Gold-Iron oxide yolk-shell nanoparticles (YSNPs) as magnetic probe for fluorescence-based detection of 3 base mismatch DNA.

ABSTRACT

Seed-mediated Gold-Iron oxide yolk-shell nanoparticles (YSNPs) were synthesized and functionalized with cy5 attached- thiolated single strand DNA probe for the detection of mutated DNA. The optimum concentration of thiolated DNA determined from a bathochromic shift of surface plasmon resonance (SPR) peak, was 0.177µM. The effect of pH (2-10), temperature (4, 37, 60 and 100 °C), and ionic strengths (1 M to 4 M) on the stability of ssDNA probe tethered YSNPs, studied with the assistance of flocculation parameter. The detection of mutation in DNA was possible using such ssDNA probe functionalized and stabilized nanoparticles. The hybridization of the oligonucleotide probe with the complementary, non-complementary and mutated DNA strands are determined via their respective intensities of the fluorescence of cy5, an efficient fluorescent marker. The intensities help in the comprehension of the specificity of the system. The report predicts controlled efficiency of hybridization with the aid of Hamaker constant, which is determined as 1.15 × 10-20 J for DNA functionalized YSNPs. The minimum concentration of target DNA detected using this methodology was 1.2 × 10-11 mol/L.