Optical method for tracking the in-vitro amplification of a nucleotide sequence

A method for tracking the in-vitro amplification of a nucleotide sequence contained in a sample, the amplification aiming to replicate said nucleotide sequence via a DNA polymerase enzyme, the method comprises the following steps:

• a) mixing the sample with a reaction medium so as to obtain multiple replications of a preset nucleotide target sequence, the mixing being carried out at an initial time;
• b) illuminating the sample using a point light source, the point light source emitting, in an illumination spectral band, an incident light wave that propagates toward the sample;
• c) acquiring, using an image sensor, a two-dimensional image of the sample, the sample being placed between the point light source and the image sensor such that the image sensor is exposed to an exposure light wave having passed through the sample, the acquisition being carried out at an acquisition time subsequent to the initial time;
• d) on the basis of the acquired image, forming an image of interest that is representative of the formation of a precipitate in the sample under the effect of the amplification;
• and
• e) calculating an indicator, called the amplification indicator, depending on a distribution of the intensity of the pixels in all or part of the image of interest, the amplification indicator being representative of a replicated amount of target sequences;
• wherein, in step c), the image is acquired in the illumination spectral band, and
• wherein the amplification indicator is determined depending on a dispersion of the intensity of the pixels in the image of interest.