TY - JOUR
T1 - Strain-Rate Dependence of Elastic Modulus Reveals Silver Nanoparticle Induced Cytotoxicity
AU - Caporizzo, Matthew Alexander
AU - Roco, Charles M.
AU - Ferrer, Maria Carme Coll
AU - Grady, Martha E.
AU - Parrish, Emmabeth
AU - Eckmann, David M.
AU - Composto, Russell John
N1 - Publisher Copyright:
© 2015, © 2015 Author(s). Licensee InTech.
PY - 2015/9/2
Y1 - 2015/9/2
N2 - Force-displacement measurements are taken at different rates with an atomic force microscope to assess the correlation between cell health and cell viscoelasticity in THP-1 cells that have been treated with a novel drug carrier. A variable indentation-rate viscoelastic analysis, VIVA, is employed to identify the relaxation time of the cells that are known to exhibit a frequency dependent stiffness. The VIVA agrees with a fluorescent viability assay. This indicates that dextran-lysozyme drug carriers are biocompatible and deliver concentrated toxic material (rhodamine or silver nanoparticles) to the cytoplasm of THP-1 cells. By modelling the frequency dependence of the elastic modulus, the VIVA provides three metrics of cytoplasmic viscoelasticity: a low frequency modulus, a high frequency modulus and viscosity. The signature of cytotoxicity by rhodamine or silver exposure is a frequency independent twofold increase in the elastic modulus and cytoplasmic viscosity, while the cytoskeletal relaxation time remains unchanged. This is consistent with the known toxic mechanism of silver nanoparticles, where metabolic stress causes an increase in the rigidity of the cytoplasm. A variable indentation-rate viscoelastic analysis is presented as a straightforward method to promote the self-consistent comparison between cells. This is paramount to the development of early diagnosis and treatment of disease.
AB - Force-displacement measurements are taken at different rates with an atomic force microscope to assess the correlation between cell health and cell viscoelasticity in THP-1 cells that have been treated with a novel drug carrier. A variable indentation-rate viscoelastic analysis, VIVA, is employed to identify the relaxation time of the cells that are known to exhibit a frequency dependent stiffness. The VIVA agrees with a fluorescent viability assay. This indicates that dextran-lysozyme drug carriers are biocompatible and deliver concentrated toxic material (rhodamine or silver nanoparticles) to the cytoplasm of THP-1 cells. By modelling the frequency dependence of the elastic modulus, the VIVA provides three metrics of cytoplasmic viscoelasticity: a low frequency modulus, a high frequency modulus and viscosity. The signature of cytotoxicity by rhodamine or silver exposure is a frequency independent twofold increase in the elastic modulus and cytoplasmic viscosity, while the cytoskeletal relaxation time remains unchanged. This is consistent with the known toxic mechanism of silver nanoparticles, where metabolic stress causes an increase in the rigidity of the cytoplasm. A variable indentation-rate viscoelastic analysis is presented as a straightforward method to promote the self-consistent comparison between cells. This is paramount to the development of early diagnosis and treatment of disease.
KW - VIVA
KW - cell viscoelasticity
KW - dextran
KW - elastic modulus
KW - nano-indentation
KW - nanogel
KW - silver cytotoxicity
KW - silver nanoparticle
KW - standard linear solid model
KW - strain-rate dependent elasticity
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U2 - 10.5772/61328
DO - 10.5772/61328
M3 - Article
AN - SCOPUS:84970923982
VL - 2
JO - Nanobiomedicine
JF - Nanobiomedicine
ER -