**5.4 Biosensors**

Biosensors measure biological, chemical, and physical signals related to health. They are used to track diseases and thus improve health. A multilayer system via LBL deposition of biopolymers, based on electrostatic interaction and intended to be applied in diabetes detection was developed. They obtained a new glucose-responsive system using poly(lysine) derivatives and alginate as polycation and polyanion, respectively [131]. Also, chitosan-based nanocapsules were demonstrated as *E. coli* bacterial quorum sensing reporter strain [132].
