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The AO is a medically guided, not-for-profit organization, a global network of surgeons, and the world's leading education, innovation, and research organization specializing in the surgical treatment of trauma and musculoskeletal disorders. We are home to people from all over the world, from different backgrounds, with diverse talents and specialist areas. What binds us together is our passion for excellence, our dedication to our mission of improving patient care, and our understanding that we are stronger together: we are one AO., For more information, visit:

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This PhD position is part of the PREPARE project (Programmable Release of Prophylactic Antibacterial & Response Enhancing agents), a collaborative initiative between the Infection Biology and Biomedical Materials Focus Areas at the AO Research Institute Davos and CK CARE (Prof. Pierre Yves Mantel). , The Ph.D. student will be formally affiliated with the University of Fribourg and will be co-supervised by Prof. Michael Walch, Department of Oncology, Microbiology and Immunology, Faculty of Science and Medicine at the University of Fribourg

The PREPARE project aims to address this problem by:

• Defining the earliest events enabling bacterial survival in the surgical field (aggregate formation, fibrin encapsulation, antibiotic tolerance)
• Identifying small-molecule immunomodulators that enhance neutrophil antibacterial activity
• Contributing to the development of next-generation responsive biomaterials for localized infection prevention

Position will remain open until role is filled, preferred start by October 2026

Main Responsibilities

• Establish and optimise advanced 3D in vitro infection models (e.g. staphylococcal abscess communities)
• Investigate early events in infection establishment, including bacterial aggregation, fibrin encapsulation, and antibiotic tolerance
• Characterise neutrophil–bacteria interactions, including phagocytosis, ROS production, and bacterial killing
• Identify and evaluate immunomodulatory compounds that enhance neutrophil function
• Perform cell culture and co-culture experiments using primary human neutrophils and bacterial pathogens
• Apply advanced techniques including confocal microscopy, flow cytometry, and molecular assays
• Analyse and interpret complex experimental datasets
• Contribute to interdisciplinary collaboration with biomaterials researchers within the PREPARE project

Main Requirements

• Master’s degree in microbiology, infection biology, immunology, or a related life science discipline
• Practical experience in microbiology and/or host–pathogen interaction studies
• Experience with cell culture and immunological assays (e.g. flow cytometry, microscopy)
• Strong interest in infection biology, innate immunity, and translational research
• Ability to design, plan, and execute experimental studies independently
• Excellent communication skills in English
• Motivation to work in a highly interdisciplinary and collaborative environment
• Additional desirable skills:
• Experience working with primary immune cells (especially neutrophils)
• Familiarity with 3D cell culture or infection models
• Knowledge of bacterial physiology, antibiotic tolerance, or biofilms
• Experience with advanced imaging or transcriptomic approaches
• Interest in translational research and biomaterials-based therapeutic strategies

We offer

• An interesting and varied job in an exciting and innovative organization
• The opportunity to be part of a highly committed international team
• Modern infrastructure
• High degree of flexibility regarding working hours and location (depending on operational requirements)
• Generous package of social benefits, including supplementary vacation days and pension scheme contributions
• Internal skills training opportunities and support for continued education

If you meet the requirements of this challenging opportunity, please submit your complete online application (motivation letter, CV, certificates, reference letters, etc) through our online application system