Cancer has been one of the most prevalent diseases around the world for many years. Its biomarkers are biological molecules found in the blood or other body fluids of people with cancer diseases. These biomarkers play a crucial role not only in the diagnosis of cancer diseases, but also in risk assessment, selection of treatment methods, and tracking its progress. Therefore, highly sensitive and selective detection and determination of cancer biomarkers are essential from the perspective of oncological diagnostics and planning the treatment process. Immunosensors are special types of biosensors that are based on the recognition of an analyte (antigen) by an antibody. Sandwich immunosensors apply two antibodies: a capture antibody and a detection antibody, with the antigen ‘sandwiched’ between them. Immunosensors’ advantages include not only high sensitivity and selectivity, but also flexible application and reusability. Surface-enhanced Raman spectroscopy, known also as the sensitive and selective method, uses the enhancement of light scattering by analyte molecules adsorbed on a nanostructured surface. The combination of immunosensors with the SERS technique further improves their analytical parameters. In this article, we followed the recent achievements in the field of sandwich SERS immunosensors for cancer biomarker detection and/or determination.

NBOMes are N-benzylmethoxy derivatives of the 2C family hallucinogens. 4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe) is one of the commonly used illicit drugs. It exhibits high binding affinity for 5-HT_2A/C and 5-HT_1A serotonin receptors. Activation of 5-HT_2A receptor induces head-twitch response (HTR) in rodents, a behavioral marker of hallucinogen effect in humans. There is not much data on neurochemical properties of NBOMes. Therefore, we aimed to investigate the effect of 25I-NBOMe on extracellular level of dopamine (DA), serotonin (5-HT), and glutamate (GLU) in the rat frontal cortex, tissue contents of monoamines, and hallucinogenic activity in rats. The extracellular levels of DA, 5-HT, and GLU were studied using microdialysis in freely moving animals. The tissue contents of DA, 5-HT and their metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the rat frontal cortex. We also tested a drug-elicited HTR. 25I-NBOMe at doses 1, 3, and 10 mg/kg (sc) increased extracellular DA, 5-HT, and GLU levels, enhanced tissue content of 5-HT and 5-HIAA, but did not affect tissue level of DA and its metabolites. The compound exhibited an inverted U-shaped dose-response curve with respect to the effect on extracellular DA and 5-HT levels, but a U-shaped dose-response curve was observed for its effect on GLU release and HTR. The data from our study suggest that hallucinogenic activity of 25I-NBOMe seems to be related with the increase in extracellular GLU level-mediated via cortical 5-HT_2A receptors. The influence of 25I-NBOMe on 5-HT_2C and 5-HT_1A receptors may modulate its effect on neurotransmitters and HTR.

Acetylcholine (ACh) is one of the most crucial neurotransmitters of the cholinergic system found in vertebrates and invertebrates and is responsible for many processes in living organisms. Disturbances in ACh transmission are closely related to dementia in Alzheimer’s and Parkinson’s disease. ACh in biological samples is most often determined using chromatographic techniques, radioenzymatic assays, enzyme-linked immunosorbent assay (ELISA), or potentiometric methods. An alternative way to detect and determine acetylcholine is applying spectroscopic techniques, due to low limits of detection and quantification, which is not possible with the methods mentioned above. In this review article, we described a detailed overview of different spectroscopic methods used to determine ACh with a collection of validation parameters as a perspective tool for routine analysis, especially in basic research on animal models on central nervous system. In addition, there is a discussion of examples of other biological materials from clinical and preclinical studies to give the whole spectrum of spectroscopic methods application. Descriptions of the developed chemical sensors, as well as the use of flow technology, were also presented. It is worth emphasizing the inclusion in the article of multi-component analysis referring to other neurotransmitters, as well as the description of the tested biological samples and extraction procedures. The motivation to use spectroscopic techniques to conduct this type of analysis and future perspectives in this field are briefly discussed. Graphical Abstract

The possibility of adapting the Standard Addition Method (SAM) to calibration in very difficult analytical conditions, namely when there is a need to determine an analyte with the use of nonlinear calibration graph and in the presence of matrix components causing additive interference effect, is investigated. To this aim the SAM in the common version and the Chemical H-point Standard Addition Method (C-HPSAM) realized by the flow injection technique were applied. Specifically, a flow manifold was used for construction of a set of nonlinear calibration graphs in different chemical conditions. As the graphs were intersected indicating both the additive interference effect and the analytical result free of this effect, the analyte concentration in the sample was able to be obtained with improved accuracy. The applicability of this approach was verified on the example of spectrophotometric determination of paracetamol in pharmaceuticals and of total acidity in wines. The C-HPSAM method enabled complete compensation of the additive effect and obtaining analytical results at a relative error not exceeding 6.0%.