A Thermodynamic Investigation into the Binding Properties of DNA Functionalized Gold Nanoparticle Probes and Molecular Fluorophore Probes

摘要

We have quantitatively determined and compared the thermodynamic values of oligonucleotide functionalized gold nanoparticle probes and molecular fluorophore probes of the same sequence. Nanoparticle probes have a higher binding constant, which increases the sensitivity of assays based upon them, as compared with their molecular counterparts. As the length of the recognition sequence increases, the enhancement of the binding strength diminishes. In designing an effective probe, a balance must be maintained between binding strength and selectivity. Moving to a longer recognition sequence can increase the binding strength but at the cost of selectivity. Nanoparticle probes with a shorter 15-base recognition sequence and the appropriate spacer provide a greater sensitivity than a molecular fluorophore, while maintaining a high selectivity without additional amplification of target sequence.