TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The fuel cell further comprises a first conductive mesh disposed along the first exterior surface of the first anion exchange membrane and a second conductive mesh disposed along the second exterior surface of the second anion exchange membrane; a fuel channel disposed adjacent to the first conductive mesh; and an oxidant channel disposed adjacent to the second conductive mesh. The first conductive mesh and the second conductive mesh each comprise a material selected from: a carbon paper, a carbon cloth, a metal mesh and combinations. The catalyst comprises particles of a metal supported by carbon. The metal comprises a metal selected from: platinum, palladium, silver, nickel and alloys. The catalyst comprises enzymatic moieties. Also, at least one of the first side and the second side of the cation exchange membrane comprises an uneven surface. The fuel cell also comprises a non-planar junction between the cation exchange membrane and at least a selected one of the first anion exchange or the second anion exchange. Preferred Stack: The stack of fuel cells further comprises a first oxidant passage disposed adjacent to the first cathode of the first fuel cell and a second oxidant passage disposed adjacent to the alkaline second cathode of the second fuel cell. The acidic first anode of the first fuel cell includes a proton exchange membrane; and the first cathode of the first fuel cell includes a selected one of a proton exchange membrane or an anion exchange membrane. Likewise, the alkaline second cathode of the second fuel cell includes an anion exchange membrane; and the second anode of the second fuel cell includes a selected one of a proton exchange membrane or an anion exchange membrane. Each of the acidic first anode, the first cathode, the second anode and the alkaline second cathode include an exterior surface into which a catalyst has been embedded. The catalyst includes particles of a metal supported by carbon. The metal comprises a metal selected from: platinum, palladium, silver, nickel and alloys. The catalyst comprises metal particles coated with enzymes. The stack as well comprises a conductive mesh disposed adjacent to at least one exterior surface, where the conductive mesh comprises a material selected from: a carbon paper, a carbon cloth, a metal mesh, an alloy and combinations.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: In the fuel cell, the cation exchange membrane comprises a material selected from: a polymer including a sulfonic group attached to it, a composite, and combinations. The cation exchange membrane comprises a sulfonated tetrafluoroethylene based fluoropolymer-copolymer membrane.