Incorporation of Au Nanoparticles on ZnO/ZnS Core Shell Nanostructures for UV Light/Hydrogen Gas Dual Sensing Enhancement

ZnO/ZnS nanocomposite-based nanostructures exhibit dual light and gas sensing capabilities. To further boost the light/dual sensing properties, gold nanoparticles (Au NPs) were incorporated into the core-shell structures. Multiple material characterizations revealed that Au NPs were successfully well spread and decorated on ZnO/ZnS nanostructures. Furthermore, our findings show that the addition of Au NPs could enhance both 365 nm UV light sensing and hydrogen gas sensing in terms of light/gas sensitivity and light/gas response time. We postulate that the optimization of gas/light dual sensing capability may result from the induced electric field and inhabitation of electron-hole recombination. Owing to their compact size, simple fabrication, and stable response, ZnO/ZnS/Au NPs-based light/gas dual sensors are promising for future extreme environmental monitoring.

Antimonene-gold Based Twin-Core SPR Sensor with Side Polished Semi-Arc Groove Dual Sensing Channel: An Investigation with 2D Material

We propose surface plasmon resonance (SPR) based single-side polished photonic crystal fiber (SSP-PCF) sensor for low as well as high refractive index (RI) sensing. To achieve this, an active metal gold (Au) is deposited on the PCF's flat narrow channels to form a dual-sensing channel. Following that, a thin nanolayer antimonene is deposited on Au, as its buckled honeycomb lattice structure aids in the trapping of numerous biomolecules. For the sensing range of 1.27 to 1.39, numerical results show that the wavelength sensitivity (WS) and amplitude sensitivity (AS) mounted on 77000 nmRIU-1 and 1320.41 RIU-1, respectively, with wavelength resolution (RW), and amplitude resolution (RA), as high as 1.298\(\times\)10-6 RIU, and 8.6\(\times\)10-7 RIU. The promising results obtained from the proposed SSP-PCF sensor offers improved refractive index sensing with a fine figure of merit (FOM), i.e., 311.74 RIU-1 for the sensing range of 1.27 to 1.39, which covers most known analytes such as proteins, cancer cells, glucose, viruses, DNA/RNA, medicinal drugs, halogenated organic acids. Further, the proposed sensor's design requires a simple fabrication procedure.

Detection of Bioavailable Cadmium by Double-Color Fluorescence Based on a Dual-Sensing Bioreporter System

Cadmium (Cd) is carcinogenic to humans and can accumulate in the liver, kidneys, and bones. There is widespread presence of cadmium in the environment as a consequence of anthropogenic activities. It is important to detect cadmium in the environment to prevent further exposure to humans. Previous whole-cell biosensor designs were focused on single-sensing constructs but have had difficulty in distinguishing cadmium from other metal ions such as lead (Pb) and mercury (Hg). We developed a dual-sensing bacterial bioreporter system to detect bioavailable cadmium by employing CadC and CadR as separate metal sensory elements and eGFP and mCherry as fluorescent reporters in one genetic construct. The capability of this dual-sensing biosensor was proved to simultaneously detect bioavailable cadmium and its toxic effects using two sets of sensing systems while still maintaining similar specificity and sensitivity of respective signal-sensing biosensors. The productions of double-color fluorescence were directly proportional to the exposure concentration of cadmium, thereby serving as an effective quantitative biosensor to detect bioavailable cadmium. This novel dual-sensing biosensor was then validated to respond to Cd(II) spiked in environmental water samples. This is the first report of the development of a novel dual-sensing, whole-cell biosensor for simultaneous detection of bioavailable cadmium. The application of two biosensing modules provides versatile biosensing signals and improved performance that can make a significant impact on monitoring high concentration of bioavailable Cd(II) in environmental water to reduce human exposure to the harmful effects of cadmium.