ETH Zürich’s bioMatter Microfluidics Group, led by Dr Eleonora Secchi and hosted within the chair of Prof. Roman Stocker at the Institute of Environmental Engineering, is offering two fully funded PhD positions focused on the biophysics and rheology of bacterial biofilms. The group’s research aims to uncover the physicochemical mechanisms governing microbial surface colonisation, biofilm assembly, structure, and rheology, using interdisciplinary approaches that span materials science, microbiology, microfluidics, and advanced imaging techniques.

These positions are part of a recently funded SNSF project dedicated to systematically investigating nonlinear biofilm rheology, with a particular emphasis on the role of extracellular DNA (eDNA). Biofilms, as complex microbial communities encased in a polymeric matrix, play critical roles in medicine, industry, and the environment, contributing to persistent infections, antibiotic resistance, and biofouling. The project seeks to understand how biofilms respond to mechanical stresses, especially in the nonlinear regime where stress-hardening and stiffening may occur, potentially mediated by the entropic elasticity of eDNA networks—a concept well established in polymer physics but largely unexplored in living biofilms.

PhD candidates will experimentally investigate nonlinear rheology and stress-hardening in bacterial biofilms of various morphologies using custom microfluidic and rheometry platforms. They will quantify the role of eDNA and its interactions with biofilm matrix components through mutant libraries, enzymatic/antibody assays, and controlled physicochemical conditions, as well as assess the incorporation of exogenous DNA into biofilms and its impact on morphology and mechanics. Advanced fluorescence and confocal imaging approaches will be developed and applied to resolve biofilm network structure and eDNA conformation in situ. Candidates will also contribute to the development of a numerical predictive model of biofilm mechanics and collaborate within an interdisciplinary team and with external partners, communicating results through publications and presentations. The role includes wet-lab experimentation, project management, numerical modeling, and teaching duties.

The ideal applicant will hold a Master’s degree in physics, biophysics, materials science, microbiology, or a related field, with a strong interest in interdisciplinary research at the interface of soft-matter physics and microbiology. Experience in experimental work such as microfluidics, rheology, microscopy, or culturing microbes, and familiarity with data analysis and quantitative modelling are highly valued. Candidates should be motivated to work both independently and collaboratively in an international research environment and to contribute actively to teaching activities.

ETH Zürich offers a vibrant, diverse, and inclusive working environment, with training opportunities, career development perspectives, mentoring programmes, and flexible working conditions. The university is committed to sustainability and equality of opportunity, fostering a climate-neutral future and a fair, open environment for all staff and students.

Applications must be submitted online via the ETH Zurich application portal by November 30th, 2025, and should include a curriculum vitae, cover letter (including motivation, research interests, and possible start date), full transcript from undergraduate studies (Bachelor and Masters), a copy of Master’s or Bachelor’s thesis (PDF), and at least two reference letters. Applications sent by email or post will not be considered. For questions regarding the position, contact Dr Eleonora Secchi at [email protected].

ETH Zürich is one of the world’s leading universities in science and technology, renowned for its excellent education, cutting-edge research, and commitment to solving global challenges.