Method and device to provide a microfluidic flow

A method to provide a microfluidic flow comprising a first material and a second material, said microfluidic flow comprising a central flow and at least one outer flow surrounding or flanking said central flow, said central flow comprising said first material and being substantially free of said second material and said at least one outer flow comprising said second material and being substantially free of said first material, with one of said first material and said second material comprising cells and the other of said first material and said second material comprising solid particles selected from the group of nanoparticles, microparticles and combinations of nanoparticles and/or microparticles, said method comprising the steps of:

• providing a first suspension comprising said first material and being free of said second material;
• providing a second suspension comprising said second material and being free of said first material;
• injecting said first suspension with a first flow rate through a central inlet oriented along a first axis to provide a flow of said first suspension;
• injecting said second suspension with a second flow rate to a first junction region of said flow of said first suspension through a first pair of side inlets to provide said microfluidic flow, said first pair of side inlets comprising a first side inlet oriented along a second axis and a second side inlet oriented along a third axis, said first axis and said second axis defining a first included angle and said first axis and said third axis defining a second included angle, said first and second included angles ranging between 10 and 80 degrees, whereby said first flow rate and said second flow rate are adjusted in order to have a ratio of said second flow rate over said first flow rate of at least 4;
• optionally injecting a fluid to said microfluidic flow with a third flow rate through at least one additional inlet oriented along a fourth axis, said fourth axis having an orientation different from the orientation of said first axis, said second axis and said third axis.