Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components’ basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers—two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take.

The benefits of silver nanoparticles (AgNPs) have been known in many fields from catalysis through optics to medicine due to their unique size-dependent properties. Recently, there is also a growing interest in novel skincare formulations containing AgNPs. In this work, AgNPs were successfully synthesised and were characterised by UV-Vis spectroscopy and Transmission Electron Microscopy (TEM). In addition, an analysis of particle size distribution (measured by Dynamic Light Scattering – DLS) and zeta potential (using the method Electrophoretic Light Scattering – ELS) were made. The obtained AgNPs were in two sizes: small (20 nm ± 5 nm) and large (100 nm ± 5 nm). The assessment of the cytotoxic effect on human skin cells was done. Smaller AgNPs showed less cytotoxicity and thus greater safety for skin, so they were introduced into new skincare formulations such as oil/water (O/W) emulsion, water/oil (W/O) emulsion and hydrogel. Moreover, the study of release AgNPs from emulsions and hydrogel using Franz diffusion chamber with pig skin as a membrane has been conducted. The receptor fluid measurements were performed by Atomic Absorption Spectroscopy (AAS). The last point of the research was the performance of microbiological tests to determine the antibacterial effect of the smaller AgNPs in both solution and cosmetic. Graphical abstract

The presented protocol outlines a comprehensive assessment of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for bacterial cell cultures. These experiments are vital for screening bacterial susceptibility to antibiotics and substances with potential antibacterial properties. The protocol not only covers the necessary preparatory steps but also introduces the application of the widely recognized Gompertz model. The protocol ensures a smooth execution of the assessment through thorough preparation and step-by-step instructions. The user-friendly instructions provided enable researchers to easily follow the protocol, facilitating the implementation of the assessment. By adhering to the outlined procedures, researchers can acquire a deeper understanding of bacterial susceptibility, evaluate the efficacy of antimicrobial agents through MIC and MBC values, and contribute to the advancement of antibacterial strategies.

Plastic waste poses a serious threat to ecosystems and human health. Similarly, the increasing use of automobiles has led to a rise in discarded tires, exacerbating environmental concerns. However, repurposing this waste into new materials promotes sustainability and supports the concept of a circular economy. In this study, we explored the combination of reclaimed ground tire rubber (rGTR) and additive manufacturing technology (3D printing) for the development of novel conductive filaments. For this purpose, a filament composed of 25% rGTR, 25% carbon black (CB), and 50% low-density polyethylene (LDPE) was formulated for constructing additively manufactured electrodes. The produced filament exhibited excellent flexibility, with successful incorporation of rGTR into the matrix, as confirmed by TGA, SEM and AFM data. 3D-printed working electrodes prepared using rGTR, CB, and LDPE subjected to an atmospheric air plasma pen (3D-CB/rGTR/LDPE-PT) were applied for detecting a hazardous fungicide, carbendazim (CBZ). Thus, under optimized differential pulse voltammetry (DPV) conditions, the sensor demonstrated a linear response ranging from 1.0 to 40.0 μmol L⁻¹ CBZ, with limits of detection (LOD) and quantification (LOQ) of 79 nmol L⁻¹ and 262 nmol L⁻¹, respectively. The proposed 3D-CB/rGTR/LDPE-PT sensor was successfully applied for detecting CBZ in drinking water and effluent samples, achieving recovery rates between 95 and 105%, highlighting its excellent analytical performance. This work demonstrates that recycled raw materials from the automotive industry can be repurposed to develop innovative devices for detecting environmental contamination caused by indiscriminate pesticide use, while also simultaneously promoting sustainability through the reuse and recycling of waste tire rubber.

Electrochemical biosensors are a well-known group of tools used widely in a variety of industries. Due to interactions between analytes and a surface, a measurable signal occurs which can then be processed to quantitative and/or qualitative data. The knowledge of surfaces’ electrochemical properties as well as their pK_a is of great importance when it comes to the construction of biosensors based on an electrochemical signal. In our work, we focused on determining electrochemical properties as well as pK_a of thiol-based SAMs – commonly used linker layers in biosensors. By applying cyclic voltammetry and electrochemical spectroscopy we were able to describe the overall resistive behaviour of SAMs synthesised with both alkanethiols and thiols with carboxyl and amine groups. Coherent use of contact angle measurements let us also describe the overall polarity of the investigated surfaces. The obtained data of pK_a values differed from the ones described for bulk solutions of modifying agents, which yields important information for further modification of the surface.