scholarly journals Concurrent Atomic Force Spectroscopy

2018 ◽  
Author(s):  
Carolina Pimenta-Lopes ◽  
Carmen Suay-Corredera ◽  
Diana Velázquez-Carreras ◽  
David Sánchez-Ortiz ◽  
Jorge Alegre-Cebollada

ABSTRACTForce-spectroscopy by Atomic Force Microscopy (AFM) is the technique of choice to measure mechanical properties of molecules, cells, tissues and materials at the nano and micro scales. However, unavoidable calibration errors of AFM probes make it cumbersome to quantify modulation of mechanics. Here, we show that concurrent AFM force measurements enable relative mechanical characterization with an accuracy that is independent of calibration uncertainty, even when averaging data from multiple, independent experiments. Compared to traditional AFM, we estimate that concurrent strategies can measure differences in protein mechanical unfolding forces with a 6-fold improvement in accuracy and a 30-fold increase in throughput. Prompted by our results, we demonstrate widely applicable orthogonal fingerprinting strategies for concurrent single-molecule nanomechanical profiling of proteins.

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2424
Author(s):  
Lyan M. van der Sleen ◽  
Katarzyna M. Tych

The mechanical properties of proteins can be studied with single molecule force spectroscopy (SMFS) using optical tweezers, atomic force microscopy and magnetic tweezers. It is common to utilize a flexible linker between the protein and trapped probe to exclude short-range interactions in SMFS experiments. One of the most prevalent linkers is DNA due to its well-defined properties, although attachment strategies between the DNA linker and protein or probe may vary. We will therefore provide a general overview of the currently existing non-covalent and covalent bioconjugation strategies to site-specifically conjugate DNA-linkers to the protein of interest. In the search for a standardized conjugation strategy, considerations include their mechanical properties in the context of SMFS, feasibility of site-directed labeling, labeling efficiency, and costs.


ACS Nano ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. 198-207 ◽  
Author(s):  
Robert Walder ◽  
William J. Van Patten ◽  
Ayush Adhikari ◽  
Thomas T. Perkins

Medicina ◽  
2013 ◽  
Vol 49 (4) ◽  
pp. 25 ◽  
Author(s):  
Inga Morkvėnaitė-Vilkončienė ◽  
Almira Ramanavičienė ◽  
Arūnas Ramanavičius

Atomic force microscopy is a valuable and useful tool for the imaging and investigation of living cells in their natural environment at high resolution. Procedures applied to living cell preparation before measurements should be adapted individually for different kinds of cells and for the desired measurement technique. Different ways of cell immobilization, such as chemical fixation on the surface, entrapment in the pores of a membrane, or growing them directly on glass cover slips or on plastic substrates, result in the distortion or appearance of artifacts in atomic force microscopy images. Cell fixation allows the multiple use of samples and storage for a prolonged period; it also increases the resolution of imaging. Different atomic force microscopy modes are used for the imaging and analysis of living cells. The contact mode is the best for cell imaging because of high resolution, but it is usually based on the following: (i) image formation at low interaction force, (ii) low scanning speed, and (iii) usage of “soft,” low resolution cantilevers. The tapping mode allows a cell to behave like a very solid material, and destructive shear forces are minimized, but imaging in liquid is difficult. The force spectroscopy mode is used for measuring the mechanical properties of cells; however, obtained results strongly depend on the cell fixation method. In this paper, the application of 3 atomic force microscopy modes including (i) contact, (ii) tapping, and (iii) force spectroscopy for the investigation of cells is described. The possibilities of cell preparation for the measurements, imaging, and determination of mechanical properties of cells are provided. The applicability of atomic force microscopy to diagnostics and other biomedical purposes is discussed.


Author(s):  
Kristin M. Warren ◽  
Jeremiah Mpagazehe ◽  
C. Fred Higgs ◽  
Philip LeDuc

From consumer productions to energy production, algae is used in many industrial processes. Understanding the mechanical behavior of algae is important to optimize these processes. To obtain a better understanding of algae cell response, we mechanically characterized single, dried Scenedesmus dimorphus cells. To accomplish this, we used atomic force microscopy (AFM) to image S. dimorphus cells, which enabled us to map the AFM measurements to a location on the individual cells. We were then able to perform force measurements on the AFM to determine the Young’s modulus of S. dimorphus. These findings enable a more detailed understanding of the mechanical properties of a single S. dimorphus cell, which may be useful in many applications.


2008 ◽  
Vol 104 (11) ◽  
pp. 114504 ◽  
Author(s):  
Shahid Naeem ◽  
Yu Liu ◽  
Heng-Yong Nie ◽  
W. M. Lau ◽  
Jun Yang

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