A high fidelity interferometric transducer is designed based on platinum-coated nanoporous alumina films. The ultrathin metal coating significantly improves fidelity of the interferometric fringe patterns in aqueous solution and increases the signal-to-noise ratio. The performance of this transducer is tested with respect to refractive index unit (RIU) sensitivity measured as a change in effective optical thickness (EOT) in response to a solvent change and compared to porous silicon based transducers. RIU sensitivity in the order of 55% is attainable for porous alumina providing excellent signal-to-noise ratio, which exceeds the sensitivity of current interferometric transducers. Finally, as a proof-of-principle, we demonstrate biosensing with two distinct immunoglobulin antibodies.
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http://dx.doi.org/10.1039/c0nr00897d | DOI Listing |
Small Methods
January 2025
Laboratory of Analytical Chemistry, Department of Biological and Environmental Sciences and Technologies (Di.S.Te.B.A.), University of Salento, via Monteroni, Lecce, 73100, Italy.
Molecularly Imprinted Polymers (MIPs) have gained prominence as synthetic receptors, combining simplicity of synthesis with robust molecular recognition akin to antibodies and enzymes. One of their main application areas is chemical sensing. However, direct integration of MIPs with nanostructured transducers, crucial for enhancing sensing capabilities and broadening MIPs sensing applications, remains limited.
View Article and Find Full Text PDFPhotoacoustics
August 2024
ASI Agenzia Spaziale Italiana - Centro di Geodesia Spaziale, Località Terlecchia, Matera, 75100, Italy.
Micromachines (Basel)
August 2024
State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China.
In this study, based on the principle of grating interferometer-based acoustic sensors, design guidelines for the grating interferometric module were obtained and analyzed considering various factors in order to obtain high sensitivity, and a glass-based grating interference component and its acoustic sensor device were developed. The key parameters of the grating interference structure were extracted, and their effects on the acoustic response sensitivity were quantified for multiple mechanisms. For the development of the acoustic sensor, the grating-on-convex-platform structure and the micromachining processes of the glass-based components were designed and developed.
View Article and Find Full Text PDFUltrasonics
September 2024
College of Aerospace Engineering, Chongiqng University, Chongqing 400044, China. Electronic address:
In this paper, we present an experimental observation of the phenomenon known as zero-group velocity (ZGV) combined harmonic generation, which is induced by the mixing of counter-directional Lamb waves. We utilize internal resonant conditions to selectively choose the primary mode pair at specific frequencies for the purpose of combined harmonic generation. To detect the ZGV combined harmonic component, we propose a hybrid system that incorporates dual wedge-transducers for generation and a laser interferometric system for receiving.
View Article and Find Full Text PDFNanoscale
June 2024
Department of Chemistry and The Photonics Center, Boston University, Boston, MA 02459, USA.
Plasmonic molecules are discrete assemblies of noble metal nanoparticles (NPs) that are of interest as transducers in optical nanosensors. So far, NPs with diameters of ∼40 nm have been the preferred building blocks for plasmonic molecules intended as optical single molecule sensors due to difficulties associated with detecting smaller NPs through elastic scattering in conventional darkfield microscopy. Here, we apply 405 nm, 445 nm two-color interferometric scattering (iSCAT) microscopy to characterize polyethylene glycol (PEG) tethered dimers of 10 nm and 20 nm Ag NPs and their monomers.
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