A new biosensor for noninvasive determination of fetal RHD status in maternal blood of RhD negative pregnant women

The Saliva Cortisol and Amylase Levels Related with Stress Response Compared by Different Analytical Methods

Sampling of salivary cortisol and amylase is a non-invasive method and important for the evaluation of the hypothalamic-pituitary-adrenal axis function and stress levels. This study aimed to compare the values of the salivary cortisol and amylase levels which were measured by three different analytical methods to discuss the alterations of stress levels of samples. The saliva samples of young adults (n = 23) were collected between 08.00 and 09.00 a.m., noon at 12.00 (before exam) and between 14.00 and 15.00 p.m. (after unaware exam). The samples were measured within the first 48 h, and no freezing/thawing was done. Salivary cortisol and amylase levels of subjects were measured by three different analytical methods as ELISA, chemiluminescence and biosensor methods. Comparison of ELISA and biosensor methods in order to determine the salivary cortisol levels showed a good correlation y = 2.971 + 0.748x (R2 = 0.839). Salivary amylase concentrations were only detected by ELISA method. Biosensor can be offered as an alternative analytic method to the conventional determination method ELISA. It can be preferred because of the detection/information effectiveness, low cost, fast results and specificity characteristics.

In situ detection of heavy metal ions in sewage with screen-printed electrode-based portable electrochemical sensors

The rapid development of industrial technologies continuously increases the heavy metal pollution of water resources. Recently, portable electrochemical analysis-based devices for detecting heavy metal ions have attracted much attention due to their excellent performance and low fabrication costs. However, it has proven difficult to accommodate complex testing needs in a cost-effective manner. To address these limitations, we propose a new system for the in situ detection of heavy metals in wastewater using an organic light-emitting diode-based panel to display data in real time and Bluetooth to transmit data to a smartphone for rapid analysis. The fabricated device integrates an in situ signal analysis circuit, a Bluetooth chip, a photocured 3D-printed shell, and an electrode sleeve interface. In addition, a fully screen-printed functional electrode plate containing chitosan/PANi-Bi nanoparticle@graphene oxide multi-walled carbon nanotubes is utilized for the rapid detection of heavy metal ions. This device can perform wireless data transmission and analysis and in situ signal acquisition and processing. The sensor exhibits a high sensitivity (Hg²⁺: 88.34 μA ppm^-1 cm^-2; Cu²⁺: 0.956 μA ppm^-1 cm^-2), low limit of detection (Hg²⁺: 10 ppb, Cu²⁺: 0.998 ppm) and high selectivity during the detection of copper and mercury ions in tap water under non-laboratory conditions, and the results of real-time tests reveal that parameters measured in the field and laboratory environments are identical. Hence, this small, portable, electrochemical sensor with a screen-printed electrode can be effectively used for the real-time detection of copper and mercury ions in complex water environments.