By comparing hairpin DNAs (HP-DNAs) with a pristine stem segment and varied loop sequences, the scientists found that the emission behaviour of the HP-DNA-hosted Au NCs is dependent on the loop sequences. The most efficient host for producing fluorescent Au NCs is the cytosine loop. What’s more, the emission properties of HP-DNA-hosted Au NCs can be modulated by the loop length.

The sequence-dependent formation of fluorescent Au NCs is believed to be caused by differences in binding nucleophilicity of the DNA heterocyclic nitrogen and exocyclic keto groups to the hydrolysed Au(III) species.

This work demonstrates the role of sequence in producing Au NCs that could serve as promising fluorescent nanoprobes in biosensing and DNA-hosted Au nanomaterials.

Additional information can be found in the journal Nanotechnology.