Using oyster shell, single-crystalline Na2Ti6O13 and Na2W4O13 one-dimensional nanostructures (ODNS) were simply synthesized from granular TiO2 and WO3 particles by thermal heating at 700 degrees C. The oyster shell was used as a source of both sodium and carbon dioxide, which have an effect on unidirectional growth of single-crystalline Na2Ti6O13 and Na2W4O13 from TiO2 and WO3. The growth of sodium metal oxide ODNS from metal oxide particles was reproduced by replacing oyster shell with chemical reagents (NaCl, CaCO3) or gas (CO2), allowing identification of the main factors for the growth of ODNS. The characteristics of biological material (i.e., oyster shell) lend certain advantages in the fabrication of sodium metal oxide ODNS: (a) low processing temperature with high yield; (b) an eco-friendly method; and (c) no requirement of additional processes such as separation or washing. This work suggests a new approach for using biological material for the crystal growth of nanostructured materials. (C) 2009 Elsevier B.V. All rights reserved.