scholarly journals A Stable Biotin-Streptavidin Surface Enables Multiplex, Label-Free Protein Detection by Aptamer and Aptamer-Protein Arrays Using Arrayed Imaging Reflectometry

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5745
Author(s):  
Alanna M. Klose ◽  
Benjamin L. Miller
Keyword(s):  
Sensor Arrays ◽  
Protein Detection ◽  
Sensor Technology ◽  
Label Free ◽  
Protein Arrays ◽  
Attachment Point ◽  
Sensing Platform ◽  
Antibody Arrays ◽  
Stable Surfaces ◽  
Tgf Β1

While label-free multiplex sensor technology enables “mixing and matching” of different capture molecules in principle, in practice this has been rarely (if ever) demonstrated. To fill this gap, we developed protocols for the preparation of mixed aptamer-protein arrays on the arrayed imaging reflectometry (AIR) sensing platform using streptavidin as a common attachment point for both biotinylated proteins and aptamers. Doing so required overcoming the noted instability of dried streptavidin monolayers on surfaces. After characterizing this degradation, stable surfaces were obtained using a commercial microarray product. Microarraying through the layer of stabilizer then provided mixed aptamer-antibody arrays. We demonstrate that sensor arrays prepared in this manner are suitable for several probes (thrombin and TGF-β1 aptamers; avi-tagged protein) and targets.

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 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.

scholarly journals An Aptamer-Based Capacitive Sensing Platform for Specific Detection of Lung Carcinoma Cells in the Microfluidic Chip

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 98 ◽  
Author(s):  
Ngoc-Viet Nguyen ◽  
Chun-Hao Yang ◽  
Chung-Jung Liu ◽  
Chao-Hung Kuo ◽  
Deng-Chyang Wu ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Lung Carcinoma ◽  
Early Stage ◽  
A549 Cells ◽  
Microfluidic Channel ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Early Stage Lung Cancer ◽  
Sensing Platform ◽  
Label Free Detection

Improvement of methods for reliable and early diagnosis of the cellular diseases is necessary. A biological selectivity probe, such as an aptamer, is one of the candidate recognition layers that can be used to detect important biomolecules. Lung cancer is currently a typical cause of cancer-related deaths. In this work, an electrical sensing platform is built based on amine-terminated aptamer modified-gold electrodes for the specific, label-free detection of a human lung carcinoma cell line (A549). The microdevice, that includes a coplanar electrodes configuration and a simple microfluidic channel on a glass substrate, is fabricated using standard photolithography and cast molding techniques. A procedure of self-assembly onto the gold surface is proposed. Optical microscope observations and electrical impedance spectroscopy measurements confirm that the fabricated microchip can specifically and effectively identify A549 cells. In the experiments, the capacitance element that is dominant in the change of the impedance is calculated at the appropriate frequency for evaluation of the sensitivity of the biosensor. Therefore, a simple, inexpensive, biocompatible, and selective biosensor that has the potential to detect early-stage lung cancer would be developed.

scholarly journals A label-free phosphorescence sensing platform for trypsin based on Mn-ZnS QDs

RSC Advances ◽  
2017 ◽  
Vol 7 (43) ◽  
pp. 26930-26934 ◽  
Author(s):  
Wei Liu ◽  
Huanhuan Li ◽  
Yanli Wei ◽  
Chuan Dong
Keyword(s):  
Label Free ◽  
Sensing Platform ◽  
Phosphorescence Probe

A label-free phosphorescence strategy to determine trypsin was proposed using Mn-ZnS QDs as the phosphorescence probe with a better validity.

Label-Free DNA Sensing Platform with Low-Voltage Electrolyte-Gated Transistors

2015 ◽  
Vol 87 (3) ◽  
pp. 1861-1866 ◽  
Author(s):  
Scott P. White ◽  
Kevin D. Dorfman ◽  
C. Daniel Frisbie
Keyword(s):  
Low Voltage ◽  
Label Free ◽  
Dna Sensing ◽  
Free Dna ◽  
Sensing Platform
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