scholarly journals Tunable control of antibody immobilization using electric field

2015 ◽  
Vol 112 (7) ◽  
pp. 1995-1999 ◽  
Author(s):  
Sam Emaminejad ◽  
Mehdi Javanmard ◽  
Chaitanya Gupta ◽  
Shuai Chang ◽  
Ronald W. Davis ◽  
...  
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Signal To Noise Ratio ◽  
Physical Adsorption ◽  
Antibody Immobilization ◽  
Proof Of Concept ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sensing Platforms ◽  
Glass Surfaces

The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption.

scholarly journals 3D phonon microscopy with sub-micron axial-resolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard J. Smith ◽  
Fernando Pérez-Cota ◽  
Leonel Marques ◽  
Matt Clark
Keyword(s):  
Signal To Noise Ratio ◽  
Single Cells ◽  
Optical Resolution ◽  
Acquisition Time ◽  
Label Free ◽  
Axial Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Accuracy And Precision ◽  
Good Agreement

AbstractBrillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.

The Electric Field of CO Tips and Its Relevance for Atomic Force Microscopy

Nano Letters ◽  
2016 ◽  
Vol 16 (3) ◽  
pp. 1974-1980 ◽  
Author(s):  
Michael Ellner ◽  
Niko Pavliček ◽  
Pablo Pou ◽  
Bruno Schuler ◽  
Nikolaj Moll ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electric Field ◽  
Force Microscopy ◽  
Atomic Force

Approximate Real-Time Force Spectroscopy Within Amplitude-Modulation Atomic Force Microscopy Topographical Imaging Using Few Harmonics and Fourier Methods

2021 ◽  
Author(s):  
Berkin Uluutku ◽  
Santiago D. Solares
Keyword(s):  
Atomic Force Microscopy ◽  
Signal To Noise Ratio ◽  
Gaussian Model ◽  
Force Curve ◽  
Simple Method ◽  
Force Microscopy ◽  
Electromagnetic Interactions ◽  
Atomic Force ◽  
Mechanical Deformations ◽  
Specialized Hardware

Abstract Quantitative measurement of the probe-sample interaction forces as a function of distance and time during imaging has been at the forefront of atomic force microscopy (AFM) research. This type of information is extremely valuable for understanding the material response to a variety of stimuli and interactions, such as mechanical deformations that vary in magnitude and rate of application, chemical interactions, or electromagnetic interactions. A variety of methods for performing such measurements simultaneously with topographical imaging is available, including methods based on Fourier analysis. Within these methods, reconstruction of the tip-sample force curve generally requires measurement of a large number of harmonics of the probe oscillation, which presents challenges such as the need for specialized hardware, low signal-to-noise ratio, and the need for extensive user expertise. In this paper, we present a simple method to perform a Gaussian-model-based fit of the tip-sample force curve across the surface, simultaneously with imaging, which requires measurement of only the first two or three harmonics for elastic materials. While such an approach only offers an approximate representation of the force curve, it can be highly accurate and fast, and has low instrumentation requirements, such that it can be relatively simple to implement on most commercial AFM setups.

Sensor Egregium – An Atomic Force Microscope Sensor for Continuously Variable Resonance Amplification

2021 ◽  
pp. 1-23
Author(s):  
Rafiul Shihab ◽  
Tasmirul Jalil ◽  
Burak Gulsacan ◽  
Matteo Aureli ◽  
Ryan Tung
Keyword(s):  
Finite Element Analysis ◽  
Atomic Force Microscope ◽  
Natural Frequencies ◽  
Proof Of Concept ◽  
Element Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Curve Veering ◽  
Dynamic Phenomena

Abstract Numerous nanometrology techniques concerned with probing a wide range of frequency dependent properties would benefit from a cantilevered sensor with tunable natural frequencies. In this work, we propose a method to arbitrarily tune the stiffness and natural frequencies of a microplate sensor for atomic force microscope applications, thereby allowing resonance amplification at a broad range of frequencies. This method is predicated on the principle of curvature-based stiffening. A macroscale experiment is conducted to verify the feasibility of the method. Next, a microscale finite element analysis is conducted on a proof-of-concept device. We show that both the stiffness and various natural frequencies of the device can be highly controlled through applied transverse curvature. Dynamic phenomena encountered in the method, such as eigenvalue curve veering, are discussed and methods are presented to accommodate these phenomena. We believe that this study will facilitate the development of future curvature-based microscale sensors for atomic force microscopy applications.

scholarly journals Electric Field Assisted Self-Assembly of Viruses into Colored Thin Films

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1310 ◽  
Author(s):  
James J. Tronolone ◽  
Michael Orrill ◽  
Wonbin Song ◽  
Hyun Soo Kim ◽  
Byung Yang Lee ◽  
...  
Keyword(s):  
Electric Field ◽  
Self Assembly ◽  
Force Microscopy ◽  
Thin Film Coatings ◽  
Atomic Force ◽  
Three Phase ◽  
Constant Rate ◽  
Alignment Technique ◽  
Manufacturing Techniques ◽  
Blue Line

Filamentous viruses called M13 bacteriophages are promising materials for devices with thin film coatings because phages are functionalizable, and they can self-assemble into smectic helicoidal nanofilament structures. However, the existing “pulling” approach to align the nanofilaments is slow and limits potential commercialization of this technology. This study uses an applied electric field to rapidly align the nanostructures in a fixed droplet. The electric field reduces pinning of the three-phase contact line, allowing it to recede at a constant rate. Atomic force microscopy reveals that the resulting aligned structures resemble those produced via the pulling method. The field-assisted alignment results in concentric color bands quantified with image analysis of red, green, and blue line profiles. The alignment technique shown here could reduce self-assembly time from hours to minutes and lend itself to scalable manufacturing techniques such as inkjet printing.

Solid-State DNA Sizing by Atomic Force Microscopy

1998 ◽  
Vol 70 (10) ◽  
pp. 2123-2129 ◽  
Author(s):  
Ye Fang ◽  
Thomas S. Spisz ◽  
Tim Wiltshire ◽  
Neill P. D'Costa ◽  
Isaac N. Bankman ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Solid State ◽  
Force Microscopy ◽  
Atomic Force
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