Effect of Isoproterenol on Local Contractile Behaviors of Rat Cardiomyocytes Measured by Atomic Force Microscopy

2012 ◽  
Vol 13 (14) ◽  
pp. 2599-2603
Author(s):  
Yusuke Mizutani ◽  
Koichi Kawahara ◽  
Takaharu Okajima
2016 ◽  
Vol 3 ◽  
pp. 184954351667534 ◽  
Author(s):  
Neerajha Nagarajan ◽  
Varun Vyas ◽  
Bryan D Huey ◽  
Pinar Zorlutuna

The ability to modulate cardiomyocyte contractility is important for bioengineering applications ranging from heart disease treatments to biorobotics. In this study, we examined the changes in contraction frequency of neonatal rat cardiomyocytes upon single-cell-level nanoscale mechanical stimulation using atomic force microscopy. To measure the response of same density of cells, they were micropatterned into micropatches of fixed geometry. To examine the effect of the substrate stiffness on the behavior of cells, they were cultured on a stiffer and a softer surface, glass and poly (dimethylsiloxane), respectively. Upon periodic cyclic stimulation of 300 nN at 5 Hz, a significant reduction in the rate of synchronous contraction of the cell patches on poly(dimethylsiloxane) substrates was observed with respect to their spontaneous beat rate, while the cell patches on glass substrates maintained or increased their contraction rate after the stimulation. On the other hand, single cells mostly maintained their contraction rate and could only withstand a lower magnitude of forces compared to micropatterned cell patches. This study reveals that the contraction behavior of cardiomyocytes can be modulated mechanically through cyclic nanomechanical stimulation, and the degree and mode of this modulation depend on the cell connectivity and substrate mechanical properties.


2000 ◽  
Vol 10 (1-2) ◽  
pp. 15
Author(s):  
Eugene Sprague ◽  
Julio C. Palmaz ◽  
Cristina Simon ◽  
Aaron Watson

2020 ◽  
Author(s):  
Mitsunori Kitta

This manuscript propose the operando detection technique of the physical properties change of electrolyte during Li-metal battery operation.The physical properties of electrolyte solution such as viscosity (η) and mass densities (ρ) highly affect the feature of electrochemical Li-metal deposition on the Li-metal electrode surface. Therefore, the operando technique for detection these properties change near the electrode surface is highly needed to investigate the true reaction of Li-metal electrode. Here, this study proved that one of the atomic force microscopy based analysis, energy dissipation analysis of cantilever during force curve motion, was really promising for the direct investigation of that. The solution drag of electrolyte, which is controlled by the physical properties, is directly concern the energy dissipation of cantilever motion. In the experiment, increasing the energy dissipation was really observed during the Li-metal dissolution (discharge) reaction, understanding as the increment of η and ρ of electrolyte via increasing of Li-ion concentration. Further, the dissipation energy change was well synchronized to the charge-discharge reaction of Li-metal electrode.This study is the first report for direct observation of the physical properties change of electrolyte on Li-metal electrode reaction, and proposed technique should be widely interesting to the basic interfacial electrochemistry, fundamental researches of solid-liquid interface, as well as the battery researches.


2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>


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