Jinghua Chen

Theranostic systems that integrate diagnostic monitoring and therapeutic intervention within unified platforms represent a transformative approach for precision medicine. While wearable microneedle (MN)‐based devices offer an ideal form factor for such systems, their development has been constrained by limitations in molecular recognition specificity, intelligent decision‐making capability, and controlled drug release precision. Nucleic acid technology emerges as a comprehensive solution to these challenges, leveraging its inherent programmability and molecular recognition versatility to address all three core theranostic components. This review systematically examines recent advances in nucleic acid‐based strategies for intelligent theranostics, focusing on three fundamental modules: (1) in situ monitoring systems employing aptamers, CRISPR mechanisms, and molecular pendulums; (2) decision‐making units utilizing threshold‐controlled circuits and feedback‐regulation networks; and (3) stimulus‐responsive drug delivery units featuring programmable release mechanisms for various therapeutic agents. We further highlight integrated nucleic acid‐MN platforms that demonstrate closed‐loop operation, continuously sensing biomarker fluctuations and triggering precise therapeutic responses. Finally, we discuss prevailing challenges in stability, specificity, and clinical translation, while outlining future research directions aimed at advancing autonomous molecular decision systems for personalized medicine applications. This comprehensive analysis provides foundational insights for developing next‐generation intelligent theranostic platforms capable of adaptive, precision healthcare delivery.

Electrochemical biosensors based on DNA assembly signal amplification have emerged as powerful tools for exosomal miRNA detection, demonstrating broad application potential in accurate early cancer diagnosis. However, due to the passivation of the electrode by DNA nanostructures and inherent limitations in assembly reaction efficiency, electrochemical biosensors still face challenges in the sensitive and rapid detection of exosomal miRNA. Herein, we propose a novel spatial confinement effect based "swing probe" in situ entropy-driven assembly strategy. By constraining two auxiliary probes in a specific space with a T-type structure, the target miRNA can induce rapid in situ swinging of the probe at the electrode interface, facilitating the assembly of the auxiliary probes and the dissociation of labeled methylene blue (MB) signal probes. Therefore, the rapid and sensitive detection of miRNA can be achieved by analyzing the signal ratio between MB and ferrocene (Fc). The [Fe(CN)₆]^3--mediated electrocatalytic signal amplification reaction was further employed to realize significant signal response by utilizing the DNA nanostructures' passivation effect on the electrode. The developed biosensor exhibited an ultralow LOD of 4.08 fM and successfully distinguished hepatocellular carcinoma (HCC) patients from healthy donors. Overall, this study provides a novel approach for exosomal miRNA detection and holds promise for advancing miRNA-based liquid biopsy in early cancer diagnosis.

Extracellular vesicles (EVs) hold promise as a new generation of noninvasive cancer diagnostic biomarkers, but the complexity and heterogeneity of clinical samples limit the detection accuracy and clinical applicability. Herein, we propose a retention-monitoring, label-free plasmonic sensing method based on a dual protein logic profiling framework nucleic acid (DP-FNA) molecular device for the specific and sensitive detection of tumor-derived EVs. The DP-FNA comprises two aptamers to determine the relative expression levels of two target proteins on single EVs through a retention-based logical profiling process. This strategy is minimally affected by the concentrations of EVs, providing significantly improved detection accuracy compared with traditional single aptamer-based assays. Using CD63/EpCAM and EpCAM/CD63 aptamer combinations, we achieved 100% accuracy in distinguishing between cancer and noncancer clinical serum samples, as well as between breast cancer and liver cancer clinical serum samples. We envision that this DP-FNA-based retention-monitoring assay will advance the potential of EVs in early cancer diagnosis.

An upconversion luminescence (UCL) nanosensor was developed based on the inner filter effect (IFE) mechanism. This involved the interaction between polyacrylic acid (PAA)-coated NaYF₄:Yb/Er upconversion nanoparticles (UCNPs) and the oxidation product (oxDPD) of N, N-diethyl-p-phenylenediamine (DPD). DPD was oxidized to oxDPD through the combined action of H₂O₂ and horseradish peroxidase (HRP). As a result, there was a large overlap between the UCL spectrum (545 nm) of Er-doped UCNPs and the UV–Vis absorption spectrum (552 nm) of oxDPD, which subsequently caused the quenching of UCL via the IFE. When 6-mercaptopurine (6-MP) reacted with oxDPD, the absorption intensity of the resulting product at 552 nm decreased, thereby restoring the intensity of UCL. Therefore, 6-MP can be sensitively detected according to the intensity change of UCL. The resulting detection range and the limit of detection (LOD) were 0–15 μg·mL⁻¹ and 0.56 μg·mL⁻¹, respectively. The “off–on” UCL nanosensor designed for the detection of 6-MP exhibits the advantages of easy operation, rapid response time, and high sensitivity, demonstrating promising potential for application in clinical monitoring. Graphical Abstract

Simultaneous detection and correlation analysis of multiple biomarkers in a single run are crucial to improving the detection specificity and indicate disease progression, but they remain a challenge. Herein, we propose a DNA fishhook electrochemical sensor based on the potassium ferricyanide-mediated dual-signal correlation enhanced electrocatalysis reaction (DEER). The designed T-shaped DNA fishhook scaffold has two "hooks" to recruit their respective "fish" (targets) with the help of the "fishing bait" (signal probes, Sp), resulting in the different targets and Sp being specifically captured by the DNA fishhook to the electrode interface, respectively. The proposed DEER not only effectively improves the detection sensitivity without introducing nucleic acid amplification but also can reflect the logical correlation between the targets. As proof of principle, the DNA fishhook sensor was successfully applied in the simultaneous detection of two related gene sequences of SARS-CoV-2 and the active-state assay of the PI3K/AKT signaling pathway. In general, our DNA fishhook sensor provides a meaningful potential tool for the sensitive simultaneous detection and correlation analysis of multiple targets.