Magnetic nanoparticle-based biomolecule imaging with a scanning magnetic particle spectrometer

COVID-19 diagnosis on the basis of nanobiosensors' prompt interactivity: A holistic review

The fast spread and severe consequences of novel coronavirus disease 2019 (COVID-19) have once again underscored the critical necessity of early detection of viral infections. Several serology-based techniques, including as point-of-care assays and high-throughput enzyme immunoassays that support the diagnosis of COVID-19 are utilized in the detection and identification of coronaviruses. A rapid, precise, simple, affordable, and adaptable diagnostic tool is required for controlling COVID-19 as well as for outbreak management, since the calculation and monitoring of viral loads are crucial for predicting the infection stage and recovery time. Nowadays, the most popular method for diagnosing COVID-19 is reverse transcription polymerase chain reaction (RT-PCR) testing, and chest computed tomography (CT) scans are also used to determine the disease's phases. This is all because of the fact that RT-PCR method caries with itself a number of downsides comprising of being immovable, expensive, and laborious. RT-PCR has not well proven to be capable of detection on the very early infection stages. Nanomaterial-based diagnostics, together with traditional clinical procedures, have a lot of promise against COVID-19. It is worthy of attention that nanotechnology has the mainstay capacity for purposes of developing even more modern stratagems fighting COVID-19 by means of focusing on state-of-the-art diagnostics. What we have centered on in this review, is bringing out even more efficient detection techniques whereby nanobiosensors are employed so that we might obstruct any further development and spreading of SARS-CoV-2.

Adaptive Model for Magnetic Particle Mapping Using Magnetoelectric Sensors

Imaging of magnetic nanoparticles (MNPs) is of great interest in the medical sciences. By using resonant magnetoelectric sensors, higher harmonic excitations of MNPs can be measured and mapped in space. The proper reconstruction of particle distribution via solving the inverse problem is paramount for any imaging technique. For this, the forward model needs to be modeled accurately. However, depending on the state of the magnetoelectric sensors, the projection axis for the magnetic field may vary and may not be known accurately beforehand. As a result, the projection axis used in the model may be inaccurate, which can result in inaccurate reconstructions and artifact formation. Here, we show an approach for mapping MNPs that includes sources of uncertainty to both select the correct particle distribution and the correct model simultaneously.

Toward Rapid and Sensitive Detection of SARS-CoV-2 with Functionalized Magnetic Nanoparticles

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global medical systems and economies and rules our daily living life. Controlling the outbreak of SARS-CoV-2 has become one of the most important and urgent strategies throughout the whole world. As of October 2020, there have not yet been any medicines or therapies to be effective against SARS-CoV-2. Thus, rapid and sensitive diagnostics is the most important measures to control the outbreak of SARS-CoV-2. Homogeneous biosensing based on magnetic nanoparticles (MNPs) is one of the most promising approaches for rapid and highly sensitive detection of biomolecules. This paper proposes an approach for rapid and sensitive detection of SARS-CoV-2 with functionalized MNPs via the measurement of their magnetic response in an ac magnetic field. For proof of concept, mimic SARS-CoV-2 consisting of spike proteins and polystyrene beads are used for experiments. Experimental results demonstrate that the proposed approach allows the rapid detection of mimic SARS-CoV-2 with a limit of detection of 0.084 nM (5.9 fmole). The proposed approach has great potential for designing a low-cost and point-of-care device for rapid and sensitive diagnostics of SARS-CoV-2.

A Portable Magnetic Particle Spectrometer for Future Rapid and Wash-Free Bioassays

Nowadays, there is an increasing demand for more accessible routine diagnostics for patients with respect to high accuracy, ease of use, and low cost. However, the quantitative and high accuracy bioassays in large hospitals and laboratories usually require trained technicians and equipment that is both bulky and expensive. In addition, the multistep bioassays and long turnaround time could severely affect the disease surveillance and control especially in pandemics such as influenza and COVID-19. In view of this, a portable, quantitative bioassay device will be valuable in regions with scarce medical resources and help relieve burden on local healthcare systems. Herein, we introduce the MagiCoil diagnostic device, an inexpensive, portable, quantitative, and rapid bioassay platform based on the magnetic particle spectrometer (MPS) technique. MPS detects the dynamic magnetic responses of magnetic nanoparticles (MNPs) and uses the harmonics from oscillating MNPs as metrics for sensitive and quantitative bioassays. This device does not require trained technicians to operate and employs a fully automatic, one-step, and wash-free assay with a user friendly smartphone interface. Using a streptavidin-biotin binding system as a model, we show that the detection limit of the current portable device for streptavidin is 64 nM (equal to 5.12 pmole). In addition, this MPS technique is very versatile and allows for the detection of different diseases just by changing the surface modifications on MNPs. Although MPS-based bioassays show high sensitivities as reported in many literatures, at the current stage, this portable device faces insufficient sensitivity and needs further improvements. It is foreseen that this kind of portable device can transform the multistep, laboratory-based bioassays to one-step field testing in nonclinical settings such as schools, homes, offices, etc.

Experimental comparison of four nonlinear magnetic detection methods and considerations on clinical usability

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising for clinical applications, because they have a characteristic nonlinear magnetic response when an external magnetic field is applied. This nonlinearity enables the distinct detection of SPIONs and makes measurements less sensitive to the human body and surgical steel instruments. In clinical applications, only a limited field strength for the magnetic detection is allowed. The signal to noise ratios (SNRs) of four nonlinear magnetic detection methods are compared. These methods include differential magnetometry and three variations of magnetic particle spectroscopy: frequency mixing, second harmonic detection and third harmonic detection. All methods were implemented on the same hardware and experimentally compared for various field strengths. To make the comparison fair, the same power was supplied to the excitation coil each time. In general, the SNR increases with increasing field strength. The SNR per drive field of all methods stabilizes or even decreases for field strengths above 6 mT. The second harmonic detection has the best SNR and the most room for improvement.