TEM was used to characterise the size of unfunctionalised and functionalised gold nanoparticles, as well as determine the distribution of disaggregated unfunctionalised gold nanoparticles and gold-aptamer-nanoconstructs. The diameter of unfunctionalized nanoparticles was centred at 13 ± 1.71 nm (n=50), Figure & Figure . The size of unfunctionalised and gold nanoparticles functionalised with Sequence-A and Sequence-B was indistinguishable when imaged using TEM Figure & S6. This observation could be due to the apparent sizes of Sequence-A and Sequence-B and the resolution power of the TEM. For example, nucleic acid sequences that are 10 base pairs long are approximately in 34 Å (0.34 nm) in length. Therefore, gold nanoparticles functionalised with Sequence-A (27 nucleotide bases, 0.918 nm) and Sequence-B (13 nucleotide bases, 0.44 nm) would be extremely challenging to differentiate as the size of the nucleotide sequences falls within the error for unfunctionalised nanoparticles size measurement.