arXiv subjects

Dolores Ortiz

Publications and source records attributed to Dolores Ortiz.

3 recordsLinked to original sources

arXiv2025

Optical discrimination of live single cancer cells using reflection-based nanohole array sensor

In this research, a reflection-based nanohole array sensor system is presented for discriminating between migration-competent cancer cells that maintain the integrity of the actin cortex and those cells lacking the actin cortex and thus unable to migrate. Unlike previous transmission-based approaches, this configuration allows for more practical integration into in situ diagnostic tools. For the first time, the system performance is analyzed by studying the spectral features of the reflected light by live single cells. We demonstrate that the presence of the actin cortex, needed for cell migration, in different types of cancer cells significantly affect their optical response, enabling high sensitivity and specificity in cell classification. Our results pave the way for reflection-based plasmonic biosensor devices as a compact and efficient platform for developing biomedical application tools.

physics.app-ph↗

arXiv2021

Gold nanodoughnut as an outstanding nanoheater for photothermal applications

Photoinduced hyperthermia is a cancer therapy technique that induces death to cancerous cells via heat generated by plasmonic nanoparticles. While previous studies have shown that some nanoparticles can be effective at killing cancer cells under certain conditions, there is still a necessity (or the need) to improve its heating efficiency. In this work, we perform a detailed thermoplasmonic study comparing the most effective nanoparticle geometries up to now with a doughnut-shaped nanoparticle, demonstrating that the latter exhibits a superior tunable photothermal response in practical illumination conditions, i.e., unpolarized light. Furthermore, we show that nanoparticle heating in fluidic environments, i.e., nanoparticles undergoing Brownian rotations, strongly depends on the particle orientation with respect to the illumination source. We conclude that the heating performance of nanodoughnuts is outstanding, with a temperature increment 35% higher than the second best nanoheater (nanodisks). Furthermore, nanodoughnuts feature a weak dependence on orientation, being therefore, ideal candidates for photothermal therapy applications. Finally, we present a designing guide, covering a wide range of toroid designs, which can help on its experimental implementation.

physics.optics↗

arXiv2017

Evaluation of effective medium theories for spherical nano-shells

Current effective medium theories for nano-shells are reviewed. A new method for calculating the effective dielectric function of a core-shell nanoparticle is presented and compared with existing theories showing clear advantages in most conditions. It consists of introducing radiating effects in the polariz- ability of the effective sphere, and considering the exact polarizability of the core-shell constructed from the Mie scattering coefficient. This new approach can be considered as an useful tool for designing coated particles with desired plasmonic properties and engineering the effective permittivity of composites with core-shell type inclusions which are used in photocatalysis and solar energy harvesting applications.

physics.optics↗