There is a growing interest in the use of nanoparticles modifiedwith DNAs, viruses, peptides and proteins for the rational designof nanostructured functional materials and their use in biosensorapplications. The challenge is to control the organization ofbiomolecules on nanoparticles while retaining their biologicalactivity as potential chemical and gene therapeutics. Thesenoble metal nanoparticles/biomolecules conjugates have specificproperties and therefore they are attractive materials fornanotechnology in biochemistry and medicine. In this book, the author review work performed dealing with theDNA structure and functionalities, interactions between DNA, noblemetal nanoparticles, surface active agents, solvents and otheradditives. Particular attention is given to how the DNA’schain length and the DNA conformation affect the interaction andstructure of the nanoconjugates and nanostructures that are formed.Also discussed are the recent advances in the preparation,characterization, and applications of noble metal nanoparticlesthat are conjugated with DNA aptamers and oligomers. The advantagesand disadvantages of functionalized nanoparticles through variousdetection modes are highlighted, including colorimetry,fluorescence, electrochemistry, SPR, and, mass spectrometry for thedetection of small molecules and biomolecules. The functionalizednoble metal nanoparticles are selective and sensitive for theanalytes, showing their great potential in biosensing. Furthermore,this book reviews recent progress in the area of DNA-noble metalnanoparticles based artificial nanostructures, that is, thepreparation, collective properties, and applications of variousDNA-based nanostructures are also described.