Organic-Inorganic Copolymerization for a Homogenous Composite without an Interphase Boundary

Rational Design of an In-Situ Polymer-Inorganic Hybrid Solid Electrolyte Interphase for Realising Stable Zn Metal Anode under Harsh Conditions

The in-depth understanding of the composition-property-performance relationship of solid electrolyte interphase (SEI) is the basis of developing a reliable SEI to stablize the Zn anode-electrolyte interface, but it remains unclear in rechargeable aqueous zinc ion batteries. Herein, a well-designed electrolyte based on 2 M Zn(CF3SO3)2-0.2 M acrylamide-0.2 M ZnSO4 is proposed. A robust polymer (polyacrylamide)-inorganic (Zn4SO4(OH)6.xH2O) hybrid SEI is in situ constructed on Zn anodes through controllable polymerization of acrylamide and coprecipitation of SO4 2- with Zn2+ and OH-. For the first time, the underlying SEI composition-property-performance relationship is systematically investigated and correlated. The results showed that the polymer-inorganic hybrid SEI, which integrates the high modulus of the inorganic component with the high toughness of the polymer ingredient, can realize high reversibility and long-term interfacial stability, even under ultrahigh areal current density and capacity (30 mA cm-2~30 mAh cm-2). The resultant Zn||NH4V4O10 cell also exhibits excellent cycling stability. This work will provide a guidance for the rational design of SEI layers in rechargeable aqueous zinc ion batteries.

Construction of Mineralization Nanostructures in Polymers for Mechanical Enhancement and Functionalization

Mineralization capable of growing inorganic nanostructures efficiently, orderly, and spontaneously shows great potential for application in the construction of high-performance organic-inorganic composites. As a thermodynamically spontaneous solid-phase crystallization reaction involving dual organic and inorganic components, mineralization allows for the self-assembly of sophisticated and exclusive nanostructures within a polymer matrix. It results in a diversity of functions such as enhanced strength, toughness, electrical conductivity, selective permeability, and biocompatibility. While there are previous reviews discussing the progress of mineralization reactions, many of them overlook the significant benefits of interfacial regulation and functionalization that come from the incorporation of mineralized structures into polymers. Focusing on different means of assembly of mineralized nanostructures in polymer, the work analyzes their design principles and implementation strategies. Then, their different advantages and disadvantages are analyzed by combining nanostructures with organic substrates as well as involving the basis of different functionalizations. It is anticipated to provide insights and guidance for the future development of mineralized polymer composites and their application designs.

Silk fibroin/methacrylated gelatine/hydroxyapatite biomimetic nanofibrous membranes for guided bone regeneration

By mimicking in vivo bionic microenvironment and promoting osteogenic differentiation, the hybrid organic-inorganic nanofibrous membranes provide promising potential for guided bone regeneration (GBR) in the treatment of clinical bone defects. To develop a degradable and osteogenic membrane for GBR by combining the natural biomacromolecule silk fibroin (SF) and gelatine with the bioactive nano hydroxyapatite (nHA), the anhydride-modified gelatine-nano hydroxyapatite (GelMA-nHA) composites were synthesized in situ and introduced into silk fibroin to prepare nanofibrous membranes with different ratios using electrospinning and photocrosslinking. The nanofibrous membranes, particularly those with a mass ratio of 7:2:1, were found to exhibit satisfactory elongation at break up to 110 %, maintain the nanofibrous structure for up to 28 days, and rapidly form bone-like apatite within 3 days, thus offering advantages when it comes to guided bone regeneration. In vitro cell results showed that the SF/GelMA/nHA membranes had excellent biocompatibility and enhanced osteogenic differentiation of hBMSCs. In vivo studies revealed that the hybrid composite membranes can improve bone regeneration of critical-sized calvarial defects in rat model. Therefore, the novel hybrid nanofibrous membrane is proposed to be a alternative candidate for creating a bionic microenvironment that promotes bone regeneration, indicating their potential application to bone injury treatment.

Sodium Silicate/Urea/Melamine Ternary Synergistic Waterborne Acrylic Acid Flame-Retardant Coating and Its Flame-Retardant Mechanism

Waterborne acrylic coatings, the largest market share of predominant environmentally friendly coatings, face limitations in their extensive application due to their flammability. The flame-retardant properties of the coatings could be significantly enhanced by incorporate inorganic flame retardants. However, inorganic flame retardants tend to aggregate and unevenly disperse in waterborne acrylic coatings, causing a substantial decrease in flame retardancy. In this work, sodium silicate was utilized as a flame retardant, with urea and melamine serving as modifiers and synergistic agents. This combination resulted in the preparation of a sodium silicate/urea/melamine ternary synergistic waterborne acrylic flame-retardant coating. This coating was applied to the surface of poplar veneer to create flame-retardant poplar veneer. Subsequently, various instruments, including a scanning electron microscope (SEM), a limiting oxygen index meter (LOI), a thermogravimetric analyzer (TG), and a cone calorimeter (CONE), were employed to investigate the relevant properties and mechanisms of both the flame-retardant coating and poplar veneer. The results demonstrated that the sodium silicate/urea/melamine ternary synergistic flame retardant did not exhibit aggregation and could be uniformly dispersed in waterborne acrylic coatings. The physical and mechanical properties of the ternary synergistic flame-retardant poplar veneer coating were satisfactory. Melamine and urea, acting as modifiers, not only greatly enhanced the dispersibility of sodium silicate in waterborne acrylic coatings, but also assisted in the formation of a silicon-containing char layer through the generation of nitrogen, achieving ternary synergistic flame retardancy. In conclusion, this work explores a novel method to efficiently and uniformly disperse inorganic flame retardants in organic coatings. It significantly improves the dispersibility and uniformity of inorganic flame retardants in organic polymers, thereby substantially enhancing the flame-retardant performance of coatings. This work provides a theoretical basis for the research and application of new flame-retardant coatings in the field of chemistry and materials.

Synthesis and Characterisation of Hemihydrate Gypsum-Polyacrylamide Composite: A Novel Inorganic/Organic Cementitious Material

This study combined inorganic α-hemihydrate gypsum (α-HHG) with organic polyacrylamide (PAM) hydrogel to create a novel α-HHG/PAM composite material. Through this facile composite strategy, this fabricated material exhibited a significantly longer initial setting time and higher mechanical strength compared to α-HHG. The effects of the addition amount and the concentration of PAM precursor solution on the flowability of the α-HHG/PAM composite material slurry, initial setting time, and mechanical properties of the hardened specimens were investigated. The structural characteristics of the composite material were examined using XRD, FE-SEM, and TGA. The results showed that the initial setting time of the α-HHG/PAM composite material was 25.7 min, which is an extension of 127.43% compared to that of α-HHG. The flexural strength and compressive strength of the oven-dried specimens were 23.4 MPa and 58.6 MPa, respectively, representing increases of 34.73% and 84.86% over values for α-HHG. The XRD, FE-SEM, and TGA results all indicated that the hydration of α-HHG in the composite material was incomplete. The incompleteness is caused by the competition between the hydration process of inorganic α-HHG and the gelation process of the acrylamide molecules for water, which hinders some α-HHG from entirely reacting with water. The enhanced mechanical strength of the α-HHG/PAM composite material results from the tight interweaving and integrating of organic and inorganic networks. This study provides a concise and efficient approach to the modification research of hemihydrate gypsum.

TiO2/Polystyrene Nanocomposite Antibacterial Material as a Hemoperfusion Adsorbent for Efficient Bilirubin Removal and Prevention of Bacterial Infection

The use of hemoperfusion adsorbents for the removal of bilirubin in patients with liver failure has become a critical treatment. However, the insufficient clearance of bilirubin and the possibility of bacterial infection during hemoperfusion limit the application. In this work, we designed a novel antibacterial bilirubin adsorbent (PSVT) through the suspension polymerization reaction between double-bond functionalized TiO2 nanoparticles and styrene. PSVT showed an excellent bilirubin adsorption ability and antibacterial performance, ensuring efficient clearance of bilirubin in liver failure patients during hemoperfusion and preventing bacterial infection. The experimental results indicated that TiO2 was uniformly dispersed in the microspheres, which improved the mesoporous structure and increased the specific surface area. Composite adsorbent PSVT showed an exceptional bilirubin adsorption capacity, with the maximum adsorption capacity reaching 24.3 mg/g. In addition, the introduction of TiO2 endowed PSVT with excellent antibacterial ability; the ultimate antibacterial rates against Escherichia coli and Staphylococcus aureus reached 97.31 and 96.47%, respectively. In summary, PSVT served as a novel antibacterial bilirubin adsorbent with excellent bilirubin clearance capacity and antibacterial performance, providing excellent application prospects for treating liver failure patients.

Bioinspired Multiscale Mineralization: From Fundamentals to Potential Applications

The wondrous and imaginative designs of nature have always been an inexhaustible treasure trove for material scientists. Throughout the long evolutionary process, biominerals with hierarchical structures possess some specific advantages such as outstanding mechanical properties, biological functions, and sensing performances, the formation of which (biomineralization) is delicately regulated by organic component. Provoked by the subtle structures and profound principles of nature, bioinspired functional minerals can be designed with the participation of organic molecules. Because of the designable morphology and functions, multiscale mineralization has attracted more and more attention in the areas of medicine, chemistry, biology, and material science. This review provides a summary of current advancements in this extending topic. The mechanisms underlying mineralization is first concisely elucidated. Next, several types of minerals are categorized according to their structural characteristic, as well as the different potential applications of these materials. At last, a comprehensive overview of future developments for bioinspired multiscale mineralization is given. Concentrating on the mechanism of fabrication and broad application prospects of multiscale mineralization, the hope is to provide inspirations for the design of other functional materials.

High Mechanical Strength Alloy-like Minerals Prepared by Inorganic Ionic Co-cross-linking

Alloys often combine different metals to generate superior mechanical properties. However, it is challenging to prepare high mechanical strength minerals with similar strategies. Using calcium carbonate (CaC) and calcium phosphate (CaP) as examples, this work synthesizes a group of compounds with the chemical formulas Ca(CO3 )x (PO4 )2(1- x )/3 (0 < x < 1, CaCPs) by cross-linking ionic oligomers. Unlike mixtures, these CaCPs exhibit a single temperature for the phase transition from amorphous to crystallized CaC (calcite) and CaP (hydroxyapatite). By heat-induced synchronous crystallization, dual-phase CaC/CaP with continuous crystallized boundaries are resembled to alloy-like minerals (ALMs). The mechanical properties of the ALMs are adjusted by tailoring their chemical compositions to reach a hardness of 5.6 GPa, which exceed those of control calcite and hydroxyapatite samples by 430% and 260%, respectively. This strategy expands the chemical scope of inorganic materials and holds promise for preparing high-performance minerals.

Self-wrinkling coating for impact resistance and mechanical enhancement

Protective materials are essential for personal, electronic, and military defenses owing to their efficient impact-resistant and energy-absorbing properties. Inspired by the bottom-up fabrication process and energy dissipation mechanism of natural organisms with hierarchical structures, we demonstrated a self-wrinkled photo-curing coating as a new protective material for enhancing the anti-impact property of the substrates. Owing to the self-assembly of polydimethylsiloxane (PDMS) containing polymeric photoinitiator on the surface, the liquid coating formulation was photo-cured by one-step UV irradiation with simultaneous generation of self-wrinkled surface morphology and a gradient cross-linked architecture. The maximum impact resistance height (hmax) of the glass substrate coated with plain coating increased from 120 to 180 cm when coated with wrinkled gradient coating. Furthermore, the Young's modulus, fracture stress, and toughness of the wrinkled gradient coating film improved from 39.6 MPa, 2.4 MPa, and 74.1 MJ/cm3 to 235.0 MPa (∼5× increase), 18.5 MPa (∼6.6× increase), and 845.0 MJ/cm3 (∼10.8× increase) compared to the pure coating film as reference. The theoretical simulation and experimental results proved that the surface self-wrinkled morphology and intrinsic hierarchical architecture contribute to the energy dissipation and impact resistance of the cured coating. The photo-curing process, a bottom-up strategy, is conducted in a non-contact mode compared with nano-printing and lithography, enabling bulk materials to be engineered.

Natural organic-inorganic hybrid structure enabled green biomass adhesive with desirable strength, toughness and mildew resistance

Plant based proteins are green, sustainable, and renewable materials that show the potential to replace traditional formaldehyde resin. High performance plywood adhesives exhibit high water resistance, strength, toughness, and desirable mildew resistance. Adding petrochemical-based crosslinkers is not economically viable or environmentally benign; this chemical crosslinking strategy makes the imparted high strength and toughness less attractive. Herein, a green approach based on natural organic-inorganic hybrid structure enhancement is proposed. The design of soybean meal-dialdehyde chitosan-amine modified halloysite nanotubes (SM-DACS-HNTs@N) adhesive with desirable strength and toughness enhanced by covalent bonding (Schiff base) crosslinking and toughened by surface-modified nanofillers is demonstrated. Consequently, the prepared adhesive showed a wet shear strength of 1.53 MPa and work of debonding of 389.7 mJ, which increased by 146.8 % and 276.5 %, respectively, due to the cross-linking effect of organic DACS and toughening effect of inorganic HNTs@N. The introduction of DACS and Schiff base generation enhanced the antimicrobial property of the adhesive and increased the mold resistance of the adhesive and plywood. In addition, the adhesive has good economic benefits. This research creates new opportunities for developing biomass composites with desirable performance.

Robust and Scalable In Vitro Surface Mineralization of Inert Polymers with a Rationally Designed Molecular Bridge

The artificial integration of inorganic materials onto polymers to create the analogues of natural biocomposites is an attractive field in materials science. However, due to significant diversity in the interfacial properties of two kinds of materials, advanced synthesis methods are quite complicated and the resultant materials are always vulnerable to external environments, which limits their application scenarios and makes them unsuitable for scalable production. Herein, we report a simple and universal approach to achieve robust and scalable surface mineralization of polymers using a rationally designed triple functional molecular bridge of fluorosilane, 3-[(perfluorohexyl sulfonyl) amino] propyltriethoxy silane (PFSS). In a two-step solution deposition, the fluoroalkyl and siloxane of the PFSS take charge of its adhesion and immobilization onto polymers by hydrophobic interaction and wrapping-like chemical cross-linking, and then the assembly and growth of inorganic nanoclusters for integration are achieved by strong chemical coordination of PFSS sulfonamide. The versatile mineralization of inorganic oxides (e.g., TiO₂, SiO₂, and Fe₂O₃) onto chemically inert polymer surfaces was realized very well. The resultant mineralized materials exhibit robust and multiple functionalities for hostile applications, such as hydrophilic membranes for removing oils in strong acidic and alkaline wastewaters, fabrics with advanced anti-bacteria for healthy wearing, and plates with strong mechanical performance for better use. Experimental results and theoretical calculations confirmed the homogenous distribution of the PFSS onto polymers via cross-linking for robust coordination with inorganic oxides. These results demonstrate a skillful enlightenment in the design of high-performance mineralized polymer materials used as membranes, fabrics, and medical devices.

In Situ Biomimetic Mineralization of Bone-Like Hydroxyapatite in Hydrogel for the Acceleration of Bone Regeneration

A critical-sized bone defect, which cannot be repaired through self-healing, is a major challenge in clinical therapeutics. The combination of biomimetic hydrogels and nano-hydroxyapatite (nano-HAP) is a promising way to solve this problem by constructing an osteogenic microenvironment. However, it is challenging to generate nano-HAP with a similar morphology and structure to that of natural bone, which limits the improvement of bone regeneration hydrogels. Inspired by our previous works on organic-inorganic cocross-linking, here, we built a strong organic-inorganic interaction by cross-linking periosteum-decellularized extracellular matrix and calcium phosphate oligomers, which ensured the in situ mineralization of bone-like nano-HAP in hydrogels. The resulting biomimetic osteogenic hydrogel (BOH) promotes bone mineralization, construction of immune microenvironment, and angiogenesis improvement in vitro. The BOH exhibited acceleration of osteogenesis in vivo, achieving large-sized bone defect regeneration and remodeling within 8 weeks, which is superior to many previously reported hydrogels. This study demonstrates the important role of bone-like nano-HAP in osteogenesis, which deepens the understanding of the design of biomaterials for hard tissue repair. The in situ mineralization of bone-like nano-HAP emphasizes the advantages of inorganic ionic oligomers in the construction of organic-inorganic interaction, which provides an alternative method for the preparation of advanced biomimetic materials.

Fast Construction of Biomimetic Organic-Inorganic Interface by Crosslinking of Calcium Phosphate Oligomers: A Strategy for Instant Regeneration of Hard Tissue

The organic-inorganic structure in biological hard tissues ensures their marvelous characteristics but these hybrids are easily destroyed by the demineralization of inorganic components, e.g., the damage of dentin. Current clinical materials for hard tissue regeneration commonly act as "fillers" and their therapeutic effect is limited by the failures of biological-linked organic-inorganic interface reconstruction. Herein, a fast in situ crosslinking of calcium phosphate oligomers (CPOs) on collagen matrixes for efficient organic-inorganic interface re-construction, which can result in a biomimetic hybrid, is demonstrated. By using damaged dentin as an example, the inorganic ionic crosslinking can instantly infiltrate into the dentin matrix to rebuild a dense and continuous calcium phosphate-collagen hybrid within only 5 min, where the structurally integrated organic-inorganic interface is identical to natural dentin. As a result, the damaged dentin can be fully recovered to a healthy one, which is superior to any current dentin treatments. The fast construction of biomimetic hybrid by inorganic ionic crosslinking provides a promising strategy for hard tissue repair and follows great potentials of CPOs as advanced biomedical materials in future.

Reinforcing hydrogels with in situ formed amorphous CaCO3

Hydrogels are often employed for tissue engineering and moistening applications. However, they are rarely used for load-bearing purposes because of their limited stiffness and the stiffness-toughness compromise inherent to them. By contrast, nature uses hydrogel-based materials as scaffolds for load-bearing and protecting materials by mineralizing them. Inspired by nature, the stiffness or toughness of synthetic hydrogels has been increased by forming minerals, such as CaCO₃, within them. However, the degree of hydrogel reinforcement achieved with CaCO₃ remains limited. To address this limitation, we form CaCO₃ biominerals in situ within a model hydrogel, poly(acrylamide) (PAM), and systematically investigate the influence of the size, structure, and morphology of the reinforcing CaCO₃ on the mechanical properties of the resulting hydrogels. We demonstrate that especially the structure of CaCO₃ and its affinity to the hydrogel matrix strongly influence the mechanical properties of mineralized hydrogels. For example, while the fracture energy of PAM hydrogels is increased 3-fold if reinforced with individual micro-sized CaCO₃ crystals, it increases by a factor of 13 if reinforced with a percolating amorphous calcium carbonate (ACC) nano-structure that forms in the presence of a sufficient quantity of Mg²⁺. If PAM is further functionalized with acrylic acid (AA) that possesses a high affinity towards ACC, the stiffness of the hydrogel increases by a factor 50. These fundamental insights on the structure-mechanical property relationship of hydrogels that have been functionalized with in situ formed minerals has the potential to enable tuning the mechanical properties of mineralized hydrogels over a much wider range than what is currently possible.

Carbon nitride-based Z-scheme heterojunctions for solar-driven advanced oxidation processes

Solar-driven advanced oxidation processes (AOPs) via direct photodegradation or indirect photocatalytic activation of typical oxidants, such as hydrogen peroxide (H₂O₂), peroxymonosulfate (PMS), and peroxydisulfate (PDS), have been deemed to be an efficient technology for wastewater remediation. Artificial Z-scheme structured materials represent a promising class of photocatalysts due to their spatially separated charge carriers and strong redox abilities. Herein, we summarize the development of metal-free graphitic carbon nitride (g-C₃N₄, CN)-based direct and indirect Z-scheme photocatalysts for solar-driven AOPs in removing organic pollutants from water. In the work, the classification of AOPs, definition and validation of Z-schemes are summarized firstly. The innovative engineering strategies (e.g., morphology and dimensionality control, element doping, defect engineering, cocatalyst loading, and tandem Z-scheme construction) over CN-based direct Z-scheme structure are then examined. Rational design of indirect CN-based Z-scheme systems using different charge mediators, such as solid conductive materials and soluble ion pairs, is further discussed. Through examining the relationship between the Z-scheme structure and activity (charge transfer and separation, light absorption, and reaction kinetics), we aim to provide more insights into the construction strategies and structure modification on CN-based Z-schemes towards improving their catalytic performances in AOPs. Lastly, limitations, challenges, and perspectives on future development in this emerging field are proposed.

A Bioinspired Ultratough Composite Produced by Integration of Inorganic Ionic Oligomers within Polymer Networks

The nacre-inspired laminates are promising materials for their excellent mechanics. However, the interfacial defects between organic-inorganic phases commonly lead to the crack propagation and fracture failure of these materials under stress. A natural biomineral, bone, has much higher bending toughness than the nacre. The small size of inorganic building units in bone improves the organic-inorganic interaction, which optimizes the material toughness. Inspired by these biological structures, here, an ultratough nanocomposite laminate is prepared by the integration of ultrasmall calcium phosphate oligomers (CPO, 1 nm in diameter) within poly(vinyl alcohol) (PVA) and sodium alginate (Alg) networks through a simple three-step strategy. Owing to the small size of inorganic building units, strong multiple molecular interactions within integrated organic-inorganic hierarchical structure are built. The resulting laminates exhibit ultrahigh bending strain (>50% without fracture) and toughness (21.5-31.0 MJ m^-3), which surpass natural nacre and almost all of the synthetic laminate materials that have been reported so far. Moreover, the mechanics of this laminate is tunable by changing the water content within the bulk structure. This work provides a way for the development of organic-inorganic nanocomposites with ultrahigh bending toughness by using inorganic ionic oligomers, which can be useful in the fields of tough protective materials and energy absorbing materials.

Fusion Bonding Possibility for Incompatible Polymers by the Novel Ultrasonic Welding Technology: Effect of Interfacial Compatibilization

Fusion bonding for polymers has been successfully welded for the same and dissimilar materials. However, it is difficult to bond incompatible polymers due to poor interfacial adhesion. Usually, interfacial compatibilization can resolve this problem. According to the mechanism, an interlayer solder sheet (ISS) consisting of maleic anhydride-functionalized polypropylene (PP-g-MAH) and polyamide6 (PA6) was introduced into the ultrasonic welding (USW) device. In this way, it successfully realized the weldability between PP and PA6. The welding strength of PP-PA6 reached 22.3 MPa, about 84% welding strength for the PP body and 63% tensile strength for PP. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) showed the formation of PP-g-PA6 copolymer in blends. This copolymer played the role of an emulsifier, which enhanced the interfacial adhesion between PP and PA6 in two phases, leading to micron-scale homogeneity. In the USW process, the copolymer could act as a bridge between PP and PA6 molecular chains to realize the fusion bonding of incompatible polymers. Finally, we proposed the fusion bonding model for PP-PA6 interfaces.

A Flexible and Degradable Hybrid Mineral as a Plastic Substitute

The development of environmentally friendly plastics is critical to ensure sustainable development. In contrast to polymer plastics derived from petrochemicals, inorganic minerals, which are the most abundant matter in Earth's crust, are environmentally friendly. However, the brittleness of these minerals limits their applications as plastics. Here, because of the advantages of both biomineralization and inorganic ionic polymerization, the calcium phosphate (CaP, a typical geological and biological mineral) oligomers are used for biomimetic mineralization under the regulation of polyvinyl alcohol and sodium alginate, resulting in flexible CaP nanofibers with periodic structural defects. The assembly of CaP nanofibers produces a hierarchically structured bulk hybrid mineral (HM), which overcomes the intrinsic brittleness of minerals and exhibits plasticity characteristics. HM exhibits better hardness and thermostability than classical polymer plastics due to its dominant mineral composition. Notably, HM is environmentally friendly and degradable in nature, as it can potentially participate in geological cycles, indicating that this material is an optimal plastic substitute. The construction of periodic structural defects within flexible minerals expands the current understanding of materials science.

Hydrogen Phosphates Play a Critical Structural Role in Amorphous Calcium Phosphates

Amorphous calcium phosphate (ACP) is an intriguing mineral phase of calcium phosphate in its own right, in addition to its relevance in biomineralization. We hereby demonstrate that ACPs prepared by...

Hydroxyapatite reinforced inorganic-organic hybrid nanocomposite as high-performance adsorbents for bilirubin removal in vitro and in pig models

Highly efficient removal of bilirubin from whole blood directly by hemoperfusion for liver failure therapy remains a challenge in the clinical field due to the low adsorption capacity, poor mechanical strength and low biocompatibility of adsorbents. In this work, a new class of nanocomposite adsorbents was constructed through an inorganic-organic co-crosslinked nanocomposite network between vinyltriethoxysilane (VTES)-functionalized hydroxyapatite nanoparticles (V-Hap) and non-ionic styrene-divinylbenzene (PS-DVB) resins (PS-DVB/V-Hap) using suspension polymerization. Notably, our adsorbent demonstrated substantially improved mechanical performance compared to the pure polymer, with the hardness and modulus increasing by nearly 3 and 2.5 times, respectively. Moreover, due to the development of a mesoporous structure, the prepared PS-DVB/V-Hap3 exhibited an ideal adsorption capacity of 40.27 mg g-1. More importantly, the obtained adsorbent beads showed outstanding blood compatibility and biocompatibility. Furthermore, in vivo extracorporeal hemoperfusion verified the efficacy and biosafety of the adsorbent for directly removing bilirubin from whole blood in pig models, and this material could potentially prevent liver damage and improve clinical outcomes. Taken together, the results suggest that PS-DVB/V-Hap3 beads can be used in commercial adsorption columns to threat hyperbilirubinemia patients through hemoperfusion, thus replacing the existing techniques where plasma separation is initially required.

Strategy to Fabricate a Strong and Supertough Bio-Inspired Fiber with Organic-Inorganic Networks in a Green and Scalable Way

Green and scalable production of some fibrous materials with higher fracture energy has long been the goal of researchers. Although some progress has been made in recent years in the research of materials with high fracture energy, inspired by the fiber structure of spider silk, it is still a great challenge to produce artificial fibers with extremely high toughness using a simple and green process. Here, we use the molecular and nanoscale engineering of calcium phosphate oligomers (CaP, < 1 nm) and waterborne polyurethanes (WPU) macromolecules that have strong interactions to form organic-inorganic networks just like β-sheet crystalline and flexible amorphous regions in spider silk. Through a simple and green route based on widespread paper string processing techniques, we fabricate a strong and supertough bioinspired fiber with a high strength (442 MPa), which is 7-15 times higher than the strength of counterpart PU (20-30 MPa), and a super toughness (640 MJ m^-3), which is 2-3.5 times higher than the toughness of spider dragline silk. This technique provides a strategy for industrially manufacturing spider fiber-like artificial fibers with a super toughness.

Digital Light Processing 4D Printing of Transparent, Strong, Highly Conductive Hydrogels

Hydrogels have excellent biocompatibility, transparency, stretchability, and ionic conductivity, but their fabrication through photopolymerization-based 3D printing is limited due to the low solubility of hydrophobic photoinitiators and lack of efficient hydrophilic photoinitiators. Herein, a type of microemulsion is synthesized and the common hydrophobic photoinitiator can be adopted and finally, a series of transparent hydrogels with high strength (up to 22.9 MPa), elasticity (up to 583%), and ionic conductivity (up to 9.64 S m^-1) are fabricated through digital light processing 3D printing technology. Objects with complex structures and a high printing resolution are printed. Hydrogels with both high strength and high ionic conductivity are obtained through chemical crosslinking and ion coordination effect. Dual-material 3D printing is applied to package the hydrogel with elastomers. Due to the high sensitivity and reliability under both stretching and compressive deformation, the hydrogel sensors are applied to monitor various human motions. In addition, the hydrogel exhibits solvent-induced dehydration and excellent water-activated shape memory properties, which are greatly beneficial for its storage and applications in the biomedical field.

Novel nanomaterial-organism hybrids with biomedical potential

Instinctive hierarchically biomineralized structures of various organisms, such as eggs, algae, and magnetotactic bacteria, afford extra protection and distinct performance, which endow fragile organisms with a tenacious ability to adapt and survive. However, spontaneous formation of hybrid materials is difficult for most organisms in nature. Rapid development of chemistry and materials science successfully obtained the combinations of organisms with nanomaterials by biomimetic mineralization thus demonstrating the reproduction of the structures and functions and generation of novel functions that organisms do not possess. The rational design of biomaterial-organism hybridization can control biological recognition, interactions, and metabolism of the organisms. Thus, nanomaterial-organism hybrids represent a next generation of organism engineering with great potential biomedical applications. This review summarizes recent advances in material-directed organism engineering and is mainly focused on biomimetic mineralization technologies and their outstanding biomedical applications. Three representative types of biomimetic mineralization are systematically introduced, including external mineralization, internal mineralization, and genetic engineering mineralization. The methods involving hybridization of nanomaterials and organisms based on biomimetic mineralization strategies are described. These strategies resulted in applications of various nanomaterial-organism hybrids with multiplex functions in cell engineering, cancer treatment, and vaccine improvement. Unlike classical biological approaches, this material-based bioregulation is universal, effective, and inexpensive. In particular, instead of traditional medical solutions, the integration of nanomaterials and organisms may exploit novel strategies to solve current biomedical problems. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Construction of Inorganic Bulks through Coalescence of Particle Precursors

Bulk inorganic materials play important roles in human society, and their construction is commonly achieved by the coalescence of inorganic nano- or micro-sized particles. Understanding the coalescence process promotes the elimination of particle interfaces, leading to continuous bulk phases with improved functions. In this review, we mainly focus on the coalescence of ceramic and metal materials for bulk construction. The basic knowledge of coalescent mechanism on inorganic materials is briefly introduced. Then, the properties of the inorganic precursors, which determine the coalescent behaviors of inorganic phases, are discussed from the views of particle interface, size, crystallinity, and orientation. The relationships between fundamental discoveries and industrial applications are emphasized. Based upon the understandings, the applications of inorganic bulk materials produced by the coalescence of their particle precursors are further presented. In conclusion, the challenges of particle coalescence for bulk material construction are presented, and the connection between recent fundamental findings and industrial applications is highlighted, aiming to provide an insightful outlook for the future development of functional inorganic materials.

Muscle-like Ultratough Hybrid Hydrogel Constructed by Heterogeneous Inorganic Polymerization on an Organic Network

Inspired by inorganic oligomers and their polymerization, we herein develop a heterogeneous inorganic polymerization tactic that can be used to prepare a muscle-like hybrid hydrogel by inducing the polymerization of calcium phosphate oligomers (CPO) onto a polyvinyl alcohol (PVA) molecular chain network. In this heterogeneous process, the CPO units bond with PVA molecules via assistance from sodium alginate (SA), and then gradually polymerize along the organic chains to form ultrafine hydroxyapatite nanolines with a diameter of ∼1 nm. Because of the well integration of organic and inorganic phases from the heterogeneous polymerization, the hierarchical structured hydrogel can exhibit ultratough mechanical properties of ∼17.84 MPa in strength and ∼8.97 kJ m^-2 in fracture energy, which exceed natural muscles and almost synthetic hydrogels. Moreover, the damaged hydrogel can be repaired readily by adding the precursors of CPO, PVA, and SA, which can induce in situ re-polymerization. The hydrogel also exhibits muscle-like rotational motion under aqueous conditions, which can be developed into a water-driven biomimetic motor. This study indicates that inorganic polymerization can achieve a novel organic-inorganic integration rather than conventional organic-inorganic composition, and it provides a novel tactic for design and manufacture of advanced materials.

Biomimetic Membranes of Methacrylated Gelatin/Nanohydroxyapatite/Poly(l-Lactic Acid) for Enhanced Bone Regeneration

Nanofibrous poly(l-lactic acid) (PLLA) membrane-simulated extracellular matrices (ECMs) can be used in the biomedical field. However, the hydrophobic nature and poor osteoinductive property of PLLA limit its application in guided bone regeneration (GBR). In this work, a methacrylated gelatin/nano-HA (GelMA/nHA) complex was first synthesized in situ and then introduced into PLLA to fabricate biomimetic GelMA/nHA/PLLA membranes, mimicking the nanofibrous architecture and composition of ECMs by electrospinning and photocrosslinking. Compared to PLLA and GelMA/PLLA membranes, the novel GelMA/nHA/PLLA membranes demonstrated better tensile, hydrophilic, water sorption, and degradation properties. An in vitro biological evaluation indicated that the membranes promoted human bone marrow-derived mesenchymal stem cell (hBMSC) proliferation, adhesion, and osteogenic differentiation. Critical-sized defects in rat models were used to evaluate the bone regeneration performances of the three kinds of membranes in vivo, and the GelMA/nHA/PLLA membranes demonstrated excellent osteogenic regeneration potential. Therefore, GelMA/nHA/PLLA membranes have wide application prospects in bioengineering applications such as GBR treatment.

Chameleon-Inspired Stress-Responsive Multicolored Ultratough Films

Chameleons have a distinguished talent to rapidly shift their colors by active tuning of a lattice of guanine nanocrystals within a superficial thick layer of dermal iridophores. This reversible structural color variation is derived from the birefringence, which is triggered by the special anisotropic structure interacting with natural light. Inspired by the inorganic oligomers and their superiorities for constructing ultratough materials with a special structure, we demonstrated here a chameleon's skin-like film constructed by ultrasmall calcium phosphate oligomers (∼1.75 nm in diameter) as the precursor of crystalline hydroxyapatite nanoline (HNL) arrays and polyvinyl alcohol as the elastic matrix. The resulting films exhibit excellent toughness (48.3 ± 5.2 MJ m^-3). Under the applied cyclic stress, the HNLs embedded in the polymer network can reversibly arrange into a highly ordered crystal arrays owing to the driving action of polymer chains. The intense birefringence of the stretched films is easily observed with the naked eye under crossed polarizers, allowing for rapid and simple measurement of the applied stress. This work provides a pathway for the development of functional composites with super toughness by ultrasmall inorganic oligomers for their potential applications in smart devices for stress detection.

Towards an Understanding of Crystallization by Attachment

Crystallization via particle attachment was used in a unified model for both classical and non-classical crystallization pathways, which have been widely observed in biomimetic mineralization and geological fields. However, much remains unknown about the detailed processes and driving mechanisms for the attachment. Here, we take calcite crystal as a model mineral to investigate the detailed attachment process using in situ Atomic Force Microscopy (AFM) force measurements and molecular dynamics simulations. The results show that hydration layers hinder the attachment; however, in supersaturated solutions, ionic bridges are formed between crystal gaps as a result of capillary condensation, which might enhance the aggregation of calcite crystals. These findings provide a more detailed understanding of the crystal attachment, which is of vital importance for a better understanding of mineral formation under biological and geological environments with a wide range of chemical and physical conditions.