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Simultaneous imaging of multiple microRNAs (miRNAs) in individual living cells is challenging due to the lack of spectrally distinct encoded fluorophores and non-cytotoxic methods. We describe a multiplexed error-robust combinatorial fluorescent label-encoding method, termed fluorophores encoded error-corrected labels (FluoELs), enabling multiplexed miRNA imaging in living cells with error-correcting capability. The FluoELs comprise proportional dual fluorophores for encoding and a constant quantitative single fluorophore for error-corrected quantification. Both are embedded in 260 nm core-shell silica nanoparticles modified with molecular beacon detection probes. The FluoELs are low cytotoxic and could accurately quantify and spatially resolve nine breast-cancer-related miRNAs and evaluate their coordination. The FluoELs enabled a single-cell analysis platform to evaluate miRNA expression profiles and the molecular mechanisms underlying miRNA-associated diseases.

The aberrant expression level of intracellular microRNAs (miRNAs) holds great promise for differentiating cell types at the molecular level. However, cell subtype discrimination based on a single miRNA molecular level is not sufficient and reliable. Herein, multiple identifiable and reporting modules are integrated into a single DNA circuit for multiple cancer cell subtypes identification based on miRNAs bispecific recognition. The DNA three-dimensional (3D) logic gate nano-hexahedron framework extends three recognition modules and three reporting modules to form three "AND" logic gates. Each Boolean operator "AND" returns an "ON" signal in the presence of bispecific miRNAs, simultaneously enabling three types of cell subtype identification. It not only enables the discrimination of cancer cells A549 and MCF-7 from normal cells NHDF but also successfully distinguishes different types of cancer cells. The bispecific intracellular miRNA controllable DNA circuit, with low signal-to-noise ratio, easily extends to various cell type discrimination by adjusting the miRNA species, provides huge opportunities for accurately differentiating multiple cell types at the molecular level.

Bimetallic nanoparticles have received considerable attention owing to synergistic effect and their multifunctionality. Herein, new multifunctional Pd@Au bimetallic nanoplates decorated hollow mesoporous MnO2 nanoplates (H-MnO2 ) are demonstrated for achieving not only nucleus-targeted NIR-II photothermal therapy (PTT), but also tumor microenvironment (TME) hypoxia relief enhanced photodynamic therapy (PDT). The Pd@Au nanoplates present a photothermal conversion efficiency (PTCE) as high as 56.9%, superior to those PTAs activated in the NIR-II region such as Cu9 S5 nanoparticles (37%), Cu3 BiS3 nanorods (40.7%), and Au/Cu2- x S nanocrystals (43.2%). They further functionalize with transactivator of transcription (TAT) moiety for cell nuclear-targeting and biodegradable hollow mesoporous MnO2 (≈100 nm) loaded with photosensitizer Ce6 (TAT-Pd@Au/Ce6/PAH/H-MnO2 ) to construct a hierarchical targeting nanoplatform. The as-made TAT-Pd@Au/Ce6/PAH/H-MnO2 demonstrates good premature renal clearance escape ability and increased tumor tissue accumulation. It can be degraded in acidic TME and generate O2 by reacting to endogenous H2 O2 to relieve the hypoxia for enhanced PDT, while the released small TAT-Pd@Au nanoplates can effectively enter into the nucleus to mediate PTT. As a result, a remarkable therapeutic effect is achieved owing to the synergistic PTT/PDT therapy. This hierarchical targeting, TME-responsive, cytoplasm hypoxia relief PDT, and nuclear NIR-II PTT synergistic therapy can pave a new avenue for nanomaterials-based cancer therapy.

Herein, a cancer cell (MCF-7 cell) membrane-encapsulated dendritic mesoporous silica nanoparticle simultaneously functionalized with DNA-photoacoustic (DNA-PA) probes and glutathione (GSH)-responsive DNA fuel strands for PA imaging of tumor-related miRNA in living mice with signal amplification ability is developed. It is demonstrated that one target miRNA can trigger disassembly of multiple PA fluorophore probes from the quencher with the aid of GSH-responsive DNA fuel strands via the entropy-driven process, resulting remarkable amplified change of PA signal ratio. Using oncogenic miRNA-21 as a model, a linear relationship between miRNA-21 concentrations and PA ratio in a dynamic range from 10 × 10-12 m to 100 × 10-9 m and a limit of detection down to 11.69 × 10-12 m are established. The accurate PA signal observation related to miRNA-21s in the tumor area in living mice is demonstrated, and the PA signal ratio increases significantly via the injection of miRNA-21. It is anticipated that the catalytic ratiometric PA imaging system can be applied to an array of molecular detection in living system by rational detection probe design.