Fe-MIL-88NH₂ Metal–Organic Framework Nanocubes Decorated with Pt Nanoparticles for the Detection of Salmonella

Abstract

Early screening of Salmonella is of utmost importance to minimize the incidence of related foodborne diseases. Here, we reported an immunosensor to fast detect Salmonella using Fe-MIL-88NH2 metal–organic framework (Fe-MOF) nanocubes to load platinum nanoparticles (PtNPs) for signal amplification and smartphone thermal imaging to monitor the temperature change. The Fe-MOF nanocubes decorated with PtNPs (Fe-MOF/PtNPs) were prepared as peroxidase mimics to catalyze hydrogen peroxide (H2O2) to produce O2. The immune magnetic nanoparticles (MNPs), the target bacteria, and the immune Fe-MOF/PtNPs were first mixed by the three-dimensional (3D) chaotic micromixer and conjugated in the microfluidic chip to form MNP–bacteria–Fe-MOF/PtNPs sandwich complexes. After magnetic separation and washing, H2O2 was injected and decomposed by Fe-MOF/PtNPs on the sandwich complexes to generate O2 in a sealed chamber. The increase in the pressure pushed the preloaded water to react with calcium oxide powder, resulting in the generation of heat, which was measured using the smartphone-based thermal sensor to determine the bacteria. The microfluidic immunosensor could detect Salmonella as low as 93 CFU/mL within 1 h.

Highly efficient peroxidase-like activity of a metal–oxide-incorporated CeO2–MIL(Fe) metal–organic framework and its application in the colorimetric detection of melamine and mercury ions via induced hydrogen and covalent bonds

“…3b shows numerous deconvoluted peaks, with those at 881, 889.4, 906.6 and 917.7 eV matching the Ce 4+ oxidation state and the peak at around 899.4 corresponding to the Ce 3+ oxidation state of the cerium ions. In the high-resolution Fe 2p spectrum of CeO 2 -MIL(Fe), two major peaks at 727.0 and 713.0 eV match the binding energies of Fe 2p 1/2 and Fe 2p 3/2 derived from MIL (Fe), respectively [25][26][27] (Fig. 3c).…”

Recent Advances in the Immunoassays Based on Nanozymes

“…The sensitivity of Escherichia coli ( E. coli O157:H7) could be measured by a linear relationship between the height of the foam and the logarithm of the E. coli O157:H7 concentration. In addition, based on the thermal sensor of a smartphone, a microfluidic immunosensor was designed for Salmonella with a double-layer microfluidic chip as the research platform and Fe-MIL-88NH 2 metal−organic framework nanocubes decorated with platinum nanoparticles (Fe-MOF/PtNPs) as the signal amplifier ( Figure 6 A) [ 75 ]. Herein, the conjugate formation of an immune magnetic nanoparticles (MNPs)–bacteria–Fe–MOF/PtNPs sandwich complex in a microfluidic chip could catalyze H 2 O 2 to generate O 2 , to increase the pressure and promote the reaction between preloaded water and calcium oxide (CaO) powder to produce heat.…”

Overview of Rapid Detection Methods for Salmonella in Foods: Progress and Challenges

“…However, this novel method is also faced with the limitation of its low sensitivity (LOD of 10 3 CFU/mL), which needs to be improved [79]. Instead of using laser irradiation to trigger the photothermal temperature, Guo et al developed a new temperature generation strategy [106]. They designed nanomaterials with the activity of peroxidase to decompose hydrogen peroxide and produce oxygen, which forced the pre-placed calcium oxide to react with water and generate heat by increasing the pressure in the space.…”