scholarly journals Nano-rheology of hydrogels using direct drive force modulation atomic force microscopy

Soft Matter ◽  
2015 ◽  
Vol 11 (41) ◽  
pp. 8165-8178 ◽  
Author(s):  
Prathima C. Nalam ◽  
Nitya N. Gosvami ◽  
Matthew A. Caporizzo ◽  
Russell J. Composto ◽  
Robert W. Carpick
Keyword(s):  
Atomic Force Microscopy ◽  
Soft Matter ◽  
Applied Strain ◽  
Strain Rates ◽  
Direct Drive ◽  
Force Microscopy ◽  
Atomic Force ◽  
Material Contact ◽  
Contact Mechanical ◽  
Probe Material

A quantitative and novel nanoscale viscoelastic spectroscopy tool for soft matter was developed. The study highlights the transition in the probe–material contact mechanical behavior of hydrogels especially when the applied strain rates and the material relaxation become comparable.

scholarly journals Imaging of viscoelastic soft matter with small indentation using higher eigenmodes in single-eigenmode amplitude-modulation atomic force microscopy

2018 ◽  
Vol 9 ◽  
pp. 1116-1122 ◽  
Author(s):  
Miead Nikfarjam ◽  
Enrique A López-Guerra ◽  
Santiago D Solares ◽  
Babak Eslami
Keyword(s):  
Atomic Force Microscopy ◽  
Amplitude Modulation ◽  
Soft Matter ◽  
Short Paper ◽  
Lower Sensitivity ◽  
Viscoelastic Materials ◽  
Force Microscopy ◽  
Atomic Force ◽  
Oscillation Frequencies ◽  
Small Indentation

In this short paper we explore the use of higher eigenmodes in single-eigenmode amplitude-modulation atomic force microscopy (AFM) for the small-indentation imaging of soft viscoelastic materials. In viscoelastic materials, whose response depends on the deformation rate, the tip–sample forces generated as a result of sample deformation increase as the tip velocity increases. Since the eigenfrequencies in a cantilever increase with eigenmode order, and since higher oscillation frequencies lead to higher tip velocities for a given amplitude (in viscoelastic materials), the sample indentation can in some cases be reduced by using higher eigenmodes of the cantilever. This effect competes with the lower sensitivity of higher eigenmodes, due to their larger force constant, which for elastic materials leads to greater indentation for similar amplitudes, compared with lower eigenmodes. We offer a short theoretical discussion of the key underlying concepts, along with numerical simulations and experiments to illustrate a simple recipe for imaging soft viscoelastic matter with reduced indentation.

scholarly journals Imaging of soft matter with tapping-mode atomic force microscopy and non-contact-mode atomic force microscopy

2007 ◽  
Vol 18 (8) ◽  
pp. 084009 ◽  
Author(s):  
Chih-Wen Yang ◽  
Ing-Shouh Hwang ◽  
Yen Fu Chen ◽  
Chia Seng Chang ◽  
Din Ping Tsai
Keyword(s):  
Atomic Force Microscopy ◽  
Soft Matter ◽  
Contact Mode ◽  
Tapping Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mode Atomic Force Microscopy

Determination of Strain-Rate-Dependent Mechanical Behavior of Living and Fixed Osteocytes and Chondrocytes Using Atomic Force Microscopy and Inverse Finite Element Analysis

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Trung Dung Nguyen ◽  
YuanTong Gu
Keyword(s):  
Finite Element Analysis ◽  
Atomic Force Microscopy ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Strain Rates ◽  
Element Analysis ◽  
Force Microscopy ◽  
Rate Dependent ◽  
Atomic Force ◽  
Inverse Finite Element Analysis

The aim of this paper is to determine the strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes, in vitro. First, atomic force microscopy (AFM) was used to obtain the force–indentation curves of these single cells at four different strain-rates. These results were then employed in inverse finite element analysis (FEA) using modified standard neo-Hookean solid (MSnHS) idealization of these cells to determine their mechanical properties. In addition, a FEA model with a newly developed spring element was employed to accurately simulate AFM evaluation in this study. We report that both cytoskeleton (CSK) and intracellular fluid govern the strain-rate-dependent mechanical property of living cells whereas intracellular fluid plays a predominant role on fixed cells' behavior. In addition, through the comparisons, it can be concluded that osteocytes are stiffer than chondrocytes at all strain-rates tested indicating that the cells could be the biomarker of their tissue origin. Finally, we report that MSnHS is able to capture the strain-rate-dependent mechanical behavior of osteocyte and chondrocyte for both living and fixed cells. Therefore, we concluded that the MSnHS is a good model for exploration of mechanical deformation responses of single osteocytes and chondrocytes. This study could open a new avenue for analysis of mechanical behavior of osteocytes and chondrocytes as well as other similar types of cells.

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