. The data are plotted in real time on the computer and are saved for ...
Similar publications
In this paper, to address the issues relevant to leakage, dead volume and contamination, we have miniaturized a pinch-type valve and a pinch-type peristaltic pump, which are surface mountable on the microfluidic lab-on-a-chip (LOC) devices. The pinch-type valve consisted of a solenoid magnetic actuator with a pinch plunger and a biomedical grade si...
Citations
... The signal generated by enhanced chemiluminescence enabled the detection of 0.1 ng mL −1 of SEB in a 10-μL sample. Later, this microfluidic platform was improved for the label-free detection of SEB and termed "biological semiconductor (BSC)" [101]. A label-free impedimetric immunosensor combined with a microfluidic chip has been constructed for the B subunit of CT [102]. ...
Considering the urgent demand for rapid and accurate determination of bacterial toxins and the recent promising developments in nanotechnology and microfluidics, this review summarizes new achievements of the past five years. Firstly, bacterial toxins will be categorized according to their antibody binding properties into low and high molecular weight compounds. Secondly, the types of antibodies and new techniques for producing antibodies are discussed, including poly- and mono-clonal antibodies, single-chain variable fragments (scFv), as well as heavy-chain and recombinant antibodies. Thirdly, the use of different nanomaterials, such as gold nanoparticles (AuNPs), magnetic nanoparticles (MNPs), quantum dots (QDs) and carbon nanomaterials (graphene and carbon nanotube), for labeling antibodies and toxins or for readout techniques will be summarized. Fourthly, microscale analysis or minimized devices, for example microfluidics or lab-on-a-chip (LOC), which have attracted increasing attention in combination with immunoassays for the robust detection or point-of-care testing (POCT), will be reviewed. Finally, some new materials and analytical strategies, which might be promising for analyzing toxins in the near future, will be shortly introduced.
... In contrast to these approaches to FET-based electronic sensing based on the electronic characteristics of the surfaces for individual nanoscale elements, a biosensor has been developed based on a different physical principle known as "electrical percolation". In electrical percolation, the electronic interactions within a randomly oriented and distributed network of nanoscale biological recognition elements is utilized as a transistor gate rather than the more ordered structures in the alternative surface-oriented approaches [18][19][20]. ...
... For biosensing, the biological recognition element (ligand) is bound to the CNT forming a "gate" for a "biological semiconductor" and the conductivity of the network is influenced by the interaction ligand-target at the gate. The utilization of electrical percolation as a transistor gate in the context of biological semiconductors (BSCs) was described recently [18][19][20]. ...
A new approach to label free biosensing has been developed based on the principle of "electrical percolation". In electrical percolation, long-range electrical connectivity is formed in randomly oriented and distributed systems of discrete elements. By applying this principle to biological interactions, it is possible to measure biological components both directly and electronically. The main element for electrical percolation biosensor is the biological semiconductor (BSC) which is a multi-layer 3-D carbon nanotube-antibody network. In the BSC, molecular interactions, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. BSCs can be fabricated by immobilizing conducting elements, such as pre-functionalized single-walled carbon nanotubes (SWNTs)-antibody complex, directly onto a substrate, such as a Poly(methyl methacrylate) (PMMA) surface (also known as plexi-glass or Acrylic). BSCs have been demonstrated for direct (label-free) electronic measurements of antibody-antigen binding using SWNTs. If the concentration of the SWNT network is slightly above the electrical percolation threshold, then binding of a specific antigen to the pre-functionalized SWNT dramatically increases the electrical resistance due to changes in the tunneling between the SWNTs. Using anti-Staphylococcal enterotoxin B (SEB) IgG as a "gate" and SEB as an "actuator", it was demonstrated that the BSC was able to detect SEB at concentrations of 1 ng/ml. Based on this concept, an automated configuration for BSCs is described here that enables real time continuous detection. The new BSC configuration may permit assembly of multiple sensors on the same chip to create "Biological Central Processing Units (CPUs)" with multiple biological elements, capable of processing and sorting out information on multiple analytes simultaneously.
... The details of our laser fabrication of LOC for assay measurement are described in previous work [24,25,43,44], the 36-well sample chips used in this study were designed in CorelDraw X4 (Corel Corp., Ontario, Canada) and then micro-machined in 1/8 in. black acrylic using a computer controlled laser cutter Epilog Legend CO 2 65W cutter (Epilog, Golden, CO). ...
Optical technologies are important for biological analysis. Current biomedical optical analyses rely on high-cost, high-sensitivity optical detectors such as photomultipliers, avalanched photodiodes or cooled CCD cameras. In contrast, Webcams, mobile phones and other popular consumer electronics use lower-sensitivity, lower-cost optical components such as photodiodes or CMOS sensors. In order for consumer electronics devices, such as webcams, to be useful for biomedical analysis, they must have increased sensitivity. We combined two strategies to increase the sensitivity of CMOS-based fluorescence detector.
... To demonstrate this approach, here we present a modular automated Point-of-care optical detection ELISA detection system that utilizes some of the fluidics modules developed for electrical percolation-based biosensors[33]The modular system integrates several elements (1) ELISA-LOC fluidics, (2) a CCD camera as detector, (3) pumps and valves for fluid delivery to the ELISA-LOC, (4) a computer interface board for controlling fluid delivery, and (5) a computer for controlling the fluidics, logging and data analysis of the CCD data. The simple modular fluid deliver automation design described here can be also used to automate other LOC systems. ...
... The ELISA-LOC described in our previous work[28; 29]incorporates microfluidics into the ELISA plate, so that an ELISA can be carried out without a washer. As shown inFigure 1, the ELISA-LOC brings together three elements: 1) an interchangeable fluid delivery system (FigureThe overall ELISA-LOC automation system for fluid delivery which is based on our previous design[33]is shown inFigure 2A. The system is composed of four basic modules: (1) the ELISA-LOC chip, (2) an electronics and computer control system, (3) a fluid delivery system and (4) a CCD-based detector. ...
... While the ELISA-LOC module is the platform for carrying out the actual assay, a support system of other modules is needed for reagent delivery to the ELISA-LOC, measurement of assay output, and analysis of the output.Figure 2Ashows a schematic of the open platform system for computer control and fluid delivery is based on our previous design[33].Figure 2Bshows the actual system which includes hardware and software.III. A fluid delivery peristaltic pump (A) for, moving fluids from fluid reservoirs through the valve and to the ELISA-LOC. ...
An automated point-of-care (POC) immunodetection system for immunological detection of staphylococcal enterotoxin B (SEB) was designed, fabricated, and tested. The system combines several elements: (i) enzyme-linked immunosorbent assay-lab-on-a-chip (ELISA-LOC) with fluidics, (ii) a charge-coupled device (CCD) camera detector, (iii) pumps and valves for fluid delivery to the ELISA-LOC, (iv) a computer interface board, and (v) a computer for controlling the fluidics, logging, and data analysis of the CCD data. The ELISA-LOC integrates a simple microfluidic system into a miniature 96-well sample plate, allowing the user to carry out immunological assays without a laboratory. The analyte is measured in a sandwich ELISA assay format combined with a sensitive electrochemiluminescence (ECL) detection method. Using the POC system, SEB, a major foodborne toxin, was detected at concentrations as low as 0.1 ng/ml. This is similar to the reported sensitivity of conventional ELISA. The open platform with simple modular fluid delivery automation design described here is interchangeable between detection systems, and because of its versatility it can also be used to automate many other LOC systems, simplifying LOC development. This new POC system is useful for carrying out various immunological and other complex medical assays without a laboratory and can easily be adapted for high-throughput biological screening in remote and resource-poor areas.
Staphylococcal enterotoxins (SEs), the major virulence factors of Staphylococcus aureus, cause a wide range of food poisoning and seriously threaten human health by infiltrating the food supply chain at different phases of manufacture, processes, distribution, and market. The significant prevalence of Staphylococcus aureus calls for efficient, fast, and sensitive methods for the early detection of SEs. Here, we provide a comprehensive review of the hazards of SEs in contaminated food, the characteristic and worldwide regulations of SEs, and various detection methods for SEs with extensive comparison and discussion of benefits and drawbacks, mainly including biological detection, genetic detection, and mass spectrometry detection and biosensors. We highlight the biosensors for the screening purpose of SEs, which are classified according to different recognition elements such as antibodies, aptamers, molecularly imprinted polymers, T‐cell receptors, and transducers such as optical, electrochemical, and piezoelectric biosensors. We analyzed challenges of biosensors for the monitoring of SEs and conclude the trends for the development of novel biosensors should pay attention to improve samples pretreatment efficiency, employ innovative nanomaterials, and develop portable instruments. This review provides new information and insightful commentary, important to the development and innovation of further detection methods for SEs in food samples.
Advances in science, which lead to increased understanding of the mechanisms of action by microbial toxins, have resulted in a more exhaustive classification. This chapter focuses on the methods employed in the industry or that are being developed for identification and quantification of bacterial toxins only. Several indirect methods of detection have also been developed that utilise the functional properties of the various toxins to trigger effects in animal/cells or involve the detection of the species of genes involved in producing specific bacterial toxins. These indirect assays include polymerase chain reaction (PCR), animal assay, cellular assay and memory antibody methods. There is need for in vitro tests for emetic toxins and specific tests for biologically active diarrheal toxins. Changes in methods of food processing and preservation will require continuous evaluation to ensure that the required safety factor with respect to C. botulinum, diarrheagenic E. coli and other enteric pathogens is built into the resulting foods.
Foodborne illnesses caused by pathogenic agents continue to be one of the most important public health concerns worldwide. Rapid and sensitive detection methods for pathogenic microorganisms are essential to mount effective responses to microbial contamination, including foodborne outbreaks and bioterrorist attacks. Advanced strategies exploiting the latest micro- and nanoscale technologies have been developed in the last decades, bringing new insights into the detection of pathogenic agents in foods. In particular, recent efforts have focused on unique sample preparation methods, novel assay formats, and miniaturized detection platforms. In this book chapter we endeavor to summarize the latest micro- and nanotechnology based approaches to detect pathogenic agents in food, as well highlighting the most promising technologies with regard to their future exploitation. Our goal is to provide the reader with new insights into how and when these technologies can be exploited to ensure the enumeration, and accurate detection of pathogenic bacteria in foods.
In order to stay in good health, people have regular checkups. Part of this process involves examining the body for abnormalities. This requires a variety of large, complicated medical equipment to measure a small amount of biomolecules or chemical substances. The rapid advances in microelectromechanical systems (MEMS) and nanotechnology have made it possible to downsize medical equipment and perform health checkups using simpler detection methods such as label-free measurements. Nanomaterials have been used to achieve these goals; however, these require high-level sensor fabrication techniques and may provide lower sensitivity than conventional methods. In this work, we developed a compact label-free small molecule measurement system using a periodically nanostructured sensor substrate. We fabricated the sensor substrate using simple techniques, namely, thermal nanoimprinting and sputtering. The sensor substrate realizes label-free measurements by utilizing surface plasmon resonance (SPR). A collimator is mounted into an optical fiber to reduce noise in real-time measurements. The flow cell height and velocity were investigated with the aim of shortening the equilibrium binding time. We demonstrate the simple yet effective method by performing label-free measurement of a small molecule, namely, cortisol (M.W. = 362 g mol−1), with a concentration of several tens of nanomoles per liter. We demonstrated that the normalized peak wavelength obtained by our measurement system shows good correlation with the cortisol concentration (0 nM, 24.3 nM and 48.6 nM). Our results had a smaller standard deviation than those of the ELISA test.
