scholarly journals Electrokinetic Formation of “Microbridges” for Protein Biomarkers as Sensors

2007 ◽  
Vol 12 (5) ◽  
pp. 311-317 ◽  
Author(s):  
Vindhya Kunduru ◽  
Shalini Prasad
Keyword(s):  
Electric Fields ◽  
Microelectrode Array ◽  
Protein Detection ◽  
High Specificity ◽  
Detection Methods ◽  
Label Free ◽  
Protein Biomarkers ◽  
Detection Scheme ◽  
Polystyrene Beads ◽  
Conducting Path

We demonstrate a technique to detect protein biomarkers contained in vulnerable coronary plaque using a platform-based microelectrode array (MEA). The detection scheme is based on the property of high specificity binding between antibody and antigen similar to most immunoassay techniques. Rapid clinical diagnosis can be achieved by detecting the amount of protein in blood by analyzing the protein's electrical signature. Polystyrene beads which act as transportation agents for the immobile proteins (antigen) are electrically aligned by application of homogenous electric fields. The principle of electrophoresis is used to produce calculated electrokinetic movement among the anti-C-reactive protein (CRP), or in other words antibody funtionalized polystyrene beads. The electrophoretic movement of antibody-functionalized polystyrene beads results in the formation of “Microbridges” between the two electrodes of interest which aid in the amplification of the antigen—antibody binding event. Sensitive electrical equipment is used for capturing the amplified signal from the “Microbridge” which essentially behaves as a conducting path between the two electrodes. The technique circumvents the disadvantages of conventional protein detection methods by being rapid, noninvasive, label-free, repeatable, and inexpensive. The same principle of detection can be applied for any receptor—ligand-based system because the technique is based only on the volume of the analyte of interest. Detection of the inflammatory coronary disease biomarker CRP is achieved at concentration levels spanning over the lower microgram/milliliter to higher order nanogram/milliliter ranges.

Nanotextured Electrical Immunoassays for Ultrasensitive Protein Detection

2011 ◽  
Vol 1346 ◽  
Author(s):  
Timothy O. Mertz ◽  
Krishna Vattipalli ◽  
Tom Barrett ◽  
John Carruthers ◽  
Shalini Prasad
Keyword(s):  
Protein Detection ◽  
Cost Effective ◽  
Disease Diagnosis ◽  
Detection Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Detection Accuracy ◽  
Label Free ◽  
Electrode Arrays ◽  
Protein Biomarkers ◽  
Hybrid Sensors

ABSTRACTThis paper describes the development of nanomonitors, which are electrical immunoassays for detection of multiple protein biomarkers. These devices are hybrid sensors with micro-fabricated electrode arrays on a silicon substrate, and integrated nanoporous alumina membranes to provide protein confinement and signal amplification. The disease biomarkers C-reactive protein and Myeloperoxidase have been detected by the nanomonitors in ultra-low concentrations. Proteins were detected in pure samples, human serum, and patient blood samples. The detection accuracy and sensitivity of the nanomonitors in patient samples was comparable to the Enzyme Linked Immunosorbent Assay (ELISA) method of protein detection. Nanomonitors provide the additional benefits of being rapid, label-free, sensitive, and cost effective, providing improvements over traditional protein detection methods, and having potential applications in disease diagnosis.

Electrical Detection of Protein Biomarkers Using Nanoneedle Biosensors

2012 ◽  
Vol 1414 ◽  
Author(s):  
Rahim Esfandyarpour ◽  
Hesaam Esfandyarpour ◽  
Mehdi Javanmard ◽  
James S. Harris ◽  
Ronald W. Davis
Keyword(s):  
Physical Adsorption ◽  
Ionic Current ◽  
Microfluidic Channel ◽  
Protein Detection ◽  
High Sensitivity ◽  
Receptor Protein ◽  
Label Free ◽  
Electrical Detection ◽  
Protein Biomarkers ◽  
Impedance Modulation

Abstract:Here we present the development of an array of electrical nano-biosensors in a microfluidic channel, called Nanoneedle biosensors. Then we present the proof of concept study for protein detection. A Nanoneedle biosensor is a real-time, label-free, direct electrical detection platform, which is capable of high sensitivity detection, measuring the change in ionic current and impedance modulation, due to the presence or reaction of biomolecules such as proteins or nucleic acids. We show that the sensors which have been fabricated and characterized for the protein detection. We have functionalized Nanoneedle biosensors with receptors specific to a target protein using physical adsorption for immobilization. We have used biotinylated bovine serum albumin as the receptor and sterptavidin as the target analyte. The detection of streptavidin binding to the receptor protein is also presented.

scholarly journals Carbon Nanotube-Based Electrochemical Biosensor for Label-Free Protein Detection

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 144 ◽  
Author(s):  
Jesslyn Janssen ◽  
Mike Lambeta ◽  
Paul White ◽  
Ahmad Byagowi
Keyword(s):  
Limit Of Detection ◽  
Protein Detection ◽  
Protein Quantification ◽  
Clinical Diagnostics ◽  
Biological Research ◽  
Label Free ◽  
Protein Biomarkers ◽  
Biosensor System ◽  
Elisa Technique ◽  
Standard Protein

There is a growing need for biosensors that are capable of efficiently and rapidly quantifying protein biomarkers, both in the biological research and clinical setting. While accurate methods for protein quantification exist, the current assays involve sophisticated techniques, take long to administer and often require highly trained personnel for execution and analysis. Herein, we explore the development of a label-free biosensor for the detection and quantification of a standard protein. The developed biosensors comprise carbon nanotubes (CNTs), a specific antibody and cellulose filtration paper. The change in electrical resistance of the CNT-based biosensor system was used to sense a standard protein, bovine serum albumin (BSA) as a proof-of-concept. The developed biosensors were found to have a limit of detection of 2.89 ng/mL, which is comparable to the performance of the typical ELISA method for BSA quantification. Additionally, the newly developed method takes no longer than 10 min to perform, greatly reducing the time of analysis compared to the traditional ELISA technique. Overall, we present a versatile, affordable, simplified and rapid biosensor device capable of providing great benefit to both biological research and clinical diagnostics.

MosaicNeedles: A tool for multi-omic liquid biopsy sensitivity and specificity enhancement.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e15019-e15019
Author(s):  
Qimin Quan ◽  
Joe Wilkinson ◽  
Joshua Ritchey ◽  
Alaina Kaiser ◽  
John Geanacopoulos ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Single Molecule ◽  
Liquid Biopsy ◽  
Dynamic Range ◽  
Color Change ◽  
Protein Detection ◽  
Target Sequence ◽  
Label Free ◽  
Protein Biomarkers ◽  
Oncology Research

e15019 Background: Liquid biopsy has evolved to be an important method complementary to tissue biopsy. It is not only non-invasive, but also has the potential to detect cancer in its earliest stages and monitor patients in remission. The integration of proteomics into liquid biopsy may transform the molecular diagnostics of cancer and accelerate basic and clinical oncology research. A recent study showed that adding just 8 protein biomarkers to a panel of circulating DNA biomarkers increased the diagnostic accuracy up to 98% sensitivity and 99% specificity. Proteomics also bridges the gaps of functional information lost due to post-transcriptional and post-translational modifications in the genomic approach. However, the proteogenomic approach normally requires the use of multiple different assay technologies and laboratory workflows, including mass spectrometry. Methods: NanoMosaic’s Tessie platform employs a densely integrated nanoneedle sensor array (thus named MosaicNeedles) which can be used to detect both nucleic acids and proteins in a single assay process with reduced workflow complexity, without the need for mass spectrometry. Results: The NanoMosaic platform is a label-free, digital, single molecule counting technology using nanoneedles. It achieves sub-pg/ml (̃fM) level sensitivity with 7 logs of dynamic range. An array of nanoneedles is densely integrated and manufactured with CMOS-compatible nanofabrication processes. Each nanoneedle is a single molecule biosensor that is functionalized with capture probes. The capture probe can be either an antibody for protein detection or an oligonucleotide with a specific target sequence to a DNA fragment, mRNA, or miRNA of interest. The scattering spectrum of each nanoneedle changes when an analyte binds to its surface. At low abundance, analytes that are captured can be quantitated by counting the presence or absence of a color change on each individual nanoneedle in a binary fashion. As an analyte concentration increases the binding events increase accordingly and achieve saturation. In this range, an analog analysis on the spectrum shift will be performed, thus providing a wider dynamic range, up to 7 logs. Ultrahigh level multiplex can be achieved by parallelizing each analyte specific sensing area without loss of sensitivity or dynamic range. A 10,000-plex study can be achieved with a total of 2.5 billion nanoneedles on a 50mm by 50mm consumable. In this consumable, a 2,000-plex proteome and 8,000 cell-free DNA fragments can be detected. Conclusions: In conclusion, a full proteogenomic quantification can be performed on the NanoMosaic platform in one reaction, with higher sensitivity, lower cost and higher throughput than is currently possible by traditional methods. In addition, the high-plexibility of the NanoMosaic platform allows the discovery of new biomarkers across the whole proteome without the need for mass spectrometry.

Effect of Media Conductivity on High Frequency Dielectrophoretic Response

2014 ◽  
Author(s):  
Hanieh Hadady ◽  
Johnson J. Wong ◽  
Sage R. Hiibel ◽  
Emil J. Geiger
Keyword(s):  
Electric Fields ◽  
Lipid Content ◽  
High Frequency ◽  
Microelectrode Array ◽  
Crossover Frequency ◽  
Label Free ◽  
Medical Field ◽  
Micro Technology ◽  
Technology Processes ◽  
Regular Medium

A method was developed for analyzing the high frequency dielectrophoresis (>20 MHz) response of microalgal cells with different lipid content on the basis of media conductivities. At these frequencies, the DEP response is expected to depend primarily on the dielectric properties of the cytoplasm. The medium used to perform DEP experiments has an important influence on their outcome since all properties are measured in relation to the medium, therefore its properties must be tightly controlled. This method is label free and only uses electric fields, and thus it is suitable for many other applications in the medical field. Chlamydomonas reinhardtii cells were cultured in regular medium and then the same cells were cultured under nitrogen-free conditions to accumulate neutral (non-polar) lipids. To measure the upper crossover frequency, two thin, needle shaped electrodes (100 nm thick) were patterned onto a glass slide using standard micro-technology processes and the motion of the cells was observed as an AC signal was swept from 20–80 MHz at ∼30Vpp (Volt peak to peak). Cells were injected to the microelectrode array in different medium conductivities that were adjusted by sodium chloride. The upper crossover frequencies of N-free cells in different media conductivities were measured. It was found that when the solution conductivity was between 4 ± 2 μs/cm and 106 ± 1 μS/cm and the operating frequency was between 20 and 80 MHz, the upper crossover frequency of the microalgae increased as the medium conductivity increased. The lipid content was verified via fluorescence microscopy and MATLAB image processing.

scholarly journals Label-free fiber-optic spherical tip biosensor to enable picomolar-level detection of CD44 protein

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aliya Bekmurzayeva ◽  
Zhannat Ashikbayeva ◽  
Zhuldyz Myrkhiyeva ◽  
Aigerim Nugmanova ◽  
Madina Shaimerdenova ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Limit Of Detection ◽  
Refractive Index Change ◽  
Protein Detection ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Label Free

AbstractIncreased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Current clinically used detection methods of this protein are time-consuming and use labeled reagents for analysis. Therefore exploring new label-free and fast methods for its quantification including its detection in situ is of importance. This study reports the first optical fiber biosensor for CD44 protein detection, based on a spherical fiber optic tip device. The sensor is easily fabricated from an inexpensive material (single-mode fiber widely used in telecommunication) in a fast and robust manner through a CO2 laser splicer. The fabricated sensor responded to refractive index change with a sensitivity of 95.76 dB/RIU. The spherical tip was further functionalized with anti-CD44 antibodies to develop a biosensor and each step of functionalization was verified by an atomic force microscope. The biosensor detected a target of interest with an achieved limit of detection of 17 pM with only minor signal change to two control proteins. Most importantly, concentrations tested in this work are very broad and are within the clinically relevant concentration range. Moreover, the configuration of the proposed biosensor allows its potential incorporation into an in situ system for quantitative detection of this biomarker in a clinical setting.

scholarly journals Metal-Modified Montmorillonite as Plasmonic Microstructure for Direct Protein Detection

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2655
Author(s):  
Giorgia Giovannini ◽  
Denis Garoli ◽  
Patrick Rupper ◽  
Antonia Neels ◽  
René M. Rossi ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Optical Sensors ◽  
Metal Ion ◽  
Protein Detection ◽  
Fluorescein Isothiocyanate ◽  
Detection Methods ◽  
Sensor Technology ◽  
Label Free ◽  
Detection Mechanism ◽  
Label Free Detection

Thanks to its negative surface charge and high swelling behavior, montmorillonite (MMT) has been widely used to design hybrid materials for applications in metal ion adsorption, drug delivery, or antibacterial substrates. The changes in photophysical and photochemical properties observed when fluorophores interact with MMT make these hybrid materials attractive for designing novel optical sensors. Sensor technology is making huge strides forward, achieving high sensitivity and selectivity, but the fabrication of the sensing platform is often time-consuming and requires expensive chemicals and facilities. Here, we synthesized metal-modified MMT particles suitable for the bio-sensing of self-fluorescent biomolecules. The fluorescent enhancement achieved by combining clay minerals and plasmonic effect was exploited to improve the sensitivity of the fluorescence-based detection mechanism. As proof of concept, we showed that the signal of fluorescein isothiocyanate can be harvested by a factor of 60 using silver-modified MMT, while bovine serum albumin was successfully detected at 1.9 µg/mL. Furthermore, we demonstrated the versatility of the proposed hybrid materials by exploiting their plasmonic properties to develop liquid label-free detection systems. Our results on the signal enhancement achieved using metal-modified MMT will allow the development of highly sensitive, easily fabricated, and cost-efficient fluorescent- and plasmonic-based detection methods for biomolecules.

scholarly journals Label-Free Sensing in Microdroplet-Based Microfluidic Systems

Chemosensors ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 23 ◽  
Author(s):  
Ali Kalantarifard ◽  
Abtin Saateh ◽  
Caglar Elbuken
Keyword(s):  
Sample Volume ◽  
Detection Methods ◽  
Label Free ◽  
Microfluidic Systems ◽  
Microfluidic Platforms ◽  
Detection Scheme ◽  
Detection Techniques ◽  
Detection Schemes ◽  
Targeted Approach

Droplet microfluidic systems have evolved as fluidic platforms that use much less sample volume and provide high throughput for biochemical analysis compared to conventional microfluidic devices. The variety of droplet fluidic applications triggered several detection techniques to be applied for analysis of droplets. In this review, we focus on label-free droplet detection techniques that were adapted to various droplet microfluidic platforms. We provide a classification of most commonly used droplet platform technologies. Then we discuss the examples of various label-free droplet detection schemes implemented for these platforms. While providing the research landscape for label-free droplet detection methods, we aim to highlight the strengths and shortcomings of each droplet platform so that a more targeted approach can be taken by researchers when selecting a droplet platform and a detection scheme for any given application.

Label-Free Mass Spectrometry-Based Plasma Proteomics Identified LY6D, DSC3, CDSN, SERPINB12, and SLURP1,as Novel Protein Biomarkers For Pulmonary Tuberculosis

2019 ◽  
Vol 17 ◽  
Author(s):  
Xiaoli Yu ◽  
Lu Zhang ◽  
Na Li ◽  
Peng Hu ◽  
Zhaoqin Zhu ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Search Algorithm ◽  
Differentially Expressed ◽  
P Value ◽  
Plasma Samples ◽  
Label Free ◽  
Protein Biomarkers ◽  
Protein Database ◽  
Leave One Out ◽  
Potential Biomarkers

Aim: We aimed to identify new plasma biomarkers for the diagnosis of Pulmonary tuberculosis. Background: Tuberculosis is an ancient infectious disease that remains one of the major global health problems. Until now, effective, convenient, and affordable methods for diagnosis of Pulmonary tuberculosis were still lacked. Objective: This study focused on construct a label-free LC-MS/MS based comparative proteomics between six tuberculosis patients and six healthy controls to identify differentially expressed proteins (DEPs) in plasma. Method: To reduce the influences of high-abundant proteins, albumin and globulin were removed from plasma samples using affinity gels. Then DEPs from the plasma samples were identified using a label-free Quadrupole-Orbitrap LC-MS/MS system. The results were analyzed by the protein database search algorithm SEQUEST-HT to identify mass spectra to peptides. The predictive abilities of combinations of host markers were investigated by general discriminant analysis (GDA), with leave-one-out cross-validation. Results: A total of 572 proteins were identified and 549 proteins were quantified. The threshold for differentially expressed protein was set as adjusted p-value < 0.05 and fold change ≥1.5 or ≤0.6667, 32 DEPs were found. ClusterVis, TBtools, and STRING were used to find new potential biomarkers of PTB. Six proteins, LY6D, DSC3, CDSN, FABP5, SERPINB12, and SLURP1, which performed well in the LOOCV method validation, were termed as potential biomarkers. The percentage of cross-validated grouped cases correctly classified and original grouped cases correctly classified is greater than or equal to 91.7%. Conclusion: We successfully identified five candidate biomarkers for immunodiagnosis of PTB in plasma, LY6D, DSC3, CDSN, SERPINB12, and SLURP1. Our work supported this group of proteins as potential biomarkers for pulmonary tuberculosis, and be worthy of further validation.

Barcode signal amplifying strategy for sensitive and accurate protein detection on LC-MS/MS

The Analyst ◽  
2021 ◽  
Author(s):  
Chang Shu ◽  
Tengfei Li ◽  
Duo Li ◽  
Zhong-Qiu Li ◽  
Xing-Hua Xia
Keyword(s):  
Side Effects ◽  
Life Science ◽  
Protein Detection ◽  
High Specificity ◽  
Protein Drugs ◽  
P Protein ◽  
Precise Evaluation ◽  
Pharmaceutical Activity ◽  
Low Toxicity

Protein drugs showing strong pharmaceutical activity, high specificity, low toxicity and side effects, have drawn extensive attention from the field of life science and medicine. Precise evaluation of the function...

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