Alkaline phosphatase (ALP), which catalyzes the dephosphorylation process of proteins, nucleic acids, and small molecules, can be found in a variety of tissues (intestine, liver, bone, kidney, and placenta) of almost all living organisms. This enzyme has been extensively used as a biomarker in enzyme immunoassays and molecular biology. ALP is also one of the most commonly assayed enzymes in routine clinical practice. Due to its close relation to a variety of pathological processes, ALP’s abnormal level is an important diagnostic biomarker of many human diseases, such as liver dysfunction, bone diseases, kidney acute injury, and cancer. Therefore, the development of convenient and reliable assay methods for monitoring ALP activity/level is extremely important and valuable, not only for clinical diagnoses but also in the area of biomedical research. This paper comprehensively reviews the strategies of optical and electrochemical detection of ALP and discusses the electrochemical techniques that have been addressed to make them suitable for ALP analysis in cell culture.

Polycyclic aromatic hydrocarbons (PAHs) are hazardous environmental pollutants found in water, soil, and air. Exposure to this family of chemicals presents a danger to human health, and as a result, it is imperative to design methods that are able to detect PAHs in the environment, thus improving the quality of drinking water and agricultural soils. This review presents emerging immunoassay techniques used for in situ detection of PAH in water samples and how they compare to common-place techniques. It will discuss their advantages and disadvantages and why it is required to find new solutions to analyze water samples. These techniques are effective in reducing detection times and complexity of measurements. Immunoassay methods presented here are able to provide in situ analysis of PAH concentrations in a water sample, which can be a great complement to existing laboratory techniques due to their real-time screening and portability for immunoassay techniques. The discussion shows in detail the most relevant state-of-the-art surface functionalization techniques used in the field of immunosensors, with the aim to improve PAH detection capabilities. Specifically, three surface functionalization techniques are key approaches to improve the detection of PAHs, namely, substrate surface reaction, layer-by-layer technique, and redox-active probes. These techniques have shown promising improvements in the detection of PAHs in water samples, since they show a wider linear range and high level of sensitivity compared to traditional PAH detection techniques. This review explores the various methods used in the detection of PAH in water environments. It provides extra knowledge to scientists on the possible solutions that can be used to save time and resources. The combination of the solutions presented here shows great promise in the development of portable solutions that will be able to analyze a sample in a matter of minutes on the field.

Alkaline phosphatase (ALP) is an important reporter gene in the gene expression system, therefore monitoring cellular behavior including cell viability during ALP release is of significance. This assay produced a quantitative resazurin-based assay for cell viability in embryonic and cancer cells during alkaline phosphatase (ALP) release. A post-confluence culture method was applied to induce ALP in the cells of Balb/c 3T3, A549, MCF-7, and Ht-29. The density of each cell type was optimized using the standard cell culture assay. The main parameters affecting the results of resazurin involve the concentration of resazurin, incubation time, and cell number. The redox reaction, in which resazurin is reduced by the cells, was measured by fluorescence at 544 nm and 590 nm. The obtained data were compared with the hemocytometer assay. ALP release was determined using the optical active substrate p-nitrophenyl phosphate and colorimetric assay.

In this study, an in situ synthesis approach based on electrochemical reduction and ion exchange was employed to detect carbaryl species using a disposable, screen-printed carbon electrode fabricated with nanocomposite materials. Reduced graphene oxide (rGO) was used to create a larger electrode surface and more active sites. Gold nanoparticles (AuNPs,) were incorporated to accelerate electron transfer and enhance sensitivity. A cation exchange Nafion polymer was used to enable the adhesion of rGO and AuNPs to the electrode surface and speed up ion exchange. Cyclic voltammetry (CV), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), electrical impedance spectroscopy (EIS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were performed to study the electrochemical and physical properties of the modified sensor. In the presence of differential pulse voltammetry (DPV), an rGO/AuNP/Nafion-modified electrode was effectively used to measure the carbaryl concentration in river and tap water samples. The developed sensor exhibited superior electrochemical performance in terms of reproducibility, stability, efficiency and selectivity for carbaryl detection with a detection limit of 0.2 µM and a concentration range between 0.5µM and 250 µM. The proposed approach was compared to capillary electrophoresis with ultraviolet detection (CE-UV).

A simple quantitative reverse phase high performance liquid chromatographic (RP-HPLC) method has been developed and validated for assay determination of cannabidiol and tetrahydrocannabinol in hemp oil infused products. The RP-HPLC method was developed and optimized for the mobile phase composition, flow rate, column selection and detector wavelength. An isocratic elution of samples were performed on SOLAS 100 Å C18 150 mm × 4.6 mm, 5 μm column with a mobile phase containing 75/25 acetonitrile/water v/v, with a flow rate of 1.5 mL/min by using an ultraviolet–visible (UV/Vis) detector operating at 214 nm. The RP-HPLC method was validated to meet regulatory requirements which covers specificity, accuracy, range, linearity, precision, system suitability and robustness. The validated assay test method was applied successfully to quantify cannabidiol and tetrahydrocannabinol in commercial hemp oil infused products such as tablets, soft gel capsules, plant extract oils, oral drops, tincture, and beverage enhancers. All the test results were found acceptable as per ICH guidelines, and this confirmed the feasibility of this method for its intended use in regular quality control and assay of cannabidiol and tetrahydrocannabinol in hemp oil infused products.