Development of a non-living model system for cell membranes and investigation of its mechanical and tribological properties

Shoaib, Tooba

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https://hdl.handle.net/2142/95436 Copy

Description

Title

Development of a non-living model system for cell membranes and investigation of its mechanical and tribological properties

Author(s)

Shoaib, Tooba

Issue Date

2016-07-22

Director of Research (if dissertation) or Advisor (if thesis)

• Abelson, John R.
• Espinosa-Marzal, Rosa M.

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• model cell membrane
• hydrogel
• soft matter friction
• lipid bilayer
• nanomechanics

Abstract

While our exposure to nanomaterials (NMs) has increased with advancements in nanotechnology, understanding harmful effects of such materials on humans is still wanting. Here we have proposed and developed a non-living model system for cell membranes which is suitable for elucidating interactions between NMs and living cells. In contrast to existing model systems for cell membranes, PAAm hydrogel was used as soft support for the lipid. Grafting of lipid with PAAm was achieved through layer by layer deposition of alternating poly(allylamine hydrochloride) (PAH)and poly(sodium 4-styrenesulfonate) (PSS) polyelectrolyte multilayers (PEM). Single step bilayer formation was observed under QCM on the PAAm-PEM support owing to high electrostatic interactions between the PEM and lipid vesicles with frequency and dissipation changes of ~-30 Hz and ~0.8x10-6, respectively. It is also shown that the PEM architecture is robust and reproducible on gels of different elastic modulus. AFM images confirm bilayer formation on top of PAAm-PEM supports with uniform bilayer patches of ~ 0.5 μm. AFM indentation experiments show significant differences in the elastic modulus and adhesion forces for systems with soft underlying supports compared to systems having a hard substrate. The physiological relevance of the developed system is clear from its mechanical characterization via AFM, where the system undergoes considerable deformation before and after bilayer rupture. This behavior is similar to behavior of real cells, in which deformation of cytoskeleton is dominant over that of the cell membrane. The model cell membrane system was also used to study shear forces at the interface of the lipid bilayer on hydrogel, which gave insights into the frictional behavior of the system and its mechanical interactions with nanoprobes.

Graduation Semester

2016-12

Type of Resource

text

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http://hdl.handle.net/2142/95436

Copyright and License Information

Copyright 2016 Tooba Shoaib

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