There is today a huge interest in the clinical community regarding circulating tumour cells (CTC), as easy and minimally invasive « liquid biopsies ». They should provide, during the « blind » period following primary treatment of a cancer, a powerful tool to evaluate the risk of metastatic development, to follow in real time the efficiency of treatments, and guide clinicians in the prescription of alternative treatment. In the present project, I want to apply my expertise in microfluidics, microfabrication and analytical biochemistry to a major bottleneck hindering progress in this field :CTCs are present in the blood at typical levels of less than 1 per ml and current systems do not provide the performances required for an efficient CTC capture and a careful analysis.The group of Dr. Viovy have developed with support of ANR MICAD and EU project CAMINEMS a microfluidic CTC sorting system (EPHESIA) based on immune-affinity capture technology. I would like to expand the performance of this system in terms of sensitivity and integrate multi-modal analysis. Our objective is first to develop a new pre-treatment module integrating biological separation protocols that are currently done manually within an automated microfluidic device. In a second step a novel generation of cell sorting microfluidic device will allow the integration and directed assembly of complex and mobile microfabricated particles (metallic or magnetic).functionalized to selectively sort CTC based on multiple antibodies capture protocols. It will provide unique opportunities to manipulate or release individual CTC for further culture and analysis.Final aims of the proposed project are to connect both modules in a microfluidic system (sample pre-treatment module and multi-ligand capture module) and transfer this technology to clinicians to address the critical question of tumour cells subpopulations in particular for patients in a early stage in which treatments have most chances of success.