Spectroscopic exploration of binding between novel cationic gemini surfactants and Flurbiprofen

Effect of surfactant's charge properties on behavior, physiology, and biochemistry and the release of microcystins of Microcystis aeruginosa

Surfactant pollution is escalatitheng in eutrophic waters, but the effect of surfactant charge properties on the physiological and biochemical properties of toxin-producing microalgae remains inadequately explored. To address this gap, this study explores the effects and mechanisms of three common surfactants-cetyltrimethylammonium bromide (CTAB, cationic), sodium dodecyl sulfate (SDS, anionic), and Triton X-100 (nonionic)-found in surface waters, on the agglomeration behavior, physiological indicators, and Microcystin-LR (MC-LR) release of Microcystis aeruginosa (M. aeruginosa) by using UV-visible spectroscope, Malvern Zetasizer, fluorescence spectrometer, etc. Results suggest that charge properties significantly affect cyanobacterial aggregation and cellular metabolism. The CTAB-treated group demonstrates a ∼5.74 and ∼9.74 times higher aggregation effect compared to Triton X-100 and SDS (300 mg/L for 180 min) due to strong electrostatic attraction. Triton X-100 outperforms CTAB and SDS in polysaccharide extraction, attributed to its higher water solubility and lower critical micelle concentration. CTAB stimulates cyanobacteria to secrete proteins, xanthohumic acid, and humic acids to maintain normal physiological cells. Additionally, the results of SEM and ion content showed that CTAB damages the cell membrane, resulting in a ∼90% increase in the release of intracellular MC-LR without cell disintegration. Ionic analyses confirm that all three surfactants alter cell membrane permeability and disrupt ionic metabolic pathways in microalgae. This study highlights the relationship between the surface charge properties of typical surfactants and the dispersion/agglomeration behavior of cyanobacteria. It provides insights into the impact mechanism of exogenous surfactants on toxic algae production in eutrophic water bodies, offering theoretical references for managing surfactant pollution and treating algae blooms.

Biodegradable Cationic and Ionizable Cationic Lipids: A Roadmap for Safer Pharmaceutical Excipients

Cationic and ionizable cationic lipids are broadly applied as auxiliary agents, but their use is associated with adverse effects. If these excipients are rapidly degraded to endogenously occurring metabolites such as amino acids and fatty acids, their toxic potential can be minimized. So far, synthesized and evaluated biodegradable cationic and ionizable cationic lipids already showed promising results in terms of functionality and safety. Within this review, an overview about the different types of such biodegradable lipids, the available building blocks, their synthesis and cleavage by endogenous enzymes is provided. Moreover, the relationship between the structure of the lipids and their toxicity is described. Their application in drug delivery systems is critically discussed and placed in context with the lead compounds used in mRNA vaccines. Moreover, their use as preservatives is reviewed, guidance for their design is provided, and an outlook on future developments is given.

Synthesis, Aggregation Behavior and Drug-binding Interactions of Fatty acid-imidazolium-based Surface-active Ionic Liquids

The renewable fatty acid-based surface-active ionic liquids (SAILs) containing ethyl-substituted imidazolium head groups were prepared and structurally analyzed by Fourier transform infrared spectroscopy (FTIR), ¹HNMR and ¹³CNMR spectroscopy. The products were named as; 3-ethyl-1-(2-dodecanoyl oxy) ethylimidazolium bromide [C₁₂Eeim]Br, 3-ethyl-1-(2-tetradecanoyl oxy) ethylimidazolium bromide [C₁₄Eeim]Br and 3-ethyl-1-(2-hexadecanoyl oxy) ethylimidazolium bromide [C₁₆Eeim]Br. The critical micelle concentration (cmc) values of the three SAILs have been evaluated using conductivity measurements, probe-less UV-visible spectroscopy and fluorescence spectroscopy. The obtained cmc values were compared with the earlier reported non-functionalized SAILs such as [C_nmim]Br and [C_neim]Br where n= 12, 14, 16. The values were found to be 3 to 9 times lower mainly due to the presence of ester chain and also ethyl substituted imidazole ring. Thermodynamic parameters were evaluated by conductivity data at three different temperatures. Further, the aggregation behavior of SAILs with anesthetic drug, lidocaine hydrochloride (LC) has been studied using fluorescence. The fluorescence and UV-visible studies showed strong synergistic interactions operating between SAILs and drug molecules involving H bonding and cation-π interactions. The interactions grew stronger with the elongation of SAIL-chain length (12C-16C). Dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements suggested the formation of vesicles in SAIL-LC mixtures. These studies may thus offer an effective candidate which would serve as vectors for drug molecules in terms of their enhanced solubilization, permeability and target-specific delivery.

N-(Benzo[d]thiazol-2-yl)-2-(2-fluoro-[1,1′-biphenyl]-4-yl)propanamide

N-(Benzo[d]thiazol-2-yl)-2-(2-fluoro-[1,1′-biphenyl]-4-yl)propanamide was prepared by a reaction between benzo[d]thiazol-2-amine and flurbiprofen in high yield. The newly obtained flurbiprofen derivative was fully analyzed and characterized via 1H, 13C, UV, IR, and mass spectral data.