Entropy-Driven Disassembly of Logic-Gated DNA Nanospheres: An All-in-One Platform for Precise Cancer Diagnosis In Vivo

DNA logic circuits, which can accurately identify specific cancer cell types, hold promise for the construction of emerging diagnostic platforms. However, they are challenged by weak output signals owing to the low abundance of biomarkers as well as the lack of an integrated, self-contained system for efficient circuit delivery that operates without extrinsic carriers. Herein, we developed all-in-one DNA nanospheres for precise cancer diagnosis that incorporate target recognition, logic analysis, signal amplification, and signal output within a single logic-gated DNA nanosphere, requiring no exogenous carriers or proteases. Programmable self-assembly of Y-shaped and I-shaped DNA motifs through sequence-specific hybridization enables the precise spatial organization of functional elements into nanosphere-shaped delivery vectors. Employing oncogenic miR-21 and/or miR-155 as molecular inputs, the DNA nanosphere performs AND or OR Boolean logic operations, which trigger entropy-driven disassembly that generates amplified fluorescence signals for multiplexed miRNA imaging. The platform exhibits a significantly enhanced biostability and sensitivity for identifying specific cancer cells. Through intratumoral injection, it achieves efficient <i>in vivo</i> delivery, enabling precise distinction between specific cancer cells and tumor types. The multi-miRNA-responsive molecular Boolean logic, in combination with entropy-driven disassembly, facilitates autonomous diagnostics operations, thus offering alternative design paradigms for accurate molecular diagnostics by using DNA logic systems.