Laparoscopic graspers are built from rigid links, hinges, and springs — mechanical assemblies with multiple parts that must be manufactured, assembled, and sterilized separately. The joints wear. The linkages introduce backlash. The springs lose tension.

A monolithic compliant grasper replaces all of this with a single 3D-printed structure that deforms elastically to grasp, and uses bistability to hold without continuous input.

The design couples a compliant trigger to a compliant end-effector through a control push-rod. The trigger uses a Two-Element Beam Constraint Model to control deformation while preventing snap-through instability — the mechanism deforms smoothly under input force without jumping unpredictably. The end-effector functions as an adaptive gripper through elastic deformation, conforming to the tissue shape rather than imposing a fixed geometry.

Bistability is the key feature. The grasper has two stable configurations — open and closed — with an energy barrier between them. Once squeezed past the threshold, it locks closed without requiring the surgeon to maintain force. This is not a ratchet or a latch. It is the elastic energy stored in the compliant structure itself, which has two local minima in its potential energy landscape. The same material that forms the structure also provides the holding force.

No rigid joints. No separate springs. No assembly. One printed part that grips, holds, and releases through the geometry of its own deformation. The complexity moved from the bill of materials into the shape.