Prussian Blue Analogues-Derived Molecularly Imprinted Nanozyme Array for Septicemia Detection

Septicemia, a severe bacterial infection, poses significant risks to human health. Early detection of septicemia by tracking specific biomarkers is crucial for a timely intervention. Herein, we developed a molecularly imprinted (MI) TiO2-Fe-CeO2 nanozyme array derived from Ce[Fe(CN)6] Prussian blue analogues (PBA), specifically targeting valine, leucine, and isoleucine, as potential indicators of septicemia. The synthesized nanozyme arrays were thoroughly characterized using various analytical techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscope, and energy-dispersive X-ray. The results confirmed their desirable physical and chemical properties, indicating their suitability for the oxidation of 3,3',5,5'-tetramethylbenzidine serving as a colorimetric probe in the presence of a persulfate oxidizing agent, further highlighting the potential of these arrays for sensitive and accurate detection applications. The MITiO2 shell selectively captures valine, leucine, and isoleucine, partially blocking the cavities for substrate access and thereby hindering the catalyzed TMB chromogenic reaction. The nanozyme array demonstrated excellent performance with linear detection ranges of 5 μM to 1 mM, 10-450 μM, and 10-450 μM for valine, leucine, and isoleucine, respectively. Notably, the corresponding limit of detection values were 0.69, 1.46, and 2.76 μM, respectively. The colorimetric assay exhibited outstanding selectivity, reproducibility, and performance in the detection of analytes in blood samples, including C-reactive protein at a concentration of 61 mg/L, procalcitonin at 870 ng/dL, and the presence of Pseudomonas aeruginosa bacteria. The utilization of Ce[Fe(CN)6]-derived MITiO2-Fe-CeO2 nanozyme arrays holds considerable potential in the field of septicemia detection. This approach offers a sensitive and specific method for early diagnosis and intervention, thereby contributing to improved patient outcomes.

Construction of nanorod structure confined Pt@CeO2 catalyst by in-situ encapsulation strategy for low temperature catalytic oxidation of toluene

In this work, the Pt@CeO2 catalyst with the nanorod structure (Pt@CeO2-R) and the bunch structure (Pt@CeO2-B) were synthesized through in situ encapsulation strategy of Pt species in Ce-MOFs, respectively. It is discovered that the Pt@CeO2-R catalyst owned the best catalytic performance for toluene catalytic combustion, and this situation was mainly caused by the confinement of Pt nanoparticles in Ce-MOFs, which was related to the chemical state of Pt species, redox ability, and the amount of active oxygen species. Among them, the Pt@CeO2-R catalyst owns more Ce3+ species, rich Pt4+ species, and abundant active oxygen species due to the existence of confined structure, which were conducive to promote catalytic oxidation of toluene. In addition, the Pt@CeO2-R catalyst also exhibited more redox ability, which may speed up the catalytic reaction rates. On the contrary, the Pt/CeO2-R catalyst was synthesized through a simple impregnation method, and exhibited the poor activity for toluene catalytic combustion due to poor Pt4+ species and active oxygen species. Therefore, this work provides a feasible experimental basis for the study of different morphologies and encapsulated metal particles.