NOVELTY - An organelle immobilized in an immobilization material is permeable to a compound smaller than the organelle. The immobilization material is either non-naturally occurring colloidal material, acellular colloidal material, micellar material, or inverted micellar material.    USE - In a bioelectrode; and in a biofuel cell for generating electricity all claimed).    ADVANTAGE - The immobilization material is permeable to the fuel fluid such that the oxidation reaction of the fuel at the bioanode can be catalyzed by the enzyme(s) contained within the immobilized organelle; and is capable of stabilizing the organelle. The enzyme in the organelle is in the appropriate concentration and geometric configuration for maximum enzyme activity. The bioelectrode has increased enzyme stability because the enzymes within the organelle are capable of regenerating. Upon immobilization of mitochondria in a bioanode, the enzymes contained within the mitochondria are able to regenerate, and thus, mitochondria are more stable than they are immobilized in an isolated form.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a bioelectrode (B1) comprising an electron conductor, at least one organelle containing at least one enzyme, and an organelle immobilization material capable of immobilizing the organelle, where either the organelle is isolated from a cell or the organelle immobilization material is non-microbial;    (2) a biofuel cell for generating electricity comprising a fuel fluid (G1) and either the bioanode (B2) and biocathode (A1), bioanode (B2) and cathode, or anode and biocathode (A1);    (3) a bioanode (b2) comprising an electron conductor, at least one enzyme capable of reacting with a fuel fluid to produce an oxidized form of the fuel fluid, where the enzyme either capable of releasing electrons to the electron conductor or capable of releasing electrons to an electron mediator; and an enzyme immobilization material capable of immobilizing and stabilizing the enzyme, where the enzyme material is permeable to the fuel fluid, and the enzyme containing glycolysis enzyme and/or Kreb's cycle enzyme;    (4) detecting a nitroaromatic explosive using the biofuel cell comprising exposing the biofuel cell to the nitroaromatic explosive such that the enzyme is reacted with the fuel fluid and the biofuel cell will generate electricity to produce the alarm signal indicating that the nitroaromatic explosive is detected.