Increased Ordering of Potassium Stearate/Stearic Acid/Glyceryl Stearate Confined between Swollen Cross-Linked Poly(acrylic acid).

In this paper, we investigate the phase behavior of a surfactant mixture comprising glyceryl stearate, potassium stearate, and stearic acid, in the presence of Carbopol, a commonly used thickener in personal care products. At low Carbopol concentrations (<0.03%), the surfactant mixture interacted with Carbopol electrostatically, increasing the degree of Carbopol swelling and, consequently, the overall viscosity.

Fluorinated polymer zwitterions on gold nanoparticles: patterned catalyst surfaces guide interfacial transport and electrochemical CO reduction.

We report the use of fluorinated polymer zwitterions to build hybrid systems for efficient CO electroreduction. The unique combination of hydrophilic phosphorylcholine and hydrophobic fluorinated moieties in these polymers creates a fractal structure with mixed branched cylinders on the surface of gold nanoparticles (AuNPs). In the presence of these polymers, the CO faradaic efficiency improves by 50-80% in the range of -0.

Computation-aided Design of Rod-Shaped Janus Base Nanopieces for Improved Tissue Penetration and Therapeutics Delivery.

Despite the development of various drug delivery technologies, there remains a significant need for vehicles that can improve targeting and biodistribution in "hard-to-penetrate" tissues. Some solid tumors, for example, are particularly challenging to penetrate due to their dense extracellular matrix (ECM). In this study, we have formulated a new family of rod-shaped delivery vehicles named Janus base nanopieces (Rod JBNps), which are more slender than conventional spherical nanoparticles, such as lipid nanoparticles (LNPs).

Block Sequence Effects on the Self-Assembly Behaviors of Polypeptide-Based Penta-Block Copolymer Hydrogels.

Peptide-based hydrogels have great potential for applications in tissue engineering, drug delivery, and so on. We systematically synthesize, characterize, and investigate the self-assembly behaviors of a series of polypeptide-based penta-block copolymers by varying block sequences and lengths. The copolymers contain hydrophobic blocks of poly(γ-benzyl-l-glutamate) (PBG, B) and two kinds of hydrophilic blocks, poly(l-lysine) (PLL, K) and poly(ethylene glycol) (PEG, EG), where and are the number of repeating units of each block, where PBG and PLL blocks have unique functions for nerve regeneration and cell adhesion.

Antivesiculation and Complete Unbinding of Tail-Tethered Lipids.

We report the effect of tail-tethering on vesiculation and complete unbinding of bilayered membranes. Amphiphilic molecules of a bolalipid, resembling the tail-tethered molecular structure of archaeal lipids, with two identical zwitterionic phosphatidylcholine headgroups self-assemble into a large flat lamellar membrane, in contrast to the multilamellar vesicles (MLVs) observed in its counterpart, monopolar nontethered zwitterionic lipids. The antivesiculation is confirmed by small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cyro-TEM).

Correlating structural changes in thermoresponsive hydrogels to the optical response of embedded plasmonic nanoparticles.

Stimuli-responsive microgels, composed of small beads with soft, deformable polymer networks swollen through a combination of synthetic control over the polymer and its interaction with water, form a versatile platform for development of multifunctional and biocompatible sensors. The interfacial structural variation of such materials at a nanometer length scale is essential to their function, but not yet fully comprehended. Here, we take advantage of the plasmonic response of a gold nanorod embedded in a thermoresponsive microgel (AuNR@PNIPMAm) to monitor structural changes in the hydrogel directly near the nanorod surface.

Strongly coupled plasmonic metal nanoparticles with reversible pH-responsiveness and highly reproducible SERS in solution.

We report a facile method to prepare polymer-grafted plasmonic metal nanoparticles (NPs) that exhibit pH-responsive surface-enhanced Raman scattering (SERS). The concept is based on the use of pH-responsive polymers, such as poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH), as multidentate ligands to wrap around the surface of NPs instead of forming polymer brushes. Upon changing the solvent quality, the grafted pH-responsive polymers would drive reversible aggregation of NPs, leading to a decreased interparticle distance.

Morphological control and modern applications of bicelles.

Bicellar systems have become popularized as their rich morphology can be applied in biochemistry, physical chemistry, and drug delivery technology. To the biochemical field, bicelles are powerful model membranes for the study of transmembrane protein behavior, membrane transport, and environmental interactions with the cell. Their morphological responses to environmental changes reveal a profound fundamental understanding of physical chemistry related to the principle of self-assembly.

Synthesis of Polymer Nanoweb via a Lipid Template.

We report a generalized platform for synthesizing a polymer nanoweb with a high specific surface area via a bicellar template, composed of 1,2-dipalmitoyl phosphocholine (DPPC), 1,2-dihexanoyl phosphocholine (DHPC), and 1,2-dipalmitoyl phosphoglycerol (DPPG). The pristine bicelle (in the absence of monomer or polymer) yields a variety of well-defined structures, including disc, vesicle, and perforated lamella. The addition of styrene monomers in the mixture causes bicelles to transform into lamellae.

Site-Specific Chemistry on Gold Nanorods: Curvature-Guided Surface Dewetting and Supracolloidal Polymerization.

Control of interparticle interactions in terms of their direction and strength highly relies on the use of anisotropic ligand grafting on nanoparticle (NP) building blocks. We report a ligand deficiency exchange strategy to achieve site-specific polymer grafting of gold nanorods (AuNRs). Patchy AuNRs with controllable surface coverage can be obtained during ligand exchange with a hydrophobic polystyrene ligand and an amphiphilic surfactant while adjusting the ligand concentration () and solvent condition ( in dimethylformamide).

Next-generation poly-L-histidine formulations for miRNA mimic delivery.

Many diseases, especially cancer, are caused by the abnormal expression of non-coding microRNAs (miRNAs), which regulate gene expression, leading to the development of miRNA-based therapeutics. Synthetic miRNA inhibitors have shown promising efficacy in blocking the activity of aberrant miRNAs that are upregulated in disease-specific pathologies. On the other hand, miRNAs that aid in preventing certain diseases and are reduced in expression in the disease state need different strategies.

Stable Discoidal Bicelles: Formulation, Characterization, and Functions.

Bicellar mixtures have been used as alignable membrane substrates under a magnetic field applicable for the structural characterization of membrane-associated proteins. Recently, it has shown that bicelles can serve as nanocarriers to effectively deliver hydrophobic therapeutic molecules to cancer cells with a three- to ten-fold enhancement compared to that of liposomes of a chemically identical composition. In this chapter, detailed preparation protocol, common structural characterization methods, the structural stability, the cellular uptake and a few unique functions of bicellar nanodiscs are discussed.

Cellular Localization, Aggregation, and Cytotoxicity of Bicelle-Quantum Dot Nanocomposites.

Bicelles are discoidal lipid nanoparticles (LNPs) in which the planar bilayer and curved rim are, respectively, composed of long- and short-chain lipids. Bicellar LNPs have a hydrophobic core, allowing hydrophobic molecules and large molecular complexes such as quantum dots (QDs) to be encapsulated. In this study, CdSe/ZnS QDs were encapsulated in bicelles made of dipalmitoyl phosphatidylcholine, dihexanoyl phosphatidylcholine, dipalmitoyl phosphatidylglycerol, and distearoyl phosphatidylethanolamine conjugated with polyethylene glycerol amine 2000 to form a well-defined bicelle-QD nanocomplex (known as NANO-QD or bicelle-QD).

Water Content in Nanoparticles Determined by Small-Angle Neutron Scattering and Light Scattering.

The amount of water in therapeutic nanoparticles (NPs) is of great importance to the pharmaceutical industry, as water content reflects the volume occupied by the solid components. For example, certain biomolecules, such as mRNA, can undergo conformational change or degradation when exposed to water. Using static light scattering (SLS) and dynamic light scattering (DLS), we estimated the water content of NPs, including extruded liposomes of two different sizes and polystyrene (PS) Latex NPs.

Facile polymerization in a bicellar template to produce polymer nano-rings.

Hypothesis: A well-defined discoidal bicelle composed of three lipids, specifically zwitterionic long-chain 1,2‑dipalmitoyl phosphocholine (DPPC) and short-chain 1,2‑dihexanoyl phosphocholine (DHPC) doped with anionic 1,2‑dipalmitoyl phosphoglycerol (DPPG) provides a generalized template for the synthesis of hydrophobic polymer nano-rings. The lipid molar ratio of DPPC/DHPC/DPPG is 0.71/0.

Self-assembled materials from cellulose nanocrystals conjugated with a thermotropic liquid crystalline moiety.

Manipulating molecular and supramolecular interactions within cellulose nanocrystals (CNCs) to introduce different levels of assemblies combined with multiple functionalities is required for the development of degradable smart materials from renewable resources. To attain hierarchical structures and stimuli-responsive properties, a new class of liquid crystalline cellulosic hybrid materials is synthesized. Herein, main-chain rigid-rod-like oxidized cellulose (CNC-COOH) is prepared from a Cellulose Whatman filter paper (Cellulose W.

Effect of drug-to-lipid ratio on nanodisc-based tenofovir drug delivery to the brain for HIV-1 infection.

Combination antiretroviral therapy has significantly advanced HIV-1 infection treatment. However, HIV-1 remains persistent in the brain; the inaccessibility of the blood-brain barrier allows for persistent HIV-1 infections and neuroinflammation. Nanotechnology-based drug carriers such as nanodiscoidal bicelles can provide a solution to combat this challenge.

Patchy metal nanoparticles with polymers: controllable growth and two-way self-assembly.

We report a new design of polymer-patched gold nanoparticles (AuNPs) with controllable interparticle interactions in terms of their direction and strength. Patchy AuNPs (pAuNPs) are prepared through hydrophobicity-driven surface dewetting under deficient ligand exchange conditions. Using the exposed surface on pAuNPs as seeds, a highly controllable growth of AuNPs is carried out seed-mediated growth while retaining the size of polymer domains.

Changes Experienced by Low-Concentration Lipid Bicelles as a Function of Temperature.

Differential scanning calorimetry (DSC) of dipalmitoyl phosphatidylcholine (DPPC), dihexanoyl phosphatidylcholine, and dipalmitoyl phosphatidylglycerol bicelles reveals two endothermic peaks. Based on analysis of small angle neutron scattering and small angle X-ray scattering data, the two DSC peaks are associated with the melting of DPPC and a change in bicellar morphology─namely, either bicelle-to-spherical vesicle or oblate-to-spherical vesicle. The reversibility of the two structural transformations was examined by DSC and found to be consistent with the corresponding small angle scattering data.

Head on Comparison of Self- and Nano-assemblies of Gamma Peptide Nucleic Acid Amphiphiles.

Peptide nucleic acids (PNAs) are nucleic acid analogs with superior hybridization properties and enzymatic stability than deoxyribonucleic acid (DNA). In addition to gene targeting applications, PNAs have garnered significant attention as bio-polymer due to the Watson-Crick -based molecular recognition and flexibility of synthesis. Here, we engineered PNA amphiphiles using chemically modified gamma PNA (8 mer in length) containing hydrophilic diethylene glycol units at the gamma position and covalently conjugated lauric acid (C12) as a hydrophobic moiety.

Outer membrane vesicles (OMVs) enabled bio-applications: A critical review.

Outer membrane vesicles (OMVs) are nanoscale spherical vesicles released from Gram-negative bacteria. The lipid bilayer membrane structure of OMVs consists of similar components as bacterial membrane and thus has attracted more and more attention in exploiting OMVs' bio-applications. Although the endotoxic lipopolysaccharide on natural OMVs may impose potential limits on their clinical applications, genetic modification can reduce their endotoxicity and decorate OMVs with multiple functional proteins.

Nanocomplex made up of antimicrobial metallo-supramolecules and model biomembranes - characterization and enhanced fluorescence.

Antimicrobial pentatopic 2,2':6',2''-terpyridines that form 3-D supramolecular hexagonal prisms with Cd through coordination driven self-assembly can be entrapped by lipid discoidal bicelles, composed of 1,2-dipalmitoyl--3-phosphocholine, 1,2-dihexanoyl--3-phosphocholine and 1,2-dipalmitoyl--3-phospho-(1'-rac-glycerol) lipid, forming a well-defined nanocomplex. Structural characterization performed by very small angle neutron scattering, small angle X-ray scattering and transmission electron microscopy suggests that the hexagonal prisms are preferably located at the rim of bicellar discs with the hexagonal face in parallel with the bilayers, instead of face-to-face stacking. Such a configuration reduces the π-π interaction and consequently enhances the fluorescence emission.

Dual-Modality Poly-l-histidine Nanoparticles to Deliver Peptide Nucleic Acids and Paclitaxel for In Vivo Cancer Therapy.

Cationic polymeric nanoformulations have been explored to increase the transfection efficiency of small molecules and nucleic acid-based drugs. However, an excessive positive charge density often leads to severe cell and tissue-based toxicity that restricts the clinical translation of cationic polymeric nanoformulations. Herein, we investigate a series of cationic poly(lactic--glycolic acid) (PLGA)-histidine-based nanoformulations for enhanced cytoplasmic delivery with minimal toxicity.

Aggregation-Enhanced Photoluminescence and Photoacoustics of Atomically Precise Gold Nanoclusters in Lipid Nanodiscs (NANO).

The authors designed a structurally stable nano-in-nano (NANO) system highly capable of bioimaging via an aggregation-enhanced NIR excited emission and photoacoustic response achieved based on atomically precise gold nanoclusters protected by linear thiolated ligands [Au(SC H), = 4-16] encapsulated in discoidal phospholipid bicelles through a one-pot synthesis. The detailed morphological characterization of NANO is conducted using cryogenic transmission electron microscopy, small/wide angle X-ray scattering with the support of molecular dynamics simulations, providing information on the location of Au nanoclusters in NANO. The photoluminescence observed for NANO is 20-60 times more intense than that of the free Au nanoclusters, with both excitation and emission wavelengths in the near-infrared range, and the photoacoustic signal is more than tripled.