The present invention relates to a channeled metal clad fiber comprising one or more surface channels that extend along directions that are substantially parallel to the longitudinal axis of such fiber. The present invention also provides a microfibrous fuel cell structure that comprises a hollow microfibrous membrane separator having an electrolyte medium therein and defining a bore side and a shell side. An inner current collector, which is formed of a channeled metal clad fiber or a channeled metal fiber that is unclad, and an inner electrocatalyst layer are positioned at the bore side of such microfibrous fuel cell, and an outer current collector and an outer electrocatalyst layer are positioned at the shell side of such microfibrous fuel cell. The surface channels on such inner current collector provide inner fluid passages for passing a fuel-containing or an oxidant-containing fluid through the microfibrous fuel cell.