Atomic Force Microscopy Investigation of Protein Adsorption on Hydrogenated Amorphous Carbon

2013 ◽  
Vol 1527 ◽  
Author(s):  
Muhammad Zeeshan Mughal ◽  
Patrick Lemoine ◽  
Gennady Lubarsky
Keyword(s):  
Atomic Force Microscopy ◽  
Protein Adsorption ◽  
Amorphous Carbon ◽  
Phosphate Buffer ◽  
Adsorbed Layer ◽  
Force Curve ◽  
Hydrogenated Amorphous Carbon ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrogenated Amorphous

ABSTRACTProtein adsorption is the first phenomenon which occurs at nanoscale level when a given surface came into contact with a living fluid cell such as blood. Investigation of this adsorption at nanoscale provides useful information about kinetics and mechanism of conformation of proteins on a given surface. The present study investigates the adsorption of proteins using tapping/intermittent mode atomic force microscopy (T-AFM). The approach taken here is that hydrogenated amorphous carbon coating (a-C:H) is used as a model surface because it is amorphous, smooth, inert and hydrophobic. Two proteins namely albumin and fibrinogen in phosphate buffer (PBS) and de-ionized water are drop casted to study the adsorption kinetics. First and second resonance AFM data was used to investigate the adsorbed layer of proteins. AFM force curve and scratch experiment were used to verify the adhesion and thickness of the adsorbed layer. Combination of height, phase images along with the AFM force curve and scratch experiment shows inhomogeneous distribution of albumin protein in phosphate buffer compared to other protein solutions.

Microscopic Electrical Conductivity of Nanodiamonds after Thermal and Plasma Treatments

MRS Advances ◽  
2016 ◽  
Vol 1 (16) ◽  
pp. 1105-1111 ◽  
Author(s):  
Jan Čermák ◽  
Halyna Kozak ◽  
Štěpán Stehlík ◽  
Vladimír Švrček ◽  
Vincent Pichot ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Atomic Force Microscopy ◽  
Electric Current ◽  
Amorphous Carbon ◽  
Rf Plasma ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Atomic Force ◽  
Plasma Treatments ◽  
Hydrogenated Amorphous

ABSTRACTAtomic force microscopy (AFM) is used to measure local electrical conductivity of HPHT nanodiamonds (NDs) dispersed on Au substrate in the as-received state and after thermal or plasma treatments. Oxygen-treated NDs are highly electrically resistive, whereas on hydrogen-treated NDs electric current around -200 pA at -2 V is detected. The as-received NDs as well as NDs after an underwater radio-frequency (RF) plasma or laser irradiation (LI) treatments contain both electrically conductive (two types: highly and weakly conductive) and highly resistive particles. The higher conductivity is attributed to H-terminated (RF) or graphitized (LI) NDs. The lower conductivity is attributed to NDs with hydrogenated amorphous carbon shell.

Comparison of atomic force microscopy force curve and solvation structure studied by integral equation theory

2021 ◽  
Vol 154 (16) ◽  
pp. 164702
Author(s):  
Kota Hashimoto ◽  
Ken-ichi Amano ◽  
Naoya Nishi ◽  
Hiroshi Onishi ◽  
Tetsuo Sakka
Keyword(s):  
Integral Equation ◽  
Atomic Force Microscopy ◽  
Integral Equation Theory ◽  
Force Curve ◽  
Force Microscopy ◽  
Atomic Force ◽  
Solvation Structure

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.

scholarly journals Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2348 ◽  
Author(s):  
Katrin Niegelhell ◽  
Thomas Ganner ◽  
Harald Plank ◽  
Evelyn Jantscher-Krenn ◽  
Stefan Spirk
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Plasmon Resonance ◽  
Protein Adsorption ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Resonance Spectroscopy ◽  
Carbohydrate Binding ◽  
Force Microscopy ◽  
Atomic Force ◽  
Slow Kinetics

Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.

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