Mn-Etched Zeolitic Imidazolate Framework-67 Nanostructures for Biomimetic Superoxide Anion Sensing

Abstract

It is a great challenge to detect superoxide anions (O2 •–) with low level concentrations and short half-life in biological systems. Herein, mild and facile Mn etching for zeolitic imidazolate framework-67 (ZIF-67) was used to synthesize Mn/ZIF-67 with a hydrangea-like nanostructure for biomimetic sensing of O2 •– released from living cells. The tailored optimal Mn/ZIF-67 sensor achieves a high selectivity, a fast response time (1.6 s), a broad linear detection range (1.5 nM–10 μM), an ultralow detection limit (0.8 nM), and a remarkably high sensitivity (439.2 μA μM–1 cm–2) that ranks the best among all reported conventional Mn- and Co-compound-based nanozymes such as Co2P and Mn3(PO4)2. The excellent sensing performances are attributed to the Mn etching-generating hydrangea-like nanostructure for a significantly increased reaction surface area and coordinating Mn2+ with Co2+ to raise the oxidation state of Co2+ for fast electron transfer during the oxidation of O2 •–. This work holds great potential for a highly sensitive O2 •– nanozyme sensor in practical clinical diagnosis and bioscience research, while shedding fundamental light on designs of sensitive nanozyme sensors by incorporating two metal ions with largely different negativity for an efficient electrocatalytic process, thereby possessing universal significance.

Interfacial Regulation of ZIF-67 on Bacteria to Generate Bifunctional Sensing Material on Chip for Qualifying Cell-Released Reactive Oxygen Species

“…Figure Ab shows the images of A549 cells (density: 3 × 10 5 cells·mL –1 ) growing on the Co/N-doped CNRs/SPE surface after DAPI staining, indicating that A549 cells successfully grew on the surface of SPE. Zym can stimulate cells to release O 2 •– , , and PMA can act as a stimulant to make cells to release H 2 O 2 . , Figure B shows a rapid increased current response of O 2 •– released from A549 cells after injection of 0.4 mg·mL –1 Zym (red curve). However, when 0.4 mg·mL –1 Zym and 300 U·mL –1 SOD were added, the current response decreased significantly (blue curve), indicating that O 2 •– released from cells was cleared by SOD.…”

“…The results in Figure 5E,F show that under the same experimental conditions, the sensor can still maintain the initial 94.9 and 96.5% of its initial response after 5 and 2 weeks, demonstrating its good stability. In addition, as shown in Table S1, the prepared sensors have the hightest sensitivities than that of other reported sensors for the simultaneous detection of O 2 •− , 34,35 and PMA can act as a stimulant to make cells to release H 2 O 2 . 36,37 Figure 6B shows a rapid increased current response of O 2…”

Understanding ZIF particle chemical etching dynamics and morphology manipulation: in situ liquid phase electron microscopy and 3D electron tomography application

“…11,19 Even though some recent reports provide the morphology transition process by using in situ liquid phase TEM, there are limited reports that give an etching speed based on the in situ liquid phase TEM imaging itself. 11,[20][21][22][23][24] In particular, there are limited methods to quantify MOF particles' etching speed, the product surface area, 3D volume and other structural properties, which are crucial to their applications, except for some limited computational model studies guided by machine learning. [25][26][27][28] This study aims to address this gap by revealing the etching mechanism of ZIF NPs using in situ liquid phase TEM in colloids.…”