NOVELTY - A unitized membrane electrode assembly comprises first and second gas-diffusion backings having sealing edges, a polymer membrane, first and second electrocatalyst coating compositions, and a thermoplastic polymer fluid-impermeable seal enveloping peripheral region of both the gas-diffusion backings and polymer membrane. The thermoplastic polymer is impregnated into a portion of the sealing edges of gas-diffusion backings.    USE - For use in electrochemical cells, e.g. fuel cell or electrolysis cell (claimed).    ADVANTAGE - The use thermoplastic polymer sealant material prevents short-circuiting between the electrodes around the membrane, speeds up MEA manufacturing process, and provides high productivity.    DETAILED DESCRIPTION - A unitized membrane electrode assembly (MEA) consists of first and second gas-diffusion backings (13, 13') having sealing edges, a polymer membrane (11), a first electrocatalyst coating composition (12) disposed at the interface of first gas-diffusion backing and polymer membrane, a second electrocatalyst coating composition (12') disposed at the interface of second gas-diffusion backing and polymer membrane, and a thermoplastic polymer fluid-impermeable seal enveloping a peripheral region of both the first and second gas-diffusion backings and polymer membrane. The thermoplastic polymer is impregnated into a portion of the sealing edges of first and second gas-diffusion backings.    INDEPENDENT CLAIMS are also included for:    (a) making a membrane electrode assembly by forming multi-layer sandwich comprising first gas-diffusion backing, first electrocatalyst coating composition, polymer membrane, second electrocatalyst coating composition, and second gas-diffusion backing; applying thermoplastic polymer to the multi-layer sandwich to form thermoplastic polymer fluid-impermeable seal;    (b) making a multi-conductor electrical component, e.g. battery, capacitor, or multi-conductor insulated wire, by placing at least one pair of electrical conductors in a mold; and applying thermoplastic polymer to the electrical conductors; and    (c) manufacture of fuel cell stack by forming multi-layer sandwich comprising repeating pattern of bipolar plate, first gas-diffusion backing layer, first electrocatalyst coating composition, polymer membrane, second electrocatalyst coating composition and second gas-diffusion backing terminating with a final bipolar plate; and applying thermoplastic polymer to the multi-layer element.    DESCRIPTION OF DRAWING(S) - The figure is a schematic illustration of a multi-layer sandwich.    Polymer membrane (11)    First and second electrocatalyst coating compositions (12, 12')    First and second gas-diffusion backings (13, 13')