Patulin (PAT) is a mycotoxin with immunotoxicity, genotoxicity, and neurotoxicity, so effective methods are needed for its detection. Fluorescence aptasensors provide a homogeneous detection method, but their sensitivity needs to be further improved. Herein, we developed a fluorescence aptasensor based on a target-oligonucleotide-driven DNAzyme motor and defective Zr-TCPE for PAT detection. The defective Zr-TCPE achieved an enhanced fluorescence intensity (increased by ∼1.9-fold) via defect engineering. The target-oligonucleotide-driven DNAzyme motor achieved effective PAT transduction, with a signal background ratio 4.4-fold that of the competitive transduction strategy. By combining defective Zr-TCPE with a target-oligonucleotide-driven DNAzyme motor, we achieved ultrasensitive detection of PAT with a detection limit as low as 9.38 fg/mL. In addition, the proposed fluorescence aptasensor could be used for the detection of PAT in apple juice, with recoveries ranging from 95.93% to 105.71%. This fluorescence aptasensor provides reasonable guidance for trace detection of hazardous substances in food and the environment.
Huiyan Du,Ensheng Xu,Yihan Xu,Qingwang Xue,Hongxia Xu,Jibin Song
The development of theragnostic nanosystems integrating FRET (fluorescence resonance energy transfer) imaging and chemodynamic therapy (CDT) for accurate diagnosis and effective treatment of lung tumors is still a big challenge. Herein, a peptide-assembled 3D DNAzyme motor nanodevice is engineered for a self-powered FRET amplifier profiling human neutrophil elastase (HNE) and self-supplied H 2 O 2 enhancing CDT. The nanodevice is prepared by depositing AuNPs on ZIF-8, in which ZIF-8 co-loaded the lysosomal targeting peptide-modified copper peroxides (PCPs) and hairpins (H1, H2, and H3), AuNPs are co-labeled by DNAzyme-peptide (DP) conjugate and H3. In the tumor micro-environment, HNE driven 3D DNAzyme walker followed by an exponential amplification constructed by a synergistic cross-activation between hybridization chain reaction and DNAzyme, generating a self-powered FRET amplifier. The FRET amplifier specifically measures HNE with a sensitivity of 0.026 pM, and successfully images exogenous HNE in living cells and monitors HNE in mouse models. Moreover, the PCPs can target lysosomes, reducing lysosome escape. The self-supplying H 2 O 2 undertaken by PCPs improves the Cu (II)-catalyzed Fenton-like reaction, effectively causing cell apoptosis to inhibit tumor growth. Significantly, the nanodevice successfully screens inhibitors and discriminates the HNE level in normal and lung cancer tissues, suggesting that the nanodevice provides an effective tool for the diagnosis and treatment of lung tumors.
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