Abstract: A method to provide a microfluidic flow comprising a central flow and at least one outer flow, such that the central flow includes a first material and the at least one outer flow comprises a second material. One of the first material and the second material has cells and the other of the first material and the second material has solid particles. The method involves injection of a first suspension including the first material through a central inlet with a flow rate Q2 and injection of a second suspension comprising the second material through a pair of side inlets with a flow rate Q2, whereby the ratio of the flow rate Q2 over the flow rate Q1 is at least 4. A device provides such microfluidic flow and a method is provided to alter biological cells.

Abstract: A method to provide a microfluidic flow comprising a central flow and at least one outer flow, such that the central flow includes a first material and the at least one outer flow comprises a second material. One of the first material and the second material has cells and the other of the first material and the second material has solid particles. The method involves injection of a first suspension including the first material through a central inlet with a flow rate Q2 and injection of a second suspension comprising the second material through a pair of side inlets with a flow rate Q2, whereby the ratio of the flow rate Q2 over the flow rate Q1 is at least 4. A device provides such microfluidic flow and a method is provided to alter biological cells.

Abstract: The device can be used for the in vitro selection of eukaryotic cells, and in particular sperm cells (SP). It comprises a transportation channel (100), preferably a DE TR transportation channel (100), in which a solution containing said eukaryotic cells can circulate (SP), a first through passage (104) opening into said transportation channel (100), a source of electromagnetic radiation (60), which is coupled to a first end of a first optical fibre (61), the other emission end (61b) of the first optical fibre being inserted into said first through passage (104), without protruding into the transportation channel (100). The device further comprises electronic control means (7), which make it possible to automatically control said source of electromagnetic radiation (60), so as to selectively alter the eukaryotic cells (SP) circulating in the transportation channel (100), by means of the electromagnetic alteration radiation (R) emitted by the source of electromagnetic radiation (60).