Apparatus and method for mass producing a monodisperse microbubble agent

A method of mass producing monodisperse microbubbles, the method comprising:

• providing an apparatus comprising at least one microfluidic flow focusing device comprising a dispersed phase fluid supply channel having an outlet that discharges into a flow focusing junction, at least one continuous phase fluid supply channel having an outlet that discharges into the flow focusing junction, and a bubble formation channel having an inlet disposed at the flow focusing junction;
• and
• supplying a flow of dispersed phase fluid through the outlet of the dispersed phase fluid supply channel into the flow focusing junction, and supplying a flow of continuous phase fluid through the outlet of the at least one continuous phase fluid supply channel into the flow focusing junction,
• such that, at the junction, the flow of dispersed phase fluid is engaged in co-flow by the focusing flow of continuous phase fluid under formation of a gradually thinning jet of dispersed phase fluid that extends into the inlet of the bubble formation channel, and monodisperse microbubbles, having a diameter smaller than the hydraulic diameter of the bubble formation channel break off a tip of said jet,
• wherein said bubble formation channel has a length that is much greater than its hydraulic diameter by a factor of at least ten.