Magnetic graphene quantum dots facilitate closed-tube one-step detection of SARS-CoV-2 with ultra-low field NMR relaxometry

Yongqiang Li; Peixiang Ma; Quan Tao; Hans-Joachim Krause; Siwei Yang; Guqiao Ding; Hui Dong; Xiaoming Xie

doi:10.1016/j.snb.2021.129786

Magnetic graphene quantum dots facilitate closed-tube one-step detection of SARS-CoV-2 with ultra-low field NMR relaxometry

Sens Actuators B Chem. 2021 Jun 15:337:129786. doi: 10.1016/j.snb.2021.129786. Epub 2021 Mar 15.

Authors

Yongqiang Li^{1

2

3

4}, Peixiang Ma⁵, Quan Tao^{1

2

3

4}, Hans-Joachim Krause^{6

3}, Siwei Yang^{1

3

4}, Guqiao Ding^{1

4}, Hui Dong^{1

2

3

4}, Xiaoming Xie^{1

2

3

4}

Affiliations

¹ State Key Laboratory of Functional Materials of Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai, 200050, PR China.
² CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai, 200050, PR China.
³ Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, Germany.
⁴ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences (UCAS), Beijing, 100049, PR China.
⁵ Shanghai Institute for Advanced Immunological Studies, ShanghaiTech University, Shanghai, 201210, PR China.
⁶ Institute of Biological Information Processing (IBI-3), Forschungszentrum Jülich (FZJ), D-52425, Jülich, Germany.

Abstract

The rapid and sensitive diagnosis of the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the crucial issues at the outbreak of the ongoing global pandemic that has no valid cure. Here, we propose a SARS-CoV-2 antibody conjugated magnetic graphene quantum dots (GQDs)-based magnetic relaxation switch (MRSw) that specifically recognizes the SARS-CoV-2. The probe of MRSw can be directly mixed with the test sample in a fully sealed vial without sample pretreatment, which largely reduces the testers' risk of infection during the operation. The closed-tube one-step strategy to detect SARS-CoV-2 is developed with home-made ultra-low field nuclear magnetic resonance (ULF NMR) relaxometry working at 118 μT. The magnetic GQDs-based probe shows ultra-high sensitivity in the detection of SARS-CoV-2 due to its high magnetic relaxivity, and the limit of detection is optimized to 248 Particles mL^‒1. Meanwhile, the detection time in ULF NMR system is only 2 min, which can significantly improve the efficiency of detection. In short, the magnetic GQDs-based MRSw coupled with ULF NMR can realize a rapid, safe, and sensitive detection of SARS-CoV-2.

Keywords: AFM, atomic force microscopy; Ab, specific antibody against SARS-CoV-2 antigen S protein; BSA, bull serum albumin; COVID-19, coronavirus disease 2019; ELISA, enzyme-linked immune-sorbent assay; Fe3O4, ferrosoferric oxide; GPG, Gd3+ loaded PEG modified GQDs; GQDs, graphene quantum dots; Graphene quantum dots; HR-TEM, high resolution TEM; LOD, limit of detection; MNPs, magnetic nanoparticles; MRSw, magnetic relaxation switch; Magnetic relaxation switch; NMR, nuclear magnetic resonance; OSR, outer sphere relaxation theory; PBS, phosphate buffer saline; PEG, polyethylene glycol; PEG6, hexaethylene glycol; RT-PCR, reverse transcription-polymerase chain reaction; S protein, spike protein; SARS-CoV-2; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; SD, standard deviation; SQUID, superconducting quantum interface device; Spike; T1, longitudinal relaxation time; TEM, transmission electron microscopy; ULF NMR, ultra-low field NMR; Ultra-low field nuclear magnetic resonance; XPS, X-ray photoelectron spectroscopy.