Membraneless nanofluidic fuel cells are devices that utilize fluid flow through nanoporous media which serve as three-dimensional electrodes. In the case of hybrid fuel cells (HFC) an enzymatic and an abiotic catalyst are incorporated on the electrodes. Here we compared two different HFC. In the first one (HFC-1), glucose oxidase- and Pt-based electrodes were used as bioanode and cathode respectively. This cell reached an open circuit voltage (OCV) of 0.55 V and a maximum power density of 5.7 mWcm(-2). In the second one (HFC-2), AuAg- and laccase-based electrodes were used as anode and biocathode respectively. This cell exhibited an OCV of 0.91 V and a maximum power density of 17 mWcm(-2). Finally, enzymatic electrodes were used to develop a high performance biofuel cell (3.2 mWcm(-2)) that exhibited high stability over 4 days. These preliminary results indicate that the incorporation of enzymes into the 3D carbon structures is an efficient alternative for miniaturized nanofluidic power sources. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.