A group of specialists from the Organization for Optoelectronic Frameworks and Microtechnology at the Universidad Politécnica de Madrid (UPM) has planned a biosensor equipped for distinguishing proteins and peptides in amounts as low as a solitary monolayer. For that, a surface acoustic wave (SAW), a sort of electrically controlled nanotremor on a chip, is produced with an incorporated transducer to follow up on a pile of 2D materials covered with the biomolecules to be distinguished.
As they report in the journal Biosensors and Bioelectronics in an article named “Surface-acoustic-wave-driven graphene plasmonic sensor for fingerprinting ultrathin biolayers down to as far as possible,” the SAW would swell the outer layer of a graphene-based stack so that it limits mid-infrared light to tiny volumes, upgrading light-matter communications at the nanoscale.
Specifically, quasiparticles that are part light (photons) and part matter (electrons and cross-section vibrations), called surface plasmon-phonon polaritons, are framed at the undulated stack, interplaying unequivocally with the particles.
“We would be able to identify analytes that require smaller quantities, reaching levels as low as a single monolayer, by improving the interaction between light and biomolecules deposited on top of the sensor.”
Raúl Izquierdo, first author of this study.
Natural particles retain specific frequencies of light in the mid-infrared range that are normal for their substance arrangement and construction. Consequently, this arrangement of retention resonances, called their vibrational unique mark, takes into consideration the recognizable proof of the natural compound.
“By fortifying the communication among light and biomolecules saved on top of the sensor, we would have the option to distinguish analytes requiring more modest amounts, arriving at levels as low as a solitary monolayer,” says Raúl Izquierdo, the first creator of this review.
As per Jorge Pedrós, driving researcher of the review, “One benefit of this system is that SAWs are effectively controlled through a high-recurrence voltage, permitting to handily switch between an ON setup, at which communication is expanded, and an OFF design, with next to no improvement to the sign. This estimating plan expands the sensor goal.”
“Notwithstanding the plan of the sensor and the estimations of its presentation, we likewise give a numerical technique to remove evidently covered-up quantitative data, further expanding the responsiveness of the sensor,” says Izquierdo.
For that, the atoms of the analyte and the surface plasmon-phonon polaritons are displayed as oscillators that interface with one another, while both are driven by an outer power (light occurrence on the sensor). Regardless of its straightforwardness, this model is displayed to repeat pleasantly the outcomes from the computations.
To close, Pedrós says, “We are certain that this study will add to the advancement of new lab-on-chip gadgets, joining the compound fingerprinting ability of this clever SAW-driven biosensor with other acoustic functionalities, for example, SAW-based mass detecting or bead streaming and blending in microfluidic circuits.”
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More information: Raúl Izquierdo-López et al, Surface-acoustic-wave-driven graphene plasmonic sensor for fingerprinting ultrathin biolayers down to the monolayer limit, Biosensors and Bioelectronics (2023). DOI: 10.1016/j.bios.2023.115498
