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International audienc

Physically stimulated nanotheranostics for next generation cancer therapy: Focus on magnetic and light stimulations

Physically or externally stimulated nanostructures often employ multimodality and show encouraging results at preclinical stage in cancer therapy. Specially designed smart nanostructures such as hybrid nanostructures are responsive to external physical stimuli such as light, magnetic field, electric, ultrasound, radio frequency, X-ray, etc. These physically responsive nanostructures have been widely explored as nonconventional innovative “nanotheranostics” in cancer therapies. Physically stimulated (particularly magnetic and light) nanotheranostics provide a unique combination of important properties to address key challenges in modern cancer therapy: (i) an active tumor targeting mechanism of therapeutic drugs driven by a physical force rather than passive antibody matching, (ii) an externally/remotely controlled drugs on-demand release mechanism, and (iii) a capability for advanced image guided tumor therapy and therapy monitoring. Although primarily addressed to the scientific community, this review offers valuable and accessible information for a wide range of readers interested in the current technological progress with direct relevance to the physics, chemistry, biomedical field, and theranostics. We herein cover magnetic and light-triggered modalities currently being developed for nonconventional cancer treatments. The physical basis of each modality is explained; so readers with a physics or, materials science background can easily grasp new developments in this field

Lithographyically defined, room temperature low threshold subwavelength red-emitting hybrid plasmonic lasers

Hybrid plasmonic lasers provide deep subwavelength optical confinement, strongly enhanced light-matter interaction and together with nanoscale footprint promise new applications in optical communication, bio-sensing and photolithography. The subwavelength hybrid plasmonic lasers reported so far often use bottom up grown nanowires, nanorods and nanosquares, making it difficult to integrate these devices into industry-relevant high density plasmonic circuits. Here, we report the first experimental demonstration of AlGaInP based, red-emitting hybrid plasmonic lasers at room temperature using lithography based fabrication processes. Resonant cavities with deep subwavelength 2D and 3D mode confinement of lambda square/56 and lambda cube/199, respectively are demonstrated. A range of cavity geometries (waveguides, rings, squares and disks) show very low lasing thresholds of 0.6-1.8 mJ/cm square with wide gain bandwidth (610 nm-685 nm), which are attributed to the heterogeneous geometry of the gain material, the optimized etching technique, and the strong overlap of the gain material with the plasmonic modes. Most importantly, we establish the connection between mode confinements and enhanced absorption and stimulated emission, which play a critical role in maintaining low lasing thresholds at extremely small hybrid plasmonic cavities. Our results pave the way for the further integration of dense arrays of hybrid plasmonic lasers with optical and electronic technology platforms.Comment: 20 page

On the role of extrinsic and intrinsic defects in the underpotential deposition of Cu on thiol-modified Au(111) electrodes

Underpotential deposition (UPD) of Cu on Au(111) electrodes modified by self-assembled monolayers (SAMs) of omega-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) was studied in situ by electrochemical scanning tunneling microscopy. The UPD layer intercalated between SAM and Au consists of monatomic high nanoislands on top of an extended Cu film. Nucleation and growth of the Cu UPD layer are accounted for by a mechanism that is fundamentally different from the one suggested in the literature for alkanethiols. Domain boundaries, vacancy islands, or step edges do not act as nucleation sites. The electrode passivation is therefore not limited by the intrinsic structure of the SAM but by extrinsic defects, which are associated with more substantial discontinuities in the SAM. These act not only as nucleation centers for the Cu UPD but throughout the whole growth process are the only sites through which Cu penetrates. The growth proceeds by diffusion of Cu at the SAM-substrate interface until completion of the UPD layer. The implications of our observations for the generation of metal-SAM-metal structures are discussed.</p

Le Laser

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