β-Carotene is a natural lipid-soluble carotenoid with diverse biological activities, but its poor water solubility and sensitivity to light, heat, and oxygen limit its application. In this study, β-carotene nanoliposomes (βC-NL-1) were prepared using the thin-film hydration method and optimized by response surface methodology. The optimized formulation consisted of a soy lecithin-to-cholesterol mass ratio of 6:1, a β-carotene loading of 0.22 mg/10 mL ethanol, and 25 mL PBS, resulting in an encapsulation efficiency of 63.89 ± 1.09%. The optimized nanoliposomes had a particle size of 121.9 ± 1.24 nm, a polydispersity index (PDI) of 0.2654 ± 0.0136, and a zeta potential of −54.25 ± 1.26 mV. Transmission electron microscopy revealed relatively uniform spherical or ellipsoidal vesicles, while Fourier transform infrared spectroscopy showed characteristic spectral changes consistent with the incorporation of β-carotene into the lipid system. After 20 days of storage at 4 °C, the β-carotene retention rate was 81.43%. During simulated gastrointestinal digestion, β-carotene exhibited a relatively low release in the gastric phase, followed by increased release in the intestinal phase. Furthermore, βC-NL-1 exhibited higher hydroxyl and DPPH radical-scavenging activities than free β-carotene under the tested conditions. These findings demonstrate the potential of βC-NL-1 as a liposomal delivery system for β-carotene and provide a basis for further investigation of its application in functional foods.
Understanding drug–lipid interactions is essential for the rational design of lipid-based nanocarriers. Dapagliflozin (DAPA), a highly selective sodium–glucose cotransporter 2 (SGLT2) inhibitor with expanding therapeutic applications, represents an attractive candidate for lipid-based delivery systems; however, the physicochemical basis of its interactions with lipid membranes remains insufficiently understood. In this study, Langmuir monolayers and lipid vesicles were employed as complementary systems to investigate DAPA–lipid interactions and their modulation by the edge activator Tween 20. Langmuir monolayer experiments demonstrated that DAPA markedly affected lipid packing, compressional properties, and relaxation behavior. Importantly, these effects depended on the presence of Tween 20, revealing a composition-dependent interplay between the drug, lipids, and edge activator rather than independent effects of the individual components. The interfacial studies also showed that the role of Tween 20 cannot be described solely in terms of monolayer fluidization. DAPA-loaded liposomes and Tween 20-containing transferosomes exhibited high apparent encapsulation efficiencies. DAPA markedly altered the particle-size distributions of both formulations, producing a multimodal distribution in liposomes and shifting the predominant intensity-weighted population of transferosomes toward the micrometer range. AFM measurements further demonstrated pronounced changes in vesicle nanomechanics, with both DAPA and Tween 20 reducing stiffness and Young’s modulus relative to empty liposomes. Adhesion parameters increased when DAPA was encapsulated in the vesicles. Overall, the combined monolayer–vesicle approach reveals a composition-dependent interplay between DAPA, lipids, and Tween 20 that governs interfacial organization, particle-size distribution, and nanomechanical behavior. These findings highlight the importance of considering the drug as an active contributor to membrane properties rather than merely an encapsulated cargo and provide a physicochemical basis for further optimization of DAPA-containing transferosomal systems.
Background: Oily skin is not synonymous with acne. However, the skin surface lipid differences between healthy and acne-associated states within an oily-skin population remain insufficiently characterised. Objectives: To characterise compositional and structural differences in skin surface lipids (SSLs) between healthy and acne-associated unhealthy states among young women with oily skin. Methods: Sixty-six women aged 18-24 years with oily skin were enrolled, including 33 with healthy oily skin and 33 with mild-to-moderate acne-associated unhealthy oily skin. SSLs were analysed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with multivariate analysis, with emphasis on lipid abundance, fatty acyl chain length and unsaturation. Results: The two groups showed distinct SSL profiles. The acne-associated unhealthy oily skin group exhibited a lower relative abundance of saturated fatty acids, a higher relative abundance of unsaturated fatty acids and a reduced monounsaturated/polyunsaturated fatty acid ratio. Abundance-weighted mean chain lengths of fatty acids and triglycerides were reduced. Ceramides showed fatty acyl chain-length redistribution, with increased long-chain and decreased very-long-chain species. Phosphatidylserine and phosphatidylinositol were also increased. Conclusions: Acne-associated unhealthy oily skin in young women is characterised by multilayered lipid remodelling involving sebum-associated, barrier-related and membrane-associated lipids. Phosphatidylserinerelated alterations may represent a candidate lipid feature associated with deviation from healthy oily skin homeostasis.
The interaction of bioactive compounds with lipid membranes strongly influences their biological activity and selectivity. In this study, the interfacial behavior of an isovanillin derivative (1) was investigated using Langmuir monolayers of DPPC and DPPS as models of zwitterionic non-tumorigenic and anionic tumor-associated membranes, respectively. Surface pressure-area isotherms, surface compressional modulus, relaxation assays, PMIRRAS, and Brewster angle microscopy (BAM) were employed to evaluate the effects of the compound on monolayer organization and mechanics. (1) incorporated into both lipid monolayers at low surface pressures, promoting film expansion and perturbation of lipid packing. However, the interaction became strongly lipiddependent at membrane-relevant pressures. In DPPC monolayers, the compound remained more persistently associated with the interface, promoting monolayer condensation together with a reduction in compressional modulus, indicating formation of a more compact but mechanically softer film. PM-IRRAS and BAM analyses revealed perturbations in the phosphate, carbonyl, and acyl-chain regions accompanied by significant morphological heterogeneity. In contrast, DPPS monolayers exhibited a more dynamic interaction. Although expansion and softening effects were observed at low pressures, compression induced partial exclusion or redistribution of the compound from the anionic film, resulting in partial recovery of DPPS-like mechanical behavior at higher surface pressures. PM-IRRAS demonstrated strong perturbation of the phosphate and carbonyl regions together with increased acyl-chain disorder. Overall, the results demonstrate that the interaction of (1) with lipid monolayers is strongly governed by lipid headgroup chemistry, hydration, and packing state. The distinct behavior observed for DPPC and DPPS provides mechanistic insight into the lipid-dependent interfacial activity and possible selective biological effects of isovanillin derivatives.
Polymers such as Styrene Maleic Acid (SMA) have become valuable tools for studying membrane proteins within lipid bilayers due to their ability to solubilize membrane proteins in their native environments. However, limitations in the use of SMA copolymers have led to the development of SMA derivatives. In this study, we investigate the impact of the charge properties of several SMA derivatives on various lipid systems, which may also carry charges. We employed neutral, positively charged, and negatively charged SMA-derivative copolymers (SMA-Neut, SMA-Pos, SMA-AE, SMA Glu, and SMA-BZ30) to investigate their impact on bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), and a 9:1 molar ratio mixture of POPC and POPG. No single technique, however, is effective across the wide array of different MPs, and there are often significant discrepancies between structures determined by different methods if the protein's environment is far from a native lipid bilayer. In this study, we utilized biophysical techniques, including dynamic light scattering (DLS), electron paramagnetic resonance (EPR) spectroscopy, and solid-state nuclear magnetic resonance (ssNMR) spectroscopy, to analyze the interactions between polymers and lipid bilayers. Our EPR findings indicate that all the polymers preserved the POPC/POPG lipid bilayer. Meanwhile, our ssNMR result analysis suggests that neutral polymers may disrupt the bilayer less than charged polymers do. This implies that the electrostatic interactions between charged polymers and lipids can significantly alter the native environment of the bilayer, potentially impacting the stability and dynamics of encapsulated membrane proteins. Although this work primarily focuses on lipid systems, our results underscore the importance of considering polymer-lipid electrostatic interactions when selecting SMA derivatives and polymers for biophysical studies of membrane proteins, as the choice of polymer can profoundly affect the integrity and behavior of the lipid bilayer system.
