The present invention discloses a medical device selected from a group consisting of medical devices, implants wound dressings, comprises at least one insoluble proton sink or source (PSS). The medical device is provided useful for killing living target cells (LTCs), or otherwise disrupting vital intracellular processes and/or intercellular interactions of the LTC upon contact. The PSS comprises, inter alia, (i) proton source or sink providing a buffering capacity; and (ii) means providing proton conductivity and/or electrical potential. The PSS is effectively disrupting the pH homeostasis and/or electrical balance within the confined volume of the LTC and/or disrupting vital intercellular interactions of the LTCs while efficiently preserving the pH of the LTCs' environment.