A sensitive chemiluminescence aptasensor for adenosine detection based on a nucleic acid cycle amplification strategy.

Three nucleic acid DNA-modified materials were synthesized and used to the highly sensitive and highly selective chemiluminescence (CL) detection of adenosine (ADE) based on a nucleic acid cycle amplification strategy. These materials include magnetic carbon nanotubes modified with an adenosine aptamer and its complementary DNA (MCNTs@Apt-cDNA), octahedral Fe3O4 nanoparticles modified with hairpin DNA (Octa-Fe3O4@H1DNA), and carbon quantum dot@luminol composites modified with auxiliary DNA (CQDs@luminol-sDNA). They were used to construct a CL aptasensor for ADE detection. When ADE is present, ADE molecules specifically recognize and bind to the Apt in MCNTs@Apt-cDNA, leading to the release of cDNA. The released cDNA then reacts with H1DNA in Octa-Fe3O4@H1DNA, opening the hairpin structure of H1DNA. Subsequently, Octa-Fe3O4 interacts with CQDs@luminol-sDNA to release cDNA again. This released cDNA triggers the opening of H1DNA in Octa-Fe3O4@H1DNA once more, thereby realizing the repeated recycling of cDNA and generating Octa-Fe3O4@H1DNA conjugated with a large amount of CQDs@luminol-sDNA. For the resulting Octa-Fe3O4@H1DNA(CQDs@luminol-sDNA)n complex, luminol acts as the CL substance, while Octa-Fe3O4 and CQDs serve as catalysts. The short distance between luminol and catalysts enhances the CL intensity. As the concentration of ADE molecules increases, more CQDs@luminol-sDNA binds to Octa-Fe3O4@H1DNA, resulting in increased CL intensity and enabling the quantitative detection of ADE. The aptasensor exhibited a linear range of 1.0 × 10− 4 ~ 10.0 nmol/L and a detection limit of 3.2 × 10− 5 nmol/L for ADE detection. Finally, it was successfully applied to the detection of ADE in serum samples.