Abstract:
:The axial deformation of a pipette-pressurized fluid membrane bag produces minuscule yet well-defined, reproducible forces. The stiffness of this ultrasensitive force transducer is tunable and largely independent of the constitutive membrane behavior. Based on a rigorous variational treatment, we present both numerical as well as approximate analytical solutions for the force-deflection relation of this unique biophysical force probe. Our numerical results predict a measurably nonlinear force-deflection behavior at moderate-to-large deformations, which we confirm experimentally using red blood cells. Furthermore, considering nearly spherical membrane shapes and enforcing proper boundary conditions, we derive an analytical solution valid at small deformations. In this linear regime the pressurized membrane bag behaves like a Hookean spring, with a spring constant that is significantly larger than previously published for the biomembrane force probe.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Heinrich V,Ounkomol Cdoi
10.1529/biophysj.107.104091subject
Has Abstractpub_date
2007-07-15 00:00:00pages
363-72issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(07)71291-2journal_volume
93pub_type
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