Microfluidic sample chip, assay system using such a chip, and pcr method for detecting dna sequences

A system to analyze PCR-type samples contained in at least one chamber of a micro-fluidic sample chip to test biological samples, for PCR or fluorescence analysis, in the form of a hollow block comprising said at least one chamber delimited by an upper wall, a lower wall and at least one side wall, into which a sample to be tested can be introduced;

• wherein the block is provided with at least a lower side and an upper side parallel to each other, the lower side being disposed onto the lower wall, the upper side being disposed on the upper wall made of a material having a thermal conductivity lower than a material of the lower side and the upper side being permeable, at least in said at least one chamber, to radiations having a wavelength between 300 nm and 900 nm;
• wherein the hollow block comprises at least two openings to introduce the sample into said at least one chamber and to discharge pressure in the chamber during the introduction of the sample;
• the system comprising:
• a thermalization film to increase or decrease, by a thermal cycling, a temperature of the micro-fluidic sample chip and the samples therein, in a thermal contact with the lower side of the micro-fluidic sample chip;
• sealers to close said at least two openings in said at least one chamber to maintain a relative internal pressure of at least 5000 Pa (50 mbar) in said at least one chamber, an increase in the temperature of the samples causing said at least one chamber to expand, thereby improving the thermal contact between the lower side of the micro-fluidic sample chip and the thermalization film;
• a pressure controller to maintain a relative external pressure greater than 50 mbar over the entire upper side of the micro-fluidic sample chip to provide a substantially uniform thermal contact between the lower side of the micro-fluidic sample chip and the thermalization film, wherein the upper wall of the micro-fluidic sample chip comprises a transparent portion traversed by light rays and located above said at least one chamber containing one of the samples;
• and
• an optical measurement instrument, comprising a camera, to optically observe the samples with a spatial resolution.