MEMS actuator for splinter-like skin penetration in glucose-sensing applications: Design and demonstration

This paper discusses the design of a new actuator mechanism for the e-Mosquito, an autonomous wearable blood glucose monitoring system with autonomous insertion of single-use needles. The actuator converts tensile force from a contracting shape memory alloy wire into non-linear extension of a needle from a casing and allows both needle and casing to be replaced. It has fewer disposable parts, no fixed rotating elements, and reduced thickness. In vitro tests demonstrate that a prototype of the mechanism is capable of driving a 28-gauge lancet needle with sufficient initial force to enter the skin, and to penetrate to a maximal depth of 1.5 mm in pig skin. This opens the way for further miniaturization of the system.