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One of the major goals of medicine is the development of portable diagnostic tools. Recent advances in nano-magnetism, reviewed in this talk, might allow the development of efficient lab-on-a-chip portable devices.
- Regarding on-chip manipulation of biological matter, we proposed and used a special type of domain walls in magnetic-nanostructures as moveable “magnetic-nanotweezers” [1, 2]. We have demonstrated precise and robust manipulation of magnetic nanoparticles [3,4] and bio-entities (proteins and cells) [1,5] labeled with magnetic nanoparticles in solution with nm-scale precision by means of an externally applied magnetic field, which allowed for remote on-chip operation.
- Regarding biosensing, plasmonic nanostructures are currently attracting great attention due to their intrinsically small size and localized sensing volume/area. Typical plasmonic sensing utilizes the localized surface-plasmon (LSP) resonance shift due to the local refractive index change upon molecular adsorption. We have shown that the use of ferromagnetic nanostructures allows for a phase sensitive detection of LSPs shift, enabled by their magneto-optical activity [6], with vastly improved performances and sensitivity down to the single molecule level [7]. We are developing further this approach and its integration into practically applicable biomedical sensing devices [8]. More specifically, we are exploring the use of specially designed “janus” particles made of 100-nm-diamter silica nanospheres half covered with multilayers of Fe/Au or Co/Au. They display simultaneous and large anisotropic magnetic and plasmonic properties to be conveniently used in our recently proposed opto-magnetic approach [8] that is being already exploited in commercialized portable device (BluSense Diagnostics, http://www.blusense-diagnostics.com/).
[1] M. Donolato et al., Adv. Mater. 22, 2706 (2010)
[2] M. Donolato et al., Adv. Mater. 25, 623 (2013)
[3] Torti et al., Appl. Phys. Lett. 101, 142405 (2013)
[4] A. Sarella et al., Adv. Mater. 26, 2384 (2014)
[5] M. Donolato et al., Lab Chip 11, 2976 (2011)
[6]N. Maccaferri et al., Phys. Rev. Lett. 111, 167401 (2013)
[7] N. Maccaferri et al., Nat. Commun. 6, 6150 (2015); R. Verre et al., Nanoscale 8, 10576 (2016)
[8] M. Donolato et al., Anal. Chem. 87, 1622 (2015); J. Yang et al., Biosensors and Bioelectronics 75, 396 (2016)
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