Excellent properties of NaF and NaBr induced DNA/gold nanoparticle conjugation system: Better stability, shorter modified time, and higher loading capacity

The functionalization of gold nanoparticle (AuNP) is the key procedure for the biochemical and biomedical application. The conventional salt-aging method requires the stepwise additions of NaCl and excessive thiolated DNA, mainly due to the poor tolerance of the DNA/AuNP mixture toward NaCl. Herein, we found that NaF is capable of improving the stability for the modification of AuNP with different bases of DNA sequences (poly A/T/C/G), and allows for adding up with a high concentration of 200 mM at one time, which greatly reduces the total modification time to 0.5–1 h. Intriguingly, the introduction of NaBr effectively increases the DNA loading capacity. Besides the advantages of NaF and NaBr, the modification performance is improved via the introduction of the oligo A/T spacer for the G-rich DNA sequences. Furthermore, this method shows the superiority to another two methods (pH 3-based and salt-aging) in terms of the loading capacity or sequence components. [Display omitted]