Silver or gold? A comparison of nanoparticle modified electrochemical genosensors based on cobalt porphyrin-DNA.

We applied a cobalt-porphyrin modified DNA as electrochemical marker, which was attached to nanoparticles, to detect specific DNA sequences. We compare the performance of gold and silver NPs in oligonucleotide sensors to determine if a change in metal will lead to either higher sensitivity or different selectivity, based on the redox behaviour of silver vs. gold.

Approaching single DNA molecule detection with an ultrasensitive electrochemical genosensor based on gold nanoparticles and cobalt-porphyrin DNA conjugates.

We describe an ultrasensitive electrochemical genosensor based on gold nanoparticles and cobalt-porphyrin functionalised ssDNA probes. The sensitivity at the attomolar concentration level arises from an increased density of redox labels on the electrode surface compared to sensors without NP modification. The electrode detects as few as 23 DNA molecules, approaching single molecule detection.