A biosensor including an external surface, and an accessory material in close proximity to the external surface. The accessory material includes a coating containing a hydrophilic material and/or a fiber modified to deliver a therapeutic agent. The biosensor modifies a biological response to the biosensor upon contact with a tissue, such as upon implantation into the skin of a subject, thereby reducing biofouling, inflammation and other undesirable tissue responses that interfere with biosensor performance. The biosensor can be any biocompatible sensor, suitable for short- or long-term use. Preferably, the biosensor is an enzymatic or electrochemical sensor, such as a glucose sensor. Also provided are a method of producing a biosensor and a method of delivering a biologically active substance to a subject.