| Autor: |
Ooi JSY; School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia., Lim CR; School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia., Hua CX; School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia., Ng JF; School of Pharmacy, Faculty of Health and Medical Sciences, Taylor's University, No. 1 Jalan Taylor's, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia., New SY; School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. |
| Abstrakt: |
This study investigates the effect of DNA hairpins on the stabilization of gold nanoparticles (AuNPs) against salt-induced aggregation (SIA) in label-free colorimetric biosensors. AuNPs were incubated with DNA hairpins of varying stem lengths and toehold sequences, followed by the addition of NaCl, before being subjected to ultraviolet-visible (UV-vis) measurement. Results showed that hairpins with longer stems generally provide better stabilization of AuNPs (18-bp >14-bp >10-bp). No improvement was observed for 14- and 18-bp hairpins with a toehold beyond 8A, which may be attributed to saturated adsorption of hairpins on the gold surface. For 14-bp hairpins with an 8-mer homopolymeric toehold, we observed a stabilization trend of A > C > G > T, similar to the reported trend of ssDNA. For variants containing ≥50% adenine as terminal bases, introducing cytosine or guanine as preceding bases could also result in strong stabilization. As the proportion of adenine decreases, variants with guanine or thymine provide less protection against SIA, especially for guanine-rich hairpins (≥6G) that could form G-quadruplexes. Such findings could serve as guidelines for researchers to design suitable DNA hairpins for label-free AuNP-based biosensors. |
