Doctoral Student in Environmental Bioengineering

100%, Zurich, fixed‑term

Bacterial conjugation, the contact-dependent transfer of plasmids between cells, speeds up bacterial evolution and is a major route for the spread of antibiotic resistance in the environment, which in turn poses a global health threat. Aquatic environments are full of microscale chemical hotspots, such as the nutrient‑rich 'phycosphere' around phytoplankton and sinking marine particles, and chemo tactic bacteria are known to find and accumulate rapidly at these locations.

This project will test the hypothesis that this accumulation enhances plasmid spreading in the environment, contributing to a cutting‑edge view of the role of antibiotic resistance in nature.

The project seeks to study when, where and how strongly this enhancement operates across different chemical hotspots, fluid flows and bacterial strains, and what it means for the spread of antibiotic resistance among aquatic bacteria.

• Design, build and characterize new instrumentation to couple existing chemotaxis assays to controlled shear systems. This includes mechanical design, 3D printing, control systems and integration with a fluorescence microscope.
• Run chemotaxis and conjugation experiments with bacterial donors and recipients of plasmids and a range of chemo attractants, with the opportunity to learn and use advanced techniques such as flow cytometry and plate‑reader‑based plasmid transfer quantification.
• Image and track fluorescently labeled bacteria and chemical plumes in shear flow, and analyze the data with quantitative image- and data‑analysis pipelines.
• Test clinically relevant bacteria and freshwater (e.g. lake) bacteria, to assess the potential for chemotaxis‑driven spread of resistance in the environment.
• Contribute data to mathematical models of plasmid spread.

• Practical experience in prototyping and manufacturing, for example CAD, 3D printing, machining (strongly preferred).
• Experience with control systems and instrumentation, for example motor control, sensors, microcontrollers, and automation or data‑acquisition code (Python, MATLAB, LabVIEW or similar) (preferred).
• Openness to gain experience in the microbiology laboratory: bacterial cultures, sterile technique, plate readers and flow cytometry.
• Familiarity with microscopy, image analysis, fluid mechanics or microfluidics (beneficial but not necessary).
• Fluency in English (oral and written), enthusiasm for working in an interdisciplinary and international team, and the drive to pursue scientific excellence (required).

You will be guided by Prof. Roman Stocker and by members of his lab with extensive experience in microbiology, experimental techniques and environmental processes. You will have the opportunity to work in a cutting‑edge, fast‑paced research environment, interact with researchers from many different disciplines (engineers, physicists, microbiologists, oceanographers, chemists, mathematicians), gain technical experience across diverse research approaches and interact with world‑class collaborators.

ETH Zurich is a family‑friendly employer with excellent working conditions. You can look forward to an exciting working environment, cultural diversity and attractive offers and benefits.

In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open environment that allows everyone to grow and flourish.

Sustainability is a core value for us – we are consistently working towards a climate‑neutral future.

Curious? So are we.

ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting‑edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow.