There has been rapidly increasing interest in design and synthesis of silicon-based nanostructured materials for bioapplications. In this review, we focus on recent research progress in design, synthesis and bioapplications of two silicon-based nanostructures, zero-dimensional silicon quantum dots and one-dimensional silicon nanowires. These two low-dimensional silicon nanomaterials have found important applications in ultrasensitive biomolecular detection and fluorescent cellular imaging. We further highlight major challenges and promises in this area. (C) 2010 Elsevier Ltd. All rights reserved.