ABSTRACT
Deoxyribonucleic acid (DNA) oligonucleotides are highly programmable in terms of creating nanoscale structures. In addition, DNA has molecular recognition and catalytic functions. Gold (Au) nanoparticles (AuNPs) have excellent optical properties, good biocompatibility and high stability. High-quality monodispersed AuNPs can be readily synthesized, and they are stable for years in clean, low-salt buffers. With DNA-functionalized AuNPs, it is quite straightforward to achieve colorimetric detection based on DNA-induced assembly or disassembly of AuNPs. DNA aptamers have been developed to bind specific target molecules in solution. These aptamers are single-stranded DNA and typically fold into well-defined structures in the presence of their target molecules. DNAzymes are DNA-based catalysts. Since most DNAzymes require specific metal ions to function, they are ideal for metal detection. DNA is a highly negatively-charged polymer, and it is naturally repelled by the negatively-charged cell surface. In summary, DNA-functionalized AuNPs are highly versatile materials, and they represent a classic example in bionanotechnology.
