The invention concerns a Thickness Shear Mode (TSM) biosensor (1 ) which comprises an ex vivo living skin explant (2), the skin explant (2) comprising at least one of the skin layers among: hypodermis, dermis (2A), epidermis (2B) and the stratum corneum (2C), a TSM transducer (3) which comprises: an AT cut quartz resonator 3C which has two opposite exterior surfaces (3A,3B), and two conducting electrodes (4A, 4B), each conducting electrode being deposited on one of the two exterior surfaces (3A,3B), the TSM transducer (3) allowing to determine micro rheological characteristics of the living skin explant (2) by piezoelectric transducing using shear waves, the TSM transducer (3) presenting: measuring means (30), monitoring and calculating means (31 ) which monitor an evolution in time of an electrical response of the living skin explant (2), and which calculate in time, from the electrical response, micro rheological characteristics of the living skin explant (2), a bottom surface of the skin explant (2) being
