What question did this study set out to answer?

This research aims to compare the conjugation behavior and loading efficiency of DNA aptamers on gold nanospheres versus gold nanoflowers.

May 15, 2026Open Access

Comparative Materials-Level Evaluation of 3′- and 5′-Thiol DNA Aptamer Conjugation on Gold Nanospheres and Nanoflowers: Apparent DNA Loading Output, Morphology Retention, and Qualitative Salt-Challenge Response

Key Points

This research aims to compare the conjugation behavior and loading efficiency of DNA aptamers on gold nanospheres versus gold nanoflowers.
Thiolated DNA aptamer constructs (3′-SH and 5′-SH) were immobilized on citrate-stabilized AuNPs and AuNFs under salt-aging conditions.
DNA output was quantified using Qubit measurements of unbound ssDNA in the supernatant.
Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were employed to assess size and morphology changes.
AuNPs exhibited a higher apparent conjugation yield (80.65% for 3′-SH, 84.76% for 5′-SH) compared to AuNFs (66.64% for 3′-SH, 73.65% for 5′-SH).
DNA loading outputs were significantly greater for AuNPs (2329.7 ng and 2448.7 ng) than for AuNFs (1925.1 ng and 2127.4 ng).
A salt-challenge test indicated that aptamer-functionalized nanoparticles were more resistant to aggregation in salt compared to unmodified nanoparticles.

Abstract

Gold nanospheres (AuNPs) and gold nanoflowers (AuNFs) are widely used as platforms for DNA aptamer functionalization, while conjugation behavior and colloidal tolerance remain important factors affecting subsequent sensing-oriented optimization. In this study, 82-nt thiolated DNA aptamer constructs bearing either 3′-SH or 5′-SH terminal modification were immobilized onto citrate-stabilized AuNPs and AuNFs under matched stepwise salt-aging conditions. Apparent nanoparticle-associated DNA output was estimated by Qubit-based measurement of unbound ssDNA in the supernatant and expressed as mass-based loading output (ng). Under the tested stock-dispersion conditions, AuNP samples showed higher apparent conjugation output than AuNF samples. Specifically, the apparent conjugation yields for AuNPs were 80.65 ± 1.64% (3′-SH) and 84.76 ± 1.98% (5′-SH), whereas those for AuNFs were 66.64 ± 3.36% (3′-SH) and 73.65 ± 1.36% (5′-SH). The corresponding apparent DNA loading outputs were 2329.7 ± 47.4 ng and 2448.7 ± 57.1 ng for AuNPs, and 1925.1 ± 97.0 ng and 2127.4 ± 39.3 ng for AuNFs. DLS size increases and zeta potential shifts toward more negative values were consistent with the formation of a DNA-associated interfacial layer, while TEM images supported morphology retention after conjugation. A qualitative visual salt-challenge assessment indicated that aptamer-functionalized nanoparticles displayed improved resistance to salt-induced aggregation relative to bare particles under the tested conditions. Because the commercially supplied AuNP and AuNF dispersions were not normalized to identical particle number or accessible surface area, the reported values should be interpreted as comparative apparent outputs rather than intrinsic loading capacities. Within this scope, the present study provides a convenient preliminary materials-level evaluation of thiolated aptamer conjugation behavior and may support future glyphosate aptasensor optimization.

Read Full Paperexternally

AI से पूछें

Bookmark

View Full Paper