There is a relatively old but interesting invention relates to skin-mounted electrodes with substantially short nano spikes. These electrodes provide positive and reliable contact without gels, shaving and/or sanding of the skin surface to enable positive electrode attachment.
Skin structure. From elmarquessecuida.blogspot.com
The invention (US20020028991A1, priority from 2000, by Medtronic Inc.) implements microblades or microneedles which used in electrical sensing applications, such as ECG electrodes, bioelectrical patches, among others. This microblades may be used in replacement of various biosensing applications needing preparation of the skin such as shaving, sanding, gelling and similar procedures to enhance physiological signal sensing.
A skin-mounted electrode
A skin-mounted electrode
Metalized nano spikes utilize the layer of dead skin, the stratum corneum, that is normally not more than 10-20 microns in depth and makes up the outer layer of the human skin. Spikes provide data transmission from the epidermal layer to electrodes configured for connection to other medical devices.
Metalized nano spikes make low impedance contact, thereby allowing good electrical contact for ECG sensing. The metalization may be applied, after completion of standard MEMs-like knife/needle/spike construction, by vapor deposition, electrolysis, or similar metallic deposition methods. The knives/needles have thin coating of conductive metal (10-100 angstroms) and connect to a backing plate that is a metalized electrode.
ECG with nano spikes
The advantages of having these spikes are that they will not contact the nerves or the capillaries that are 200 to 300 microns deep of human’s body. Thus, there is no pain/discomfort and no bleeding. Fitting over the metalized electrode is preferably an adhesive. The adhesives may be useful for short term use, for example, about two days, or long term, up to a week!!!
Skin-mounted memory patch placed on the patient’s body
The invention may be adapted to serve as an electroencephalogram (EEG) electrode for making contact with a patient’s head. In this embodiment, a round flexible substrate for electrode is used to attach the nano spikes.
Also it’s implemented as a “smart patch” (for e.g. insulin injections) or extended memory device to receive Body Wave and Body Bus transmissions. As a memory patch, the device’s electrode would be provided with a memory chip and a power source.