Functional metal organic framework mediated G-quadruplex DNA nanostructures for improved self-powered smartphone-assisted dual-mode biosensing

Abstract

Accurate detection of major disease biomarkers is frequently hindered by complex environmental factors and their inherently low expression levels. To overcome these challenges, a self-powered, smartphone-assisted dual-mode biosensing platform has been developed, utilizing functional metal-organic frameworks (MOFs) and G-quadruplex (G-4s) DNA nanostructures to significantly amplify signal output and enhance detection accuracy. This innovative system utilizes gold nanoparticle/zirconium-based MOF/graphdiyne composites (AuNPs/Zr-MOF/GDY) and self-assembles methylene blue (MB) with G-quadruplex (G-4s) DNA nanostructures for detecting the thalassemia gene CD122. Upon target detection, the G-4s structure triggers strand displacement and cation coordination, followed by MB adsorption to form a biocathode. This biocathode facilitates electron transfer to a glucose oxidase-functionalized anode, driving redox reactions with system-generated electrons. The MB/G-4s structure not only amplifies the CD122 signal but also induces proportional color changes for dual electrochemical and colorimetric detection. A high-output-power capacitor is integrated to further amplify signals, enhancing sensitivity by 7.2 times. The platform offers a broad linear range from 0.0001 to 1000 pM and achieves low detection limits of 18.9 aM (electrochemical) and 23.9 aM (colorimetric) (S/N = 3). This work presents a highly accurate, sensitive, and portable detection platform for rapid analysis in various environments, including remote and challenging settings.