Job opportunity
The bioMatter Microfluidics Group of Dr. Eleonora Secchi at ETH Zurich is seeking two PhD candidates. Our research focuses on uncovering the physicochemical mechanisms that control microbial surface colonisation and biofilm assembly, structure, and rheology. We employ a wide array of technologies in materials science, microbiology, and microfluidics, as well as advanced imaging techniques to explore our scientific questions. Our team is highly interdisciplinary, international, and collaborative, consisting of about 10 members, and is hosted within the chair of Prof. Roman Stocker in the Institute of Environmental Engineering.
The two PhD positions are part of a newly funded SNSF project aimed at systematically investigating nonlinear biofilm rheology, with a specific emphasis on the role of extracellular DNA (eDNA). Biofilms represent a widespread form of microbial life, with significant implications in medicine, industry, and the environment. They contribute to persistent infections, antibiotic resistance, and biofouling, resulting in economic costs of billions of dollars annually and thousands of deaths.
Biofilms are microbial communities encapsulated in a polymeric matrix that provides mechanical stability and protection from mechanical stresses through its viscoelastic properties. While the linear viscoelastic response under small deformations is well characterized and acknowledged as a virulence factor, the response to large deformations remains inadequately understood. There is a particular lack of systematic investigation into the nonlinear regime, where externally applied loads can induce stress-hardening and stiffening of the biofilm matrix.
Recent findings from our group suggest that eDNA may play a central role in the stress-hardening of biofilms. We hypothesize that this behavior arises from the entropic elasticity of the eDNA network, a mechanism that is well described in polymer physics but has largely been unexplored in living biofilms. This could facilitate both short- and long-term adaptation to flow fluctuations. Initial experiments support this hypothesis; however, further investigation is needed to validate the underlying molecular mechanisms and to ascertain if stress-hardening is specific to streamers or reflects a broader feature of biofilm mechanical adaptation across various morphologies. This project will test these hypotheses through a combination of structural, biochemical, and rheological analyses of the biofilms, along with mathematical modeling, with the potential to uncover fundamental principles of biofilm resilience.
The tasks include wet-lab experimentation, project management, numerical modeling, and teaching duties.
Start date: February 1st, 2026, or by agreement.
Fully funded PhD position (approximately 4 years). Final admission to the doctoral programme follows a successful Aptitude Colloquium at the end of year 1; contracts are extended annually.
The ideal candidate holds a Master's degree in:
ETH Zurich is a leading university specializing in science and technology, renowned for its excellent education, cutting-edge fundamental research, and direct knowledge transfer into society. Over 30,000 individuals from more than 120 countries consider ETH Zurich a place that promotes independent thinking and inspires excellence. Located in the heart of Europe yet forging connections worldwide, we collaborate to develop solutions for the global challenges of today and tomorrow.
In line with our core values, ETH Zurich fosters an inclusive culture. We promote equal opportunities, value diversity, and nurture a working and learning environment that respects the rights and dignity of all staff and students. Sustainability is central to our mission, and we are continuously working towards a climate-neutral future.
Interested candidates should apply online using the form below. Please note that only applications matching the job profile will be considered.