A Voltage-Controlled Surface Acoustic Wave Oscillator Based on Lithium Niobate on Sapphire Low-Loss Acoustic Delay Line.

In this work, we investigate, for the first time, a low phase noise and wide tuning range voltage-controlled surface acoustic wave oscillator (VCSO) based on a lithium niobate on sapphire (LNOS) low-loss acoustic delay line (ADL). The thin-film LN/SiO2 bilayer acoustic waveguide, together with the single-phase unidirectional transducer (SPUDT) design, is key to attaining low insertion loss (IL) by enhancing energy confinement and directionality. Based on a high-performance ADL with an IL of only 5.2 dB, a fractional bandwidth (FBW) of 5.38%, and a group delay of 110 ns, the VCSO is implemented by commercially available circuit components using a series-resonant topology. The LNOS ADL oscillator operates at 888 MHz, showcasing a low phase noise of -94.1 dBc/Hz at 1-kHz offset and a root-mean-square (rms) jitter of only 30.26 fs (integrated from 12 kHz to 20 MHz) while only consuming 16 mA of supply current. Featuring a wide frequency tuning range of 6630 ppm, the proposed VCSO is a promising low-noise, low-power, and high-frequency timing device for emerging applications.Index Terms- Acoustic delay line (ADL), jitter, lithium niobate (LN), oscillator, phase noise, surface acoustic wave (SAW), thin film.skiptabldblfloatfix.

Application of a dual-modality colorimetric analysis method to inkjet printing lateral flow detection of Salmonella typhimurium.

Lateral flow assay (LFA) color signal quantification methods were developed by utilizing both International Commission on Illumination (CIE) LAB (CIELAB) color space and grayscale intensity differences. The CIELAB image processing procedure included calibration, test, control band detection, and color difference calculation, which can minimize the noise from the background. The LFA platform showcases its ability to accurately discern relevant colorimetric signals. The rising occurrence of infectious outbreaks from foodborne pathogens like Salmonella typhimurium presents significant economic, healthcare, and public health risks. The study introduces an aptamer-based lateral flow (ABLF) platform by using inkjet printing for specially detecting S. typhimurium. The ABLF utilized gold-decorated polystyrene microparticles, functionalized with specific S. typhimurium aptamers (Ps-AuNPs-ssDNA). The platform demonstrates a detection limit of 102 CFU mL-1 in buffer solutions and 103 CFU mL-1 in romaine lettuce tests. Furthermore, it sustained performance for over 8 weeks at room temperature. The ABLF platform and analysis methods are expected to effectively resolve the low-sensitivity problems of the former LFA systems and to bridge the gap between lab-scale platforms to market-ready solutions by offering a simple, cost-effective, and consistent approach to detecting foodborne pathogens in real samples.

A smartphone-integrated aptasensor for pesticide detection using gold-decorated microparticles.

The increasing incidence of environmental concerns related to excessive use of pesticides, such as imidacloprid and carbendazim, poses risks to pollinators, water bodies, and human health, prompting regulatory scrutiny and bans in developed countries. In this study, we propose a portable smartphone-based biosensor for rapid and label-free colorimetric detection by using the gold-decorated polystyrene microparticles (Ps-AuNP) functionalized with specific aptamers to imidacloprid and carbendazim on a microfluidic paper-based analytical device (µ-PAD). Four aptamers were selected for the detection of these pesticides and their sensitivity and selectivity performance was evaluated. The sensitivity results show a detection limit for imidacloprid of 3.12 ppm and 1.56 ppm for carbendazim. The aptamers also exhibited high selectivity performance against other pesticides, such as thiamethoxam, fenamiphos, isoproturon, and atrazine. However, the platform presented cross-selectivity when detecting imidacloprid, carbendazim, and linuron, which is discussed herein. Overall, we present a promising platform for simple, on-site, and rapid colorimetric screening of specific pesticides, while highlighting the challenges of aptasensors in achieving selectivity amidst diverse molecular structures.

Harnessing Acoustic Dispersions in YX-LN/SiO2/Si SH-SAW Resonators for Electromechanical Coupling Optimization and Rayleigh Mode Suppression.

In this study, we investigate the dispersive behavior of the electromechanical coupling coefficient ( [Formula: see text]) for shear-horizontal (SH) and Rayleigh surface acoustic wave (SAW) modes in a YX-LiNbO3 (LN)/SiO2/Si substrate across various wavelengths. Due to the difference in velocity dispersion between the SH and Rayleigh modes, mode coupling can be observed when these two modes operate at closely proximate frequencies, leading to a notable variation in their [Formula: see text]. With a careful design, SH and Rayleigh modes can be tuned to achieve a mode-decoupling state for enhancing [Formula: see text] of the SH-SAW and suppressing the presence of the Rayleigh mode in YX-LN/SiO2/Si. Consequently, a series of proof-of-concept SH-SAW resonators with wavelengths ( λ ) ranging from 1.6 to [Formula: see text] are fabricated. The optimized resonator with a λ of [Formula: see text] exhibits a resonant frequency of 1.064 GHz, an effective [Formula: see text] of 47.7%, a maximum Bode- Q of around 900, and an 18-dB rejection of spurious modes spanning from 0.5 to 3 GHz, without the presence of the Rayleigh mode.