Hydrophobic Chain Length Research Articles

Insight into the Antibacterial Activities of Pyridinium-Based Cationic Pillar[5]arene with Controllable Hydrophobic Chain Lengths against Staphylococcus aureus.

The increasing number of infections caused by pathogenic bacteria has severely affected human society. More and more deaths were originated from Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) infection each year. The potential and excellent bacteriostatic activity and resistance to biofilm formation of pillar[5]arene with different functional groups attract important attention to further study the relationship between antimicrobial activity and cytotoxicity by varying the length of the hydrophobic chain, the number of positive charges, and the hydrophobic/hydrophilic balance of the molecule. In this work, four pyridinium-based cationic pillar[5]arene (PPs) with linear aliphatic chains of different lengths were synthesized. After systematic characterization, their inhibition activities against S. aureus were investigated. It revealed that PP6 (six methylenes in each linker) exhibited excellent inhibition activity against S. aureus (ATCC 6538) with a minimum inhibitory concentration (MIC) of 3.91 μg/mL and a minimum bactericidal concentration (MBC) of 62.50 μg/mL. As expected, PP6 exhibited the strongest antibiofilm ability and negligible antimicrobial resistance even after the 20th passage. A study of the action mechanism of selected PPs on the bacterial membrane depolarization and permeability by transmission electron microscopy (TEM) disclosed that the cationic pyridine groups of PPs inserted into the negatively charged bacterial membranes, thereby leading to membranolysis, cytoplasmic content leakage, and cell death. Importantly, PPs all showed very low toxicity to mammalian cells (L929 and HBZY-1), which provided a significant reference for the construction of hypotoxic antibacterial biomaterials for multiple drug-resistant bacteria based on pyridinium-grafted cationic macrocycles with controllable hydrophobic chain lengths.

Impacts of hydrophobic chain length on foam stability and CO2 geo-sequestration capacity of sugar-based nonionic surfactants: Molecular dynamics simulation and laboratory experiments

Impacts of hydrophobic chain length on foam stability and CO2 geo-sequestration capacity of sugar-based nonionic surfactants: Molecular dynamics simulation and laboratory experiments

Probing the Influence of Hydrophobicity of Modified Gold Nanoparticles in Modulating the Lipid Surface Behavior Using Vibrational Sum Frequency Generation Spectroscopy.

A deep understanding of how the surface modifications of nanoparticles impact their interactions with cell membranes is vital for advancing safe and effective biomedical applications. Among the pivotal factors governing these interactions, the hydrophobicity of nanoparticles plays a crucial role, predominantly driven by the hydrophobic interactions with the cell membrane. Herein, we study the influence of the hydrophobic alkyl chain length of thiol-capped gold nanoparticles (GNPs) on lipid surfaces with the help of vibrational sum frequency generation spectroscopy. We have utilized the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer as a representative model of cell membranes on the water surface. Our findings revealed that GNPs capped with the thiol ligand having a shorter alkyl chain such as heptanethiol (HT, C7) show minimal changes in the C-H stretching vibrations while interacting with the lipid monolayer. These observations could be attributed to the perturbation of the lipid chain due to hydrophobic-hydrophobic interactions between the alkyl chain of thiol-capped GNPs and the hydrophobic group of the lipid membrane or simply by the adsorption of GNPs at the interface without disrupting the monolayer structure. However, with increasing the chain length of thiol-capped GNPs from decanethiol (DDT, C10) to octadecanethiol (ODT, C18), the extent of spectral change in the C-H stretching vibration is increased. The controlled experiment performed with the deuterated lipids conforms that the changes observed in the C-H stretching vibration after adding HT (C7) GNPs are only because of their presence in the surface without altering the monolayer structure. However, in the case of DT (C10) and DDT (C12) GNPs, the strong hydrophobic interactions between the monolayer and the alkyl chain of the thiol-capped GNPs result in the increased orientational order of the monolayer. Moreover, in the case of ODT (C18) GNPs, the very long alkyl chain induces pronounced perturbations in the monolayer structure with net disordering of the monolayer. These observations are further supported by the spectral changes observed in the O-H vibration of the interfacial water molecules. Our findings reveal the crucial role of the hydrophobic nature of GNPs in influencing the interface. Understanding these effects is crucial for drug delivery applications and improving the stability and effectiveness of lipid-based systems.

Influence of hydrophobic groups in polyglycerol ester emulsifier at oil-polyol interface: Interfacial adsorption behavior and its relationship with emulsification effect

This study investigated the variance in adsorption behavior of polyglycerol emulsifiers at the oil- polyol interface and its consequential impact on emulsion properties and stability. The critical micelle concentration (CMCIFT), saturation adsorption capacity (Γ∞), and Langmuir constant (κ) of the emulsifier were determined through measurements of dynamic interfacial tension between glycerol and mineral oil with varying hydrophobic chains. Results indicated that the CMCIFT exhibits an increase corresponding to the rising number of hydrophobic chains. Emulsifiers with differing initial particle sizes were synthesized, and the actual emulsifying area (SA), theoretical covering area (ST), and emulsifying index (EI) at the interface were calculated. Variations in coverage rate led to disparate adsorption behavior and arrangement of the emulsifier at the interface, thereby impacting emulsion stability. This study establishes a theoretical foundation for predicting the stability trend of polyol/oil (P/O) emulsions.

Synthesis of Newly Ester Type Gemini Cationic Surfactants: Surface Properties, Fabric Softness and Antibacterial Properties

AbstractFour ester cationic Gemini surfactants (EDQ‐n, n represents the carbon number in the raw fatty acid of 12, 14, 16 and 18) were synthesized from fatty acid, N, N‐dimethylethanolamine and 1, 4‐dibromobutane by two‐step reaction of esterification and quaternization. Their surface activities at air/water interface were investigated. The application performance such as water solubility, antistatic property, fabric softness, fabric whiteness, biodegradability, and antibacterial activities were tested and compared with traditional quaternary ammonium salt. The results showed that the γcmc increases with increasing the hydrophobic chain length and EDQ‐12 presented the highest surface activity. The diffusion coefficients calculated from the Ward‐Tordai equation indicates the adsorption process is a mixed‐diffusion kinetic adsorption mechanism. The water solubility of EDQ‐n is higher than dioctadecyl dimethyl ammonium chloride (D1821) and ester quaternary ammonium salt (Esterquats). The fabric softness and whiteness properties of EDQ‐16 and EDQ‐18 are similar to D1821 and Esterquats, which can significantly reduce the cotton fabric softness and have no significant difference in whiteness retention. EDQ‐n demonstrated more readily biodegradation(>90 %) than D1821(0 %) after seven days. In addition, EDQ‐12 and EDQ‐14 show excellent antibacterial activities against Staphylococcus aureus and Escherichia coli in comparison with conventional bacteriostatic agent didecyl dimethyl ammonium chloride (DDAC).

Spatiotemporal coordination of antigen presentation and co-stimulatory signal for enhanced anti-tumor vaccination

Controlled-release systems enhance anti-tumor effects by leveraging local antigen persistence for antigen-presenting cells (APCs) recruitment and T cell engagement. However, constant antigen presentation alone tends to induce dysfunction in tumor-specific CD8+ T cells, neglecting the synergistic effects of co-stimulatory signal. To address this, we developed a soft particle-stabilized emulsion (SPE) to deliver lipopeptides with controlled release profiles by adjusting their hydrophobic chain lengths: C6-SPE (fast release), C10-SPE (medium release), and C16-SPE (slow release). Following administration, C6-SPE release antigen rapidly, inducing early antigen presentation, whereas C16-SPE's slow-release delays antigen presentation. Both scenarios missed the critical window for coordinating with the expression of CD86, leading to either T cell apoptosis or suboptimal activation. In contrast, C10-SPE achieved a spatiotemporally synergetic effect of the MHC-I-peptide complex and co-stimulatory signal (CD86), leading to effective dendritic cell (DC) activation, enhanced T cell activation, and tumor regression in EG7-OVA bearing mice. Additionally, co-delivery of cytosine-phosphate-guanine (CpG) with SPE provided a sustained expression of the CD86 window for DC activation, improving the immune response and producing robust anti-tumor effects with C6-SPE comparable to C10-SPE. These findings highlight that synchronizing the spatiotemporal dynamics of antigen presentation and APC activation may confer an optimal strategy for enhanced vaccinations.

Photophysical Response of Propranolol in Biomimetic Micellar Media of Alkyltrimethylammonium Bromide Surfactants: Effect of pH and Alkyl Chain Length.

The photophysical behavior of a β-blocker drug propranolol (PPL) in micellar environments, formed by alkyltrimethylammonium bromide surfactants viz.; Cetyltrimethylammonium bromide (CTAB), Tetradecyltrimethylammonium bromide (TTAB), and Dodecyltrimethylammonium bromide (DTAB), has been investigated through fluorescence and UV-visible spectroscopic techniques at pH levels of 3.5, 7.4, and 10.4. The impact of pH on the critical micelle concentration (cmc) and micropolarity of micelles were assessed using pyrene as a photophysical probe. The cmc values were found to be lower at pH 10.4 compared to pH 7.4 and pH 3.5. Fluorescence emission intensities of PPL at 323nm, 338nm, and 352nm were significantly influenced by pH, hydrophobic alkyl chain length of surfactants, and their concentrations. Quenching experiments with Cetylpyridinium chloride (CpCl) indicated the localization of charged and uncharged forms of PPL within micelles, with quenching constant (Ksv) values dependent on alkyl chain length and pH. At pH < pKa, PPL is positioned near the Stern layer, whereas at pH 10.4, its naphthalene moiety resides near the hydrophobic micellar core. UV spectroscopy showed that the charged form of PPL interacted with micelles only above cmc, while the neutral form interacted even below the cmc. Density Functional Theory (DFT) reveals the HOMO of the surfactants to be localized on the hydrocarbon chains, and the LUMO localized around the quaternary ammonium unit. Upon complexation with PPL, both HOMO and LUMO shifted to the drug, thereby decreasing energy levels. The findings are explained based on weak noncovalent interactions, further supported and analyzed through Reduced Density Gradient (RDG) and Noncovalent Interaction (NCI) methods, confirming synergistic non-covalent interactions in surfactant-PPL complexes.

Dissipative particle dynamics simulation and experimental studies of pseudo-gemini surfactants with different hydrophobic chain lengths

In this work new pseudo-gemini type surfactants are constructed via a simple, energy and material efficient way, using piperazine, propylene oxide and seven different fatty acids: capric, lauric, myristic, stearic, oleic and linolenic. The compounds are characterized by 1H NMR, 13C NMR and FTIR studies. Micellization and adsorption properties of the novel pseudo-gemini surfactants are investigated via surface tension and conductivity measurements. Antimicrobial properties are evaluated using the simple disk diffusion test method. Dissipative Particle Dynamics (DPD) simulations are performed to model aggregation behavior of the new pseudo-gemini surfactants. Experimental studies revealed that Critical Micelle Concentration (CMC) of the obtained pseudo-gemini surfactants are lower than 1 mmol/L. Theoretically calculated CMC values are slightly higher than experimental CMC values. However, overall, very good agreement between theoretical and experimental CMC values is observed. Radial Distribution Function (RDF) and radius of gyration (Rg) plots are analyzed to gain further insight into aggregation of the surfactant molecules in aqueous environment. The DPD model of the pseudo-gemini amphiphiles successfully predicts the most important traits of the aggregation process.

Modulating lipid bilayer permeability and structure: Impact of hydrophobic chain length, C-3 hydroxyl group, and double bond in sphingosine

Sphingosine, an amphiphilic molecule, plays a pivotal role as the core structure of sphingolipids, essential constituents of cell membranes. Its unique capability to enhance the permeability of lipid membranes profoundly influences crucial life processes. The molecular structure of sphingosine dictates its mode of entry into lipid bilayers and governs its interactions with lipids, thereby determining membrane permeability. However, the incomplete elucidation of the relationship between the molecular structure of sphingosine and the permeability of lipid membranes persists due to challenges associated with synthesizing sphingosine molecules. A series of sphingosine-derived molecules, featuring diverse hydrophobic chain lengths and distinct headgroup structure, were meticulously designed and successfully synthesized. These molecules were employed to investigate the permeability of large unilamellar vesicles, functioning as model lipid bilayers. With a decrease in the hydrophobic chain length of sphingosine from C15 to C11, the transient leakage ratio of vesicle contents escalated from ∼ 13 % to ∼ 28 %. Although the presence of double bond did not exert a pronounced influence on transient leakage, it significantly affected the continuous leakage ratio. Conversely, modifying the chirality of the C-3 hydroxyl group gives the opposite result. Notably, methylation at the C-3 hydroxyl significantly elevates transient leakage while suppressing the continuous leakage ratio. Additionally, sphingosines that significantly affect vesicle permeability tend to have a more pronounced impact on cell viability. Throughout this leakage process, the charge state of sphingosine-derived molecule aggregates in the solution emerged as a pivotal factor influencing vesicle permeability. Fluorescence lifetime experiments further revealed discernible variations in the effect of sphingosine molecular structure on the mobility of hydrophobic regions within lipid bilayers. These observed distinctions emphasize the impact of molecular structure on intermolecular interactions, extending to the microscopic architecture of membranes, and underscore the significance of subtle alterations in molecular structure and their associated aggregation behaviors in governing membrane permeability.

Enhancement of antifouling and mechanical properties of polysulfone membrane using zwitterionic biphenyl polyimide as additive

Biphenyl polyimides, which are known by its excellent heat resistance and mechanical properties, were synthesized by adjusting the molar ratio of monomers, followed by end-functionalized with zwitterionic group via reaction with 1,3-propanesultone. The zwitterionic sulfobetaine biphenyl polyimide (z-biph-PI) copolymers with different hydrophobic chain lengths were employed as the additive for the preparation of polysulfone (PSf) membrane. X-ray photoelectron spectrometry (XPS) measurement on membrane surfaces revealed that the sulfobetaine groups of z-biph-PI migrated toward water in the membrane formation process, during which a large amount of porous, narrow and densely packed pores were created as illustrated in scanning electron microscopy (SEM) images. Therefore, the incorporation of z-biph-PI simultaneously enhanced the pure water flux and protein rejection ratio of membranes, overcoming the trade-off effects between permeability and selectivity. The adsorption of bovine serum albumin decreased from ∼47.7 μg/cm2 for the pristine membrane to a minimum of ∼12.4 μg/cm2 for the blend membrane. More importantly, the tensile strength and elongation at break were also simultaneously improved due to the unique mechanical property of biph-PI and the strong π-π interaction between biphe-PI and PSf. Meanwhile, the blend membrane exhibited excellent filtration and thermal stability. All these characteristics of the blend membrane made it promising in ultrafiltration application.

The aggregation structure and rheological properties of catanionic surfactant mixtures and potential applications in fracturing fluids

Clean fracturing fluids are widely used in reservoir stimulation and increasing production due to their characteristics of simple preparation, no residue, easy flowback, and low damage. At present, clean fracturing fluids are mainly prepared by cationic surfactants as main agent and inorganic or organic salts as additives, which can lead to unavoidable losses of cationic surfactants due to their adsorption in the formation. Anionic-cationic surfactants composite system can not only compensate for the shortcomings of a single surfactant system, but also improve the reservoir adaptability of the surfactant system. In this paper, a clean fracturing fluid was prepared with long-chain anionic surfactant, Sodium erucate (NaOEr), as main agent and a series of cationic surfactants with different as additive. Then, the aggregation behavior of mixed system was determined by visual appearance, rheology experiments, differential scanning calorimetry and cryogenic transmission electron microscopy. The phase transition mechanism induced by temperature was proposed, and the performance of the mixed system as a fracturing fluid was evaluated. The results showed the mixed systems could self-assemble into wormlike micelles when the length of hydrophobic carbon chains of cationic surfactant was 6 and 8. Increasing the length of the hydrophobic carbon chain could enhance the electrostatic effect, leading to precipitation in the mixed system. When the ratio of cationic surfactant was between 0.5 and 0.6 and the concentration was between 68 and 175 mmol∙L-1, the mixed systems tended to form three-dimensional structures by entangling and stacking wormlike micelles, showing high viscoelasticity and viscosity. The aggregation structure of the mixed system transformed from vesicles to wormlike micelles at 46.8 °C, which is attributed to the transition of carbon chains of NaOEr from non-flexible to flexible. Finally, the mixed system as a fracturing fluid has good shear resistance and temperature resistance. The viscosity of NaOEr/HTAB can reach above 50 mPa⋅s after sheared for 60 min at the conditions of 170 s−1 and 80 °C. This study provides an anionic clean fracturing fluid and broaden the application of viscoelastic surfactants in oilfield development.

Physicochemical Effect on Coal Pores of Hydrocarbon Chain Length and Mixing of Viscoelastic Surfactants in Clean Fracturing Fluids.

Clean fracturing fluids are environmentally friendly and could have broad applications in permeability enhancement of coal seams. The hydrophobic chain length of the viscoelastic surfactant (VES) and the mixing of VESs with different ionic types have marked effects on the performance of clean fracturing fluids. This paper analyzes the effects of the hydrocarbon chain length of VES and mixing of VESs with different ion types on the pores of coal and discusses the mechanisms controlling the pore changes from a physical and chemical perspective. We found that the coal samples treated with clean fracturing fluid B had the largest porosity change. Adding two methylene groups to the hydrocarbon chain of the cationic VES will increase clay swelling in coal treated with fracturing fluids. Adding 0.1 wt % cocoamidopropyl betaine (zwitterionic VES) to cationic VES fracturing fluids can reduce the extent of clay expansion induced by fracturing fluids. VES with a long hydrocarbon chain has a strong ability to remove kaolinite in hard coal, and the addition of zwitterion VES increases the ability of a clean fracturing fluid to remove kaolinite. These results provide theoretical guidance for the synthesis of new VES molecules and the design of new fracturing fluid formulations.

Elucidation of binding mechanisms of bovine serum albumin and 1-alkylsulfonates with different hydrophobic chain lengths

In this article, the binding interactions between bovine serum albumin (BSA) and three 1-alkylsulfonates, namely sodium 1-dodecanesulfonate, sodium 1-decanesulfonate, and sodium 1-octanesulfonate, have been thoroughly investigated. The study employed various experimental techniques such as isothermal titration calorimetry (ITC), steady-state fluorescence spectroscopy (SF), circular dichroism spectroscopy (CD), and molecular dynamics-based simulations. The objective was to understand the influence of the alkyl chain length of the investigated ligands on several aspects, including the strength of the interaction, the stoichiometry of the resulting complexes, the number of BSA binding sites, and the underlying mechanisms of binding. Notably, the study also demonstrated that sodium dodecyl sulfate (S12S) can serve as an effective site marker for BSA when studying ligands with similar structural and topological features. These findings may have significant implications for enhancing our understanding of the interactions between small amphiphilic molecules and proteins.

Hierarchical aerogels based on cellulose nanofibers and long-chain polymers for enhancing oil–water separation efficiency

The hydrophobic chain length of biomass-based aerogels used for oil–water separation was evaluated as a major parameter influencing the aerogels’ hydrophobicity. The properties of the porous structure were enhanced by the hierarchical assembly of the aerogels with biopolymeric structural units and polymer mineralization. The cellulose network was strengthened through silanization, and the nanocellulose network was further enhanced through coating with mineralizers containing long-chain hydrophobic molecules. Interfacial engineering was employed to establish multiscale interactions through the freeze-drying-induced modification of cellulose nanofibers and mineralized coatings of long-chain alkyl polymers. The resulting hierarchically structured aerogel exhibits low density (11.4 kg/m3), excellent mechanical compression properties across a wide temperature range (capable of enduring 100 cycles of compression), high porosity (99.2%), superhydrophobicity (152°), and recyclability. It maintains a 57.9% adsorption rate even after 40 adsorption–desorption tests, while also preserving its shape integrity. Moreover, it can be recycled and reused. At a temperature of 700 °C, the mass loss was only 44.47%, with excellent thermal stability. The aerogel can reduce oil pollutants in the ocean by adsorption, recover oil resources, and protect the natural environment. The assembly and optimization of nanofibrous matrix interfaces through the mineralization of long-chain polymers enhanced the performance of functionalized cellulose-based aerogels.

Synthesis, self-aggregation, thermal stability and cytotoxicity trends of alkyloxypropoxycyclohexane based pyridinium ionic liquids

New ether-functionalized pyridinium ionic liquids (ILs) has been synthesized by simple methodology and described by different spectroscopic techniques. Presence of two positional isomers has been confirmed with the help of NMR spectroscopy. The critical micelle concentration and other surface parameters of these ILs were deduced by conductivity, surface tension and fluorescence method. A collection of useful physical parameters i.e. critical micelle concentration (cmc), surface tension accomplished at cmc (γcmc), effectiveness of diminution in surface tension (Πcmc), maximum surface excess concentration (Ʈmax) and minimum surface area per molecule (Amin) at the air–water interface were also estimated. The average size of aggregates formed by investigated pyridinium ILs have been well examined by dynamic light scattering (DLS) experiments. The thermal degradation analysis of the present ILs has also been suggested that these ILs possessed thermal stability ranges from 200 °C to 240 °C. The investigated ILs have also been tested by MTT assay (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) on the C6 glioma cell line and found to revealed very low cytotoxicity in the concentration range required for biomedical applications. Such a low cytotoxicity of present ILs opens several new applications in the many biological purposes like drug and gene delivery agents. The physical study of investigated ILs indicate that the presence of ether functionality and varying hydrophobic chain length significantly altered the physicochemical properties of these pyridinium ILs than related to earlier synthesized N-(cyclohexanoxycarbonylmethyl) and 3-Cyclohexyloxy-2-Hydroxypropyl Pyridinium and Imidazolium surface active ILs.

Preparation of bamboo-shaped mesoporous silica using long-chain alcohol cosurfactants

Herein, orderly arranged bamboo-like mesoporous silica materials were prepared using cetyltrimethylammonium bromide (CTAB) as the template and n-hexanol as the long-chain alcohol cosurfactant. The ordered meso-structure was characterized by XRD analysis, field emission scanning electron microscopy (FE-SEM, Hitachi S4800), transmission electron microscopy, BET and IR spectroscopy analysis. The effects of the CTAB/n-hexanol molar ratio(R), length of the hydrophobic chain with a terminating hydroxyl group on the long-chain alcohol cosurfactant, parity of the hydrophobic carbon atoms on the surface topography, specific surface area, and pore size of the powder were investigated. The results showed that when the molar ratio = 1, the mesoporous silica presented neatly arranged bamboo segment lengths of 19.6–23.9 μm, platycodon grandiflorum widths of 2.13–3.32 μm, pore size of 3.04 nm, and surface area of 820.034 m2/g. Increasing or decreasing the amount of n-hexanol directing led to denser or looser lateral molecular interactions between CTAB and the co-structure-directing agents that respectively reduced or increased the pore size, with the latter resulting in the formation of spherical particles. When n-hexanol was replaced by n-heptanol or n-octanol, the pore size and surface area of the mesoporous silica decreased significantly with the increase in the hydrophobic chain length.

Supramolecular Organo/hydrogel-Fabricated Long Alkyl Chain α-Amidoamides as a Smart Soft Material for pH-Responsive Curcumin Release.

Low-molecular-mass gelators, due to their excellent biocompatibility, low toxicological profile, innate biodegradability and ease of fabrication have garnered significant interest as they self-assemble through non-covalent interactions. In this study, we have designed and synthesized a series of six α-amidoamides by varying the hydrophobic alkyl chain length (C12-C22), which were well characterized using different spectral techniques. These α-amidoamides formed self-assembled aggregates in a DMSO/water solvent system affording organo/hydrogels at 0.66% w/v, which is the minimum gelation concentration (MGC) making them as remarkable supergelators. The various functionalities present in these gelators such as amides and alkyl chain length pave the way toward excellent gelation mechanism through hydrogen bonding and van der Waals interaction as evidenced from FTIR spectroscopy. Notably, as the chain length increased, organo/hydrogels became more thermally stable. Rheological results showed that the stability and strength of these gelators were considerably impacted by variations in chain length. The SEM morphology revealed dense sheet architectures of the organo/hydrogel samples. Organo/hydrogels have a significant impact on the advancement of innovative drug delivery systems that respond to various stimuli, ushering in a new era in pharmaceutical technology. Inspired by this, we encapsulated curcumin, a chemopreventive medication, into the gel core and further released via gel-to-sol transition induced by pH variation at 37 °C, without any alteration in structure-activity relationship. The drug release behavior was observed by UV-vis spectroscopy. Moreover, cell viability and cell invasion experiments demonstrate that the gel formulations exhibit high biocompatibility and low cytotoxicity. Among the tested formulations, 5e+Cur exhibited remarkable efficacy in controlling A549 cell migration, suggesting significant potential for applications in the pharmaceutical industry.

Varying the hydrophobic core composition of polymeric nanoparticles affects NLRP3 inflammasome activation.

Understanding the interactions of nanoparticle carriers with innate immune cells is crucial for informing the design and efficacy of future nano-immunotherapies. An intriguing aspect of their interaction with the immune system has recently emerged, i.e., their ability to activate the NLRP3 inflammasome, a key component of the innate immune response. While the effect of the surface properties of nanoparticles has been extensively investigated in the context of nanoparticle-immune cell interactions, the influence of core composition remains largely unexplored, particularly regarding its impact on inflammasome activation. To shed light on these interactions, we developed a library of supramolecular polymer nanoparticles (SNPs) with different core compositions, varying their hydrophobic quotient by virtue of the side chain length and the repeating units in the polymer construct. The impact of modulating SNP core hydrophobic properties was investigated in macrophages by evaluating their cellular internalization, cytokine release, lysosomal rupture-calcium signaling, calcium flux-mitochondrial ROS production and their ability to activate the NLRP3 inflammasome, providing mechanistic insights into inflammasome activation. We established a direct correlation between increasing the side chain length of the polymer construct, thereby increasing the core hydrophobicity of SNPs and enhanced NLRP3 complex formation, as indicated by ASC speck imaging analysis and the elevated 1L-1β expression. Furthermore, the results demonstrated that the inflammasome signaling cascades and kinetics varied based on the SNP's hydrophobic side chain length and repeating units. Specifically, the nanoparticle with the longest alkyl side chain effectuated NLRP3 activation preferentially through the mitochondrial damage pathway. In vivo evaluation of SNPs in C57BL/6 mice confirmed elevated proinflammatory cytokines, notably with the SNP having the longest C12-alkyl side chain. This confirms that the higher core hydrophobicity composition of the SNP results in inflammasome activation in vivo. In summary, this study established SNP core composition as a novel nanoparticle-associated molecular pattern (NAMP) responsible for NLRP3 inflammasome activation, shedding light on intricate cellular pathways for informed nanoparticle design in immunotherapy and vaccine applications.

Self-Assembled Metal-Coordination Nanohelices as Efficient and Robust Chiral Supramolecular Catalysts for Enantioselective Reactions.

The development of chiral nanostructures-based supramolecular catalysts with satisfied enantioselectivity remains a significantly more challenging task. Herein, the synthesis and self-assembly of various amino acid amphiphiles as chiral supramolecular catalysts after metal ion coordination is reported and systematically investigate their enantioselectivity in asymmetric Diels-Alder reactions. In particular, the self-assembly of l/d-phenylglycine-based amphiphiles (l/d-PhgC16) and Cu(II) into chiral supramolecular catalysts in the methanol/water solution mixture is described, which features the interesting M/P nanohelices (diameter ≈8nm) and mostly well-aligned M/P nanoribbons (NRs). The M/P supramolecular catalysts show both high but inverse enantioselectivity (>90% ee) in Diels-Alder reactions, while their monomeric counterparts display nearly racemic products. Analysis of the catalytic results suggests the outstanding enantioselectivities are closely related to the specific stereochemical microenvironment provided by the arrangement of the amphiphiles in the supramolecular assembly. Based on the experimental evidence of chirality transfer from supramolecular nanohelices to coordinated Cu(II) and substrate aza-chalcone and the molecular dynamics simulations, the enantioselective catalytic mechanisms are proposed. Moreover, the relationships between molecular structures of amino acid amphiphiles (the hydrophilic head group and hydrophobic alkyl chain length) in supramolecular catalysts and enantioselectivity in Diels-Alder reactions are elaborated.

Effect of Hydrophobic Chain Length in Amphiphilic Chitosan Conjugates on Intracellular Drug Delivery and Smart Drug Release of Redox-Responsive Micelle.

Three redox-sensitive nanocarriers were rationally designed based on amphiphilic low molecular weight chitosan-cystamine-octylamine/dodecylamin/cetylamine (LC-Cys-OA, LC-Cys-DA, LC-Cys-CA) conjugates containing disulfide linkage for maximizing therapeutic effect by regulating hydrophobic interaction. The resultant spherical micelles had the characteristics of low CMC, suitable size, excellent biosafety and desired stability. The drug-loaded micelles were fabricated by embedding doxorubicin (Dox) into the hydrophobic cores. The effect of hydrophobic chain lengths of amphiphilic conjugates on encapsulation capacity, redox sensitivity, trigger-release behavior, cellular uptake efficacy, antitumor effect and antimigratory activity of Dox-loaded micelles was systematically investigated. Studies found that Dox-loaded LC-Cys-CA micelle had superior loading capacity and enhanced redox sensitivity compared with the other two micelles. Release assay indicated that the three Dox-loaded micelles maintained sufficiently stability in normal blood circulation but rapidly disintegrated in tumor cells. More importantly, the LC-Cys-CA micelle with a longer hydrophobic chain length exhibited a higher accumulative Dox release percentage than the other two micelles. Additionally, an increase in hydrophobic chain lengths of amphiphilic conjugates improved cellular uptake efficiency, antitumor effect and antimigration activity of Dox-loaded micelles, which could be explained by enhanced loading ability and redox sensitivity. Our research was expected to provide a viable platform for achieving a desired therapeutic efficacy via the alteration of hydrophobic interaction.