Multispectral bioactivity studies of N-terminal fatty acid modified antimicrobial peptide Andricin B.

A series of Andricin B derivatives were designed and synthesized using fatty acid modification at N-terminus of the antimicrobial peptides. The hydrophobicity of Andricin B was altered through fatty acid modification, and the bioactivity was investigated. The interaction between Andricin B and its derivatives with DNA was measured using multi-spectroscopy. Spectroscopic analysis revealed that Andricin B and its derivatives can interact with ct-DNA and G-quadruplexes DNA, and the interaction related with the length of fatty acid chain. Antimicrobial activity tests showed a significant increase using peptides with 8-10 carbons fatty acid chain. C10-Andricin B exhibited the highest antimicrobial activity, with up to a 16-fold enhancement compared to the original peptide Andricin B. Meanwhile, the protease hydrolysis stability test showed that fatty acid modification improved the stability of Andricin B against protease. Scanning electron microscopy results distinctly showed that C8-Andricin B could rupture the cell wall of bacteria. All results indicated that fatty acid modification peptides are an effective strategy for enhancing activity and stability of antimicrobial peptides. This research provides valuable insights for further research on antimicrobial peptides.

Bovine serum albumin as a nanocarrier for efficient encapsulation of hydrophobic garcinol-A strategy for modifying the in vitro drug release kinetics.

Garcinia indica, known as kokum, has been extensively researched for its therapeutic potential. Among the wide variety of phytoconstituents, garcinol is the most efficacious, holding anti-inflammatory, anti-cancer, and anti-diabetic properties. Hydrophobicity and a certain level of toxicity have constrained the drug's application and necessitated a modified dosage form design. The drug has been well explored in the form of extracts but bears very limited application in dosage forms. These prompted in implementation of protein polymers, due to non-toxicity, biocompatibility, and biodegradability. BSA encapsulates the drug, by the desolvation method. The unavailability of past exploration of garcinol with protein polymer accelerated the novelty of this study, to improve the solubility and bioavailability of the drug, modify the drug release kinetics, and ascertain the effectiveness of the NPs to combat inflammation in-vitro. NPs were characterized and satisfactory outcomes were retrieved in terms of all characterizations. The drug release studies depicted a sustained release of up to 85 % over 16 h, ensuring that garcinol can be modulated to give a desired scale of modified release. In vitro cellular uptake studies suggested a substantial uptake of NPs in cell lines and its effectiveness to mitigate inflammation was affirmed by in-vitro anti-inflammatory studies, using ELISA.

Multiscale Tunable Nanorings Based on Bi-Component Micellar-Configuration-Transformation Induced by Hydrophobicity.

Ringy nanostructures are amazing materials, displaying unique optical, magnetic, and electronic properties highly related to their dimensions. A strategy capable of continuously tailoring the diameter of nanorings is the key to elucidating their structure-function relationship. Herein, a method of bi-component micellar-configuration-transformation induced by hydrophobicity for the synthesis of nanorings with diameters ranging from submicron (≈143 nm) to micron (≈4.8 µm) and their carbonaceous analogs is established. Remarkably, the nanorings fabricated with this liquid phase strategy achieve the record for the largest diameter span. Through varying the molecular lengths of fatty alcohols and copolymers, shortening the molecular length of fatty alcohol can swell the primary micelles, improve the exposure of hydrophobic component and boost the assembly kinetics for ultra-large nanorings is shown here. On the other hand, shortening the molecular length of the copolymer will give rise to ultra-small nanorings by reducing the size of primary micelles and shortening the assembly time. When assembling the nanorings into monolayer arrays and then depositing Au, such substrate displays enhanced surface-enhanced Raman scattering (SERS) performance. This research develops a facile method for the controllable synthesis of ringy materials with multiscale tunable diameters and may inspire more interesting applications in physics, optical, and sensors.

Substrates with Tunable Hydrophobicity for Optimal Cell Adhesion.

Electrospinning is a technique used to create nano/micro-fibrous materials from various polymers for biomedical uses. Polymers like polycaprolactone (PCL) are commonly used, but their hydrophobic properties can limit their applications. To enhance hydrophilicity, nonionic surfactants such as sorbitane monooleate (Span80) and poloxamer (P188) can be added to the PCL electrospinning solution without altering its net charge density. These additions enable the successful production of PCL/P188 and PCL/Span80 fibrous substrates. In this study, P188 and Span80 are incorporated into the PCL solutions; they are successfully electrospun into PCL/P188 and PCL/Span80 substrates, respectively. PCL/P188 substrates show that until a specific P188 concentration, fiber and pore sizes are similar to PCL substrates. However, exceeding 0.30% P188 concentration enlarges fibers, impacting fiber uniformity at higher concentrations. Conversely, higher concentrations of Span80 result in thicker, less uniform fibers, indicating potential disruptions in the electrospinning process. Notably, both surfactants significantly improve substrate hydrophilicity, enhancing the adhesion and proliferation of fibroblasts, endothelial cells, and smooth muscle cells. P188, in particular, shows superior efficacy in promoting cell adhesion and growth at concentrations optimized for different cell types. Therefore, precise surfactant concentrations in the electrospinning solution can lead to the optimization of electrospun substrates for tissue engineering applications.

Endowing Three-Dimensional Porous Wood with Hydrophobicity/Superhydrophobicity Based on Binary Silanization.

Wood, as a natural biomass material, has long been a research focus. Superhydrophobic modified wood, in particular, has shown great promise in a myriad of engineering applications such as architecture, landscape, and shipbuilding. However, commercial development has encountered significant resistance due to preparation difficulties and sometimes unsatisfactory performance. In this study, hydrophobic/superhydrophobic wood comodified with methyltrimethoxysilane (MTMS) and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PFDTMS) was fabricated by a one-step sol-gel method that uses an in situ growth process. Low-molecular-weight MTMS was allowed to permeate the three-dimensional porous wood interior. Then, acid-base catalysts were used to regulate the hydrolytic condensation process of MTMS and PFDTMS composite silanes to generate micro/nano hierarchical structures with low surface energy on the wood surface. The physicochemical characteristics of modified wood were investigated and the reaction mechanism established. The modified wood displayed excellent internal hydrophobicity/surface superhydrophobicity, water-moisture resistance, and dimensional stability at low fluorine concentrations. The resulting superhydrophobic surface provided stain resistance, self-cleaning ability, and loading capacity in water while exhibiting good mechanochemical stability; wood mechanical strength was also enhanced. This methodology created a superhydrophobic surface and bulk hydrophobization of wood in one step. Beyond wood, this approach is expected to provide a promising approach for functional modification of other porous composite materials.

Ultrasensitive detection of contaminants in milk using a novel NMS-Ag modified water-resistant paper substrate.

Rapid and precise detection of harmful substances in food products is essential for ensuring public health and safety. This study introduces a novel surface-enhanced Raman spectroscopy (SERS) substrate, composed of a molybdenum disulfide­silver nanocomposite, applied to flexible, water-resistant filter paper for detecting melamine and bisphenol A (BPA) in milk. Optimized molybdenum disulfide (NMS) nanoflowers (NFs) were synthesized through hydrothermal methods and high-temperature annealing, then modified with silver (Ag) nanoparticles to form the NMS-Ag nanocomposite (NMSA6). This substrate greatly enhances the Raman signal, achieving an enhancement factor of approximately 1.49 × 107 and a detection limit as low as 10-11 M for simultaneous multi-component analysis. Finite-difference time-domain (FDTD) simulations confirm the enhancement mechanism. The NMSA6 substrate demonstrates remarkably low detection limits for BPA and melamine, facilitating the analysis of various hazardous substances. These findings highlight the substrate's potential for highly sensitive, label-free detection, presenting a viable tool for food safety monitoring.

Macro and micro enhancers of the 8-anilino-1-naphthalenesulfonate (ANS) fluorescence. Is ANS indeed a hydrophobic probe?

A study on the absorption and fluorescence properties of the 8-anilino-1-naphthalenesulfonate (ANS) fluorescent probe was performed in order to (i) verify the validity of its classification as hydrophobic probe and (ii) to assess the reliability of the interpretation of the ANS fluorescence enhancement upon protein binding as the evidence for the existence of hydrophobic binding sites on the protein molecules. We observed an enhancement of the ANS fluorescence in hydrophilic media: DMSO, polyethylene glycol (PEG400) and glycerol to the values characteristic of ANS complexes with globular proteins, and all ANS fluorescence characteristics (except anisotropy) in PEG400 and in complex with bovine serum albumin are identical. We observed an increase in the ANS fluorescence with a nonzero anisotropy in an aqueous medium in the presence of an amphiphilic cetyltrimethylammonium cation as a result of the formation of the 1:1 complex with ANS. Water molecules quench the fluorescence of ANS. The enhancement of the ANS fluorescence in aqueous media in the presence of fluorescence enhancers is accounted for by their blocking the access of water molecules to the region close to the excited ANS molecule, which is critical for the fluorescence.

Preparation and characterization of acetate cellulose electrospun nanofibers membrane: Potential application on wastewater treatment.

Development of nanofiber membranes with the ability to remove organic dye such as Indigo Carmine (IC) from effluent wastewater is of immense help to the textile industry. In the present study, we investigate the preparation of cellulose acetate (CA) nanofiber membranes with optimized performances using electrospinning technique for effective removal of Indigo Carmine (IC) dye. Electrospinning parameters and solvent system containing acetic acid were adjusted to obtain CA nanofibers membranes which better suits dye removal application. The obtained nanofiber membranes were characterized using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR) and contact angle analysis. Results show that nanofiber webs with optimized electrospinning parameters were continuously formed and are substantially free of defects such as beading, with an average diameter of 950 ± 50 nm. Hydrophobicity of membranes were successfully modified and showed important increase of contact angle values from 37° to 107°. The stirring time was varied to improve the solution homogeneity and consequently the response of membranes in filtration treatment. The CA membranes performance was evaluated through water flux and permeability measurement and tested on IC dye removal. The results showed a rate of dye removal around 83 % and a maximum adsorption capacity (Qm) of 13.09 mg/g for the optimized CA membranes.

Electroreduction of CO to 2.8 A cm⁻2 C2+ Products: Maximizing Efficiency with Minimalist Electrode Design Featuring a Mesopore-Rich Hydrophobic Copper Catalyst Layer.

This work shows how hydrophobicity and porosity can be incorporated into copper catalyst layers (CLs) for the efficient electroreduction of CO (CORR) in a flow cell. Oxide-derived (OD) Cu catalysts are synthesized using K+ and Cs+ as templates, termed respectively as OD-Cu-K and OD-Cu-Cs. CLs, assembled from OD-Cu-K and OD-Cu-Cs, exhibit enhanced CORR performance compared to "unmodified" OD-Cu CL. OD-Cu-Cs can notably reduce CO to C2+ products with Faradaic efficiencies (FE) as high as 96% (or 4% FE H2). During CO electrolysis at -3000 mA cm-2 (-0.73 V vs reversible hydrogen electrode), C2+ products and the alcohols are formed with respective current densities of -2804 and -1205 mA cm- 2. The mesopores in the OD-Cu-Cs CL act as barriers against electrolyte flooding. Contact angle measurements confirm the CL's hydrophobicity ranking: OD-Cu-Cs > OD-Cu-K > OD-Cu. The enhanced hydrophobicity of a catalyst is proposed to allow more triple-phase (CO-electrolyte-catalyst) interfaces to be available for CORR. This study shows how the pore size-hydrophobicity relationship can be harvested to guide the design of a less-is-more Cu electrode, which can attain high CORR current density and selectivity, without the additional use of hydrophobic polytetrafluoroethylene particles or dopants, such as Ag.

Chitosan nanocoatings N-acylated with decanoic anhydride: Hydrophobic, hygroscopic and structural properties.

Thin (ca. 340 nm) chitosan coatings were deposited onto glass substrates via dip-coating, then modified with the methanol solution of decanoic anhydride (0.17-56 mM). NMR, FTIR and XPS measurements confirmed that the acylation degree increased from 18 % to 45 %, and at the highest degree, the whole layer was acylated homogeneously by the reagent molecules. The coating thickness increased (up to 60 %), and the refractive index decreased (from 1.541 to 1.532) due to the acylation, that was determined by UV-visible spectroscopy. The AFM did not reveal morphological changes, but wetting tests showed that the acylation rendered the coating hydrophobic (water contact angle increased from ca. 75° to 100°). The contact angle, however, decreased to 85° due to the development of a second molecular layer of the decanoic acid by-product at the highest (over 25 mM) reagent concentrations. XRD studies showed a self-assembling structuring of the alkyl-chains in the bulk phase, which occurred in the case of the highest degree of acylation. This also manifested itself in a significant decrease of the layer hygroscopicity: the swelling degree decreased from 40 % to 8 % in a saturated water atmosphere monitored by spectroscopic ellipsometry.

Effect of different chain-length fatty acids on the retrogradation properties of rice starch.

In order to delay the retrogradation of rice starch, the effects of three different chain length fatty acids (lauric acid, myristic acid and palmitic acid) on rice starch were studied. The fatty acids with longer carbon chains had strong steric hindrance and hydrophobicity, which formed a more compact structure in the helical cavity of amylose, and significantly reduced degree of expansion, migration of water, short-range ordered structure, number of double helical structures and crystallinity. These structural changes endowed the rice starch-long chain fatty acid complexes with better gel viscosity, liquid fluidity and thermal stability than in the rice starch-short chain fatty acid complexes. The results showed that fatty acids with longer chain length inhibited the retrogradation of rice starch, most obviously when 5% palmitic acid was added. This study provides an important reference for the processing of rice starch-based foods.

Novel Approach for the Preparation of a Highly Hydrophobic Coating Material Exhibiting Self-Healing Properties.

A concept to prepare a highly hydrophobic composite with self-healing properties has been designed and verified. The new material is based on a composite of a crystalline hydrophobic fluoro wax, synthesized from montan waxes and perfluoroethylene alcohols, combined with spherical silica nanoparticles equipped with a hydrophobic shell. Highly repellent layers were prepared using this combination of a hydrophobic crystalline wax and silica nanoparticles. The novel aspect of our concept was to prepare a ladder-like structure of the hydrophobic shell allowing the inclusion of a certain share of wax molecules. Wax molecules trapped in the hydrophobic structure during mixing are hindered from crystallizing; therefore, these molecules maintain a higher mobility compared to crystallized molecules. When a thin layer of the composite material is mechanically damaged, the mobile wax molecules can migrate and heal the defects to a certain extent. The general preparation of the composite is described and XRD analysis demonstrated that a certain share of wax molecules in the composite are hindered to crystallize. Furthermore, we show that the resulting material can recovery its repellent properties after surface damage.

Direct Acrylation of Soybean Oil and the Influence of the Acrylation Degree on Waterborne Acrylic Systems.

The direct acrylation of soybean oil was investigated by the activation of soybean oil's (SO's) internal fatty unsaturation with acidic catalysts. The effect of the catalyst and the reactant ratio with respect to the unsaturation and reaction time on the direct acrylation process were explored. ASO (acrylated soybean oil) with acrylation degrees (the number of acrylate molecules introduced in a triglyceride molecule) between 1.6 and 2.55 were obtained. The effect of the ASO acrylation degree on copolymerization processes was investigated. The resulting monomers were successfully copolymerized with meth(acrylate) monomers by the miniemulsion polymerization process, favoring the droplet nucleation mechanism and showing conversions higher than 97%. The acrylic-ASO copolymers presented lower Tg and higher hydrophobicity and oleophobicity than the acrylic copolymer.

Coarse-Grained Molecular Dynamics Simulation of Heterogeneous Polysorbate 80 Surfactants and their Interactions with Small Molecules and Proteins.

Polysorbate 80 (PS80) is widely used in pharmaceutical formulations, and its commercial grades exhibit certain levels of structural heterogeneity. The objective of this study was to apply coarse-grained molecular dynamics simulations to better understand the effect of PS80 heterogeneity on micelle self-assembly, the loading of hydrophobic small molecules into the micelle core, and the interactions between PS80 and a protein, bovine serum albumin (BSA). Four representative PS80 variants with different head and tail structures were studied. Our simulations found that PS80 structural heterogeneity could affect blank micelle properties such as solvent-accessible surface area, aggregation number, and micelle aspect ratio. It was also found that hydrophobic small molecules such as ethinyl estradiol preferentially partitioned into the PS80 micelle core and PS80 dioleates formed a more hydrophobic core compared to PS80 monooleates. Furthermore, multiple PS80 molecules could bind to BSA, and PS80 heterogeneity profoundly changed the binding ratio as well as the surfactant-protein contact area.

Enhancing Esthetics in Direct Dental Resin Composite: Investigating Surface Roughness and Color Stability.

Dental restorations must replicate the natural appearance of teeth while ensuring biocompatibility and durability. This study evaluated the surface characteristics and color stability of three dental composites-Herculite Ultra XRV, G-ænial A'CHORD, and Omnichroma-exposed to acidic beverages (red wine, black coffee, and Coca-Cola). Sixty disk-shaped specimens were prepared, polished, and immersed in these beverages. Surface roughness was assessed using profilometry and SEM analysis, hydrophobicity via contact angle analysis, and surface charge through streaming potential measurements. Color stability was evaluated using a spectrophotometer, and the pH levels of the solutions were recorded. Results showed that Herculite Ultra XRV had the highest mean contact angle (79.46° ± 6.52), indicating superior hydrophobicity, while Omnichroma had the lowest (64.94° ± 3.08), indicating more hydrophilicity. Significant color changes were observed, especially in black coffee, with ∆E values indicating notable discoloration. The acidic pH of the solutions increased surface roughness and color changes. Statistical analyses confirmed significant increases in surface roughness and color change for all composites, with the nanohybrid resin composite showing the greatest variability. These findings highlight the need for dental restorative materials with enhanced resistance to acidic environments to improve the longevity and esthetics of dental treatments.

Effects of E-Liquids and Their Aerosols on Biofilm Formation and Growth of Oral Commensal Streptococcal Communities: Effect of Cinnamon and Menthol Flavors.

(1) Background: The rise in electronic cigarette (E-cigarette) popularity, especially among adolescents, has prompted research to investigate potential effects on health. Although much research has been carried out on the effect on lung health, the first site exposed to vaping-the oral cavity-has received relatively little attention. The aims of this study were twofold: to examine the effects of E-liquids on the viability and hydrophobicity of oral commensal streptococci, and the effects of E-cigarette-generated aerosols on the biomass and viability of oral commensal streptococci. (2) Methods: Quantitative and confocal biofilm analysis, live-dead staining, and hydrophobicity assays were used to determine the effect on oral commensal streptococci after exposure to E-liquids and/or E-cigarette-generated aerosols. (3) Results: E-liquids and flavors have a bactericidal effect on multispecies oral commensal biofilms and increase the hydrophobicity of oral commensal streptococci. Flavorless and some flavored E-liquid aerosols have a bactericidal effect on oral commensal biofilms while having no effect on overall biomass. (4) Conclusions: These results indicate that E-liquids/E-cigarette-generated aerosols alter the chemical interactions and viability of oral commensal streptococci. Consequently, the use of E-cigarettes has the potential to alter the status of disease and health in the oral cavity and, by extension, affect systemic health.

Construction of a durable, halogen-free, and phosphorus-free flame retardant cotton fabric system with hydrophobic properties by phase separation and interface polymerization.

Inspired by the synthesis of polyurethane, a multifunctional fabric with hydrophobic and long-lasting flame retardancy was prepared through the phase separation and interfacial reaction process between PEI (polyethyleneimine)/BX (borax) aqueous solution and isocyanate terminated polydimethylsiloxane (PDMS-NCO) in tetrahydrofuran solution. The limit oxygen index of the treated fabric increased from 18.0 % to 33.7 %, and the total heat release decreased by 34.2 %. The enhancement of flame retardant performance and thermal stability is attributed to the enhanced char-forming capacity. After 50 cycles of water washing, the cotton fabric can still pass the vertical flammability test because of the curing effect of PDMS-NCO on functional additives. Furthermore, SEM analysis revealed that the formation of nano-rough structures on the fibers was promoted by phase separation, thus leading an increased water contact angle of sample to 139°. The materials utilized in this modified process do not contain elements such as F, Cl, Br, and P, indicating its potential as an environmentally friendly methodology for fabric functionalization.

Triphase Enzyme Electrode Based on ZIF-8 with Enhanced Oxidase Catalytic Kinetics and Bioassay Performance.

Oxidase enzyme-based electrochemical bioassays have garnered considerable interest due to their specificity and high efficiency. However, in traditional solid-liquid diphase enzyme electrode systems, the low solubility of oxygen and its slow mass transfer rate limit the oxidase catalytic reaction kinetics, thereby affecting the bioassay performance, including the detection accuracy, sensitivity, and linear dynamic range. ZIF-8 nanoparticles (NPs) possess hydrophobic and high-porosity characteristics, enabling them to serve as oxygen nanocarriers. In this work, we constructed a solid-liquid-air triphase enzyme electrode by encapsulating ZIF-8 NPs within an oxidase network. Hydrophobic ZIF-8 NPs can provide a rapid and sufficient supply of oxygen for the oxidase-catalyzed reactions, which enhances and stabilizes the kinetics of oxidase-catalyzed reactions. This approach eliminates the issue of "oxygen deficiency" at the traditional solid-liquid diphase interface. Consequently, the triphase enzyme electrode exhibits a 12-fold higher linear detection range than the diphase system and possesses good detection accuracy in electrolytes even with fluctuating oxygen levels. This work proposes a novel approach to construct triphase reaction systems for addressing the gas deficiency problem in heterogeneous catalysis.

The dynamic ethylene adsorption on carbon xerogels as a three-way game between porosity, surface chemistry and humidity.

Novel carbon xerogels doped with heteroatoms (O, N, S) were prepared by sol-gel polymerization of resorcinol with heterocyclic aldehydes containing them. All doped materials presented higher O-contents than the reference material prepared with formaldehyde, and significant S- or N-loadings in the corresponding samples. Carbon xerogels were micro-mesoporous and N-doping favoured the formation of mesopores. Their efficiency in the dynamic ethylene adsorption is presented as an interplay between porosity, surface chemistry and humidity. The surface hydrophilicity was also studied by water adsorption assays, a quick adsorption being favoured in microporous samples with hydrophilic O-groups. Breakthrough curves for ethylene adsorption were recorded in both dry and humid conditions and analysed according to the mass transference zone (MTZ). The material behaviour was correlated with the physicochemical properties, elucitating the mechanism of the simultaneous water/ethylene adsorption. The adsorption capacity depended linearly on the microporous characteristics of samples; however, MTZ parameters (efficiency of the column) varied linearly with the electronegativity of the dopant element. Both doping and humidity in the stream hindered the ethylene adsorption kinetic and capacity (up to 33% for N-doped material under humidity compared to undoped-material under dry conditions), due to reduced adsorbate-adsorbent interactions and the accessibility into narrow pores.

Oral formulations for highly lipophilic drugs: Impact of surface decoration on the efficacy of self-emulsifying drug delivery systems.

AIM: To evaluate the impact of the surface decoration of cannabidiol (CBD) loaded self-emulsifying drug delivery systems (SEDDS) on the efficacy of the formulations to cross the various barriers faced by orally administered drugs. METHODS: Polyethylene glycol (PEG)-free polyglycerol (PG)-based SEDDS, mixed zwitterionic phosphatidyl choline (PC)/PEG-containing SEDDS and PEG-based SEDDS were compared regarding stability against lipid degrading enzymes, surface properties, permeation across porcine mucus, cellular uptake and cytocompatibility. RESULTS: SEDDS with a size of about 200 nm with narrow size distributions were developed and loaded with 20-21 % of CBD. For PG containing PEG-free SEDDS increased degradation by lipid degrading enzymes was observed compared to PEG-containing formulations. The surface hydrophobicity of placebo SEDDS increased in the order of PG-based to mixed PC/PEG-based to PEG-based SEDDS. The influence of this surface hydrophobicity was also observed on the ability of the SEDDS to cross the mucus gel layer where highest mucus permeation was achieved for most hydrophobic PEG-based SEDDS. Highest cellular internalization was observed for PEG-based Lumogen Yellow (LY) loaded SEDDS with 92 % in Caco-2 cells compared to only 30 % for mixed PC/PEG-based SEDDS and 1 % for PG-based SEDDS, leading to a 100-fold improvement in cellular uptake for SEDDS having highest surface hydrophobicity. For cytocompatibility all developed placebo SEDDS showed similar results with a cell survival of above 75 % for concentrations below 0.05 % on Caco-2 cells. CONCLUSION: Higher surface hydrophobicity of SEDDS to orally deliver lipophilic drugs as CBD seems to be a promising approach to increase the intracellular drug concentration by an enhanced permeation through the mucus layer and cellular internalization.