Sensing device, and sensing system and sensing method using the same

A sensing device applied to an analyte molecule of a liquid sample and a buffer flow, comprising:

• at least one first inlet, for inputting the liquid sample;
• at least one second inlet, for inputting the buffer flow;
• a micro-flow channel, communicating with the first inlet and the second inlet;
• and
• at least one immobilization element for immobilizing a sensing molecule for the analyte molecule and the buffer flow in the micro-flow channel,
• wherein the micro-flow channel has two ends which are respectively connected to the first inlet and the second inlet, and the micro-flow channel is between the first inlet and the second inlet,
• wherein the sensing molecule is capable of generating an association reaction with the analyte molecule of the liquid sample, and generating a dissociation reaction with the analyte molecule and the buffer flow in reverse direction,
• wherein the sensing molecule and the analyte molecule of the liquid sample are configured to generate the association reaction after the liquid sample flows into the micro-flow channel for association reaction observation,
• and then the sensing molecule and the analyte molecule are configured to generate the dissociation reaction after the buffer flow flows reversely into the micro-flow channel for dissociation reaction observation.