Researchers from the New York University Tandon School of Engineering in the US have developed new biosensor devices that can rapidly identify even the smallest amounts of a specific virus, antibody or cancer protein marker in blood.
The biosensors contain a tunable laser within a fibre optic filament and a detector at the bottom of the filament to measure the intensity and resonance of the light.
In addition, a silica bead is inserted beside the filament to divert a portion of the light beam that resonates within the bead.
The team based their project on the university’s Applied Physics professor Stephen Arnold’s discovery that an optical fibre can trigger ‘Whispering Gallery Mode’ (WGM) in polymer micro-beads.
Initially, the researchers devised WGM biosensors to measure the mass of viruses, proteins and other nanoparticles by sending them into an orbit-like space around the micro-bead using a photonic ‘tractor beam’ caused by resonating light.
They further advanced the sensors to detect the smallest individual bio-particles such as the RNA virus MS2, single molecules and particles sized up to 6 zepto-grams (6×10-21 g), which is below the mass of all known cancer markers.
The WGM sensor is designed to identify the particles by analysing the fluctuations caused in light frequency during their movement.
It is predicted that these biosensors could help make targeted devices for various medical applications such as wearable sensors for soldiers and rescuers, which detect even small amounts of nerve agent in the air and improve nanoparticle drug uptake and redistribution.
Arnold said: “Charge controls the ability to transport particles that are interacting with cells and other objects that possess electric fields.
“You need to understand this mechanism in order to engineer a WGM micro-bead that has a specific antigen at a specific region of its surface so that the biosensor can attract specific pathogens or other biomolecules.”
The researchers intend to further create a photonic printing technology to rapidly generate several task-specific WGM biosensors.