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AFM nanoindentation reveals decrease of elastic modulus of lipid bilayers near freezing point of water.

ABSTRACT: Cell lipid membranes are the primary site of irreversible injury during freezing/thawing and cryopreservation of cells, but the underlying causes remain unknown. Here, we probe the effect of cooling from 20?°C to 0?°C on the structure and mechanical properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers using atomic force microscopy (AFM) imaging and AFM-based nanoindentation in a liquid environment. The Young's modulus of elasticity (E) at each temperature for DPPC was obtained at different ionic strengths. Both at 20?mM and 150?mM NaCl, E of DPPC bilayers increases exponentially -as expected-as the temperature is lowered between 20?°C and 5?°C, but at 0?°C E drops from the values measured at 5?°C. Our results support the hypothesis that mechanical weakening of the bilayer at 0?°C is produced by structural changes at the lipid-fluid interface.

SUBMITTER: Gabbutt C

PROVIDER: S-EPMC6923397 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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AFM nanoindentation reveals decrease of elastic modulus of lipid bilayers near freezing point of water.

Gabbutt Calum C Shen Wuyi W Seifert Jacob J Contera Sonia S

Scientific reports 20191219 1

Cell lipid membranes are the primary site of irreversible injury during freezing/thawing and cryopreservation of cells, but the underlying causes remain unknown. Here, we probe the effect of cooling from 20 °C to 0 °C on the structure and mechanical properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers using atomic force microscopy (AFM) imaging and AFM-based nanoindentation in a liquid environment. The Young's modulus of elasticity (E) at each temperature for DPPC was obtain ...[more]

PMID: 31857622

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