Application of an enteric coat increases the resistance to gastric juices for swallowable biosensors

This paper describes a biosensor with an immobilized-electron mediator that was covered with an enteric coat to generate a swallowable biosensor. Ferrocene-attached poly-l-lysine was crosslinked with glucose oxidase and bovine serum albumin by glutaraldehyde on a Au- or Pt-disc electrode, or a screen-printed electrode. The electrode was dip-coated to generate the enteric coat. The glucose sensor with enteric coat retained its activity under anaerobic conditions after 3 h of artificial gastric juice treatment. Mixing the enteric coat solution with plasticizer resulted in an enhanced stability of the coat. The proposed method is useful to construct the swallowable biosensor for non-invasive continuous glucose monitoring.