Evaluation the effect of nanoparticles on the structure of aptamers by analyzing the recognition dynamics of aptamer functionalized nanoparticles.

Aptamer-functionalized nanoparticles have been widely studied as targeted probes in biomedical applications for targeted therapy and imaging. The rigidity of the nanoparticle could stabilized the spatial structure of the aptamer, ensuring the selectivity and affinity for target recognition in the complex environment. The main aim of this article study was to explore the effect of the spatial structure of aptamer in the interaction between aptamer nanoprobes and receptors. We designed and synthesized aptamer functionalized nanoparticle systems with different derivation lengths, and developed a unique kinetic analysis to quantify affinity interactions. The system used silver decahedral nanoparticles (AgNPs), which was then chemically functionalized with thrombin (or IgE) aptamers of different tail lengths to produced different nanoprobes, and employed thrombin (or IgE) as target on a surface plasmon resonance (SPR) biosensor to evaluate the binding of these nanoprobes. Kinetic analysis of the SPR binding curve was performed to evaluated the affinity between nanoprobes and targets. Under the premise of eliminating multivalent interactions, we found that the distance between aptamer and nanoparticle could affect the affinity between nanoprobe and target. Furthermore, we found that keeping a certain distance between aptamer and nanoparticle could effectively improved the recognition efficiency of the aptamer nanoprobe and target. It shows that the rigidity of nanomaterials could maintain the spatial structure of the aptamer.