A device for measuring a 
mechanical property of a tissue includes a probe configured to perturb the tissue with movement relative to a surface of the tissue, an 
actuator coupled to the probe to move the probe, a 
detector configured to measure a response of the tissue to the perturbation, and a controller coupled to the 
actuator and the 
detector. The controller drives the 
actuator using a stochastic sequence and determines the 
mechanical property of the tissue using the measured response received from the 
detector. The probe can be coupled to the 
tissue surface. The device can include a 
reference surface configured to contact the 
tissue surface. The probe may include a set of interchangeable heads, the set including a head for 
lateral movement of the probe and a head for perpendicular movement of the probe. The perturbation can include extension of the tissue with the probe or sliding the probe across the 
tissue surface and may also include indentation of the tissue with the probe. In some embodiments, the actuator includes a 
Lorentz force linear actuator. The 
mechanical property may be determined using non-linear stochastic 
system identification. The mechanical property may be indicative of, for example, tissue compliance and 
tissue elasticity. The device can further include a 
handle for manual application of the probe to the surface of the tissue and may include an 
accelerometer detecting an orientation of the probe. The device can be used to test 
skin tissue of an animal, 
plant tissue, such as fruit and vegetables, or any other 
biological tissue.