Electrochemical probe

The problem it addresses

Fine wire electrodes cause less disturbance to tissue, but the smaller the exposed metal tip, the harder it is for the electrode to pick up faint electrical and chemical signals. The patent describes a way to keep each wire very thin while giving its tip a much more effective working surface.

What the patent describes

The granted claims describe a probe made from a bundle of wire electrodes lying alongside one another. In the main claim:

• each electrode has a conducting core surrounded by insulation, and is 25 micrometres or less in diameter, with a front end that tapers to a point;
• the polished tip of each electrode carries a layer of metal or metal-oxide nanostructures, each 500 nanometres wide or less, which reduces the electrode’s impedance without making the tip wider than the electrode itself;
• a further functionalisation layer sits on top of that nanostructured layer, so the tip can be tailored to sense particular substances; and
• along the sides of the electrodes, the insulation sits directly on the conductor, with no nanostructure layer in between.

Further claims cover nanostructures made of gold or another noble metal; different groups of electrodes carrying different functionalisation layers; a harness of threads that can steer the orientation of the bundle’s tip; pairing the probe with an integrated circuit that receives and amplifies its signals; and methods for manufacturing the probe. The patent states that the probe is intended for electrochemical sensing, such as neuronal scanning.

Why it matters

The idea separates two jobs that usually compete: the wire’s size, which determines how gently it meets tissue, and the tip’s surface, which determines how well it senses. The same principle, fine insulated wires with gold nanostructured tips, underpins the jULIEs electrodes described in a later peer-reviewed paper. Read our article on that paper.

What a patent is, and is not

A granted patent records that an invention was disclosed and examined for novelty. It is not, on its own, evidence of clinical performance or adoption. The rights in this patent are assigned to The Francis Crick Institute Ltd.