Thermal stability of DNA functionalized gold nanoparticles

Area of Science:

• Nanotechnology
• Bioconjugation Chemistry
• Materials Science

Background:

• DNA functionalized gold nanoparticles (DNA-AuNPs) offer significant potential in disease diagnostics and therapeutics.
• Ensuring stable DNA-nanoparticle conjugation under thermal stress is critical for practical applications.
• Organosulfur anchor groups and packing density are key factors influencing DNA-AuNP stability.

Purpose of the Study:

• To systematically investigate the thermal stability of DNA-AuNPs.
• To evaluate the impact of different organosulfur anchor groups and DNA packing densities on thermal stability.
• To understand the relationship between temperature-induced and chemical-induced DNA release.

Main Methods:

• Utilized a fluorescence assay to quantify DNA release kinetics from DNA-AuNPs.
• Compared DNA-AuNPs constructed with varying anchor groups (thiol, acyclic disulfide, cyclic disulfide).
• Assessed the effect of DNA packing density on thermal stability at different temperatures (37 °C and 85 °C).

Main Results:

• Bidentate Au-S bonds (cyclic disulfide) showed lower thermal stability but higher chemical stability against competing thiols compared to thiol or acyclic disulfide anchors.
• DNA packing density significantly affected thermal stability at 37 °C, with a diminishing effect at higher temperatures (85 °C).
• Observed opposing trends in DNA release between temperature-induced and chemical-induced conditions based on anchor group type.

Conclusions:

• Understanding the influence of anchor groups and packing density is essential for designing stable DNA-AuNPs.
• Developed a strategy to enhance DNA-AuNP stability by employing double-stranded DNA with multiple thiol anchors.
• Findings provide insights for optimizing DNA-AuNPs for reliable performance in diagnostic and therapeutic applications.