BIOACTIVE SURFACE-COATINGS FOR NANOSCALE INSTRUMENTS - EFFECTS ON CNSNEURONS

A method is described for depositing onto medical instruments highly b iocompatible and bioactive surface coatings that can promote and stabi lize cell attachment. The coatings were made by first depositing thin films of materials, such as diamond-like carbon, or metals, including tantalum, tungsten, platinum, gold, iridium, palladium, and brass. The se surfaces were further altered to either promote or inhibit cell gro wth and spreading by an additional over-coat of biological materials, including the extracellular matrix proteins, laminin, fibronectin, and collagen IV. The deposition technique used a metal or carbon plasma, and the important properties of film adhesion, hardness, density, and smoothness are tailored by control of the ion bombardment energy. The films are translucent enough to permit high resolution light microscop y for rapid and detailed examination of tissue response. These bioacti ve substrates have been tested on primary central nervous system neuro ns, and the growth response is excellent. Equally successful ha ve bee n our attempts to anchor neurons, without associated proliferation of non-neuronal cells, using coatings of poly-d-lysine. The method and th e materials could have important ramifications in a number of areas of research and biotechnology, for example for chronic implantation of m icroelectrode arrays in the cerebral cortex for neuroprosthetic and ne ural monitoring application and for research on the human central nerv ous system. Possible applications in non-neuronal fields, such as for coronary artery stents and pace-maker electrodes, also are discussed. (C) 1998 John Wiley & Sons, Inc.