Electro-adhesive forceps for tissue manipulation

Capturing, separation and removal of thin, evasive, and often transparent membranes attached to the underlying tissue is typically a very difficult task in vitreoretinal surgery. The most challenging part of such procedures is in initial separation of the membrane, which then allows for a strong grip of the micro-tweezers holding it from two sides. Attempts of performing this procedure often lead to piercing and otherwise damaging the underlying tissue. Accordingly, there is a need for devices that could attach to tissue in a minimally-traumatic manner approaching it from only one side. It is desirable that such a device would attach to a tissue on a push of a button and release it on demand. We developed a technique that allows for strong attachment of an electrode to tissue with a single electrical pulse, and disconnection of it from the tissue with a different pulse. Adhesion does not require any electrical support after the pulse, and the adhesive forces generated on a wire electrode of 50 µm in diameter are sufficient for manipulation of all types of cellular and non-cellular intraocular tissues. To reduce electroporation-related tissue damage the bipolar train of pulses is applied with burst duration 50-200µs. At optimal pulse parameters the tissue damage is limited to a single layer of cells adjacent to the surface of electrode. Electrically-induced adhesion is very convenient for lifting and manipulation of vitreoretinal membranes. It can also be used for attachment of a needle to a membrane for injection of liquid into the sub-membrane space, thus separating the membrane from the underlying tissue without peeling. Similarly, injection of medication into small retinal blood vessels can be performed without insertion of the needle into it.