We report a novel microwave plasma enhanced chemical vapor deposition strategy for the efficient synthesis of multilayer graphene nanoflake films (MGNFs) on Si substrates. The constituent graphene nanoflakes have a highly graphitized knife‐edge structure with a 2–3 nm thick sharp edge and show a preferred vertical orientation with respect to the Si substrate as established by near‐edge X‐ray absorption fine structure spectroscopy. The growth rate is approximately 1.6 µm min−1, which is 10 times faster than the previously reported best value. The MGNFs are shown to demonstrate fast electron‐transfer (ET) kinetics for the Fe(CN)63−/4− redox system and excellent electrocatalytic activity for simultaneously determining dopamine (DA), ascorbic acid (AA) and uric acid (UA). Their biosensing DA performance in the presence of common interfering agents AA and UA is superior to other bare solid‐state electrodes and is comparable only to that of edge plane pyrolytic graphite. Our work here, establishes that the abundance of graphitic edge planes/defects are essentially responsible for the fast ET kinetics, active electrocatalytic and biosensing properties. This novel edge‐plane‐based electrochemical platform with the high surface area and electrocatalytic activity offers great promise for creating a revolutionary new class of nanostructured electrodes for biosensing, biofuel cells and energy‐conversion applications.

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We demonstrate a novel and highly sensitive electrochemical detection of estrone based on an immunosensor platform, composed of bioassembled nanocircuits of Mo 6S 9- x I x nanowires (MoSI NWs) covalently connected to anti-estrone antibodies. The one-step, label-free, and quantitative detection of estrone is realized by employing the [Ru(NH 3) 6] (3+/2+) redox ions to sense anti-estrone antibody and estrone interactions. The MoSI NWs/anti-estrone antibody nanocircuit architectures provide an amplification and conductive pathway for the specific electrochemical sensing of estrone hapten. A detection limit of 1.4 pg x mL (-1) was achieved in contrast to previous electrochemical techniques in which the sensitivity was limited to the nanomolar range.