Pomegranate-Bionic Encapsulating Horseradish Peroxidase Using Dopamine Flexible Scaffold-Coated Multishell Porous ZIF-8 To Enhance Immunochromatographic Diagnosis.

Nanoparticle-natural enzyme complexes are receiving increasing attention as the promising signal reporters for colorimetric lateral flow immunoassay (LFIA). Nonetheless, it remains a challenge to develop the nanocomplexes with high loading efficiency, catalytic efficiency, and colorimetric signal brightness. Herein, inspired by pomegranate structure, we reported the synthesis of a colorimetric catalytic nanocomplex ((HRP@ZIF-8)3@PDA@HRP), using dopamine flexible scaffold-coated multishell porous zeolitic imidazolate framework-8 (ZIF-8) as a hierarchical scaffold to encapsulate horseradish peroxidase (HRP), and described its potential to promote an ultrasensitive colorimetric LFIA of cardiac troponin I (cTnI). (HRP@ZIF-8)3@PDA@HRP exhibited ultrahigh HRP loading efficiency and catalytic activity due to the epitaxial shell-by-shell overgrowth of porous ZIF-8 scaffold, which provided more cavities for enzyme immobilization and a diffusion path for the catalytic substrate. Furthermore, the polydopamine (PDA) layer on the (HRP@ZIF-8)3 surface both enhanced the colorimetric signal brightness and acted as a flexible scaffold to immobilize HRP, further increasing the amount of enzyme. Following integration with LFIA, the developed platform achieved an ultrasensitive colorimetric test strip assay for cTnI with pre- and postcatalytic naked-eye detection sensitivities of 0.5 ng mL-1 and 0.01 ng mL-1, respectively, which were 4/2- and 200/100-fold higher than gold nanoparticles (AuNPs)/PDA-based LFIA and comparable to chemiluminescence immunoassay. Further, the quantitative testing results of the developed colorimetric LFIA on 57 clinical serum samples agreed well with the clinical data. This work provides ideas for the design of natural enzymes-based colorimetric catalytic nanocomplex to encourage applications for the development of ultrasensitive LFIA for early diseases diagnosis.

Highly sensitive fluorescence multiplexed miRNAs biosensors for accurate clinically diagnosis lung cancer disease using LNA-modified DNA probe and DSN enzyme.

With the emergence of microRNAs as key biomarkers for disease diagnosis such as lung cancer, various techniques have been settled for their detection. However, these current methods require different amplification steps since numerous challenges for detecting circulating miRNAs are attributable to their intrinsic properties accounting for tiny sizes, high sequence similarity, and low abundance. Duplex specific nuclease (DSN)-based microRNA amplification has recently gained interest in biosensing applications thanks to its catalytic activity based on target recycling. In this context, we designed a highly selective, sensitive, and multiplexed fluorescence-based biosensor combining DSN enzyme and magnetic beads to detect three distinct microRNAs, including microRNA-21, microRNA-210, and microRNA-486-5p. By exploiting the above approach, we were able to detect as low as 98 aM, 120 aM, and 300 aM of mir-21, miR-210, and miR-486-5p, respectively. Furthermore, this recommended strategy displays a high selectivity toward an entirely matched target than the off-target. These results are ascribed to the potent DSN enzyme activity and to the locked nucleic acid (LNA)-modified DNA probe that boosted the hetero-duplex probe/target stability. Lastly, our proposed method was applied to detect microRNAs in the serum samples and displayed a high efficacy to discriminate between healthy controls and lung cancer patients. Furthermore, the analytical accuracy of the proposed strategy was validated with the computed tomography (CT) technique of the chest. Thus based on these findings, this strategy could open new directions for detecting microRNAs associated with several diseases.