Sequence-specifically platinum metal deposition on enzymatically synthesized DNA block copolymer

摘要

Platinum metal was sequence-speeifically deposited on the DNA block copolymer synthesized by the Klenow fragment of E. coli DNA polymerase I (3'-5' exonuclease deficient).rnDue to their long linear structure and the high molecular recognition between not only complementary bases, but also DNA and proteins and other small molecules, DNA molecules have attracted considerable attention as a potential template for the fabrication of nanowires used in future electronic circuits through methods such as doping to DNA, polymerization of conducting polymers on DNA, reduction of metal ions pre-adsorbed to DNA, photoreduction, directed metallization of specifically labelled DNA with aldehyde groups and electroless plating. In particular, DNA-based metal deposition has potential application to the fabrication of thin conductive nanowires (below 10 nm). In general, metal deposition occurs randomly as the metal ions and metal seeds for the electroless plating are not sequence-speeifically bound to DNA. Cisplatin is a sequence-selective metal complex that preferentially binds to the dGpG of DNA rather than other sequences. Since a free platinum complex binds to a Pt atom already covalently bound to DNA in the process of reduction, platinum complex bound to DNA can act as preferential nucleation sites. We have reported that, after reduction, cisplatin can act as a metal seed for the preparation of Ag nanowires on a Lambda DNA template by electroless plating. Through precise control of cisplatin reduction, a platinum nanowire is expected to be fabricated only on the continuous guanine sequences of DNA. If metal complexes containing different types of metal with affinities to a variety of base sequences are used for the metal deposition method on sequence-designed DNA, programmable deposition of different metals can be achieved depending on the base sequence. In order to demonstrate such base sequence programmable nanofabrica-tion, we synthesized a sequence-designed DNA, diblock copoly-mer-type DNA (poly(dG)(poly(dC)-poly[d(AT)]) since block copolymers have been used as a template for fabrication of programmable deposition of nanoparticle.