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Transition metal nitrides (TMN) are promising material alternative to replace noble metals in the field of plasmonic applications, especially surface‐enhanced Raman spectroscopy (SERS). Here we demonstrate a practical surface enhanced Raman spectroscopy (SERS) substrate using zirconium nitride (ZrN) thin films grown by reactive gas‐timing (RGT) rf magnetron sputtering. The tailored properties of ZrN thin film exploited for SERS activity could be achieved to obtain a highly sensitive ZrN thin film SERS substrate with the enhancement factor (EF) of 1.24 × 106 and 4.8 %RSD at 1626 cm‐1 toward methylene blue (MB) analyte which are comparable to the optimized Au sputtered thin films (EF=1.18 × 106 and with 5.1%RSD). We find that the spatial plasmonic hotspots on the surface of ZrN SERS substrate controlled by the turn‐on timing of Ar:N2 sputtered gas sequence, leading to the discrete conductive surface profile, strongly relates to non‐stoichiometric composition and the degree of (200)‐oriented texture at the surface of ZrN thin film. Furthermore, ZrN thin film SERS substrates exhibit an excellent recyclability more than 30 cycles with simple cleaning process and a storage time longer than 6 months. The detection and reusability of ZrN SERS substrate on the low concentration of trinitrotoluene (TNT) for homeland security are also performed. [ABSTRACT FROM AUTHOR]

The development of an immunosensor‐based biosensor to detect the human serum albumin (HSA) was developed as a low‐cost and label‐free electrical detection through silicon nitride ion‐sensitive field‐effect transistor (Si3N4‐ISFET). This sensor was functionalized using 3‐Aminopropyltriethoxysilane (APTES). The silanized Si3N4‐ISFET surface was covalently linked with antibody against HSA (Anti‐HSA) via glutaraldehyde (GA) to function as an HSA immunosensor for detection of HSA. The interaction between HSA and Anti‐HSA on this device is monitored by changing of the gate potential at a constant drain current of 50 μA. The relationship between HSA concentration and the gate potential change of HSA immunosensor is linear up to 500 μg/ml with a detection limit of 5 μg/ml. This HSA immunosensor offers a good precision in both intra‐ and inter‐assay with a relative standard deviation of 6.61%, 7.48%, 10.69%, and 9.67%, 13.16%, 15.52% for 100, 200, and 400 μg/ml. The average percentage of recovery assay for the concentration of 32.1, 102.1, and 202.1 μg/ml is 96.55%. This sensor also provides its satisfactory selectivity when testing with Bence Jones protein solution. In addition, the results that was done by this HSA immunosensor is similar to the conventional method using immunoturbidimetric detection with a linear regression of 0.99; n = 40 with a paired sample t‐test of <0.01. Thus, this HSA immunosensor could be applied to urinary microalbumin detection because of its simplicity and satisfactory correlation value. [ABSTRACT FROM AUTHOR]

Surface treatment of titanium (Ti) surface has been extensively studied to improve its properties for biomedical applications, including hydrophilicity, corrosion resistance, and tissue integration. In this present work, we present the effects of thermal oxidation as surface modification method on metallic titanium (Ti). The Ti foils were oxidized at 300°C, 400°C, 500°C, and 600°C under air atmosphere for 3 hours, which formed oxide layer on Ti surface. The physicochemical properties including surface chemistry, roughness, and thickness of the oxide layer were evaluated in order to investigate how these factors affected surface hydrophilicity, microhardness, and corrosion resistance properties of the Ti surface. The results revealed that surfaces of all oxidized samples were modified by formation of titanium dioxide layer, of which morphology, phase, and thickness were changed according to the oxidized temperatures. Increasing oxidation temperature led to the formation of thicker oxide layer and phase transformation of anatase to rutile. The presence of the oxide layer helped the improvement of corrosion resistance and microhardness. The most improvement in surface roughness was found in the specimens treated at 400°C, which significantly improved surface hydrophilicity. But both surface roughness and hydrophilicity reduced when oxidized at 500°C and 600°C, suggesting that hydrophilicity was dominated by the surface roughness. In addition, this surface treatment did not reduce the biocompatibility of the metallic Ti substrates against murine osteoblasts (MC3T3). [ABSTRACT FROM AUTHOR]

• Polyvinyl Chloride ion-selective membrane was modified based on ISFET. • Nitrate-Nitrogen detection limit is 1.20 ppm, linear range from 3−20 ppm. • This sensor could be applied in many applications such as agricultural industry. In this work, a Polyvinyl Chloride (PVC) ion-selective membrane was modified to detect nitrate based on Ion Selective Field Effect Transistor (ISFET) sensing technology in order to eliminate chloride interference. A modification was done with ethylenediamine solution to achieve animated PVC, which was then oxidized with sodium tungstate to form nitrone coated PVC membrane. The modified PVC was characterized using FTIR, 1H NMR, GPC, FE-SEM and EIS. The FTIR spectrum of animate PVC demonstrated -NH 2 bending at 1580 cm−1, NO 2 asymmetric stretching at 1650 cm−1 and N O out-of-plane deformation vibration at 837 cm−1. GPC analysis of the modified PVC showed that the PVC molecular weight was shifted to a high molecular weight. The PVC ion-selective membrane was immobilized on the ISFET to create nitrate sensors with the following characteristics. The Nitrate-Nitrogen detection limit is 1.20 ppm with linear range from 3−20 ppm at sensitivity of 56 ± 2 mV/dec. The sensor is useful for detecting small amount of nitrate in a mixed solution, which usually is the case in most situations. This sensor could be applied in many applications, such as agricultural industry, water reserve management and medical field as well. [ABSTRACT FROM AUTHOR]