Abstract: The present invention relates to a micro-device for selective and non-invasive separation of particles in polydispersed suspensions through the strategic use of ultrasounds, laminar flow and standing wave effects in a channel produced in a chip by means of microtechnology. Said device is a resonant multi-layer system with a modified lambda quarter-type treatment channel, which enables the particles to be channeled and separated in a flow inside the substrate channel without touching the walls of the device, in order to avoid problems of adherence. Said micro-device can be used in the field of biomedicine and/or biotechnology for the separation and concentration of cells, preferably human cells, applicable to research and medical processes for diagnosis and treatment.