Layer-by-layer (LBL) assembly has been Biomedical Materials I used to prepare single-walled carbon nanotube (SWNT) freestanding structures that can be used for implantable devices with unique mechanical and electrical properties (see Figure). The thin LBL membranes prepared are biocompatible and support extensive neurite outgrowth. The stretched fiber-like LBL freestanding films exhibit neuronal guiding. The SWNT structures described may potentially enable connectivity between neurons.