Jose García Guirado

Last Name

García Guirado

First Name

Jose

ORCID

0000-0003-4574-4356

Organisational unit

09698 - Quidant, Romain / Quidant, Romain

Show all metadata

Search Results

Publications 1 - 10 of 11

Enhanced Chiral Sensing with Dielectric Nanoresonators
García Guirado, Jose; Svedendahl, Mikael; Puigdollers, Joaquim; et al. (2020)
Nano Letters
Chiro-sensitive molecular detection is highly relevant as many biochemical compounds, the building blocks of life, are chiral. Optical chirality is conventionally detected through circular dichroism (CD) in the UV range, where molecules naturally absorb. Recently, plasmonics has been proposed as a way to boost the otherwise very weak CD signal and translate it to the visible/NIR range, where technology is friendlier. Here, we explore how dielectric nanoresonators can contribute to efficiently differentiate molecular enantiomers. We study the influence of the detuning between electric (ED) and magnetic dipole (MD) resonances in silicon nanocylinders on the quality of the CD signal. While our experimental data, supported by numerical simulations, demonstrate that dielectric nanoresonators can perform even better than their plasmonic counterpart, exhibiting larger CD enhancements, we do not observe any significant influence of the optical chirality. © 2019 American Chemical Society.
Molecular fingerprinting of biological nanoparticles with a label-free optofluidic platform
Stollmann, Alexia; García Guirado, Jose; Hong, Jae-Sang; et al. (2023)
arXiv
Label-free detecting multiple analytes in a high-throughput fashion has been one of the long-sought goals in biosensing applications. Yet, for all-optical approaches, interfacing state-of-the-art label-free techniques with microfluidics tools that can process small volumes of sample with high throughput, and with surface chemistry that grants analyte specificity, poses a critical challenge to date. Here, we introduce an optofluidic platform that brings together state-of-the-art digital holography with PDMS microfluidics by using supported lipid bilayers as a surface chemistry building block to integrate both technologies. Specifically, this platform fingerprints heterogeneous biological nanoparticle populations via a multiplexed label-free immunoaffinity assay with single particle sensitivity. Herein, we first thoroughly characterise the robustness and performance of the platform, and then apply it to profile four distinct ovarian cell-derived extracellular vesicle populations over a panel of surface protein biomarkers, thus developing a unique biomarker fingerprint for each cell line. We foresee that our approach will find many applications where routine and multiplexed characterisation of biological nanoparticles is required.
Molecular fingerprinting of biological nanoparticles with a label-free optofluidic platform
Stollmann, Alexia; García Guirado, Jose; Hong, Jae-Sang; et al. (2024)
Nature Communications
Label-free detection of multiple analytes in a high-throughput fashion has been one of the long-sought goals in biosensing applications. Yet, for all-optical approaches, interfacing state-of-the-art label-free techniques with microfluidics tools that can process small volumes of sample with high throughput, and with surface chemistry that grants analyte specificity, poses a critical challenge to date. Here, we introduce an optofluidic platform that brings together state-of-the-art digital holography with PDMS microfluidics by using supported lipid bilayers as a surface chemistry building block to integrate both technologies. Specifically, this platform fingerprints heterogeneous biological nanoparticle populations via a multiplexed label-free immunoaffinity assay with single particle sensitivity. First, we characterise the robustness and performance of the platform, and then apply it to profile four distinct ovarian cell-derived extracellular vesicle populations over a panel of surface protein biomarkers, thus developing a unique biomarker fingerprint for each cell line. We foresee that our approach will find many applications where routine and multiplexed characterisation of biological nanoparticles are required.
Self-Calibrating On-Chip Localized Surface Plasmon Resonance Sensing for Quantitative and Multiplexed Detection of Cancer Markers in Human Serum
Yavas, Ozlem; Aćimović, Srdjan S.; García Guirado, Jose; et al. (2018)
ACS Sensors
The need for point-of-care devices able to detect diseases early and monitor their status, out of a lab environment, has stimulated the development of compact biosensing configurations. Whereas localized surface plasmon resonance (LSPR) sensing integrated into a state-of-the-art microfluidic chip stands as a promising approach to meet this demand, its implementation into an operating sensing platform capable of quantitatively detecting a set of molecular biomarkers in an unknown biological sample is only in its infancy. Here, we present an on-chip LSPR sensor capable of performing automatic, quantitative, and multiplexed screening of biomarkers. We demonstrate its versatility by programming it to detect and quantify in human serum four relevant human serum protein markers associated with breast cancer. © 2018 American Chemical Society.
Long-range optofluidic control with plasmon heating
Ciraulo, Bernard; García Guirado, Jose; de Miguel, Ignacio; et al. (2021)
Nature Communications
Using light to manipulate fluids has been a long-sought-after goal for lab-on-a-chip applications to address the size mismatch between bulky external fluid controllers and microfluidic devices. Yet, this goal has remained elusive due to the complexity of thermally driven fluid dynamic phenomena, and the lack of approaches that allow comprehensive multiscale and multiparameter studies. Here, we report an innovative optofluidic platform that fulfills this need by combining digital holographic microscopy with state-of-the-art thermoplasmonics, allowing us to identify the different contributions from thermophoresis, thermo-osmosis, convection, and radiation pressure. In our experiments, we demonstrate that a local thermal perturbation at the microscale can lead to mm-scale changes in both the particle and fluid dynamics, thus achieving long-range transport. Furthermore, thanks to a comprehensive parameter study involving sample geometry, temperature increase, light fluence, and size of the heat source, we showcase an integrated and reconfigurable all-optical control strategy for microfluidic devices, thereby opening new frontiers in fluid actuation technology.
A hybrid dielectrophoretic trap-optical tweezers platform for manipulating microparticles in aqueous suspension
González-Gómez, Carlos David; García Guirado, Jose; Quidant, Romain; et al. (2025)
Lab on a Chip
We demonstrate that a set of microfabricated electrodes can be coupled to a commercial optical tweezers device, implementing a hybrid electro-optical platform with multiple functionalities for the manipulation of micro-/nanoparticles in suspension. We show that the hybrid scheme allows enhanced manipulation capabilities, including hybrid dynamics, controlled accumulation in the dielectrophoretic trap from the optical tweezers, selectivity, and video tracking of the individual trajectories of trapped particles. This creates opportunities for novel studies in statistical physics and stochastic thermodynamics with multi-particle systems, previously limited to investigations with individual particles.
Overcoming Diffusion-Limited Biosensing by Electrothermoplasmonics
García Guirado, Jose; Rica, Raúl A.; Ortega, Jaime; et al. (2018)
ACS Photonics
Biosensing based on optical micro- and nanoresonators integrated in a microfluidic environment is a promising approach to lab-on-a-chip platforms capable of detecting low concentrations of analytes from small sample volumes. While sensitivity has reached the single molecule level, in practice, the applicability to real-life settings is limited by Brownian diffusion of the analyte to the sensor surface, which dictates the total duration of the sensing assay. Here, we use the electrothermoplasmonic (ETP) effect to overcome this limit through opto-electrical fluid convective flow generation. To this end, we designed a Localized Surface Plasmon Resonance (LSPR) sensing chip that integrates ETP operation into state-of-the-art microfluidics. First, we optimize and characterize the ETP dynamics inside the microfluidic chamber, showing high fluid velocities. Then, we perform proof-of-concept experiments on model immunoglobulin G detection to demonstrate ETP-enhanced biosensing. Our results demonstrate the synergetic effect of temperature and electric field proving that ETP-LSPR has improved performances over standard LSPR. © 2018 American Chemical Society.
Light Phase Modulation with Transparent Paraffin‐Based Phase Change Materials
Otaegui, Jaume R.; Bertschy, Yannick; Vallan, Lorenzo; et al. (2024)
Advanced Optical Materials
Phase change materials (PCM) have greatly contributed to optics with applications ranging from rewritable memories to smart windows. This is possible thanks to the variation in optical properties that PCMs undergo upon thermally-induced phase change. However, this behavior is accompanied by a loss of optical transparency in one (or more) of their phases, posing a major limitation for transmission-based functionalities. Here this challenge is addressed by producing PCM-based composites that remain transparent in the visible spectrum during their phase transition. The cornerstone of this innovative material is the use of 30 nm-in-size nanoparticles of paraffin as PCMs, which minimizes the scattering within the polymer host matrix regardless of the paraffin's phase. To demonstrate the potential of this approach, it is shown that thin composite layers can modulate the phase of the incident visible light using temperature, achieving uniform phase profiles with maximum phase shifts up to π radians. Notably, the composites studied exhibit up to threefold larger phase changes for the same input power over reference thermo-optical materials like polydimethylsiloxane. These findings position paraffin-based composites as promising materials for various thermo-optical applications, including wavefront shaping and aberration correction, with the potential to significantly impact a variety of optical technologies.
Reconfigurable Integrated Thermo-Optics for Aberration Correction
Panadés, Josep M.; Rutz, Nadja; Robert, Hadrien M. L.; et al. (2024)
ACS Photonics
As miniaturization becomes a growing trend in optical systems, the ability to precisely manipulate wavefronts within micrometric pupils becomes crucial. Extensive efforts to develop integrated micro-optics primarily led to tunable microlenses. Among these approaches, SmartLenses, which use predesigned microheaters to locally change the refractive index in a transparent thermo-optical material, allow to produce tunable micro-optics with free-form shape. However, the shape and sign of the generated wavefront profile are fixed, predetermined by the geometry of the resistor, which severely limits its use, e.g., for aberration correction. Here, we report a precise reconfigurability of the generated wavefront through dynamic shaping of the temperature distribution, enabled by an independent control of concentric resistors. As a proof of principle, we demonstrate a bimodal SmartLens that simultaneously acts as a converging/diverging lens and a positive/negative spherical aberration corrector. Through independent control of Zernike modes, this approach paves the way for compact, broadband, transparent and polarization-insensitive wavefront shapers, with a broad range of potential applications, from endoscopy to information technology.
Enantiomer-Selective Molecular Sensing Using Racemic Nanoplasmonic Arrays
García Guirado, Jose; Svedendahl, Mikael; Puigdollers, Joaquim; et al. (2018)
Nano Letters
Building blocks of life show well-defined chiral symmetry which has a direct influence on their properties and role in Nature. Chiral molecules are typically characterized by optical techniques such as circular dichroism (CD) where they exhibit signatures in the ultraviolet frequency region. Plasmonic nanostructures have the potential to enhance the sensitivity of chiral detection and translate the molecular chirality to the visible spectral range. Despite recent progress, to date, it remains unclear which properties plasmonic sensors should exhibit to maximize this effect and apply it to reliable enantiomer discrimination. Here, we bring further insight into this complex problem and present a chiral plasmonic sensor composed of a racemic mixture of gammadions with no intrinsic CD, but high optical chirality and electric field enhancements in the near-fields. Owing to its unique set of properties, this configuration enables us to directly differentiate phenylalanine enantiomers in the visible frequency range.

Publications 1 - 10 of 11

Jose García Guirado

Last Name

First Name

ORCID

Organisational unit

Filters

Search Results