Molecular Diagnostic System Using Engineered Fusion Protein-Conjugated Magnetic Nanoparticles

Abstract

To effectively control the spread of new infectious diseases, there is a need for highly sensitive diagnostic methods to detect viral nucleic acids rapidly. This study outlines a universal and simple detection strategy that uses magnetic nanoparticles (MNPs) and a novel MagR-MazE fusion protein for molecular diagnostics to facilitate sensitive detection. This study has engineered a novel MNP conjugate that can be generated easily, without using many chemical reagents. The technique is a nucleic acid detection method, using MagR-MazE fusion protein-conjugated MNPs, where the results can be visualized with the naked eye, regardless of the oligonucleotide sequences of the target in the lateral flow assay. This method could sensitively detect polymerase chain reaction (PCR) products of 16S ribosomal RNA (rRNA) and the 2019-nCoV-N-positive control gene in 5 min. It shows a low limit of detection (LoD) of 0.013 ng/μL for dsDNA. It is simpler and more rapid, sensitive, and versatile than other techniques, making it suitable for point-of-care testing. The proposed detection system and MNP conjugation strategy using a fusion protein can be widely applied to various fields requiring rapid on-site diagnosis.

Proteins as nanomagnets and magnetoreceptors

“…First, at least three independent laboratories have had success using Fe 3 O 4 -SiO 2 magnetic beads to purify and immobilise catalytically active enzymes when expressed as MagR fusion proteins (Jiang et al, 2017;Kang et al, 2021;Liu et al, 2022;Wang et al, 2019). In no case was an attempt made to co-express cryptochrome suggesting, perhaps, that it is not a prerequisite for MagR magnetization.…”

Applications of magnetic and electromagnetic forces in micro-analytical systems

“…There have been many reports on the use of magnetic beads in SPE for a wide variety of analytes. [111][112][113][114][115][116][117][118] Further, it is possible to decorate MNPs with a layer of metal-organic frameworks (MOFs) for use in SPE. MOFs are porous polymeric materials composed of metal ions as crosslinking points and organic ligands as bridges.…”

“…There have been many reports on the use of magnetic beads in SPE for a wide variety of analytes. 111–118…”

Unexpected divergence in magnetoreceptor MagR from robin and pigeon linked to two sequence variations

“…An increasing number of applications leveraging the magnetic properties of MagR have been reported, utilizing MagR or the MagR/Cry complex as magnetic tags ( Jiang et al, 2017 ; Kang et al, 2021 ; Wang et al, 2019 ), bionic magnetic sensors ( Cheng et al, 2023 ; Xue et al, 2020 ), and MRI contrast enhancers ( Li et al, 2023 ). The functional significance of MagR has been extensively explored, with studies revealing daily oscillations in the expression patterns of MagR in certain species and higher expression levels in migratory populations, hinting at the physiological relevance of MagR in magnetoreception ( Chang et al, 2017 , 2018 ; Jin et al, 2023 ; Mannino et al, 2023 ).…”