ABSTRACT
Nanotechnology is enabling technology at a leading edge that deals with nanometersized objects (Feynman, 1991) at several levels: materials, devices, and systems. At present, the nanomaterials level is the most advanced, both in scienti c knowledge and in commercial applications. A decade ago, nanoparticles were studied because of their size-dependent physical and chemical properties (Murray et al., 2000). However now, they have entered a commercial exploration period (Mazzola, 2003; Paull et al., 2003). The development of synthetic procedures for uniform nanometersized particles is essential for many advanced applications (Schmid et al., 2004) because the monodispersity of metal nanoparticles induces their precise size and shape-dependent properties. From this point of view, a current research interest has been focused on the synthesis and properties of metal nanoparticles. Therefore, a large number of methods have been developed for the synthesis of metal nanoparticles over the last decades. A wide variety of physical, chemical, and biological processes results in the synthesis of nanoparticles, some of these are novel and others
15.1 Introduction .................................................................................................. 315 15.2 Biological Synthesis of Nanoparticles .......................................................... 318
15.2.1 Synthesis of Nanoparticles Using Bacteria ....................................... 320 15.2.2 Synthesis of Nanoparticles Using Yeast ........................................... 323 15.2.3 Synthesis of Nanoparticles Using Algae .......................................... 323 15.2.4 Synthesis of Nanoparticles Using Actinomycetes ............................ 323 15.2.5 Synthesis of Nanoparticles Using Fungus ........................................ 324 15.2.6 Synthesis of Ag Nanoparticles Using White Rot Fungus,
Coriolus Versicolor ........................................................................... 329 15.3 Synthesis of CdS Nanoparticles Using Immobilized Fungus, C. Versicolor ................................................................................................. 332 15.4 Conclusions and Future Directions ............................................................... 334 References .............................................................................................................. 334
are quite common. Normally, the size, shape, and surface modi cation of metal nanoparticles are some of the most important factors that may dramatically affect their physical/chemical properties. For example, the silver nanoparticles can be prepared by the chemical reduction of a homogeneous solution containing silver salt and a large amount of stabilizers (Bradley and Schmid, 2004), such as reverse micelles (Taleb et al., 1997), surfactants (Liz-Marzan and Tourinõ, 1996), dendrimers (Balogh et al., 2001), alkanethiol (Pileni, 2001), alkylamine (Bunge et al., 2003), and carboxylic acid (Lin et al., 2003). Despite numerous reports, the synthetic methods based on chemical reduction still have dif culty in removing halides, by-products, and excess stabilizers such as surfactants.
