Principles Of Atomic Force Microscopy Research Articles

Research progress of single molecule force spectroscopy technology based on atomic force microscopy in polymer materials: Structure, design strategy and probe modification

AbstractWith the rapid development of polymer materials, the simultaneous acquisition of micro‐nano structure and mesoscopic mechanical properties from the material surface with the transverse resolution of nanoscale has become a hot spot in the research of polymer materials. Atomic force microscopy‐based high‐resolution imaging and single‐molecule force spectroscopy techniques have been widely used in various related fields. This review introduces the basic design and working principles of atomic force microscopy as well as single‐molecule force microscopy and their applications in the characterization of polymer surface morphologies, polymer film phase separation, polymer crystallization behavior, polymer chain stretching, protein folding/unfolding, G quadruplex intermolecular and intramolecular interactions, living cell surface proteins, and sugars. The research status of AFM probe modification strategies such as nanomaterial processing, single molecule manipulation and biomolecule etching is reviewed, finally, the limitations and improvement potential of single molecule force spectroscopy based on atomic force microscopy (AFM‐ SMFS) are summarized and discussed, and the new research practice in the field of polymer materials is prospected.

Applications of atomic force microscopy in immunology.

Cellular mechanics, a major regulating factor of cellular architecture and biological functions, responds to intrinsic stresses and extrinsic forces exerted by other cells and the extracellular matrix in the microenvironment. Cellular mechanics also acts as a fundamental mediator in complicated immune responses, such as cell migration, immune cell activation, and pathogen clearance. The principle of atomic force microscopy (AFM) and its three running modes are introduced for the mechanical characterization of living cells. The peak force tapping mode provides the most delicate and desirable virtues to collect high-resolution images of morphology and force curves. For a concrete description of AFM capabilities, three AFM applications are discussed. These applications include the dynamic progress of a neutrophil-extracellular-trap release by neutrophils, the immunological functions of macrophages, and the membrane pore formation mediated by perforin, streptolysin O, gasdermin D, or membrane attack complex.

Study of the control process and fabrication of microstructures using a tip-based force control system

The atomic force microscopy tip-based nanomechanical machining method has already been employed to machine different kinds of nanostructures with the control of the normal force of the tip. The previous studies verified the feasibility of the nanomachining approach with the force control. However, there are still some shortcomings of small normal force, small machining scale, high cost and low machining efficiency. Therefore, in this study, a tip-based micromachining system with normal force closed-loop control is established based on the principle of atomic force microscopy. The control parameters are optimized based on an analysis of the control process to enable the production of a constant normal force during machining when using a tip tool. The maximum machining velocity that can be attained using this system while maintaining a constant normal force is obtained based on an analysis of the normal force variations during machining. By controlling nanoscale accuracy and high-precision stage, more complex microstructures, including microsquares, millimeter-scale microchannels and three-dimensional step microchannels, are successfully fabricated using the proposed force control method. Experimental results show that the tip-based normal force control method is a simple, low-cost and versatile micromachining method with the potential ability to machine more complex structures and is likely to find wider applications in the micromachining field.

A homemade atomic force microscope based on a quartz tuning fork for undergraduate instruction

Atomic force microscopes are a key tool in nanotechnology that overcome the limitations of optical microscopes and provide imaging capabilities with nanoscale resolution. We have developed an atomic force microscope that uses an inexpensive quartz tuning fork as a micro cantilever. Because of its ease of operation and its open structure, it can be easily customized by students. Due to its low costs, it is possible that every student in the course has access to one setup, allowing all students to obtain deep insights into nanotechnology and to understand the principles of atomic force microscopy.

Morphological and optical investigation of Sol-Gel ZnO films

This paper presents morphological and optical studies of the properties of spin-coated ZnO films depending on the annealing temperatures. The films microstructure was explored using a scanning nano-hardness measuring device of the NanoScan family, based on the principles of atomic force microscopy, in a constant frequency mode. The surface study revealed that the root-mean-square (RMS) surface roughness of 985.64×985.64 nm ZnO films becomes greater with the increase of the annealing temperature, but the film surface remains uniform and smooth. The results were confirmed by XRD analysis, which demonstrated that the crystallite size grew from 25 to 36 nm with the thermal treatments. The ZnO films possessed high transmittance in the visible spectral range and the optical band gaps in ZnO films varied from 3.25 eV to 3.52 eV. The optical and morphological properties of the ZnO films formed on Si and quartz substrates are very good. The sol-gel approach proposed for deposition of nanostructured ZnO films is promising for applications in optoelectronic devices or solar cells.

Basic Principles of Atomic Force Microscopy for Life Sciences

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Development of a Flexible Robotic System for Multiscale Applications of Micro/Nanoscale Manipulation and Assembly

A flexible robotic system (FRS) developed for multiscale manipulation and assembly from nanoscale to microscale is presented. This system is based on the principle of atomic force microscopy and comprises two individually functionalized cantilevers. After reconfiguration, the robotic system could be used for pick-and-place manipulation from nanoscale to the scale of several micrometers, as well as parallel imaging/nanomanipulation. Flexibilities and manipulation capabilities of the developed system were validated by pick-and-place manipulation of microspheres and silicon nanowires to build 3-D micro/nanoscale structures in ambient conditions. Moreover, the capability of parallel nanomanipulation is certified by high-efficiency fabrication of a 2-D pattern with nanoparticles. Complicated micro/nanoscale manipulation and assembly can be reliably and efficiently performed using the proposed FRS.

Determination of Lysozyme Using Microcantilever Sensor Based on Atomic Force Microscopy

Abstract A microcantilever sensor was developed to detect lysozyme in a pharmaceutical formulation based on the principle of atomic force microscopy. By measuring the cantilever bending and deflection using the optical reflection technique, the lysozyme adsorption on a dodecanethiol-modified cantilever surface was detected. Under optimal conditions, a good linear relationship between the deflection of the microcantilever and the logarithm of the lysozyme concentration in the range from 10 ng L−1 to 0.1 mg L−1, with a correlation coefficient of 0.998, was established. The limit of detection was 5.0 ng L−1. The lysozyme in the pharmaceutical formulation sample was determined with the desirable results by using the present method.

Atomic force microscopy for imaging human metaphase chromosomes

The present study introduces the principle of atomic force microscopy (AFM) and reviews our results of human metaphase chromosomes obtained by AFM. AFM imaging of the chromosomes revealed that the chromatid arm was not uniform in structure but had ridges and grooves along its length, which was most prominent in the late metaphase. The arrangement of these ridges and grooves was roughly symmetrical with the counterpart of the paired sister chromatids. AFM imaging of banded chromosomes also showed that the ridges and grooves were related to the G/Q-positive and G/Q-negative bands, respectively. At high magnification, the chromatid was seen to be produced by the compaction of highly twisted chromatin fiber loops, and its compaction tended to be stronger in the ridged regions of the chromosomes than in the grooved regions. Our AFM studies also showed the presence of catenation of chromatin fibers between the ridged portions of the chromatid in the late metaphase. Thus, AFM is useful for obtaining the three-dimensional surface topography not only in ambient conditions but also in physiological liquid conditions, and is expected to be an attractive tool for investigating the structure of chromosomes.

Badania polimerow z wykorzystaniem metody mikroskopii sil atomowych (AFM). Cz. I. Podstawy AFM i jej zastosowanie w badaniach morfologii polimerow

On the basis of recent literature data the principles of Atomic Force Microscopy (AFM) and progress in the development of this technique have been reported. Its advantages and shortcomings as well as the possibilities it creates have also been discussed. Application of AFM method for geometric structure of polymer surface determining as well as determining of surface roughness and morphology of polymer blends and copolymers. AFM is especially useful for investigation of the surface defects, impurities, wettability, polymer miscibility, phase separation, selforganized structures and molecular interactions. Owing to AFM the influence of polymer surface morphology on the polymer properties (in nanometer scale) can be estimated.

Read/write mechanisms and data storage system using atomic force microscopy and MEMS technology

Information storage system that has a potentially ultrahigh storage density based on the principles of atomic force microscopy (AFM) has been developed. Micro-electro-mechanical systems (MEMS) technology plays a major role in integration and miniaturization of the standard AFM. Its potential application for ultrahigh storage density has been demonstrated by AFM with a piezoresponse mode to write and read information bits in ferroelectric Pb(Zr x Ti 1− x )O 3 films. With this technique, bits as small as 40 nm in diameter have been achieved, resulting in a data storage density of simply more than 200 Gb/in 2. Retention loss phenomenon has also been observed and investigated by AFM in the piezoresponse mode. Finally, local piezoelectric measurements of PZT films by different processing technologies are discussed in detail.

Atomic force microscopy and proteins.

This review briefly introduces the principles of atomic force microscopy (AFM) applied to protein samples. AFM provides three-dimensional surface images of the proteins with high resolution. The advantage of AFM for protein studies is that AFM can visualize directly the molecule under physiological conditions without previous treatment. AFM operated in the force-spectroscopy mode is now a widespread technique, often used to investigate ligand receptor interactions with the goal of measuring forces at the individual molecule level.

Adhesion and Friction Forces between Spherical Micrometer-Sized Particles

An experimental setup, based on the principles of atomic force microscopy (AFM), was used to measure directly the adhesion and rolling-friction forces between individual silica microspheres of radii between 0.5 and 2.5 \ensuremath{\mu}m. It showed that the linear dependence of the pull-off force on the particle radius is still valid for micron-sized particles. Rolling-friction forces between silica microspheres were measured for the first time by combining AFM methods and optical microscopy: They are $\ensuremath{\sim}100$ times lower than the corresponding adhesion forces.

The principles of atomic force microscopy in polymer studies

The principles of atomic force microscopy in polymer studies

Two-bit gates are universal for quantum computation.

A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of three-bit gates, by analogy to the universality of the Toffoli three-bit gate of classical reversible computing. Two-bit quantum gates may be implemented by magnetic resonance operations applied to a pair of electronic or nuclear spins. A ``gearbox quantum computer'' proposed here, based on the principles of atomic-force microscopy, would permit the operation of such two-bit gates in a physical system with very long phase-breaking (i.e., quantum-phase-coherence) times. Simpler versions of the gearbox computer could be used to do experiments on Einstein-Podolsky-Rosen states and related entangled quantum states.

Atomic force microscopy

The basic principles of atomic force microscopy are discussed. Various deflection sensors are described and compared with each other. A simple theoretical basis of the fundamental forces, such as van der Waals, electrostatic, magnetic, capillary, ionic repulsion and frictional forces, is given and the relevant experimental work is summarized.