MAGNETIC BIOSENSING

Magnetoresistive (MR) devices, exploiting giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR), are widely used in hard disks as well as magnetoresistive random access memory (MRAM) technology. MR devices can be miniaturized, and the sensitivity in general increases when the device dimension reduces. 

In terms of biosensing, MR devices detect the stray field emanated from magnetic nanoparticles (MNPs). Mostly, superparamagnetic MNPs (SP-MNPs) are used since 1) they merely have hysteresis and 2) their fast responses (to external field) make them ideal for biosensing.

Among many magnetic sensors available today, MR devices outstand for point-of-care (PoC) applications. In addition to the inherent advantages of magnetic biosensing with MNPs, MR biosensors can be operated at room temperature, have high low-field sensitivity, and have comparably high transduction efficiency.

SINGLE-CELL TARGETED PROTEOMICS 

On March 31, 2022, the last 8% of the human genome was totally completed after the essentially-finished version was announced 20 years ago. DNA, possessing the “recipe” for how to make proteins, is relatively constant over time; while an individual's proteome constantly varies. Therefore, proteomics is highly indicative of what is happening inside an organism at a certain time. Genomics, for instance, may be able to predict the possibility of having a particular cancer, while proteomics can determine whether the patient is actually afflicted with cancer (and if so, at what stage).

We are developing the magneto-protein microarray to complement global proteomics where low-abundance proteins are usually masked by high-abundance ones in mass spectrometry. To probe targeted proteomics, we will integrate single-cell microfluidics with an MRAM array to detect low-copy-number proteins (existing <1000 per cell). Promisingly, the next-generation protein profiling technology is aim to 1) study tumor heterogeneity at a single-cell level, 2) address challenges in early cancer diagnostics, and 3) advance precision medicine with quantitative and functional proteomics.

MAGNETORELAXATION

In magnetic biosensing, traditional magnetometry detects stray field (emanated from MNPs) while applying external field. As such, it requires complicated electronics to accommodate high baseline-to-signal ratio. 

Magnetorelaxometry (MRX), in contrast, senses stray field when turning off external field. MRX can either utilize Néel relaxation or Brownian relaxation to run size-dependent assays. Néel relaxation is the result of internal magnetic domain movement within the MNP while Brownian relaxation is a rigid rotation of the entire MNP complexes. To enable magnetic biosensing in mHealth, miniaturization of the field source is more feasible in MRX than conventional magnetometry,

MAGNETOBIOLOGY

Is magnetoreception a myth? If not, how does it work?

To unveil the underlying mechanism, BioMagNES Group would approach it from biomineralization (e.g., in vivo MNP synthesis) combined with MR biosensing.

Several efforts around the world are being taken; while, to unravel biosystems' magnetoreception functioning at Earth's magnetic field (~50 µT), the tools operating at a high field (e.g., the applied field used in MRI is ~2 T) is unfavorable. Alternatively, the existing MR biosensors, working at ~5 mT, could have a better shot towards exploration of biocompassing mechanism.

The project would start with biomimetic motion monitoring to establish a platform and then step-by-step dig out the roles of magneto-proteins.