The Use of Streptavidin Coated Magnetic Beads for Detecting Pathogenic Bacteria by Light Addressable Potentiometric Sensor (Laps)

Tu, Shu‐I; Uknalis, Joseph; Irwin, Peter L.; Yu, Linda

doi:10.1111/j.1745-4581.2000.tb00353.x

Cited by 34 publications

(12 citation statements)

References 11 publications

(14 reference statements)

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“…This two-step procedure is used because in-liquid measurement is compromised because of viscous damping. The current methods capable of pathogen detection at low concentrations under liquid include traditional enrichment and plating methods in selective media, 52 polymerase chain reaction (PCR), 53 fiber-optic biosensors, 44,[54][55][56] immunomagnetic beads, 57 and quartz crystal microbalance. 58 Enrichment and plating approach lack sensitivity and specificity and often take 24-96 h to identify the contaminant organism.…”

Section: Discussionmentioning

confidence: 99%

Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples

et al. 2007

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Rapid (∼10 min) measurement of very low concentration of pathogens (∼10 cells/mL) and protein (∼fg/mL) has widespread use in medical diagnostics, monitoring biothreat agents, and in a broader context as a research method. For low-level pathogen, we currently use culture enrichment methods and, thus, rapid analysis is not possible. For low protein concentration, no direct method is currently available. We report here a novel macrocantilever design whose high-order resonant mode near 1 MHz exhibits mass detection sensitivity of 10 cells/mL for cells and 100 fg/mL for protein. The sensor is 1 × 3 mm and uses a piezoelectric layer for both actuation and sensing resonance. Sample is flowed (∼1 mL/min) past the antibody-immobilized sensor, and as antigen binds to the sensor, resonance frequency decreases in proportion to antigen concentration. The sensor showed selectivity to the pathogen even though copious nonpathogenic variant was simultaneously present.Rapid and single-step label-free direct detection of proteins in flowing liquid samples at a concentration of 100 fg/mL has not been reported to date. Neither has there been any report on detecting pathogens at 10 cells per mL from samples of tens of milliliters under flow conditions. Both measurements have significant applications in medicine (for biomarkers in body fluids), 1 environmental monitoring (pathogens in drinking water), food safety (Listeria, 2 Cyrptosporidium, Giardia, 3 and Escherichia coli poisoning 4 ), and biodefense (biothreat agents). In this paper, we show designs of millimeter-sized cantilever sensors that exhibit mass change sensitivity of femtograms under liquid flow conditions and that are potentially useful in the applications mentioned above. Three types of experiments are reported to demonstrate the high detection sensitivity.Cantilever biosensors have attracted considerable interest in the past decade for label-free detection of proteins and pathogens because of their promise of very high sensitivity. 5,6 Excellent reviews have appeared that summarize progress. 7,8 Briefly, the binding of an antigenic target to an antibody-immobilized cantilever surface changes the cantilever's surface stress resulting in a deflection response. 9,10 Cantilever biosensors 11,12 have been successfully used in DNA hybridization studies, 9,13 detection of known cancer proteins, 14 environmental and foodborne pathogens, 15,16 biomarkers, 17,18 and explosives. 19 In dynamic mode, the attachment of antigen causes a resonant frequency decrease because of increase in mass. 7 Magnitude of bending deflection can be monitored by various transduction mechanisms. 7,[20][21][22] Because significant damping occurs in the dynamic mode, static deflection method is preferred when continuous measurement under liquid immersion is needed. When measurement in liquid flow condition is required, the bending mode becomes noisy and less trustworthy because of fluctuating hydrodynamic forces. It is well established 23 that for the dynamic method to provide reasonable signals, c...

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Section: Discussionmentioning

confidence: 99%

Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples

et al. 2007

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“…Origi-nally the design of most biosensors is based on the sandwich immunoassay, which forms an immuno-complex consisting of the immobilized primary antibodies, the captured target bacteria, and the second antibodies labeled with enzymes. The signal resulting from the enzymatic reaction is detected by optical absorbance (Demarco and Lim, 2002;Liu and Li, 2001), chemiluminescence (Liu et al, 2003), potentiometry (Tu et al, 2000), or electrochemical impedance (Ruan et al, 2002). Though these immunosensors can improve the detection sensitivity and reduce the assay time, they are label-dependent, so costly and complicated.…”

Section: Introductionmentioning

confidence: 99%

Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

Wang

et al. 2008

J. Zhejiang Univ. Sci. B

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By means of the specific immuno-recognition and ultra-sensitive mass detection, a quartz crystal microbalance (QCM) biosensor for Escherichia coli O157:H7 detection was developed in this work. As a suitable surfactant, 16-mercaptohexadecanoic acid (MHDA) was introduced onto the Au surface of QCM, and then self-assembled with N-hydroxysuccinimide (NHS) raster as a reactive intermediate to provide an active interface for the specific antibody immobilization. The binding of target bacteria with the immobilized antibodies decreased the sensor's resonant frequency, and the frequency shift was correlated to the bacterial concentration. The stepwise assembly of the immunosensor was characterized by means of the electrochemical techniques. Using the immersion-dry-immersion procedure, this QCM biosensor could detect 2.0×10 2 colony forming units (CFU)/ml E. coli O157:H7. In order to reduce the fabrication time, a polyelectrolyte layer-by-layer self-assembly (LBL-SA) method was adopted for fast construction. Finally, the reproducibility of this biosensor was discussed.

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“…[48] 10-Streptavidin coated magnetic beads were used for bacteria detection. [49] 11-Supra-magnetic iron oxide microspheres have been used for detection of metastases in non-enlarged lymph nodes. [50] 12-Magnetic Dynabeads have been used in immune-magnetic techniques for the enrichment and detection of isolated breast carcinoma cells in bone marrow and peripheral blood.…”

Section: Farah World Journal Of Pharmacy and Pharmaceutical Sciencesmentioning

confidence: 99%

Magnetic Microspheres: A Novel Drug Delivery System

Farah¹

2017

WJPPS

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A well designed controlled drug delivery system can provide a therapeutic amount of drug to the proper site in the body and then maintain the desired drug concentration for the specific period of time.A number of approaches are available in delivering therapeutic substance to the target site in sustained and controlled release fashion.One such approach is using magnetic microspheres as carriers for drugs. Microsphere drug delivery system has gained vast attention due to its diverse applications that range from targeting the drug to specific site to imaging and helping the diagnostic features. One of its important application is that it is used for targeting tumors using anticancer drugs. Being more stable, it has an advantage over other delivery systems like liposomes. The main objectives of this review is to highlight some important aspects of magnetic microspheres as a novel drug delivery system. The review shall cover definitions, concepts, types, mechanism of targeting, evaluation and characteristics of magnetic microspheres as well as various methods and techniques used in their preparations. The review also entails various applications and future prospects of magnetic microspheres.

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The Use of Streptavidin Coated Magnetic Beads for Detecting Pathogenic Bacteria by Light Addressable Potentiometric Sensor (Laps)

Cited by 34 publications

References 11 publications

Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples

Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples

Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

Magnetic Microspheres: A Novel Drug Delivery System

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