RAT SCIATIC-NERVE REGENERATION THROUGH A MICROMACHINED SILICON CHIP

The capacity of regenerating nerve fibres to grow through a perforated silicon chip was tested using the silicone chamber model for nerve re generation. The chips were fabricated as circular membranes, 4 mm in d iameter, thickness 60 mu m, with a perforated area, 2 mm in diameter, in the centre. Three types of chips were fabricated utilizing anisotro pic etching. The chips were glued with silicone adhesive between two h alves of a silicone rubber tubing (total length 8 mm, inner diameter 1 .8 mm, outer diameter 3.0 mm) which was used to bridge a 4 mm gap betw een the proximal and distal nerve stumps of a transected rat sciatic n erve. The capacity of regenerating nerve fibres to grow through the ho les of the chip was analysed by light and scanning electron microscopy after 4 or 16 weeks of regeneration. Furthermore, the muscle contract ility force of the gastrocnemius muscle was measured after 16 weeks of regeneration and compared as a percentage of the contralateral uninju red side. Nerves generated through chips with hole diameters of 10 or 50 mu m were morphological and functional failures. The nerve structur es distal to chips with hole diameters of 100 mu m contained many myel inated nerve fibres in a minifascicular pattern after both 4 and 16 we eks of regeneration. The muscle contractility force was 56% of that of contralateral control muscles. (C) 1996 Elsevier Science Limited