The device and method relate to microfluidic particle analysis. The device is designed for trapping particles for solution analysis. Exemplary particles include beads and cells. The device has a microfluidics body, and a microfluidics channel formed in the body for receiving particles at an upstream region thereof. The channel has a deformable wall portion that defines a particle-capture region, and is responsive to a change in fluid pressure applied thereto, to selectively vary the particle-flow dimensions of the capture region. In this way, particles having a given size may be selectively retained in the capture region. In one embodiment, the deformable wall portion is expandable in response to a positive fluid pressure applied within the channel. In another embodiment, the deformable wall portion is expandable in response to a negative pressure applied to a cavity communicating with the wall portion, external to the channel.