Nature-Inspired Design and Application of Lipidic Lyotropic Liquid Crystals

Unlocking new dimensions in long-acting injectables using lipid mesophase-based beads

In this study, we explored the use of lipid mesophases (LMPs) as a biocompatible and biodegradable material for sustained drug delivery. Our hypothesis centered on leveraging the high surface-to-volume ratio of LMP-based beads to enhance strength, stability, and surface interaction compared to the LMP bulk gel. To modulate drug release, we introduced antioxidant vitamin E into the beads, influencing mesophase topologies and controlling drug diffusion coefficients. Four drugs with distinct chemical properties and intended for three different pathologies and administration routes were successfully loaded into the beads with a drug entrapment efficiency exceeding 80 %. Notably, our findings revealed sustained drug release, irrespective of the drugs' chemical properties, culminating in the development of an injectable formulation. This formulation allows direct administration into the target site, minimizing systemic exposure, and thereby mitigating adverse effects. Our approach demonstrates the potential of LMP-based beads for tailored drug delivery systems with broad applications in diverse therapeutic scenarios.

Three-Dimensional Imaging of Bioinspired Lipidic Mesophases Using Multicolored Light-Emitting Carbon Nanodots

Recent progress in the design of carbon nanostructures exhibiting strong multiphoton-excited emission opens new pathways to explore the self-organization of lipids found in living organisms. Phospholipid-based lyotropic myelin figures (MFs) are promising materials as simplified models of biomembranes due to their structural resemblance to a multilamellar sheath insulating the axon. This study demonstrates the possibility of selective labeling of MFs by strongly emitting multicolor phloroglucinol-derived carbon nanodots (PG CNDs). Such dopants are efficiently excited by visible and near-infrared light; therefore, one- and two-photon fluorescence microscopies are incorporated to gain 3D insights into the MFs. Combining nondestructive fluorescence microscopy and spectroscopy techniques along with polarized light microscopy gives details on the stability and morphology of lipidic mesophases. Our findings suggest that PG CNDs can be a viable and simple alternative to conventional fluorescent lipid stains to image biologically relevant phospholipid-based structures.

Small-angle X-ray and neutron scattering applied to lipid-based nanoparticles: Recent advancements across different length scales

Lipid-based nanoparticles (LNPs), ranging from nanovesicles to non-lamellar assemblies, have gained significant attention in recent years, as versatile carriers for delivering drugs, vaccines, and nutrients. Small-angle scattering methods, employing X-rays (SAXS) or neutrons (SANS), represent unique tools to unveil structure, dynamics, and interactions of such particles on different length scales, spanning from the nano to the molecular scale. This review explores the state-of-the-art on scattering methods applied to unveil the structure of lipid-based nanoparticles and their interactions with drugs and bioactive molecules, to inform their rational design and formulation for medical applications. We will focus on complementary information accessible with X-rays or neutrons, ranging from insights on the structure and colloidal processes at a nanoscale level (SAXS) to details on the lipid organization and molecular interactions of LNPs (SANS). In addition, we will review new opportunities offered by Time-resolved (TR)-SAXS and -SANS for the investigation of dynamic processes involving LNPs. These span from real-time monitoring of LNPs structural evolution in response to endogenous or external stimuli (TR-SANS), to the investigation of the kinetics of lipid diffusion and exchange upon interaction with biomolecules (TR-SANS). Finally, we will spotlight novel combinations of SAXS and SANS with complementary on-line techniques, recently enabled at Large Scale Facilities for X-rays and neutrons. This emerging technology enables synchronized multi-method investigation, offering exciting opportunities for the simultaneous characterization of the structure and chemical or mechanical properties of LNPs.

Self-Assembling Anti-Freezing Lamellar Nanostructures in Subzero Temperatures

The requirement for cryogenic supramolecular self-assembly of amphiphiles in subzero environments is a challenging topic. Here, the self-assembly of lamellar lyotropic liquid crystals (LLCs) are presented to a subzero temperature of -70 °C. These lamellar nanostructures are assembled from specifically tailored ultra-long-chain surfactant stearyl diethanolamine (SDA) in water/glycerol binary solvent. As the temperature falls below zero, LLCs with a liquid-crystalline Lα phase, a tilted Lβ phase, and a new folded configuration are obtained consecutively. A comprehensive experimental and computational study is performed to uncover the precise microstructure and formation mechanism. Both the ultra-long alkyl chain and head group of SDA play a crucial role in the formation of lamellar nanostructures. SDA head group is prone to forming hydrogen bonds with water, rather than glycerol. Glycerol cannot penetrate the lipid layer, which mixes with water arranging outside of the lipid bilayer, providing an ideal anti-freezing environment for SDA self-assembly. Based on these nanostructures and the ultra-low freezing point of the system, a series of novel cryogenic materials are created with potential applications in extremely cold environments. These findings would contribute to enriching the theory and research methodology of supramolecular self-assembly in extreme conditions and to developing novel anti-freezing materials.

A Versatile Synthesis Platform Based on Polymer Cubosomes for a Library of Highly Ordered Nanoporous Metal Oxides Particles

Polymer cubosomes (PCs) have well-defined inverse bicontinuous cubic mesophases formed by amphiphilic block copolymer bilayers. The open hydrophilic channels, large periods, and robust physical properties of PCs are advantageous to many host-guest interactions and yet not fully exploited, especially in the fields of functional nanomaterials. Here, the self-assembly of poly(ethylene oxide)-block-polystyrene block copolymers is systematically investigated and a series of robust PCs is developed via a cosolvent method. Ordered nanoporous metal oxide particles are obtained by selectively filling the hydrophilic channels of PCs via an impregnation strategy, followed by a two-step thermal treatment. Based on this versatile PC platform, the general synthesis of a library of ordered porous particles with different pore structures3 ¯ $\bar{3}$ 3 ¯ $\bar{3}$ , tunable large pore size (18-78 nm), high specific surface areas (up to 123.3 m2 g-1 for WO3) and diverse framework compositions, such as transition and non-transition metal oxides, rare earth chloride oxides, perovskite, pyrochlore, and high-entropy metal oxides is demonstrated. As typical materials obtained via this method, ordered porous WO3 particles have the advantages of open continuous structure and semiconducting properties, thus showing superior gas sensing performances toward hydrogen sulfide.

Toward Ultrahigh Rate and Cycling Performance of Cathode Materials of Sodium Ion Battery by Introducing a Bicontinuous Porous Structure

The emerging sodium-ion batteries (SIBs) are one of the most promising candidates expected to complement lithium-ion batteries and diversify the battery market. However, the exploitation of cathode materials with high-rate performance and long-cycle stability for SIBs has remained one of the major challenges. To this end, an efficient approach to enhance rate and cycling performance by introducing an ordered bicontinuous porous structure into cathode materials of SIBs is demonstrated. Prussian blue analogues (PBAs) are selected because they are recognized as a type of most promising SIB cathode materials. Thanks to the presence of 3D continuous channels enabling fast Na+ ions diffusion as well as the intrinsic mechanical stability of bicontinuous architecture, the resultant PBAs exhibit excellent rate capability (80 mAh g-1 at 2.5 A g-1) and ultralong cycling life (>3000 circulations at 0.5 A g-1), reaching the top performance of the reported PBA-based cathode materials. This study opens a new avenue for boosting sluggish ion diffusion kinetics in electrodes of rechargeable batteries and also provides a new paradigm for solving the dilemma that electrodes' failure due to high-stress concentration upon ion storage.

Molecular Interactions Between Egg White Peptides and Giant Unilamellar Vesicle Membranes: Effect of Peptide Localization on Membrane Fluidity

Bioactive peptides have been shown to affect cell membrane fluidity, which is an important indicator of the cell membrane structure and function. However, the underlying mechanism of egg white-derived bioactive peptide regulation of cell membrane fluidity has not been elucidated yet. The cell membrane fluidity was investigated by giant unilamellar vesicles in the present study. The results showed that peptides TCNW, ADWAK, ESIINF, VPIEGII, LVEEY, and WKLC connect to membranes through intermolecular interactions, such as hydrogen bonding and regulated membrane fluidity, in a concentration-dependent way. In addition, peptides prefer to localize in the hydrophobic core of the bilayers. This study provides a theoretical basis for analyzing the localization of egg white bioactive peptides in specific cell membrane regions and their influence on the cell membrane fluidity.

Construction of the single-diamond-structured titania scaffold-Recreation of the holy grail photonic structure

As one of the most stunning biological nanostructures, the single-diamond (SD) surface discovered in beetles and weevils exoskeletons possesses the widest complete photonic bandgap known to date and is renowned as the "holy grail" of photonic materials. However, the synthesis of SD is difficult due to its thermodynamical instability compared to the energetically favoured bicontinuous double diamond and other easily formed lattices; thus, the artificial fabrication of SD has long been a formidable challenge. Herein, we report a bottom-up approach to fabricate SD titania networks via a one-pot cooperative assembly scenario employing the diblock copolymer poly(ethylene oxide)-block-polystyrene as a soft template and titanium diisopropoxide bis(acetylacetonate) as an inorganic precursor in a mixed solvent, in which the SD scaffold was obtained by kinetically controlled nucleation and growth in the skeletal channels of the diamond minimal surface formed by the polymer matrix. Electron crystallography investigations revealed the formation of tetrahedrally connected SD frameworks with the space group Fd [Formula: see text] m in a polycrystalline anatase form. A photonic bandgap calculation showed that the resulting SD structure has a wide and complete bandgap. This work solves the complex synthetic enigmas and offers a frontier in hyperbolic surfaces, biorelevant materials, next-generation optical devices, etc.

Angiopep-2-Functionalized Lipid Cubosomes for Blood-Brain Barrier Crossing and Glioblastoma Treatment

Glioblastoma multiforme (GBM) is an aggressive brain cancer with high malignancy and resistance to conventional treatments, resulting in a bleak prognosis. Nanoparticles offer a way to cross the blood-brain barrier (BBB) and deliver precise therapies to tumor sites with reduced side effects. In this study, we developed angiopep-2 (Ang2)-functionalized lipid cubosomes loaded with cisplatin (CDDP) and temozolomide (TMZ) for crossing the BBB and providing targeted glioblastoma therapy. Developed lipid cubosomes showed a particle size of around 300 nm and possessed an internal ordered inverse primitive cubic phase, a high conjugation efficiency of Ang2 to the particle surface, and an encapsulation efficiency of more than 70% of CDDP and TMZ. In vitro models, including BBB hCMEC/D3 cell tight monolayer, 3D BBB cell spheroid, and microfluidic BBB/GBM-on-a-chip models with cocultured BBB and glioblastoma cells, were employed to study the efficiency of the developed cubosomes to cross the BBB and showed that Ang2-functionalized cubosomes can penetrate the BBB more effectively. Furthermore, Ang2-functionalized cubosomes showed significantly higher uptake by U87 glioblastoma cells, with a 3-fold increase observed in the BBB/GBM-on-a-chip model as compared to that of the bare cubosomes. Additionally, the in vivo biodistribution showed that Ang2 modification could significantly enhance the brain accumulation of cubosomes in comparison to that of non-functionalized particles. Moreover, CDDP-loaded Ang2-functionalized cubosomes presented an enhanced toxic effect on U87 spheroids. These findings suggest that the developed Ang2-cubosomes are prospective for improved BBB crossing and enhanced delivery of therapeutics to glioblastoma and are worth pursuing further as a potential application of nanomedicine for GBM treatment.

Composite material in the sea urchin Cidaris rugosa: ordered and disordered micrometre-scale bicontinuous geometries

The sponge-like biomineralized calcite materials found in echinoderm skeletons are of interest in terms of both structure formation and biological function. Despite their crystalline atomic structure, they exhibit curved interfaces that have been related to known triply periodic minimal surfaces. Here, we investigate the endoskeleton of the sea urchin Cidaris rugosa that has long been known to form a microstructure related to the Primitive surface. Using X-ray tomography, we find that the endoskeleton is organized as a composite material consisting of domains of bicontinuous microstructures with different structural properties. We describe, for the first time, the co-occurrence of ordered single Primitive and single Diamond structures and of a disordered structure within a single skeletal plate. We show that these structures can be distinguished by structural properties including solid volume fraction, trabeculae width and, to a lesser extent, interface area and mean curvature. In doing so, we present a robust method that extracts interface areas and curvature integrals from voxelized datasets using the Steiner polynomial for parallel body volumes. We discuss these very large-scale bicontinuous structures in the context of their function, formation and evolution.

Microviscosity-Assisted Disaggregation of a Model Ophthalmic Drug and FRET-Controlled Singlet Oxygen Generation in Lyotropic Liquid Crystals

Different phases of lyotropic liquid crystals (LLCs), made up of mesogen-like sodium dodecyl sulfate (SDS), mainly bestow different bulk viscosities. Along with this, the role of microviscosities of the individual LLC phases is of immense interest because a minute change in it due to guest incorporation can cause significant alteration in their property as a potential energy transfer scaffold. Recently, LLCs have been identified as plausible drug delivery agents for ocular treatments. In this direction, the present work illustrates photophysical modulations of an important laser dye as well as an ophthalmic medicine, coumarin 6 (C6), inside different LLC phases in an aqueous medium. C6 molecules spontaneously accumulate in water, leading to aggregation-caused quenching (ACQ) of fluorescence. However, the different phases of the LLCs prepared from SDS and water helped in disintegrating the C6 colonies to various extents depending upon the microviscosity. The heterogeneity in the LLC phases, in turn, could modulate the Förster resonance energy transfer (FRET) between C6 and the LLC incorporated with N-doped carbon nanoparticles (N-CNPs). The N-CNPs act as potential photosensitizers and generate singlet oxygen (1O2), a reactive oxygen species (ROS), to different extents. Microviscosities of the prepared LLCs were calculated by using fluorescence correlation spectroscopy (FCS). The different phases of the LLCs, viz., lamellar and hexagonal, with different microviscosities controlled the extent of C6 disaggregation and hence the FRET and the ROS generation. The results are encouraging since ROS generation has a significant role in the vision mechanism and PDT-based applications. LLC-based drug administration with potential FRET to control ROS generation may become handy in ophthalmology. The LLC phases used in this experiment not only served the purpose of drug delivery but also the photophysical events therein are compatible with the ocular environment.

Lipid cubic phase with an organic-inorganic hybrid structure formed by organoalkoxysilane lipid

A lipid cubic phase encompassing a cross-linked siloxane structure was formed by the self-assembly of a synthetic organoalkoxysilane lipid in water. The spontaneous sol-gel reaction of the alkoxysilane moiety on the lipid head group produced an organic-inorganic hybrid material with a double gyroid Ia3d cubic structure.

Self-Assembly of Unusually Stable Thermotropic Network Phases by Cellobiose-Based Guerbet Glycolipids

Bicontinuous thermotropic liquid crystal (LC) materials, e.g., double gyroid (DG) phases, have garnered significant attention due to the potential utility of their 3D network structures in wide-ranging applications. However, the utility of these materials is significantly constrained by the lack of robust molecular design rules for shape-filling amphiphiles that spontaneously adopt the saddle curvatures required to access these useful supramolecular assemblies. Toward this aim, we synthesized anomerically pure Guerbet-type glycolipids bearing cellobiose head groups and branched alkyl tails and studied their thermotropic LC self-assembly. Using a combination of differential scanning calorimetry, polarized optical microscopy, and small-angle X-ray scattering, our studies demonstrate that Guerbet cellobiosides exhibit a strong propensity to self-assemble into DG morphologies over wide thermotropic phase windows. The stabilities of these assemblies sensitively depend on the branched alkyl tail structure and the anomeric configuration of the glycolipid in a previously unrecognized manner. Complementary molecular simulations furnish detailed insights into the observed self-assembly characteristics, thus unveiling molecular motifs that foster network phase self-assembly that will enable future designs and applications of network LC materials.

Water-lipid interface in lipidic mesophases with excess water

This study investigates the influence of excess water on the lipidic mesophase during the phase transition from diamond cubic phase (Pn3̄m) to reverse hexagonal phase (HII). Using a combination of small angle X-ray scattering (SAXS), broadband dielectric spectroscopy (BDS), and Fourier transform infrared (FTIR) techniques, we explore the dynamics of lipids and their interaction with water during phase transition. Our BDS results reveal three relaxation processes originating from lipids, all of which exhibit a kink during the phase transition. With the excess water, these processes accelerate due to the plasticizing effect of water. Additionally, our results demonstrate that the headgroups in the HII phase are more densely packed than those in the Pn3̄m phase, which agrees with the FTIR results. Meanwhile, we investigate the influence of excess water on the lipid headgroups, the H-bond network of water, the lipid tail, and the interface carbonyl group between the head and tail of the lipid molecule. The results indicate that excess water permeates the lipid interface and forms additional hydrogen bonds with the carbonyl groups. As a result, the headgroups are more flexible in a lipidic mesophase with excess water than those in mesophases without excess water.

Aquatic Functional Liquid Crystals: Design, Functionalization, and Molecular Simulation

Aquatic functional liquid crystals, which are ordered molecular assemblies that work in water environment, are described in this review. Aquatic functional liquid crystals are liquid-crystalline (LC) materials interacting water molecules or aquatic environment. They include aquatic lyotropic liquid crystals and LC based materials that have aquatic interfaces, for example, nanoporous water treatment membranes that are solids preserving LC order. They can remove ions and viruses with nano- and subnano-porous structures. Columnar, smectic, bicontinuous LC structures are used for fabrication of these 1D, 2D, 3D materials. Design and functionalization of aquatic LC sensors based on aqueous/LC interfaces are also described. The ordering transitions of liquid crystals induced by molecular recognition at the aqueous interfaces provide distinct optical responses. Molecular orientation and dynamic behavior of these aquatic functional LC materials are studied by molecular dynamics simulations. The molecular interactions of LC materials and water are key of these investigations. New insights into aquatic functional LC materials contribute to the fields of environment, healthcare, and biotechnology.

Gac Fruit Oils Encapsulated by Palm Oil-based Monoacylglycerols: The Effect of Drying Methods

Lyotropic liquid crystals (LLCs) are interesting wall-materials for encapsulation technology, in which monoacylglycerols (MAGs) are considered as potential ingredient for LLC formulation. This study, therefore, applied palm oil-based MAGs to encapsulate Gac fruit oils and compared the effect of two drying methods (freeze-drying and spray-drying) on the quality of products during storage. Wall-materials were prepared by ultrasound dispersing MAGs/water mixtures (40/60, w/w) into Pluronic solution (2%, w/w) to formulate LLC dispersions. Then, Gac fruit oils were encapsulated by freeze-drying and spray-drying. Various technologies were applied to characterize the properties of dispersions, the encapsulated powder morphology and the loading capacity. Obtained results showed that LLC dispersions made of palm oilbased MAG were micro- and nano-emulsions which were very convenient for encapsulating Gac fruit oils. For both drying methods, β-carotene of Gac fruit oils was successfully entrapped by MAGs with a high loading capacity (200 µg β-carotene/g powder). The degradation of encapsulated β-carotene after four storage weeks was 10 - 40% and freeze-dried samples showed a better protection effect in comparison to spray-dried samples.

Geometry-structure models for liquid crystal interfaces, drops and membranes: wrinkling, shape selection and dissipative shape evolution

We review our recent contributions to anisotropic soft matter models for liquid crystal interfaces, drops and membranes, emphasizing validations with experimental and biological data, and with related theory and simulation literature. The presentation aims to illustrate and characterize the rich output and future opportunities of using a methodology based on the liquid crystal-membrane shape equation applied to static and dynamic pattern formation phenomena. The geometry of static and kinetic shapes is usually described with dimensional curvatures that co-mingle shape and curvedness. In this review, we systematically show how the application of a novel decoupled shape-curvedness framework to practical and ubiquitous soft matter phenomena, such as the shape of drops and tactoids and bending of evolving membranes, leads to deeper quantitative insights than when using traditional dimensional mean and Gaussian curvatures. The review focuses only on (1) statics of wrinkling and shape selection in liquid crystal interfaces and membranes; (2) kinetics and dissipative dynamics of shape evolution in membranes; and (3) computational methods for shape selection and shape evolution; due to various limitations other important topics are excluded. Finally, the outlook follows a similar structure. The main results include: (1) single and multiple wavelength corrugations in liquid crystal interfaces appear naturally in the presence of surface splay and bend orientation distortions with scaling laws governed by ratios of anchoring-to-isotropic tension energy; adding membrane elasticity to liquid crystal anchoring generates multiple scales wrinkling as in tulips; drops of liquid crystals encapsulates in membranes can adopt, according to the ratios of anchoring/tension/bending, families of shapes as multilobal, tactoidal, and serrated as observed in biological cells. (2) Mapping the liquid crystal director to a membrane unit normal. The dissipative shape evolution model with irreversible thermodynamics for flows dominated by bending rates, yields new insights. The model explains the kinetic stability of cylinders, while spheres and saddles are attractors. The model also adds to the evolving understanding of outer hair cells in the inner ear. (3) Computational soft matter geometry includes solving shape equations, trajectories on energy and orientation landscapes, and shape-curvedness evolutions on entropy production landscape with efficient numerical methods and adaptive approaches.

Coencapsulation of Gemcitabine and Thymoquinone in Citrem-Phosphatidylcholine Hexosome Nanocarriers Improves In Vitro Cellular Uptake in Breast Cancer Cells

Lyotropic liquid crystalline nanoassemblies (LLCNs) are internally self-assembled (ISA)-somes formed by amphiphilic molecules in a mixture comprising a lipid, stabilizer, and/or surfactant and aqueous media/dispersant. LLCNs are unique nanoassemblies with versatile applications in a wide range of biomedical functions. However, they comprise a nanosystem that is yet to be fully explored for targeted systemic treatment of breast cancer. In this study, LLCNs proposed for gemcitabine and thymoquinone (Gem-TQ) co-delivery were prepared from soy phosphatidylcholine (SPC), phytantriol (PHYT), or glycerol monostearate (MYVR) in optimized ratios containing a component of citric and fatty acid ester-based emulsifier (Grinsted citrem) or a triblock copolymer, Pluronic F127 (F127). Hydrodynamic particle sizes determined were below 400 nm (ranged between 96 and 365 nm), and the series of nanoformulations displayed negative surface charge. Nonlamellar phases identified by small-angle X-ray scattering (SAXS) profiles comprise the hexagonal, cubic, and micellar phases. In addition, high entrapment efficiency that accounted for 98.3 ± 0.1% of Gem and 99.5 ± 0.1% of TQ encapsulated was demonstrated by the coloaded nanocarrier system, SPC/citrem/Gem-TQ hexosomes. Low cytotoxicity of SPC-citrem hexosomes was demonstrated in MCF10A cells consistent with hemo- and biocompatibility observed in zebrafish (Danio rerio) embryos for up to 96 h postfertilization (hpf). SPC/citrem/Gem-TQ hexosomes demonstrated IC50 of 24.7 ± 4.2 μM in MCF7 breast cancer cells following a 24 h treatment period with the moderately synergistic interaction between Gem and TQ retained (CI = 0.84). Taken together, biocompatible SPC/citrem/Gem-TQ hexosomes can be further developed as a multifunctional therapeutic nanodelivery approach, plausible for targeting breast cancer cells by incorporation of targeting ligands.

Lipid doping of the sponge (L3) mesophase

The polymorphism of lipid aggregates has long attracted detailed study due to the myriad factors that determine the final mesophase observed. This study is driven by the need to understand mesophase behaviour for a number of applications, such as drug delivery and membrane protein crystallography. In the case of the latter, the role of the so-called 'sponge' (L3) mesophase has been often noted, but not extensively studied by itself. The L3 mesophase can be formed in monoolein/water systems on the addition of butanediol to water, which partitions the headgroup region of the membrane, and decreases its elastic moduli. Like cubic mesophases, it is bicontinuous, but unlike them, has no long-range translational symmetry. In our present study, we show that the formation of the L3 phase can delicately depend on the addition of dopant lipids to the mesophase. While electrostatically neutral molecules similar in shape to monoolein (DOPE, cholesterol) have little effect on the general mesophase behaviour, others (DOPC, DDM) significantly reduce the composition at which it can form. Additionally, we show that by combining cholesterol with the anionic lipid DOPG, it is possible to form the largest stable L3 mesophases observed to date, with characteristic lengths over 220 Å.

A microfluidic platform for the controlled synthesis of architecturally complex liquid crystalline nanoparticles

Soft-matter nanoparticles are of great interest for their applications in biotechnology, therapeutic delivery, and in vivo imaging. Underpinning this is their biocompatibility, potential for selective targeting, attractive pharmacokinetic properties, and amenability to downstream functionalisation. Morphological diversity inherent to soft-matter particles can give rise to enhanced functionality. However, this diversity remains untapped in clinical and industrial settings, and only the simplest of particle architectures [spherical lipid vesicles and lipid/polymer nanoparticles (LNPs)] have been routinely exploited. This is partially due to a lack of appropriate methods for their synthesis. To address this, we have designed a scalable microfluidic hydrodynamic focusing (MHF) technology for the controllable, rapid, and continuous production of lyotropic liquid crystalline (LLC) nanoparticles (both cubosomes and hexosomes), colloidal dispersions of higher-order lipid assemblies with intricate internal structures of 3-D and 2-D symmetry. These particles have been proposed as the next generation of soft-matter nano-carriers, with unique fusogenic and physical properties. Crucially, unlike alternative approaches, our microfluidic method gives control over LLC size, a feature we go on to exploit in a fusogenic study with model cell membranes, where a dependency of fusion on particle diameter is evident. We believe our platform has the potential to serve as a tool for future studies involving non-lamellar soft nanoparticles, and anticipate it allowing for the rapid prototyping of LLC particles of diverse functionality, paving the way toward their eventual wide uptake at an industrial level.

Strongly Emitting Folic Acid-Derived Carbon Nanodots for One- and Two-Photon Imaging of Lyotropic Myelin Figures

Non-invasive imaging of morphological changes in biologically relevant lipidic mesophases is essential for the understanding of membrane-mediated processes. However, its methodological aspects need to be further explored, with particular attention paid to the design of new excellent fluorescent probes. Here, we have demonstrated that bright and biocompatible folic acid-derived carbon nanodots (FA CNDs) may be successfully applied as fluorescent markers in one- and two-photon imaging of bioinspired myelin figures (MFs). Structural and optical properties of these new FA CNDs were first extensively characterized; they revealed remarkable fluorescence performance in linear and non-linear excitation regimes, justifying further applications. Then, confocal fluorescence microscopy and two-photon excited fluorescence microscopy were used to investigate a three-dimensional distribution of FA CNDs within the phospholipid-based MFs. Our results showed that FA CNDs are effective markers for imaging various forms and parts of multilamellar microstructures.

Spatio-temporal programming of lyotropic phase transition in nanoporous microfluidic confinements

HYPOTHESIS

The nanoporous polydimethylsiloxane (PDMS) surfaces of a rectangular microfluidic channel, selectively uptakes water molecules, concentrating the solute molecules in an aqueous phase, that could drive phase transitions. Factors such as surface wettability, channel geometry, the surface-to-volume ratio, and surface topography of the confinements could play a key role in tuning the phase transitions spatio-temporally.

EXPERIMENTS

Using a lyotropic chromonic liquid crystal as model biological material, confined within nanoporous microfluidic environments, we study molecular assembly driven by nanoporous substrates. By combining timelapse polarized imaging, quantitative image processing, and a simple mathematical model, we analyze the phase transitions and construct a master diagram capturing the role of surface wettability, channel geometry and embedded topography on programmable lyotropic phase transitions.

FINDINGS

Intrinsic PDMS nanoporosity and confinement cross-section, together with the imposed wettability regulate the rate of the N-M phase transition; whereas the microfluidic geometry and embedded topography enable phase transition at targeted locations. We harness the emergent long-range order during N-M transition to actuate elasto-advective transport of embedded micro-cargo, demonstrating particle manipulation concepts governed by tunable phase transitions. Our results present a programmable physical route to material assembly in microfluidic environment, and offer a new paradigm for assembling genetic components, biological cargo, and minimal synthetic cells.

Lyotropic Liquid Crystal (LLC)-Templated Nanofiltration Membranes by Precisely Administering LLC/Substrate Interfacial Structure

Mesoporous materials based on lyotropic liquid crystal templates with precisely defined and flexible nanostructures offer an alluring solution to the age-old challenge of water scarcity. In contrast, polyamide (PA)-based thin-film composite (TFC) membranes have long been hailed as the state of the art in desalination. They grapple with a common trade-off between permeability and selectivity. However, the tides are turning as these novel materials, with pore sizes ranging from 0.2 to 5 nm, take center stage as highly coveted active layers in TFC membranes. With the ability to regulate water transport and influence the formation of the active layer, the middle porous substrate of TFC membranes becomes an essential player in unlocking their true potential. This review delves deep into the recent advancements in fabricating active layers using lyotropic liquid crystal templates on porous substrates. It meticulously analyzes the retention of the liquid crystal phase structure, explores the membrane fabrication processes, and evaluates the water filtration performance. Additionally, it presents an exhaustive comparison between the effects of substrates on both polyamide and lyotropic liquid crystal template top layer-based TFC membranes, covering crucial aspects such as surface pore structures, hydrophilicity, and heterogeneity. To push the boundaries even further, the review explores a diverse array of promising strategies for surface modification and interlayer introduction, all aimed at achieving an ideal substrate surface design. Moreover, it delves into the realm of cutting-edge techniques for detecting and unraveling the intricate interfacial structures between the lyotropic liquid crystal and the substrate. This review is a passport to unravel the enigmatic world of lyotropic liquid crystal-templated TFC membranes and their transformative role in global water challenges.

Synergetic Role of Nano-/Microscale Structures of the Trifolium Leaf Surface for Self-Cleaning Properties

Wetting has an essential pertinence to surface applications. The exemplary water-repelling and self-cleaning surfaces in nature have stimulated considerable scientific exploration, given their practical leverage in cleaning window glasses, painted surfaces, fabrics, and solar cells. Here, we explored the three-tier hierarchical surface structure of the Trifolium leaf with distinguished self-cleaning characteristics. The leaf remains fresh, withstands adverse weather, thrives throughout the year, and self-cleans itself against mud or dust. Self-cleaning features are attributed to a three-tier hierarchical synergetic design. The leaf surface is explicated by an optical microscope, a scanning electron microscope, a three-dimensional profilometer, and a water contact angle measuring device. Hierarchical base roughness (i.e., nano-/microscale) comprises a fascinating arrangement, which imparts a superhydrophobic feature to the surface. As a result, the contaminants present on the leaf surface are washed with rolling water droplets. We noticed that self-cleaning is a function of impacting or rolling droplets, and the rolling mechanism is identified as efficient. The self-cleaning phenomenon is studied for contaminations of variable sizes, shapes, and compositions. The contaminations are supplied in both dry and aqueous mixtures. Furthermore, we examined the self-cleaning effect of the Trifolium leaf surface by atmospheric water harvesting. The captured water drops fuse, roll, descend, and wash away the contaminating particles. The diversity of contaminants investigated makes this study applicable to different environmental conditions. And, along with other parallel technologies, this investigation could be useful for crafting sustainable self-cleaning surfaces for regions with acute water scarcity.

Multiple Routes to Bicontinuous Cubic Liquid Crystal Phases Discovered by High-Throughput Self-Assembly Screening of Multi-Tail Lipidoids

Bicontinuous cubic phases offer advantageous routes to a broad range of applied materials ranging from drug delivery devices to membranes. However, a priori design of molecules that assemble into these phases remains a technological challenge. In this article, a high-throughput synthesis of lipidoids that undergo protonation-driven self-assembly (PrSA) into liquid crystalline (LC) phases is conducted. With this screening approach, 12 different multi-tail lipidoid structures capable of assembling into the bicontinuous double gyroid phase are discovered. The large volume of small-angle X-ray scattering (SAXS) data uncovers unexpected design criteria that enable phase selection as a function of lipidoid headgroup size and architecture, tail length and architecture, and counterion identity. Surprisingly, combining branched headgroups with bulky tails forces lipidoids to adopt unconventional pseudo-disc conformations that pack into double gyroid networks, entirely distinct from other synthetic or biological amphiphiles within bicontinuous cubic phases. From a multitude of possible applications, two examples of functional materials from lipidoid liquid crystals are demonstrated. First, the fabrication of gyroid nanostructured films by interfacial PrSA, which are rapidly responsive to the external medium. Second, it is shown that colloidally-dispersed lipidoid cubosomes, for example, for drug delivery, are easily assembled using top-down solvent evaporation methods.

An intelligent phase transformation system based on lyotropic liquid crystals for sequential biomolecule delivery to enhance bone regeneration

Endogenous repair of critical bone defects is typically hampered by inadequate vascularization in the early stages and insufficient bone regeneration later on. Therefore, drug delivery systems with the ability to couple angiogenesis and osteogenesis in a spatiotemporal manner are highly desirable for vascularized bone formation. Herein, we devoted to develop a liquid crystal formulation system (LCFS) attaining a controlled temporal release of angiogenic and osteoinductive bioactive molecules that could orchestrate the coupling of angiogenesis and osteogenesis in an optimal way. It has been demonstrated that the release kinetics of biomolecules depend on the hydrophobicity of the loaded molecules, making the delivery profile programmable and controllable. The hydrophilic deferoxamine (DFO) could be released rapidly within 5 days to activate angiogenic signaling, while the lipophilic simvastatin (SIM) showed a slow and sustained release for continuous osteogenic induction. Apart from its good biocompatibility with mesenchymal stem cells derived from rat bone marrow (rBMSCs), the DFO/SIM loaded LCFS could stimulate the formation of a vascular morphology in human umbilical vein endothelial cells (HUVECs) and the osteogenic differentiation of rBMSCs in vitro. The in vivo rat femoral defect models have witnessed the prominent angiogenic and osteogenic effects induced by the sequential presentation of DFO and SIM. This study suggests that the sequential release of DFO and SIM from the LCFS results in enhanced bone formation, offering a facile and viable treatment option for bone defects by mimicking the physiological process of bone regeneration.

Paradigm of lyotropic liquid crystals in tissue regeneration

The liquid crystalline phase has attracted tremendous attention from researchers across the globe due to its intriguing properties. In this article, we enumerate the different classes of liquid crystals. Lyotropic liquid crystals (LLCs) exhibit their liquid crystalline nature based on the surrounding solvent media, which opens novel horizons in drug delivery and tissue regeneration. The advantages of LLCs in the said fields and the thermodynamic mechanistic insights responsible for their structural stabilization have been conveyed. Various fabrication and characterization techniques, along with factors influencing the formation of LLCs, have been discussed. Applications in novel therapeutic avenues like bone extracellular matrix, cardiac remodeling, wound management, and implants have been unveiled. Also, regulatory considerations, patent, and clinical portfolios to circumvent the hurdles of clinical translation have been discussed. LLCs could be a promising approach in diverse avenues of tissue regeneration.

Characterizing the Self-Assembly Properties of Monoolein Lipid Isosteres

Living cells feature lipid compartments which exhibit a variety of shapes and structures that assist essential cellular processes. Many natural cell compartments frequently adopt convoluted nonlamellar lipid architectures that facilitate specific biological reactions. Improved methods for controlling the structural organization of artificial model membranes would facilitate investigations into how membrane morphology affects biological functions. Monoolein (MO) is a single-chain amphiphile which forms nonlamellar lipid phases in aqueous solution and has wide applications in nanomaterial development, the food industry, drug delivery, and protein crystallization. However, even if MO has been extensively studied, simple isosteres of MO, while readily accessible, have seen limited characterization. An improved understanding of how relatively minor changes in lipid chemical structure affect self-assembly and membrane topology could instruct the construction of artificial cells and organelles for modeling biological structures and facilitate nanomaterial-based applications. Here, we investigate the differences in self-assembly and large-scale organization between MO and two MO lipid isosteres. We show that replacing the ester linkage between the hydrophilic headgroup and hydrophobic hydrocarbon chain with a thioesther or amide functional group results in the assembly of lipid structures with different phases not resembling those formed by MO. Using light and cryo-electron microscopy, small-angle X-ray scattering, and infrared spectroscopy, we demonstrate differences in the molecular ordering and large-scale architectures of the self-assembled structures made from MO and its isosteric analogues. These results improve our understanding of the molecular underpinnings of lipid mesophase assembly and may facilitate the development of MO-based materials for biomedicine and as model lipid compartments.

Lipidic lyotropic liquid crystals: Insights on biomedical applications

Liquid crystals (LCs) possess unique physicochemical properties, translatable into a wide range of applications. To date, lipidic lyotropic LCs (LLCs) have been extensively explored in drug delivery and imaging owing to the capability to encapsulate and release payloads with different characteristics. The current landscape of lipidic LLCs in biomedical applications is provided in this review. Initially, the main properties, types, methods of fabrication and applications of LCs are showcased. Then, a comprehensive discussion of the main biomedical applications of lipidic LLCs accordingly to the application (drug and biomacromolecule delivery, tissue engineering and molecular imaging) and route of administration is examined. Further discussion of the main limitations and perspectives of lipidic LLCs in biomedical applications are also provided. STATEMENT OF SIGNIFICANCE: Liquid crystals (LCs) are those systems between a solid and liquid state that possess unique morphological and physicochemical properties, translatable into a wide range of biomedical applications. A short description of the properties of LCs, their types and manufacturing procedures is given to serve as a background to the topic. Then, the latest and most innovative research in the field of biomedicine is examined, specifically the areas of drug and biomacromolecule delivery, tissue engineering and molecular imaging. Finally, prospects of LCs in biomedicine are discussed to show future trends and perspectives that might be utilized. This article is an ampliation, improvement and actualization of our previous short forum article "Bringing lipidic lyotropic liquid crystal technology into biomedicine" published in TIPS.

Mapping hyperbolic order in curved materials

Nature employs an impressive range of topologically complex ordered nanostructures that occur in various forms in both natural and synthetic materials. A particular class of these exhibits negative curvature and forms periodic saddle-shaped surfaces in three dimensions. Unlike pattern formation on flat or positively curved surfaces like spherical systems, the understanding of patterning on such surfaces is highly complicated due to the structures being intrinsically intertwined in three dimensions. We present a new method for visualisation and analysis of patterns on triply periodic negatively curved surfaces by mapping to two-dimensional hyperbolic space analogous to spherical projections in cartography thus effectively creating a more accessible "hyperbolic map" of the pattern. Specifically, we exemplify the method via the simplest triply periodic minimal surfaces: the Primitive, Diamond, and Gyroid in their universal cover along with decorations from a soft materials, whose structures involve decorations of soft matter on negatively curved surfaces, not necessarily minimal.

Block Copolymer Self-Assembly Directed Synthesis of Porous Materials with Ordered Bicontinuous Structures and Their Potential Applications

Porous materials with their ordered bicontinuous structures have attracted great interest owing to ordered periodic structures as well as 3D interconnected network and pore channels. Bicontinuous structures may favor efficient mass diffusion to the interior of materials, thus increasing the utilization ratio of active sites. In addition, ordered bicontinuous structures confer materials with exceptional optical and magnetic properties, including tunable photonic bandgap, negative refraction, and multiple equivalent magnetization configurations. The attractive structural advantages and physical properties have inspired people to develop strategies for preparing bicontinuous-structured porous materials. Among a few synthetic approaches, the self-assembly of block copolymers represents a versatile strategy to prepare various bicontinuous-structured functional materials with pore sizes and lattice parameters ranging from 1 to 500 nm. This article overviews progress in this appealing area, with an emphasis on the synthetic strategies, the structural control (including topologies, pore sizes, and unit cell parameters), and their potential applications in energy storage and conversion, metamaterials, photonic crystals, cargo delivery and release, nanoreactors, and biomolecule selection.

Amyloid Fibrils Enhance the Topical Bio-Adhesivity of Liquid Crystalline Mesophase-Based Drug Formulations

Despite their distinctive secondary structure based on cross β-strands, amyloid fibrils (AF) are stable fibrous protein aggregates with features similar to collagen, one of the main components of the extracellular matrix, and thus constitute a potential scaffold for enhancing cell adhesion for topical applications. Here, the contribution of AF to skin bio-adhesivity aiming toward topical treatments is investigated. Liquid crystalline mesophase (LCM) based on phytantriol is formulated, with the aqueous phase containing either water or a solution of 4 wt% amyloid fibrils. Then resveratrol is added as a model anti-inflammatory molecule. The developed LCM presents a double gyroid Ia3d mesophase. The incorporation of AF into the LCM increases its bio-adhesive properties. In vitro release and ex vivo permeation and retention confirm the controlled release property of the system, and that resveratrol is retained in epidermis and dermis, but is also permeated through the skin. All formulations are biocompatible with L929 cells. The in vivo assay confirms that systems with AF lead to a higher anti-inflammatory effect of resveratrol. These results confirm the hypothesis that the incorporation of AF in the LCM increases the bio-adhesiveness and efficiency of the system for topical treatment, and consequently, the therapeutical action of the encapsulated drug.

Network Phases with Multiple-Junction Geometries at the Gyroid-Diamond Transition

A novel phase sequence for the transition from the double diamond to the double gyroid cubic phases via two non-cubic intermediate phases, an orthorhombic Fmmm (O⁶⁹) phase and a hexagonal P6₃/m (H¹⁷⁶) phase, is reported for specifically designed bolapolyphiles composed of a linear rod-like bistolane core with sticky glycerol ends and two branched central and two linear peripheral side chains. These liquid crystalline (LC) phases represent members of a new class of unicontinuous network phases, formed by longitudinal rod bundles with polar spheres acting as junctions and the alkyl chains forming the continuum around them. In contrast to previously known bicontinuous cubic networks, they combine different junctions with different angles in a common structure, and one of them even represents a triple network instead of the usually found double networks. This provides new perspectives for the design of soft network phases with enhanced structural complexity, inspiring the search for new supramolecular networks, nano-particle arrays, and photonic band-gap materials.

Paclitaxel-loaded cubosome lipid nanocarriers stabilised with pH and hydrogen peroxide-responsive steric stabilisers as drug delivery vehicles

Responsive nanoparticle delivery systems hold great potential for next-generation chemotherapeutic treatment with reduced off-target side effects. In this work, we formulated responsive lipid-based cubosomes loaded with paclitaxel (PTX) as a model drug and stabilised by novel amphiphilic block copolymers (ABCs) containing the pH-responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and/or the hydrogen peroxide (H₂O₂)-responsive poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) blocks. The results showed that these cubosomes with a particle size of around 250 nm exhibited excellent PTX encapsulation efficiency of up to 60% and had the ability to control the release rate of the drug in response to pH and H₂O₂ changes. Specifically, compared to the physiological pH of 7.4, PTX was released faster from the cubosome carriers when exposed to pH 5.5 and/or 50 mM H₂O₂ conditions, which are pathological conditions found in a tumour microenvironment. In vitro cytotoxicity and cell uptake studies further investigated the cellular interactions of these cubosomes. It was found that cubosomes containing PTX had more toxic effects than the control free PTX sample. Compared to cubosomes stabilised by the non-responsive block copolymer Pluronic® F127, the ABC-stabilised cubosomes also had higher cell internalisation efficiency demonstrated by the cytoplasmic fluorescence intensities using confocal microscopy. These results demonstrated that ABCs containing responsive moieties can stabilise lipid cubosomes and enhance controlled release of poorly soluble chemotherapeutics and cellular uptake.

Enhancing the photoluminescence and cellular uptake of fluorescent carbon nanodots via cubosome lipid nanocarriers

Carbon nanodots (C-dots) have attracted much attention for their use in the fields of bioimaging, drug delivery, and sensing due to their excellent fluorescent and photoluminescent properties, photostability, biocompatibility, and amenability to surface modification. Herein, we report a nanocomposite formulation of C-dots (<5 nm) encapsulated in lipid-based lyotropic liquid crystalline nanoparticles (∼250 nm) via either passive diffusion or electrostatic mechanisms. The physicochemical properties of the nanocomposite formulation including particle size, surface charge, internal cubic nanostructures, and pH-dependent fluorescent properties were characterised. Upon loading of C-dots into lipid nanoparticles, the highly ordered inverse bicontinuous cubic mesophase existed in the internal phase of the nanoparticles, demonstrated by synchrotron small angle X-ray scattering, molecular dynamic simulation and cryogenic transmission electron microscopy. The pH-dependent fluorescent property of the C-dots was modified via electrostatic interaction between the C-dots and cationic lipid nanoparticles, which further enhanced the brightness of C-dots through self-quenching prevention. The cytotoxicity and cellular uptake efficiency of the developed nanocomposites were also examined in an epithelial gastric adenocarcinoma cell line (AGS) and a macrophage cell line (stimulated THP-1). Compared to free C-dots, the uptake and cell imaging potential of the C-dot nanocomposites was significantly improved, by several orders of magnitude as demonstrated by cytoplasmic fluorescent intensities using confocal microscopy. Loading C-dots into mesoporous lipid nanocarriers presents a new way of modifying C-dot physicochemical and fluorescent properties, alternative to direct chemical surface modification, and advances the bioimaging potential of C-dots by enhancing cellular uptake efficiency and converging C-dot light emission.

Obtaining and Characterizing Stable Bicontinuous Cubic Morphologies and Their Nanochannels in Lyotropic Liquid Crystal Membranes

Amphiphilic monomers in polar solvents can self-assemble into lyotropic liquid crystal (LLC) bicontinuous cubic structures under the right composition and temperature conditions. After cross-linking, the resulting polymer membranes with three-dimensional (3D) continuous uniform channels are excellent candidates for filtration applications. Designing such membranes with the desired physical and chemical properties requires molecular-level understanding of the structure, which can be obtained through molecular modeling. However, building molecular models of bicontinuous cubic structures is challenging due to their narrow regime of stability and the difficulty of self-assembly of large unit cells in molecular simulations. We developed a protocol for building stable bicontinuous cubic unit cells involving both parameterization and assembly of the components. We validate the theoretical structure against experimental results for one such LLC monomer and provide insight into the structure missing in experimental data, as well as demonstrate the qualitative nature of water and solute transport through these membranes.

Swollen cubic phases with reduced hardness solubilizing a model fragrance oil as a co-surfactant

Swollen cubic lyotropic ternary phases with Pn3m symmetry and reduced hardness were obtained from a specific binary mixture of cubic phase-forming (phytantriol) and lamellar phase-forming (decaglycerol monooleate) compounds. The microstructures were determined by using a small-angle x-ray scattering technique. The softness and temperature-induced phase transitions were investigated by means of rheology. The incorporation of a surface-active fragrance compound (linalool) at concentrations up to 6 wt. % induced a structural transition toward a softer Im3m bulk cubic phase with longer water channels. Higher linalool concentrations allowed for the spontaneous dispersion of the bulk cubic phase into microscopic particles with a cubic structure (cubosomes).

Interaction mechanism of three egg protein derived ACE inhibitory tri-peptides and DPPC membrane using FS, FTIR, and DSC studies

Understanding the interaction of food derived angiotensin converting enzyme (ACE) inhibitory peptides and intestinal epithelial cell membrane may help to improve their absorption. This research aimed to study the molecular interaction of ACE inhibitory tri-peptides ADF, FGR, and MIR with DPPC membrane during absorption process. The DPPC liposome was prepared and characterized, then used as a model membrane. The permeability of tri-peptides across the membrane was investigated using Fluorescence spectroscopy. The effect of tri-peptides on the structure and dynamics of DPPC bilayers was determined using Fourier transform infrared spectroscopy. The effect of tri-peptides on the phase transition temperature in the DPPC membrane was also analyzed using Differential scanning calorimetry. The results showed that ACE inhibitory tri-peptides ADF, FGR, and MIR can penetrate into both the membrane-water interface and hydrophobic region of DPPC bilayer, and the tri-peptide FGR have higher permeability across the membrane.

Automated Calculation of Liquid Crystal Sensing Images Based on Deep Learning

Liquid crystal (LC)-based sensors have been extensively applied in the detection of chemical and biological events. However, the calculation of the optical images of the LC-based sensors is usually time-consuming and also might bring some errors due to the use of different judgment criteria by different users. In the present study, an automated calculation method for LC sensing images based on deep learning is provided. A convolutional network is trained with the prepared LC sensing images and their corresponding segmentation annotations to predict the positive responses. The ratio is calculated from the area of positive response to the total area selected by our image processing method. The robustness of the proposed algorithm is validated on both the test set and the label-free Cd²⁺ detection. The results show that the method based on deep learning can detect the positive response area in real time and the speed is much faster than the manual processing method. In addition, deep learning method can be directly applied to other label-free molecular detection assays.

Insights into characterizing and producing anisotropic food structures

Besides the flavor profile of food, texture plays a major role in terms of the acceptance and likeability of food products. In contrast to gel-like homogenous isotropic structures, where the characterization is established and structure-texture mechanisms are well understood, there is still a lack of knowledge in the field of anisotropic complex food matrices. Food systems that show anisotropic properties in terms of macroscopic mechanical anisotropy as in grown meat, or mixed complex systems where anisotropic shaped particles or fibers are embedded into an isotropic matrix are challenging to characterize, hence the structure-texture correlation is not trivial to understand. In this paper, we bring together the state of the art of different anisotropic structures as a source of food, their formation in terms of structured plant proteins, and consequently the structure-texture correlation of those. Characteristic terms and properties to differentiate between anisotropic systems are introduced with the purpose to facilitate characterization of those. Based on the here provided terms and characteristics, further studies toward understanding such systems and their perception can be conducted. Beyond that, a first opinion on crucial influencing factors on the perception of anisotropic systems and their mechanistic background is provided.

Long-acting injectable formulation technologies: Challenges and opportunities for the delivery of fragile molecules

INTRODUCTION

The development of long acting injectables (LAIs) for protein and peptide therapeutics has been a key challenge over the last 20 years. If these molecules offer advantages due to their high specificity and selectivity, their controlled release may confer several additional benefits in terms of extended half-life, local delivery, and patient compliance.

AREA COVERED

This manuscript aims to give an overview of peptide and protein based LAIs from an industrial perspective, describing both approved and promising technologies (with exceptions of protein engineering strategies and devices), their advantages and potential improvements to aid their access to the market.

EXPERT OPINION

Many LAIs have been developed for peptides, with formulations on the market for several decades. On the contrary, LAIs for proteins are still far from the market and issues related to manufacturing and sterilization of these products still need to be overcome. In situ forming depots (ISFDs), whose simple manufacturing conditions and easy administration procedures (without reconstitution) are strong advantages, appear as one of the most promising technologies for the delivery of these molecules. In this regard, the approval of ELIGARD® in the early 2000's (which still requires a complex reconstitution process), paved the way for the development of second-generation, ready-to-use ISFD technologies like BEPO® and FluidCrystal®.

Liquid crystal-templated chiral nanomaterials: from chiral plasmonics to circularly polarized luminescence

Chiral nanomaterials with intrinsic chirality or spatial asymmetry at the nanoscale are currently in the limelight of both fundamental research and diverse important technological applications due to their unprecedented physicochemical characteristics such as intense light-matter interactions, enhanced circular dichroism, and strong circularly polarized luminescence. Herein, we provide a comprehensive overview of the state-of-the-art advances in liquid crystal-templated chiral nanomaterials. The chiroptical properties of chiral nanomaterials are touched, and their fundamental design principles and bottom-up synthesis strategies are discussed. Different chiral functional nanomaterials based on liquid-crystalline soft templates, including chiral plasmonic nanomaterials and chiral luminescent nanomaterials, are systematically introduced, and their underlying mechanisms, properties, and potential applications are emphasized. This review concludes with a perspective on the emerging applications, challenges, and future opportunities of such fascinating chiral nanomaterials. This review can not only deepen our understanding of the fundamentals of soft-matter chirality, but also shine light on the development of advanced chiral functional nanomaterials toward their versatile applications in optics, biology, catalysis, electronics, and beyond.

Interaction of Metallic Nanoparticles With Biomimetic Lipid Liquid Crystalline Cubic Interfaces

In the past decades, events occurring at the nano-bio interface (i.e., where engineered nanoparticles (NPs) meet biological interfaces such as biomembranes) have been intensively investigated, to address the cytotoxicity of nanomaterials and boost their clinical translation. In this field, lamellar synthetic model membranes have been instrumental to disentangle non-specific interactions between NPs and planar biological interfaces. Much less is known on nano-biointeractions occurring at highly curved biological interfaces, such as cubic membranes. These non-lamellar architectures play a crucial -but far from understood-role in several biological processes and occur in cells as a defence mechanism against bacterial and viral pathologies, including coronaviruses infections. Despite its relevance, the interaction of cubic membranes with nano-sized objects (such as viral pathogens, biological macromolecules and synthetic NPs) remains largely unexplored to date. Here, we address the interaction of model lipid cubic phase membranes with two prototypical classes of NPs for Nanomedicine, i.e., gold (AuNPs) and silver NPs (AgNPs). To this purpose, we challenged lipid cubic phase membranes, either in the form of dispersed nanoparticles (i.e., cubosomes) or solid-supported layers of nanometric thickness, with citrate-stabilized AuNPs and AgNPs and monitored the interaction combining bulk techniques (UV-visible spectroscopy, Light and Synchrotron Small-Angle X-ray Scattering) with surface methods (Quartz Crystal Microbalance and Confocal Laser Scanning Microscopy). We show that the composition of the metal core of NPs (i.e., Au vs Ag) modulates their adsorption and self-assembly at cubic interfaces, leading to an extensive membrane-induced clustering of AuNPs, while only to a mild adsorption of isolated AgNPs. Such differences mirror opposite effects at the membrane level, where AuNPs induce lipid extraction followed by a fast disruption of the cubic assembly, while AgNPs do not affect the membrane morphology. Finally, we propose an interaction mechanism accounting for the different behaviour of AuNPs and AgNPs at the cubic interface, highlighting a prominent role of NPs’ composition and surface chemistry in the overall interaction mechanism.

Tamarillo Polyphenols Encapsulated-Cubosome: Formation, Characterization, Stability during Digestion and Application in Yoghurt

Tamarillo extract is a good source of phenolic and anthocyanin compounds which are well-known for beneficial antioxidant activity, but their bioactivity maybe lost during digestion. In this study, promising prospects of tamarillo polyphenols encapsulated in cubosome nanoparticles prepared via a top-down method were explored. The prepared nanocarriers were examined for their morphology, entrapment efficiency, particle size and stability during in vitro digestion as well as potential fortification of yoghurt. Tamarillo polyphenol-loaded cubosomes showed cubic shape with a mean particle size of 322.4 ± 7.27 nm and the entrapment efficiency for most polyphenols was over 50%. The encapsulated polyphenols showed high stability during the gastric phase of in vitro digestion and were almost completely, but slowly released in the intestinal phase. Addition of encapsulated tamarillo polyphenols to yoghurt (5, 10 and 15 wt% through pre- and post-fermentation) improved the physicochemical and potential nutritional properties (polyphenols concentration, TPC) as well as antioxidant activity. The encapsulation of tamarillo polyphenols protected against pH changes and enzymatic digestion and facilitated a targeted delivery and slow release of the encapsulated compounds to the intestine. Overall, the cubosomal delivery system demonstrated the potential for encapsulation of polyphenols from tamarillo for value-added food product development with yoghurt as the vehicle.

SPIRE-a software tool for bicontinuous phase recognition: application for plastid cubic membranes

Bicontinuous membranes in cell organelles epitomize nature's ability to create complex functional nanostructures. Like their synthetic counterparts, these membranes are characterized by continuous membrane sheets draped onto topologically complex saddle-shaped surfaces with a periodic network-like structure. Their structure sizes, (around 50-500 nm), and fluid nature make transmission electron microscopy (TEM) the analysis method of choice to decipher their nanostructural features. Here we present a tool, Surface Projection Image Recognition Environment (SPIRE), to identify bicontinuous structures from TEM sections through interactive identification by comparison to mathematical "nodal surface" models. The prolamellar body (PLB) of plant etioplasts is a bicontinuous membrane structure with a key physiological role in chloroplast biogenesis. However, the determination of its spatial structural features has been held back by the lack of tools enabling the identification and quantitative analysis of symmetric membrane conformations. Using our SPIRE tool, we achieved a robust identification of the bicontinuous diamond surface as the dominant PLB geometry in angiosperm etioplasts in contrast to earlier long-standing assertions in the literature. Our data also provide insights into membrane storage capacities of PLBs with different volume proportions and hint at the limited role of a plastid ribosome localization directly inside the PLB grid for its proper functioning. This represents an important step in understanding their as yet elusive structure-function relationship.

Crystal Channel Engineering for Rapid Ion Transport: From Nature to Batteries

Ion transport behaviours through cell membranes are commonly identified in biological systems, which are crucial for sustaining life for organisms. Similarly, ion transport is significant for electrochemical ion storage in rechargeable batteries, which has attracted much attention in recent years. Rapid ion transport can be well achieved by crystal channels engineering, such as creating pores or tailoring interlayer spacing down to the nanometre or even sub-nanometre scale. Furthermore, some functional channels, such as ion selective channels and stimulus-responsive channels, are developed for smart ion storage applications. In this review, the typical ion transport phenomena in the biological systems, including ion channels and pumps, are first introduced, and then ion transport mechanisms in solid and liquid crystals are comprehensively reviewed, particularly for the widely studied porous inorganic/organic hybrid crystals and ultrathin inorganic materials. Subsequently, recent progress on the ion transport properties in electrodes and electrolytes is reviewed for rechargeable batteries. Finally, current challenges in the ion transport behaviours in rechargeable batteries are analysed and some potential research approaches, such as bioinspired ultrafast ion transport structures and membranes, are proposed for future studies. It is expected that this review can give a comprehensive understanding on the ion transport mechanisms within crystals and provide some novel design concepts on promoting electrochemical ion storage capability in rechargeable batteries.