Microfluidic thermalization chip with variable temperature cycles, system using such a chip and PCR method for detecting DNA sequences

A micro-fluidic thermalization chip with variable temperature cycles, formed by a block of material in which are arranged successively:

• a fluid injection zone comprising at least one micro-fluidic injection channel to inject a fluid;
• a parallelepiped-shaped cavity having an upper side comprising a heat exchange zone provided with a thermalization zone with a surface S at the upper side of the parallelepiped-shaped cavity, the thermalization zone comprising at least one micro-fluidic circulation channel to circulate the fluid, the parallelepiped-shaped cavity being provided with a fluid inlet orifice from the fluid injection zone and a fluid outlet orifice, between which the heat exchange zone extends;
• and
• at least one micro-fluidic bypass channel configured to bypass the parallelepiped-shaped cavity, wherein said at least one micro-fluidic bypass channel is directly connected at a first end to said at least one micro-fluidic injection channel, a junction disposed at an intersection of said at least one micro-fluidic bypass channel and said at least one micro-fluidic injection channel, said junction being at a distance L from the fluid inlet orifice, the distance L between the junction and the fluid inlet orifice being L<S/a, where S is the surface of the thermalization zone at the upper side of the cavity expressed in m2 and where a is a correction coefficient equal to 0.005 m.