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The inelastic scattering of light, Raman scattering, presents a very low cross section. However, the signal can be amplified by several orders of magnitude, leading to the so-called surface-enhanced Raman scattering (SERS) phenomenon. Basically, the SERS effect is achieved when the target molecule (analyte) is adsorbed onto metallic nanoparticles, usually noble metals. This article presents an overview of the applications of SERS to cancer diagnosis and the detection of pesticides, explosives, and drugs (illicit and pharmacological). SERS is routinely applied nowadays to detect and identify analytes at very low concentrations, including for single-molecule detection. However, the application of SERS as an analytical tool requires reliable and reproducible SERS substrates, in terms of enhancement factors, which depends on the size, shape, and aggregation of the metallic nanoparticles. Therefore, the production of reliable and reproducible SERS substrates is a challenge in the field. Besides, the metallic nanoparticles can also induce changes in the system by possible interactions with the analyte under investigation, which must be taken into account. This review will present work in which, under certain specific experimental conditions, SERS has been analytically applied. [ABSTRACT FROM AUTHOR]

• an electrochemical sensor was built for carbofuran detection. • the sensor was composed by reduced graphene-oxide and magnetite nanoparticles. • carbofuran was indirectly detected by differential pulse voltammetry. • carbofuran was successfully detected in tap water and soil samples. Carbofuran (CBF) is a pesticide currently prohibited in many countries. It can cause serious damages in the nervous system and has been associated with cancer. However, CBF residues are still found in food samples around the world. Here, we develop an electrochemical non-enzymatic sensor for rapid and low-cost detection of CBF. Commercial indium tin oxide (ITO) electrodes were modified with a two-step Layer-by-Layer (LbL) approach: i) an LbL film of poly(diallyldimethyl ammonium) (PDDA) and graphene oxide (GO), which is further electrochemically reduced to produce (PDDA/ERGO)-modified ITO electrodes; and ii) an LbL film of magnetite nanoparticles (MNP) and poly(styrene sulfonate) (PSS) to form the ITO/(PDDA/ERGO) 5 /(MNP/PSS) 5 , with 5 representing the number of bilayers. The growth mechanism and morphology of the modified electrode were characterized by combining microscopy and optical spectroscopy. The ITO/(PDDA/ERGO) 5 /(MNP/PSS) 5 was applied in the electrochemical detection of CBF by differential pulse voltammetry (DPV) in standard solutions, reaching a sensitivity of 0.2543 (μA cm−2) (μmol L-1) and LOD of 0.407 μmol L-1, and then in real samples of tap water and soil. [ABSTRACT FROM AUTHOR]

• AgNP induces vesicle rupture in DOPC lipid membranes. • SiO 2 coating reduces rupture effects of AgNP. • AuNP exhibits partial wrapping, envelopment, and permeation on lipid bilayer. • Material and coating were crucial in NP-membrane interactions. Understanding the interaction between nanoparticles (NP) and lipid membranes is crucial for various biomedical applications. In this study, we investigated the effects of silver nanoparticles (AgNP), silica-coated silver nanoparticles (Ag@SiO 2), and gold nanoparticles (AuNP) on 1,2-dioleoyl- sn -glycero-3-phosphocholine (DOPC) lipid vesicles. The dynamic light scattering (DLS) and zeta potential measurements were employed to evaluate DOPC large unilamellar vesicles (LUVs) exposed to AgNP, AgNP@SiO 2 , or AuNP for 180 min. The DOPC giant unilamellar vesicles (GUVs) exposed to the same NP were evaluated by phase-contrast microscopy. The AgNP showed higher reactivity along the exposition time, leading the vesicles to rupture (LUVs and GUVs). The SiO 2 coating from Ag@SiO 2 decreases the rupture effects compared to uncovered AgNP, showing surface adsorption and, consequently, vesicle morphological changes. The AuNP showed a partial wrapping on the GUVs bilayer and permeation on the LUVs, however the integrity of the bilayer structure is maintained in both GUVs and LUVs. These findings highlight the varying effects of AgNP, Ag@SiO 2 , and AuNP on lipid vesicles, underscoring the importance of nanoparticle material and coating in their interactions with biological membranes. [ABSTRACT FROM AUTHOR]