We investigated the efficient nucleation of silver nanoparticles on aldehyde-modified DNA strands. The aldehyde-bearing DNA was prepared by PCR incorporation of diol-modified synthetic deoxyuridine derivatives and subsequent cleavage of the diol groups to aldehyde functions using sodium periodate. Formerly unavailable dialdehyde-bearing DNA could be prepared by this mild and selective method. Both dialdehyde-DNA and monoaldehyde-DNA are capable of inducing silver nanoparticle formation without the addition of any external reductant. Interestingly, dialdehyde-DNA shows a different kinetic behavior and is about four times as efficient in silver nanoparticle formation as monoaldehyde-DNA. These data suggest a potentially unique mechanism of silver nanocluster formation induced by the dialdehyde groups. SEM measurements of fully metallized DNA strands show homogeneous metal coverage and selective metal deposition exclusively on the DNA template.
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