Programming ultrasensitive and stimuli-responsive DNAzyme-based probes that contain logic gate biocomputation hold great potential for precise molecular imaging. In this work, a DNA computationmediated DNAzyme platform that can be activated by 808 nm NIR light and target c-MYC was designed for spatiotemporally controlled ultrasensitive AND-gated molecular imaging. Particularly, the sensing and recognition function of the traditional DNAzyme platform was inhibited by introducing a blocking sequence containing a photo-cleavable linker (PC-linker) that can be indirectly cleaved by 808 nm NIR light and thus enables the AND-gated molecular imaging. According to the responses toward three designed SDz, nPC-SDz, and m-SDz DNAzyme probes, the fluorescence recovery in diverse cell lines (MCF-7, HeLa, and L02) and inhibitor-treated cells was investigated to confirm the ANDgated sensing mechanism. It is worth noting that thanks to the strand displacement amplification and the ability of gold nanopyramids (Au NBPs) to enhance fluorescence, the fluorescence intensity increased by ∼7.9 times and the detection limit decreased by nearly 40.5 times. Moreover, false positive signals can be also excluded due to such AND-gated design. Furthermore, such a designed "AND-gate" sensing manner can also be applied to spatiotemporally controlled ultrasensitive in vivo molecular imaging, indicating its promising potential in precise biological molecular imaging.

Strategies for achieving tumor-specific molecular imaging based on signal amplification hold great potential for evaluating the risk of tumor metastasis and progression. However, traditional amplification strategies are still constrained with limited tumor specificity because of the off-tumor signal leakage. Herein, an endogenous enzyme-activated autonomous-motion DNAzyme signal amplification strategy (E-DNAzyme) was rationally designed for tumor-specific molecular imaging with improved spatial specificity. The sensing function of E-DNAzyme can be specifically activated by the overexpressed apurinic/apyrimidinic endonuclease 1 (APE1) in the cytoplasm of tumor cells instead of normal cells, ensuring the tumor cell-specific molecular imaging with improved spatial specificity. Of note, benefiting from the target analogue-triggered autonomous motion of the DNAzyme signal amplification strategy, the detection limit can be decreased by approx. ∼7.8 times. Moreover, the discrimination ratio of tumor/normal cells of the proposed E-DNAzyme was ∼3.44-fold higher than the traditional amplification strategy, indicating the prospect of this universal design for tumor-specific molecular imaging.

Developing an endogenous stimuli-responsive and ultrasensitive DNA sensing platform that contains a logic gate biocomputation for precise cell subtype identification holds great potential for disease diagnosis and prognostic estimation. Herein, a fluorescence-enhanced "OR-AND" DNA logic platform dual-driven by intracellular apurinic/apyrimidinic endonuclease 1 (APE 1) or a DNA strand anchored on membrane protein Mucin 1 (MUC 1) for sensitive and accurate cell subtype identification was rationally designed. The recognition toehold of the traditional activated probe (TP) was restrained by introducing a blocking sequence containing an APE 1 cleavable site (AP-site) that can be either cleaved by APE 1 or replaced by Mk-apt, ensuring the "OR-AND" gated molecular imaging for cell subtype identification. It is worth noting that this "OR-AND" gated design can effectively avoid the missing logical computation caused by membrane protein heterogeneous spatial distribution as a single input. In addition, a benefit from the excellent plasmon-enhanced fluorescence (PEF) ability of Au NSTs is that the detection limit can be decreased by nearly 165 times. Based on this, not only different kinds of MCF-7, HepG2, and L02 cells, but also different breast cancer cell subtypes, including malignant MCF-7, metastatic MDA-MB-231, and nontumorigenic MCF-10A cells, can be accurately identified by the proposed "OR-AND" gated DNA logic platform, indicating the prospect of this simple and universal design in accurate cancer screening.

Nanogap antennas with strong electromagnetic fields of the “hot spot” in the gap region of two adjacent particles that can significantly improve the optical properties of fluorophores hold great potential for ultrasensitive bioanalysis. Herein, a DNA computation-mediated self-assembly of Au NBP dimer-based plasmonic nanogap antennas was designed for imaging of intracellular correlated dual disease biomarkers. It is worth noting that with the benefit from the electromagnetic fields of the “hot spot” in the gap region and strand displacement amplification, the fluorescence intensity can be enhanced ∼14.7-fold by Au NBP dimer-based plasmonic nanogap antennas. In addition, the AND-gate sensing mechanism was confirmed through monitoring the response of three designed nAP-PH1, m-PH1, and PH1 probes, the fluorescence recovery in different cell lines (Hela and L02), and inhibitor-treated cells, respectively. Furthermore, thanks to the “dual keys” activation design, such an “AND-gate” sensing manner can be used for ultrasensitive correlated multiplexed molecular imaging, demonstrating its feasible prospect in correlated multiplexed molecular imaging.

Optical cross-reactive sensor arrays inspired by the mammalian olfactory system that can realize straightforward discrimination of plasma from cancer patients hold great potential for point-ofcare diseases diagnostics. Herein, a pH programmed fluorescence sensor array based on protein-responsive patterns was designed for straightforward discrimination of different types of cancer plasma. It is worth noting that plasma discrimination can be realized only by programming one nanomaterial using different pH values, which greatly simplifies the programmable design of the sensor array, making it an important highlight of this work. In addition, the mechanism of the pH programmed fluorescence sensor array for protein responsiveness was systematically investigated through molecular docking simulation, fluorescence resonance energy transfer (FRET), and fluorescence lifetime experiments. Most importantly, not only can the differences between plasma from healthy people and and from patients with different cancer species including gastric cancer, liver cancer, breast cancer, and cervical cancer be discriminated by this pH programmed fluorescence sensor array, but also the blind test of unknown plasma samples can be well identified with 100% accuracy, indicating its promising prospect in clinical application.