Karin John

This fully funded PhD position at Université Grenoble Alpes, supported by the MSCA COFUND PhD@Tec21 program, aims to uncover the physical mechanisms driving bacterial aggregation during the early stages of biofilm formation. Biofilms are structured communities of bacteria that provide increased resistance to antibiotics and mechanical stress, contributing to the rise of multidrug-resistant infections. While genetic and biochemical factors in biofilm formation are well understood, the physical forces that facilitate the transition from free-swimming to sessile, cooperative bacterial lifestyles remain largely unexplored. The project focuses on surface-motile bacteria, particularly Pseudomonas aeruginosa, which move via twitching motility and form microcolonies through mechanisms that are not yet fully clear. The research will integrate theoretical modeling and numerical simulations with experimental data to test whether Motility Induced Phase Separation (MIPS)—an active matter phenomenon where local slow-downs in bacterial movement due to increased density drive clustering—is the dominant mechanism for microcolony initiation, or whether biological factors such as adhesion-induced phenotypic switches are more decisive. Hosted at the Laboratory for Interdisciplinary Physics (LIPhy) in Grenoble, the PhD will be supervised by Dr. Karin John (MC2 Team) and Dr. Eric Bertin (PSM Team), with co-supervision from Dr. Alexandre Chauvière (BCM Team, TIMC Grenoble). The candidate will collaborate with experimentalists and may participate in image analysis of bacterial motility experiments. The project involves developing both microscopic and continuum models to study the onset of microcolony formation and early bacterial aggregation, using coarse-graining techniques from active matter physics. The PhD is part of the German-French doctoral school “Living Fluids,” offering opportunities for secondments at partner institutions such as the University of Münster. The position provides a 36-month full-time contract, a competitive salary, full social security and health benefits, access to high-level training, and support for international students. Applicants must have a Master’s degree (or equivalent) by the application deadline, a strong background in statistical physics or biophysics, basic scientific computing skills, and excellent English proficiency. The program is open to all nationalities, but applicants must not have resided in France for more than 12 months in the 3 years prior to the deadline. The application deadline is 28 February 2026, with the position starting on 1 October 2026. For more information and to apply, visit the PhD@Tec21 website.