Constructing Porous Energetic Spherulites via Solvation-Growth Coupling for Enhanced Combustion.

The fabrication of materials with hierarchical structures has garnered great interest, owing to the potential for significantly enhancing their functions. Herein, a strategy of coupling molecular solvation and crystal growth is presented to fabricate porous spherulites of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), an important energetic material. With the addition of polyvinylpyrrolidone in the antisolvent crystallization, the metastable solvate of CL-20 is formed and grows spherulitically, and spontaneously desolvates to obtain the porous spherulite when filtration, in which the characteristic peak of the nitro group of CL-20 shifts detected by the in situ micro-confocal Raman spectroscopy. The effect of polyvinylpyrrolidone is thought to induce the solvation of CL-20, confirmed by density functional theory calculations, meanwhile acting on the (020) face of CL-20 to trigger spherulitic growth, demonstrated through infrared spectroscopy and Rietveld refinement of powder X-ray diffraction. Moreover, compared to common CL-20 crystals, porous spherulites exhibit enhanced combustion with increases of 6.24% in peak pressure, 40.21% in pressurization rate, and 9.63% in pressure duration effect, indicating the capability of hierarchical structures to boost the energy release of energetic crystals. This work demonstrates a new route via solvation-growth coupling to construct hierarchical structures for organic crystals and provides insight into the structure-property relations for material design.

Uncovering the Recent Progress of CNC-Derived Chirality Nanomaterials: Structure and Functions.

Cellulose nanocrystal (CNC), as a renewable resource, with excellent mechanical performance, low thermal expansion coefficient, and unique optical performance, is becoming a novel candidate for the development of smart material. Herein, the recent progress of CNC-based chirality nanomaterials is uncovered, mainly covering structure regulations and function design. Undergoing a simple evaporation process, the cellulose nanorods can spontaneously assemble into chiral nematic films, accompanied by a vivid structural color. Various film structure-controlling strategies, including assembly means, physical modulation, additive engineering, surface modification, geometric structure regulation, and external field optimization, are summarized in this work. The intrinsic correlation between structure and performance is emphasized. Next, the applications of CNC-based nanomaterials is systematically reviewed. Layer-by-layer stacking structure and unique optical activity endow the nanomaterials with wide applications in the mineralization, bone regeneration, and synthesis of mesoporous materials. Besides, the vivid structural color broadens the functions in anti-counterfeiting engineering, synthesis of the shape-memory and self-healing materials. Finally, the challenges for the CNC-based nanomaterials are proposed.

Highly efficient in crystallo energy transduction of light to work.

Various mechanical effects have been reported with molecular materials, yet organic crystals capable of multiple dynamic effects are rare, and at present, their performance is worse than some of the common actuators. Here, we report a confluence of different mechanical effects across three polymorphs of an organic crystal that can efficiently convert light into work. Upon photodimerization, acicular crystals of polymorph I display output work densities of about 0.06-3.94 kJ m-3, comparable to ceramic piezoelectric actuators. Prismatic crystals of the same form exhibit very high work densities of about 1.5-28.5 kJ m-3, values that are comparable to thermal actuators. Moreover, while crystals of polymorph II roll under the same conditions, crystals of polymorph III are not photochemically reactive; however, they are mechanically flexible. The results demonstrate that multiple and possibly combined mechanical effects can be anticipated even for a simple organic crystal.

All-Round Passivation Strategy Yield Flexible Perovskite/CuInGaSe2 Tandem Solar Cells with Efficiency Exceeding 26.5.

The perovskite/Cu(InGa)Se2 (CIGS) tandem solar cells (TSCs) presents a compelling technological combination poised for the next generation of flexible and lightweight photovoltaic (PV) tandem devices, featuring a tunable bandgap, high power conversion efficiency (PCE), lightweight flexibility, and enhanced stability and durability. Over the years, the imperative to enhance the performance of wide bandgap (WBG) perovskite solar cells (PSCs) has grown significantly, particularly in the context of a flexible tandem device. In this study, an all-round passivation strategy known as Dual Passivation at Grains and Interfaces (DPGI) is introduced for WBG PSCs in perovskite/CIGS tandem structures. The implementation of DPGI is tailored to improve film crystallinity and passivate defects across the solar cell structure, leading to a substantial performance enhancement for WBG PSCs. Subsequently, both rigid and flexible tandem devices are assembled. Impressively, a fully flexible 4T perovskite/CIGS TSCs is successfully fabricated with a PCE of 26.57%, making it the highest value in this field and highlighting its potential applications in the next generation of flexible lightweight PV tandem devices.

Bifunctional Chiral Agent Enables One-pot Spontaneous Deracemization of Racemic Compounds.

A novel one-pot deracemization method using a bifunctional chiral agent (BCA) is proposed for the first time to convert a racemate to the desired enantiomer. Specifically, chiral α, (α-diphenyl-2-pyrrolidinemethanol) formed enantiospecific cocrystals with racemic dihydromyricetin, and used its own alkaline catalysis to catalyze the racemization between the (2R,3R)-enantiomer and (2S,3S)-enantiomer in solution, achieving a one-pot spontaneous deracemization. This strategy was also successfully extended to the deracemization of three other racemic compound drugs: (R,S)-carprofen, (R,S)-indoprofen, and (R,S)-indobufen. The one-pot deracemization method based on the BCA strategy provides a feasible approach to address the incompatibility between cocrystallization and racemization reactions that are commonly encountered in the cocrystallization-induced deracemization process and opens a new window to develop essential enantiomerically pure pharmaceutical products with atom economy.

Growth "self-inhibition" of irbesartan desmotrope: surface intra-annular tautomer inter-conversion is the culprit.

The newly discovered growth self-inhibition phenomenon of tautomeric crystals is now generalized to the demostrope (form B) of irbesartan that displays intra-annular tautomerism in neutral aqueous solutions. The dynamic intra-annular tautomer inter-conversion on the surface is the key factor. Our findings provide implications for producing and engineering tautomeric materials.

Uncovering the mechanism of Tenofovir amibufenamide fumarate punch sticking by combining direct compression experiment and computational simulation.

Punch sticking during tablet manufacturing is a prevalent issue for many active pharmaceutical ingredients (APIs) encountered by the pharmaceutical industry. Tenofovir amibufenamide fumarate (TMF), a heavyweight drug for the treatment of hepatitis B, was selected as a model drug due to its tendency to punch sticking during tablet compression. In this study, the cause of sticking was explored by investigating crystal habits, excipients and structure characteristics. The difference in sticking of three crystal habits can be visually represented through direct compression experiments on powdered samples and analysis of crystal surfaces. The excipients play a direct role in decreasing the probability of sticking, and the extent of sticking can be assessed by measuring the tensile strength of the tablet. Additionally, the plasticity index was utilized to theoretically analyze the potential enhancements of four excipients. These experimental results indicate that the block-shaped crystals have superior ability of anti-sticking and that suitable excipients can significantly improve the sticking situation of TMF. Ultimately, the phenomenon of punch sticking was additionally examined through computational calculations, focusing on the mechanical characteristics of TMF molecules and intermolecular interactions. The strategy of combining experiments and simulation calculations has broader significance for the study of drug production.

The effects of dextran in residual impurity on trehalose crystallization and formula in food preservation.

The residual dextran impurities in the upstream process significantly impact the crystallization of starch-based functional sugar and the related food properties. This study intends to reveal the mechanism of dextran's influence on trehalose crystallization, and build a relationship among the dextran in syrup and the physicochemical and functional properties of trehalose. Instead of incorporating into the crystal lattice, dextran changes the assembly rate of trehalose molecules on crystal surface. The different sensitivity and adsorption capacity of the crystal surface to the chain length of dextran determines the growth rate of crystal surfaces, resulting in different crystal morphology. The bulk trehalose crystals, which were obtained from syrups with short chain dextran, have excellent powder properties, including best flowability (35◦), highest crystal strength (2.7 N), lowest caking rate (62.22 %), and the most uniform mixing with other sweeteners (sucrose/xylitol) in food formulations, achieving more stable starch preservation.

A Triptycene-Based Layered/Flower-Like 2D Conductive Metal-Organic Framework with 3D Extension as an Electrode for Efficient Li Storage.

2D metal-organic frameworks (2D MOFs) with π conjugation have attracted widespread attention in the field of lithium storage due to their unique electron transfer units and structural characteristics. However, the periodic 2D planar extension structure hides some active sites, which is not conducive to the utilization of its structural advantages. In this work, a series of triptycene-based 2D conductive MOFs (M-DBH, M = Ni, Mn, and Co) with 3D extension structures are constructed by coordinating 9,10-dihydro-9,10-[1,2]benzenoanthracene-2,3,6,7,14,15-hexaol with metal ions to explore their potential applications in lithium-ion and lithium-sulfur batteries. This is the first study in which 2D conductive MOFs with the 3D extended molecule are used as electrode materials for lithium storage. The designed material generates rich active sites through staggered stacking layers and shows excellent performance in lithium-ion and lithium-sulfur batteries. The capacity retention rate of Ni-DBH can reach over 70% after 500 cycles at 0.2 C in lithium-ion batteries, while the capacity of S@Mn-DBH exceeds 305 mAh g-1 after 480 cycles at 0.5 C in lithium-sulfur batteries. Compared with the materials with 2D planar extended structures, the M-DBH electrodes with 3D extended structures in this work exhibit better performance in terms of cycle time and lithium storage capacity.

Chirality Supramolecular Systems: Helical Assemblies, Structure Designs, and Functions.

Chirality, as one of the most striking characteristics, exists at various scales in nature. Originating from the interactions of host and guest molecules, supramolecular chirality possesses huge potential in the design of functional materials. Here, an overview of the recent progress in structure designs and functions of chiral supramolecular materials is present. First, three design routes of the chiral supramolecular structure are summarized. Compared with the template-induced and chemical synthesis strategies that depend on accurate molecular identification, the twisted-assembly technique creates chiral materials through the ordered stacking of the nanowire or films. Next, chirality inversion and amplification are reviewed to explain the chirality transfer from the molecular level to the macroscopic scale, where the available external stimuli on the chirality inversion are also given. Lastly, owing to the optical activity and the characteristics of the layer-by-layer stacking structure, the supramolecular chirality materials display various excellent performances, including smart response, shape-memorization, superior mechanical performance, and applications in biomedical fields. To sum up, this work provides a systematic review of the helical assemblies, structure design, and applications of supramolecular chirality systems.

Enhancing physicochemical and functional properties of myo-inositol in crystallization with edible sugar additives.

Myo-inositol, referred to as vitamin B8, is an essential nutrient for maintaining human physiological functions. However, the morphology of myo-inositol products is predominantly powder or needle shaped, leading to poor food properties. In this work, three edible sugar additives, i.e. d-glucose, l-arabinose and d-fructose, are adopted in the crystallization of myo-inositol to improve its food properties. The results show that these additives change the morphology of myo-inositol crystals. d-glucose and l-arabinose reduced the aspect ratio of myo-inositol crystals, and d-glucose transformed elongated lamellar myo-inositol crystals into diamond-shaped lamellar crystals. The diamond-shaped lamellar myo-inositol products exhibited outstanding functional food properties. It offered a smoother texture and more pleasant mouthfeel when the products were added to infant formulas and nutraceuticals. When they were applied to functional beverages, the dissolution rate was increased by 35 %. This work provides a theoretical guidance for improving food properties through crystallization and possesses considerable potential for industrialization.

Fabrication of targeted and pH responsive lysozyme-hyaluronan nanoparticles for 5-fluorouracil and curcumin co-delivery in colorectal cancer therapy.

Green nanotechnology is considered a promising method to construct functional materials with significant anticancer activity, while overcoming the shortcomings of traditional synthesis process complexity and high organic solvents consumption. Thus, in this study, we report for the first time the rational design and green synthesis of functionalized 5-fluorouracil and curcumin co-loaded lysozyme-hyaluronan composite colloidal nanoparticles (5-Fu/Cur@LHNPs) for better targeted colorectal cancer therapy with minimized side effects. The functionalized 5-Fu/Cur@LHNPs exhibit stabilized particle size (126.1 nm) with excellent homogeneity (PDI = 0.1), favorable colloidal stabilities, and excellent re-dispersibility. In vitro cell experiments illustrate that the cellular uptake of 5-Fu/Cur@LHNPs was significantly improved and further promoted a higher apoptosis ratio of HCT-116 cells. Compared with the control group, the 5-Fu/Cur@LHNPs formulation group achieved effective inhibition (60.1 %) of colorectal tumor growth. The alcohol-free self-assembly method to construct 5-Fu/Cur@LHNPs is simple and safe for a translational chemotherapy drug, also to promote more robust delivery systems for treating colorectal cancer.

Amorphization of different furosemide polymorphic forms during ball milling: Tracking solid-to-solid phase transformations.

Ball milling is used, not only to reduce the particle size of pharmaceutical powders, but also to induce changes in the physical properties of drugs. In this work we prepared three crystal forms of furosemide (forms Ⅰ, Ⅱ, and Ⅲ) and studied their solid phase transformations during ball milling. Powder X-ray diffraction and modulated differential scanning calorimetry were used to characterize the samples after each milling time on their path to amorphization. Our results show that forms Ⅰ and III directly converted into an amorphous phase, while form Ⅱ first undergoes a polymorphic transition to form Ⅰ, and then gradually loses its crystallinity, finally reaching full amorphousness. During ball milling of forms Ⅰ and Ⅱ, the glass transition temperature (Tg) of the amorphous fraction of the milled material remains almost unchanged at 75 °C and 74 °C, respectively (whilst the amorphous content increases). In contrast, the Tg values of the amorphous fraction of milled form III increase with increasing milling times, from 63 °C to 71 °C, indicating an unexpected phenomenon of amorphous-to-amorphous transformation. The amorphous fraction of milled forms I and II samples presented a longer structural relaxation (i.e., lower molecular mobility) than the amorphous fraction of milled form III samples. Moreover, the structural relaxation time remained the same for the increasing amorphous fraction during milling of forms I and II. In contrast, the structural relaxation times were always shorter for the amorphous fraction of form III, but increased with increasing amorphous content during milling, confirming amorphous-to-amorphous transformation.

COF@COF: Constructing Core-Shell Structured Covalent-Organic Frameworks from Interpenetration Isomers.

Core-shell structured covalent-organic frameworks (COFs) have rarely been reported because of the essentially inevitable crystallographic structural distinctions of different COF species. In this contribution, we outline a novel strategy for constructing core-shell structured COFs from interpenetration isomers and take the classic three-dimensional COF-300 as a proof-of-concept. Core-shell particles with 5-fold interpenetrated COF-300 as the core and 7-fold interpenetrated COF-300 as the shell were prepared via a two-step process, using exactly the same monomers but under different reaction conditions within each step. Moreover, the thicknesses of both the core and shell show adjustable characteristics. This approach may promote the future advancement of hierarchical microstructures with predesigned functions in different hierarchies.

From 3D to 2D: Directional Morphological Evolution of a Three-Dimensional Covalent Organic Framework.

The morphology of materials has a huge impact on their properties and functions; however, the precise control and direct evolution toward specific morphologies remains challenging. Herein, we outline a novel strategy for the morphology modulation of covalent organic frameworks based on COF-300 with the diamond structure, which usually exhibits a three-dimensional shuttle morphology. A monofunctional structural regulator has been designed to break the continuity of the three-dimensional structure. As the proportion of the monofunctional structural regulator increases, the morphology of COF-300 shows a directional evolution from a shuttle morphology to a two-dimensional nanosheet, while still retaining the consistency of the crystal structure. Our study reports the first two-dimensional nanosheet based on a three-dimensional structured COF to date and will inspire future research into the traced morphological evolution in materials by predesign.

The Influence of Solvent Selection upon the Crystallizability and Nucleation Kinetics of Tolfenamic Acid Form II.

The influence of the solution environment on the solution thermodynamics, crystallizability, and nucleation of tolfenamic acid (TFA) in five different solvents (isopropanol, ethanol, methanol, toluene, and acetonitrile) is examined using an integrated workflow encompassing both experimental studies and intermolecular modeling. The solubility of TFA in isopropanol is found to be the highest, consistent with the strongest solvent-solute interactions, and a concomitantly higher than ideal solubility. The crystallizability is found to be highly dependent on the solvent type with the overall order being isopropanol < ethanol < methanol < toluene < acetonitrile with the widest solution metastable zone width in isopropanol (24.49 to 47.41 °C) and the narrowest in acetonitrile (8.23 to 16.17 °C). Nucleation is found to occur via progressive mechanism in all the solvents studied. The calculated nucleation parameters reveal a considerably higher interfacial tension and larger critical nucleus radius in the isopropanol solutions, indicating the higher energy barrier hindering nucleation and hence lowering the nucleation rate. This is supported by diffusion coefficient measurements which are lowest in isopropanol, highlighting the lower molecular diffusion in the bulk of solution compared to the other solutions. The TFA concentration and critical supersaturation at the crystallization onset is found to be directly correlated with TFA/isopropanol solutions having the highest values of solubility and critical supersaturation. Intermolecular modeling of solute-solvent interactions supports the experimental observations of the solubility and crystallizability, highlighting the importance of understanding solvent selection and solution state structure at the molecular level in directing the solubility, solute mass transfer, crystallizability, and nucleation kinetics.

Study on polycyclic macromolecular drug solid stability: A case exploration of methylcobalamin.

As one of derivatives of Vitamin B12, methylcobalamin (MeCbl) is an indispensable "Life Element" and plays an essential role in maintaining human normal physiology function and clinical medicine application. Because of the intricate molecular structure, strong hygroscopicity and optical instability, maintaining its solid stability is a great challenge in pharmaceutical preparation. Based on the structure features of MeCbl hydrates, this study explored the drug solid stability by designing solid-solid phase transformation (SSPT) experiments. Three hydrate powders of MeCbl that had special structure with isolated site and channel water molecules were discovered. It was found that drying condition and surrounding humidity were controlling factors influencing the final solid form. The inter-conversion relations relevant to heating-induced and humidity-induced structure changes were established among the three hydrate powders. Powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, high performance liquid chromatography and dynamic vapor sorption were used to characterize the differences and related properties of stably prepared MeCbl hydrate powders. The particle size of product could be regulated and controlled by optimizing operating conditions of crystallization process, where ultrasound-assisted and seeding-introduced were applied as promising strategies to enhance solution crystallization process. This study opens up the possibility for the stable preparation and large-scale production of polycyclic macromolecular bulk drugs like methylcobalamin.

Systematic study on lysozyme-hyaluronan complexes: Multi-spectroscopic characterization and molecular dynamics simulation.

This study systematically investigated the complexation mechanism of lysozyme (LYS) and hyaluronan (HA) as well as their complex-formation process using multi-spectroscopy combined with molecular dynamics simulation. Overall, the results demonstrated that electrostatic interaction provides the primary self-assembly driving forces for LYS-HA complex formation. Circular dichroism spectroscopy revealed that the LYS-HA complexes formation primarily alters the α-helix and ß-sheet structures of LYS. Fluorescence spectroscopy yielded an entropy of 0.12 kJ/mol·K and enthalpy of -44.46 kJ/mol for LYS-HA complexes. Molecular dynamics simulation indicated that the amino acid residues of ARG114 in LYS and 4ZB4 in HA contributed most significantly. HT-29 and HCT-116 cell experiments demonstrated that LYS-HA complexes possess excellent biocompatibility. Furthermore, LYS-HA complexes were found to be potentially useful the efficient encapsulation of several insoluble drugs and bioactives. These findings provide new insight into the binding mechanism between LYS and HA, and prove indispensable to promoting the potential application of LYS-HA complexes as bioactive compound delivery systems, emulsion stabilizers, or foaming agents in the food industry.

Polymer-mediated and ultrasound-assisted crystallization of ropivacaine: Crystal growth and morphology modulation.

The objective of this research was to modify the crystal shape and size of poorly water-soluble drug ropivacaine, and to reveal the effects of polymeric additive and ultrasound on crystal nucleation and growth. Ropivacaine often grow as needle-like crystals extended along the a-axis and the shape was hardly controllable by altering solvent types and operating conditions for the crystallization process. We found that ropivacaine crystallized as block-like crystals when polyvinylpyrrolidone (PVP) was used. The control over crystal morphology by the additive was related to crystallization temperature, solute concentration, additive concentration, and molecular weight. SEM and AFM analyses were performed providing insights into crystal growth pattern and cavities on the surface induced by the polymeric additive. In ultrasound-assisted crystallization, the impacts of ultrasonic time, ultrasonic power, and additive concentration were investigated. The particles precipitated at extended ultrasonic time exhibited plate-like crystals with shorter aspect ratio. Combined use of polymeric additive and ultrasound led to rice-shaped crystals, which the average particle size was further decreased. The induction time measurement and single crystal growth experiments were carried out. The results suggested that PVP worked as strong nucleation and growth inhibitor. Molecular dynamics simulation was performed to explore the action mechanism of the polymer. The interaction energies between PVP and crystal faces were calculated, and mobility of the additive with different chain length in crystal-solution system was evaluated by mean square displacement. Based on the study, a possible mechanism for the morphological evolution of ropivacaine crystals assisted by PVP and ultrasound was proposed.

Effects of organic pollutants on struvite crystallization kinetics and the molecular mechanism of inhibition on crystal growth.

The abilities of improving phosphorus (P) resources sustainability and reducing water eutrophication make struvite crystallization technology attract increasing interest in wastewater treatment, but struvite crystallization process may be affected by various impurities in wastewater. In this study, the effects of nine representative ionic surfactants including three types (anionic, cationic and zwitterionic) on crystallization kinetics and product quality of struvite were investigated, and the influencing mechanism was further probed. The results demonstrated that anionic surfactants significantly inhibit crystal growth so as to reduce crystal size especially in a-axis direction, change crystal morphology and decrease P recovery efficiency, and also lead to a slight decline in product purity. In contrast, cationic and zwitterionic surfactants have no obvious influence on the formation of struvite. A series of experimental characterizations and molecular simulations collectively revealed that the inhibition of crystal growth by anionic surfactants is attributed to the adsorption of anionic surfactant molecules on struvite crystal surface and subsequent blockage of active growth sites. The binding ability of surfactant molecules with the Mg2+ exposed on struvite crystal surface was highlighted to be the most essential factor determining the adsorption behavior and adsorption capacity. Anionic surfactants with stronger binding ability with Mg2+ have more intense inhibitory effect, but a large molecular volume of anionic surfactants will weaken the adsorption capacity on crystal surface so as to reduce the inhibitory effect. Contrastively, cationic and zwitterion surfactants without binding ability with Mg2+ have no inhibitory effect. These findings enable us to have a clearer understanding of the impact of organic pollutants on struvite crystallization and make a preliminary judgment on the organic pollutants that may have the ability to inhibit the crystal growth of struvite.