Radio Frequency Characterization of Gold Nanoparticles With 3-D Printed U-Cavity Sensor

This article presents a novel radio frequency characterization of gold nanoparticles (AuNPs) based on their geometric shapes with a 3-D printed U-cavity sensor. Traditional methods for nanoparticle characterization, such as spectroscopy and scanning electron microscopy, are costly, time-consuming, and require specialized equipment. In contrast, the fabricated U-cavity sensor offers a rapid and cost-effective method for discerning nanoparticles based on their morphology. The sensor features an embedded U-cavity within its substrate, designed to contain the test liquid. To streamline the fabrication process, the substrate with the embedded U-cavity was fabricated in a single step using an additive manufacturing process. The various distinctly shaped nanoparticles were injected into the cavity, and return loss measurements were performed. The study’s findings revealed that distinct AuNP shapes induced unique spectral signatures, enabling accurate characterization based on their geometric shapes. The variation in the resonance characteristics of the sensor resulting from the presence of AuNPs is termed effective shift throughout the article. As the geometric symmetry of the nanoparticles increased from cylindrical to quasi-spherical to spherical, a more pronounced effective shift was observed. This novel U-cavity microfluidic sensor demonstrates cost-effectiveness, ease of fabrication, and rapid characterization, highlighting the potential for nanoparticle characterization using radio frequency methods.