NOVELTY - Microbial fuel cell (10) comprises a bio-compatible first body have a micro-pillar structure defining a cathode (14), a bio-compatible second body having a micro-pillar structure defining an anode compartment (18) adapted to contain a catalyst that metabolizes glucose to generate electrons and protons, and a nano-porous membrane (20) preventing loss of the catalyst from the anode compartment, while providing fluid access (30) for ingress of glucose fuel and egress of waste. The first body and the second body are made from a flexible polymeric material.    USE - The microelectromechanical system (MEMS)-based microbial fuel cell is used for implantable devices, e.g. pacemakers.    ADVANTAGE - The fuel cell has flexible substrate which minimizes damage to the human body, and has larger surface-area-to-volume ratio using a micro-pillar structure, which improves power output. Integration with a nano-porous membrane completely eliminates the need for micro-fluid ports.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method of fabricating a microbial fuel cell, comprising:    (A) forming a mold for an anode micro-pillar structure in a silicon substrate;    (B) coating the mold with a sacrificial gold film with a deposition rate of less than 2 A/s;    (C) distributing a thin layer of bio-compatible polymeric materials into the mold;    (D) curing the polymeric materials;    (E) forming conducting electrodes and fluid access ports on the polymeric materials;    (F) assembling the anode micro-pillar structure with a cathode and a proton exchange membrane;    (G) placing a catalyst that metabolizes glucose within the anode micro-pillar structure; and    (H) covering the fluid access ports with a nano-porous membrane to prevent loss of the catalyst while facilitating fluid access through the fluid access ports for the ingress of glucose fuel and egress of waste.    DESCRIPTION OF DRAWING(S) - The figure is an exploded perspective view of a microbial fuel cell.    Microbial fuel cell (10)    Cathode (14)    Anode compartment (18)    Nano-porous membrane (20)    Fluid access (30)