Label-Free Protein and Pathogen Detection Using the Atomic Force Microscope

2004 ◽  
Vol 9 (6) ◽  
pp. 491-497 ◽  
Author(s):  
Janice L. Huff ◽  
Michael P. Lynch ◽  
Saju Nettikadan ◽  
James C. Johnson ◽  
Srikanth Vengasandra ◽  
...  
Keyword(s):  
Biological Sciences ◽  
Atomic Force Microscope ◽  
Pathogen Detection ◽  
Label Free ◽  
Time Data ◽  
Surface Profiling ◽  
Atomic Force ◽  
Viral Particles ◽  
Label Free Detection ◽  
Direct Label

The atomic force microscope (AFM) uses a sharp micron-scale tip to scan and amplify surface features, providing exceptionally detailed topographical information with magnification on the order of ×106. This instrument is used extensively for quality control in the computer and semiconductor industries and is becoming a progressively more important tool in the biological sciences. Advantages of the AFM for biological application include the ability to obtain information in a direct, label-free manner and the ability to image in solution, providing real-time data acquisition under physiologically relevant conditions. A novel application of the AFM currently under development combines its surface profiling capabilities with fixed immuno-capture using antibodies immobilized in a nanoarray format. This provides a distinctive platform for direct, label-free detection and characterization of viral particles and other pathogens.

scholarly journals Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1872
Author(s):  
Holger Schulze ◽  
Harry Wilson ◽  
Ines Cara ◽  
Steven Carter ◽  
Edward N. Dyson ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Electrochemical Impedance ◽  
Point Of Care ◽  
Branched Polymers ◽  
Label Free ◽  
Conformation Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Staphylococcus Carnosus ◽  
Label Free Detection

Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

scholarly journals A liquid-crystal-based DNA biosensor for pathogen detection

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Mashooq Khan ◽  
Abdur Rahim Khan ◽  
Jae-Ho Shin ◽  
Soo-Young Park
Keyword(s):  
Liquid Crystal ◽  
Pathogen Detection ◽  
Grid Cell ◽  
High Specificity ◽  
Erwinia Carotovora ◽  
Optical Microscope ◽  
Label Free ◽  
Label Free Detection ◽  
Homeotropic Orientation ◽  
Tem Grid

Abstract A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

scholarly journals An Aptamer-Based Biosensor for Direct, Label-Free Detection of Melamine in Raw Milk

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3227 ◽  
Author(s):  
Naoto Kaneko ◽  
Katsunori Horii ◽  
Joe Akitomi ◽  
Shintaro Kato ◽  
Ikuo Shiratori ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Background Noise ◽  
Colorimetric Detection ◽  
Raw Milk ◽  
Detection Methods ◽  
Label Free ◽  
Label Free Detection ◽  
High Concentrations ◽  
Direct Label ◽  
Urinary Problems

Melamine, a nitrogen-rich compound, has been used as a food and milk additive to falsely increase the protein content. However, melamine is toxic, and high melamine levels in food or in milk can cause kidney and urinary problems, or even death. Hence, the detection of melamine in food and milk is desirable, for which numerous detection methods have been developed. Several methods have successfully detected melamine in raw milk; however, they require a sample preparation before the analyses. This study aimed to develop an aptamer-DNAzyme conjugated biosensor for label-free detection of melamine, in raw milk, without any sample preparation. An aptamer-DNAzyme conjugated biosensor was developed via screening using microarray analysis to identify the candidate aptamers followed by an optimization, to reduce the background noise and improve the aptamer properties, thereby, enhancing the signal-to-noise (S/N) ratio of the screened biosensor. The developed biosensor was evaluated via colorimetric detection and tested with raw milk without any sample preparation, using N-methylmesoporphyrin IX for fluorescence detection. The biosensor displayed significantly higher signal intensity at 2 mM melamine (S/N ratio, 20.2), which was sufficient to detect melamine at high concentrations, in raw milk.

scholarly journals Real-time, label-free monitoring of cell viability based on cell adhesion measurements with an atomic force microscope

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Fang Yang ◽  
René Riedel ◽  
Pablo del Pino ◽  
Beatriz Pelaz ◽  
Alaa Hassan Said ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Viability ◽  
Atomic Force Microscope ◽  
Real Time ◽  
Label Free ◽  
Atomic Force

Direct label-free detection of Rotavirus using a hydrogel based nanoporous photonic crystal

RSC Advances ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 7384-7390 ◽  
Author(s):  
Bohee Maeng ◽  
Youngkyu Park ◽  
Jungyul Park
Keyword(s):  
Photonic Crystal ◽  
Crystal Structures ◽  
Virus Detection ◽  
Label Free ◽  
Label Free Detection ◽  
Near Future ◽  
Direct Label

A direct label-free biosensor based on 3D photonic crystal structures for Rotavirus has been demonstrated. This proposed method will be useful for developing a direct and easy-to-use virus detection kit in the form of POCT in the near future.

Direct Label Free Detection of Orchid Virus Using a Micro/Nano Hybrid Structured Biosensor

2019 ◽  
Author(s):  
Wei-Jhen Wang ◽  
Chia-Hwa Lee ◽  
Chin-Wen Li ◽  
Stephen Liao ◽  
Fuh-Jyh Jan ◽  
...  
Keyword(s):  
Label Free ◽  
Self Assembled Monolayer ◽  
Detection Range ◽  
Elisa Kit ◽  
Detection Approach ◽  
Linear Detection ◽  
Label Free Detection ◽  
Semiconductor Fabrication ◽  
Direct Label ◽  
Higher Sensitivity

Abstract In this study, a label-free detection approach for effective detection of the odontoglossum ringspot virus (ORSV) infected orchids has been developed. We used semiconductor fabrication process to fabricate 1,810 micro/nano hybrid structured sensing electrodes on a 8 inch reclaimed wafer. The self-assembled monolayer (SAM) process was then employed to sequentially modify the electrode surface with 11-mercaptoundecanoic acid (11-MUA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/ N-hydroxysuccinimide (NHS), anti-ORSV, and ORSV. EIS was conducted for the ORSV concentration detection. Experimental results demonstrated that the ORSV concentration in a virus infected orchid leaf could be effectively detected. When compared with the ELISA kit, our device possesses a wider linear detection range (0.5–50,000 ng/mL) and a higher sensitivity. The specificity of our device on ORSV detection was also confirmed. Our sensing device retains advantages, such as label-free, lower amounts of the antibody and target sample required, low detection time, and a wider linear detection range. Those results imply the feasibility of our sensing device in field applications.

scholarly journals Quantitative nanoscale electrostatics of viruses

Nanoscale ◽  
2015 ◽  
Vol 7 (41) ◽  
pp. 17289-17298 ◽  
Author(s):  
M. Hernando-Pérez ◽  
A. X. Cartagena-Rivera ◽  
A. Lošdorfer Božič ◽  
P. J. P. Carrillo ◽  
C. San Martín ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Electrostatic Interactions ◽  
Viral Particle ◽  
Electrostatic Force ◽  
Host Cells ◽  
Atomic Force ◽  
Viral Particles

The recognition events between viruses and host cells are dominated by both specific and non-specific electrostatic interactions determined by the charge of viral particles. Here we probe the charge of individual viruses in aqueous solutions by measuring the electrostatic force between each viral particle and the Atomic Force Microscope tip.

Label Free Detection of NAPPA via Atomic Force Microscopy

2019 ◽  
pp. 109-120
Author(s):  
Marco Sartore ◽  
Roberto Eggenhöffner ◽  
Tercio Bezerra Correia Terencio ◽  
Enrico Stura ◽  
Eugenie Hainsworth ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Label Free ◽  
Force Microscopy ◽  
Atomic Force ◽  
Label Free Detection
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