Engineering Micromechanical Systems for the Next Generation Wireless Capsule Endoscopy

Wireless capsule endoscopy (WCE) enables the detection and diagnosis of inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. However treatment of these pathologies can only be achieved through conventional means. This paper describes the next generation WCE with increased functionality to enable targeted drug delivery in the small intestinal tract. A prototype microrobot fabricated in Nylon 6 is presented which is capable of resisting peristaltic pressure through the deployment of an integrated holding mechanism and delivering targeted therapy. The holding action is achieved by extending an "anchor" spanning a 60.4 mm circumference, for an 11.0 mm diameter WCE. This function is achieved by a mechanism that occupies only 347.0 mm(3) volume, including mechanics and actuator. A micropositioning mechanism is described which utilises a single micromotor to radially position and then deploy a needle 1.5 mm outside the microrobot's body to deliver a 1 mL dose of medication to a targeted site. An analysis of the mechanics required to drive the holding mechanism is presented and an overview of microactuators and the state of the art in WCE is discussed. It is envisaged that this novel functionality will empower the next generation of WCE to help diagnose and treat pathologies of the GI tract.