Defence of doctoral thesis in the field of applied physics, M.Sc. Lahja Martikainen

Title of the doctoral thesis is "Biomimetic materials design – Towards tough nanocomposites and strain-stiffening hydrogels"
Some ice cube like material in the front, two testing tubes in the backround

The field of biomimetics aims to borrow nature's well-adapted design strategies, structures, and functions to solve material engineering problems. Biomimetic material design is an approach that can provide alternative ways of achieving light weight, durable, and sustainable materials, and processes. Biomimetic development in cell culturing systems allows more reliable preclinical models for pharma industry.

This thesis focuses on two nature-inspired systems: (i) tough and strong nacre-mimetic nanocomposites, and (ii) strain-stiffening biopolymer hydrogels and their application for cell culturing. Biological hydrogels and nanocomposites have fundamentally different mechanical properties. However, both have several hierarchical levels in their structure from the atomic to the macroscale. Importantly, both these material categories incorporate mechanisms that are believed to be important in protecting the mechanical integrity of biological organisms.

In this work, clay-polymer nanocomposite films and agarose hydrogels were prepared and their mechanical properties and connection to structure were studied. Both materials consist of nanoscale components that self-assemble into macroscopic materials.

Base on a biomimetic materials design approach, the first part of the thesis illustrates a simple method to control the mechanical properties of clay-polymer nanocomposites and shows that the glass transition temperature of the nanoconfined polymer is lowered due to residual water. The second part presents insights into the fibril network mechanics: The strain-stiffening, negative apparent normal stress upon shearing and helical twisting of the agarose fibrils are demonstrated. Finally, the work introduces a reliable agarose-based preclinical model for breast cancer drug development and offers opportunities towards personalized cancer treatments.

Opponent is Associate Professor Ali Miserez, Nanyang Technological University, School of Materials Science and Engineering, Singapore

Custos is Professor Olli Ikkala, Aalto University School of Science, Department of Applied Physics

Contact information of the doctoral student: [email protected], +358405445326

The public defence will be organised via Zoom. Link to the event.

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The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic thesis

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