ICFO is offering postdoctoral positions to a well\-qualified, highly motivated and dynamic young scientists who wish to enhance their scientific career in a friendly and stimulating environment. The successful candidate will be joining the **Neurophotonics and Mechanical Systems Biology** group led by **Prof. Dr. Michael Krieg** who is searching for highly motivated researcher to join his team and investigate how intracellular pH changes regulate the mechanical properties and phase transitions of biomolecular condensates. The position is part of the funded project pHACE.transitions, an interdisciplinary initiative combining biophysics, molecular biology, optical trapping, NMR spectroscopy, microfluidics, and neurophysiology to uncover a fundamentally new mechanism of sensory adaptation in neurons. Biomolecular condensates are dynamic, membraneless organelles formed through phase separation. Their material properties—fluidity, elasticity, and internal architecture—can shift dramatically in response to subtle biochemical cues. Our recent findings show that MEC\-2 stomatin, a protein involved force transmission during the sense of touch, undergoes a viscoelastic phase transition upon binding to UNC\-89, a neuronal titn homolog. These changes affect intermolecular interactions and ultimately reshape condensate mechanics to facilitate neuronal mechanotransduction. The goal of this position is to unravel how pH\-dependent molecular interactions translate into macroscopic mechanical behaviors of condensates, both in vitro and in living cells. The successful candidate will lead optical tweezer microrheology experiments to quantify the viscoelastic properties and phase transitions of MEC\-2 and related protein condensates. Working closely with team members and collaborators in NMR spectroscopy, and C. elegans neurobiology, the candidate will: * Perform optical tweezer–based force microrheology to measure condensate mechanics (elasticity, viscosity, relaxation dynamics) using existing technology of the lab. * Quantify pH\-dependent changes in condensate material properties and relate them to specific molecular interactions. * Design and execute in vitro reconstitution experiments with purified proteins and targeted mutants. * Collaborate with cell biologists and electrophysiologists to extend in vitro findings to heterologous cells and C. elegans neurons. * An optional asset is the integrate the optical measurements with microfluidics\-based buffer handling and automation of the optical rheology assays. ### **Share this opening!** Use the following URL: https://jobs.icfo.eu/?detail\=1058 The succesful candidate has a strong background in biophysics, physics, physical chemistry, bioengineering, or a related field. The candidate should have a proven track record in one or more of the following: * Experience with optical trapping of biomolecules or cells, biochemistry and, microfluidic buffer handling techniques (preferred but not strictly required). * Strong quantitative skills (signal processing, rheology models, Python/Matlab analysis) and an interest in phase transitions, protein biophysics, or intracellular mechanics. The candidate is expected to communicate their results in group meetings, conferences, and publications, and provided regular feedback to the PI and the collaborators. Proven track record in team work is a must. The offered position is embedded in an international, highly collaborative environment spanning optical physics, structural biology, neurophysiology, and microfluidics. The successful candidate gains access to state\-of\-the\-art optical tweezer platforms, microfluidic fabrication facilities, advanced imaging systems, and will collaborate with structural biologists, neuroscientists and biosystem engineers to obtain a systems understanding of pH\-regulated force transmission in living systems. Suitable candidates are requested to submit: * Presentation letter with a declaration of interest, * Curriculum Vitae, including contact details, * The contact e\-mail of two potential referees. Candidates will be assessed as they apply and the call will remain open until the suitable candidate is identified. Candidates may contact jobs@icfo.eu for formal enquiries regarding the application, as well as address scientific enquiries to michael.krieg@icfo.eu. For update information about the hosting group, please visit https://www.icfo.eu/research\-group/29/nmsb/home/437\. For updated information about ICFO, please visit https://www.icfo.eu/. 16th of December, 2025