Guidelines derived from biomineralized tissues for design and construction of high-performance biomimetic materials: from weak to strong

Biomimetic Hierarchical Construction of Anti-Tumor Polyoxopalladates for Cancer Therapy

Inspired by the construction scheme of biomacromolecules, a hierarchical assembly based on the lacunary polyoxopalladate (POP) of [SrPd12O6(OH)3(PhAsO3)6(OAc)3]4- (SrPd12) has been achieved. As a structurally programmable molecular building block, SrPd12 is used to evolve from monomer via dimer to supramolecular aggregates in a controlled manner. In such process, the open-shell-type monomers are covalently integrated into bowl- or cage-like dimers via a direct or indirect splicing strategy. Upon that, hydrogen bond and hydrophobic effects are further hired to fabricate supramolecular aggregates of varied host-guest archetypes, thereby completing a hierarchical construction. In consideration of the combined advantages of noble metals and polyoxometalates in cancer treatment, both in vitro and in vivo anti-tumor assays of these SrPd12-derived POPs were studied in detail. A structure-dependent anti-tumor activitywas observed, originating from an imbalance of damage and repair of DNA as anti-tumor mechanism.

A novel Liesegang-patterned mineralized hydrogel drives bone regeneration with microstructure control

Bone regeneration remains a critical challenge in modern medicine. Recent advancements have focused on incorporating hierarchical microstructures into biomaterials to enhance osteogenesis. Mineralized hydrogels, while promising, face limitations in precise microstructure control due to technical complexities. In this study, we present a biomimetic hierarchical structural mineralized hydrogel featuring a Liesegang pattern. In vitro experiments confirm that it significantly promotes the migration and osteogenic differentiation of bone mesenchymal stem cells (BMSCs). In vivo experiments further demonstrate its ability to significantly promote bone regeneration, with newly formed bone closely replicating the hydrogel's architecture. Notably, this hydrogel synthesis strategy eliminates time-consuming fabrication and extensive post-processing, offering a scalable and efficient route for advanced bone-regenerative materials.

Remodeling the Senescent Microenvironment for Promoting Osteoporotic Tendon-to-Bone Healing via Synergizing Senolytic Quercetin and Aligned Nanowire-Structured Hydrogels

Osteoporotic tendon-to-bone healing remains a major challenge, as cellular senescence disrupts tissue regeneration and impairs repair outcomes. Although the role of cellular senescence in rotator cuff repair is increasingly recognized, current strategies often overlook the complex pathological context, particularly the dual impacts of senescence on both bone marrow-derived mesenchymal stem cells (BMSCs) and tendon-derived stem cells (TDSCs). This gap hampers effective tendon-to-bone healing and integration, especially under osteoporotic conditions. Herein, a composite hydrogel system, quercetin-loaded aligned ultralong hydroxyapatite nanowire/gelatin-hyaluronic acid hydrogel (Que-AHNW/GH), has been developed to address these challenges. By integrating senolytic quercetin as a biological cue with highly aligned ultralong hydroxyapatite (HAP) nanowires as a topographical cue, the system remodels the senescent microenvironment, alleviating senescence in both BMSCs and TDSCs and promoting osteogenesis and tenogenesis. Que-AHNW/GH suppresses the PI3K/AKT pathway, enhances autophagy, and reduces senescence in both cell types. In vivo, Que-AHNW/GH improves bone tunnel regeneration, tendon repair, and tendon-to-bone integration in osteoporotic rats with rotator cuff injury. This system enhances biomechanical strength and gait performance and demonstrates excellent biosafety. These findings highlight the promising potential of Que-AHNW/GH as a multifunctional biomaterial for effectively promoting senescence-related tendon-to-bone healing, offering a promising solution for treating osteoporotic tendon-to-bone injuries.

Injectable and drug-loaded gelatin methacrylate and carboxymethylated-sulfated xanthan gum hydrogels as biomimetic mineralization constructs

Injectable and drug-loaded hydrogels based on gelatin and xanthan gum derivatives were biomineralized to form organic-inorganic hybrid composites with osteoconductivity and controllable release of antibiotic drug for inducing bone generation. Gelatin was amidated to get gelatin methacrylate (GM) for supporting cell adhesion and photo-crosslinkability. Xanthan gum was chemically modified to obtain carboxymethalated and sulfated derivatives (CMXG and SXG) with high negative charges for mimicking chondroitin sulfate in bone. GM was co-dissolved with CMXG/SXG and ciprofloxacin hydrochloride (CPFXH), and photo-crosslinked with lithium phenyl-2,4,6-tri methylbenzoylphosphinate (LAP) to fabricate drug-loaded CMXG/SXG-GM-CPFXH-LAP hydrogels, which possessed swelling ratio of 1.30 ± 0.03 and controlled release of CPFXH in PBS for 24 h. The 7d-mineralized CMXG/SXG3-GM12-CPFXH-LAP hydrogel showed dense mineral layers with Ca/P atomic ratio of 1.79, degree of crystalline of 77.3 %, mineral content of 50.8 %, and 2.6 times higher shear modulus than original one. The CMXG/SXG3-GM12-CPFXH-LAP solution was acted as "inks" to "write" word (BONE) and Chinese character ("Gu") manually, and was transferred into moulds to obtain hydrogel constructs with good fidelity of patterns, suggesting injectability and printability. The injectable, mineralizable, biocompatible and drug-loaded CMXG/SXG-GM-CPFXH-LAP hydrogels possess promising applications in bone tissue engineering due to facilitating osteoconductivity, recruiting cells, and reducing inflammation.

Metastable Calcium Phosphate Cluster-Involved Mineralization Process Regulated by a Dual Biomolecule System Toward the Application in Dentinal Tubules Occlusion

Dentin hypersensitivity caused by the exposure of dentinal tubules is affecting a significant portion of the population. With promising prospects, the biomimetic mineralization materials used in treating dentin hypersensitivity are expected to possess a metastable characteristic, for which they can easily penetrate the tubules and the surrounding tissues, but then occlude them via a transformation of size and phase immediately. Herein, this study develops a metastable calcium phosphate cluster (MCPC)-involved mineralization process, which is regulated by dual biological macromolecules: bovine serum albumin (BSA) and poly-L-lysine (PLL). BSA functions to stabilize the primary calcium phosphate clusters; PLL further tunes the cluster's evolution (toward larger and crystalline particles) into a metastable fashion, and meanwhile inhibits the local bacteria. Upon treatments, the system generates amorphous MCPC with ultrasmall size (1-2 nm); then they enter the deep dentinal tubules, subsequently aggregate and crystalline into immobile larger particles, which finally seal the exposed dentinal tubules. The effective occlusion of dentinal tubules as well as significant antibacterial performance are confirmed both in vivo and in vitro. This study has devised not only a regulatory approach for the evolution of mineralization-active clusters but also established an efficient method for managing dentin hypersensitivity.

Bioinspired Materials for Controlling Mineral Adhesion: From Innovation Design to Diverse Applications

The advancement of controllable mineral adhesion materials has significantly impacted various sectors, including industrial production, energy utilization, biomedicine, construction engineering, food safety, and environmental management. Natural biological materials exhibit distinctive and controllable adhesion properties that inspire the design of artificial systems for controlling mineral adhesion. In recent decades, researchers have sought to create bioinspired materials that effectively regulate mineral adhesion, significantly accelerating the development of functional materials across various emerging fields. Herein, we review recent advances in bioinspired materials for controlling mineral adhesion, including bioinspired mineralized materials and bioinspired antiscaling materials. First, a systematic overview of biological materials that exhibit controllable mineral adhesion in nature is provided. Then, the mechanism of mineral adhesion and the latest adhesion characterization between minerals and material surfaces are introduced. Later, the latest advances in bioinspired materials designed for controlling mineral adhesion are presented, ranging from the molecular level to micro/nanostructures, including bioinspired mineralized materials and bioinspired antiscaling materials. Additionally, recent applications of these bioinspired materials in emerging fields are discussed, such as industrial production, energy utilization, biomedicine, construction engineering, and environmental management, highlighting their roles in promoting or inhibiting aspects. Finally, we summarize the ongoing challenges and offer a perspective on the future of this charming field.

Microwave-Heating-Assisted Synthesis of Ultrathin and Ultralong Hydroxyapatite Nanowires Using Biogenic Creatine Phosphate and Their Derived Flexible Bio-Paper with Drug Delivery Function

With an ultrahigh aspect ratio and a similar chemical composition to the biomineral in bone and tooth, ultralong hydroxyapatite nanowires (UHAPNWs) exhibit a meritorious combination of high flexibility, excellent mechanical performance, high biocompatibility, and bioactivity. Despite these exciting merits, the rapid and green synthesis of UHAPNWs remains challenging. In this work, we have developed an environment-friendly, rapid, and highly efficient synthesis of ultrathin UHAPNWs by the microwave-assisted calcium oleate precursor hydrothermal method using biogenic creatine phosphate as the bio-phosphorus source. Owing to the controllable hydrolysis of bio-phosphorus-containing creatine phosphate and the highly efficient heating of microwave irradiation, ultrathin UHAPNWs with a homogeneous morphology of several nanometers in diameter (single nanowire), several hundred micrometers in length, and ultrahigh aspect ratios (>10,000) can be rapidly synthesized within 60 min. This effectively shortens the synthesis time by about two orders of magnitude compared with the traditional hydrothermal method. Furthermore, ultrathin UHAPNWs are decorated in situ with bioactive creatine and self-assembled into nanowire bundles along their longitudinal direction at the nanoscale. In addition, ultrathin UHAPNWs exhibit a relatively high specific surface area of 84.30 m2 g-1 and high ibuprofen drug loading capacity. The flexible bio-paper constructed from interwoven ibuprofen-loaded ultrathin UHAPNWs can sustainably deliver ibuprofen in phosphate-buffered saline, which is promising for various biomedical applications such as tissue regeneration with anti-inflammatory and analgesic functions.

A Fish-Gill-Inspired Biomimetic Multiscale-Ordered Hydrogel-Based Solar Water Evaporator for Highly Efficient Salt-Rejecting Seawater Desalination

Solar energy-driven steam generation is a renewable, energy-efficient technology that can alleviate the global clean water shortage through seawater desalination. However, the contradiction between resistance to salinity accretion and maintaining high water evaporation properties remains a challenging bottleneck. Herein, we have developed a biomimetic multiscale-ordered hydrogel-based solar water evaporator for efficient seawater desalination. The as-prepared solar water evaporator consists of highly ordered ultralong hydroxyapatite (HAP) nanowires as a supporting backbone and heat insulator, MXene as a sunlight absorber, and hydrophilic hyaluronic acid methacryloyl (HAMA) as an interfacial bonding agent, and a modifier to reduce the water evaporation enthalpy. The MXene/ultralong HAP nanowires/HAMA (MHH) photothermal hydrogel evaporator with the multiscale-ordered hierarchical structure mimics the fish-gill structure. The highly ordered alignment of ultralong HAP nanowires is realized at multiple scales, from the nanoscale to the microscale to the macroscale and from 1D to 2D to 3D in the as-prepared photothermal hydrogel evaporator. The high-performance MHH photothermal hydrogel water evaporator exhibits high efficiency of photothermal conversion, low water evaporation enthalpy, excellent heat management capability, and high solar water evaporation performance. The water evaporation enthalpy decreases from 2431 J g-1 (pure water) to 1113 J g-1 using the MHH photothermal hydrogel evaporator. As a result, the high-performance MHH hydrogel water evaporator can realize a high water evaporation rate of 6.278 kg m-2 h-1 under one sun illumination (1 kW m-2). Moreover, the as-prepared MHH hydrogel evaporator is able to achieve a water evaporation rate of 4.931 kg m-2 h-1 using the real seawater sample, exhibiting excellent salt-rejecting performance. It is expected that the as-prepared MHH hydrogel evaporator has promising applications in high-performance seawater desalination and wastewater purification using the sustainable solar energy.

A Moldable, Tough Mineral-Dominated Nanocomposite as a Recyclable Structural Material

Flexible hybrid minerals, primarily composed of inorganic ionic crystal nanolines and a small amount of organic molecules, have significant potential for the development of sustainable structural materials. However, the weak interactions and insufficient crosslinking among the inorganic nanolines limit the mechanical enhancement and application of these hybrid minerals in high-strength structural materials. Inspired by tough biominerals and modern reinforced concrete structures, this study proposes introducing an aramid nanofiber (ANF) network as a flexible framework during the polymerization of calcium phosphate oligomers (CPO), crosslinked by polyvinyl alcohol (PVA) and sodium alginate (SA). This approach allows the flexible inorganic nanolines formed through CPO polymerization to be integrated into the organic framework, thereby creating tough mineral-based structural materials (inorganic content: 70.7 wt.%), denoted as PVA/SA/ANF/CPO (PSAC). The multiple intermolecular interactions between the organic and inorganic phases, combined with the integrated nano-reinforced concrete structure, endow PSAC with significantly enhanced tensile strength (86.6 ± 8.6 MPa), comparable to that of high-strength polymer plastics. Moreover, PSAC possesses excellent plasticity and flame retardancy. The noncovalent molecular interactions within PSAC enable efficient recyclability. Consequently, PSAC has the potential to replace high-strength polymer plastics and structural components, providing a promising avenue for developing high-strength and toughness mineral-based structural materials.

A composite dressing combining ultralong hydroxyapatite nanowire bio-paper and a calcium alginate hydrogel accelerates wound healing

An acute wound is the most common type of skin injury. Developing wound dressings with excellent mechanical properties, wound protection, comfort, angiogenic capacity and therapeutic effects is significant for effective treatments, yet remains challenging. Herein, we have designed a novel HAP-Alg composite dressing comprising a complementary ultralong hydroxyapatite (HAP) nanowire bio-paper and calcium alginate hydrogel. The HAP bio-paper assembled by ultralong HAP nanowires, in contrast to typical brittle HAP bio-ceramics, exhibits a highly flexible and interwoven structure to enhance the mechanical and protective performance of an alginate hydrogel, and the alginate matrix creates a moist environment for skin regeneration. Therefore, the HAP-Alg composite dressing presents good mechanical properties and high resistance to swelling and shrinkage, along with a reliable bacterial shielding ability. In addition, its moisturizing effect can deliver bioactive calcium ions to promote angiogenesis, accelerate re-epithelialization and reduce scar formation. In vitro studies reveal that the HAP-Alg composite dressing has excellent biocompatibility, promotes cell migration and angiogenesis, and enhances calcium ion influx. In vivo wound models further prove the ability of the HAP-Alg composite dressing to accelerate wound closure, enhance collagen deposition, and induce neovascularization. This work demonstrates that the HAP-Alg composite dressing offers a promising wound dressing for acute wound treatment and protection.

A pH-responsive microneedle patch for the transdermal delivery of biomineralized insulin nanoparticles to diabetes treatment

Diabetes mellitus is a chronic metabolic disease, and insulin injection administration remains the most commonly used treatment approach in clinical practice. However, this method faces the risks of insufficient specificity and high toxic side effects on normal tissues. Therefore, developing more effective drug administration methods is crucial for improving the safety and bioavailability of insulin. In this study, a swellable composite microneedle delivery system loaded with biomineralized insulin nanoparticles was constructed for effective diabetes treatment via percutaneous administration. The microneedle arrays were prepared by using N-2-hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) and hyaluronic acid (HA) with the assistance of β-Glycerophosphate Tetrahydrate (β-GP). Glucose oxidase (GOx) and calcium phosphate-biomineralized insulin nanoparticles (BINPs) were co-encapsulated in the microneedle arrays. After insertion into the skin, the interstitial fluid and high glucose concentration facilitated the sustained transdermal delivery of BINPs from the tips of the microneedle patches and the glucose-responsive release of insulin. The constructed composite microneedle patches demonstrated desirable therapeutic effects for diabetes with high biosafety, biodegradation and long-lasting effects. This study proposes a new strategy for developing intelligent drug delivery systems based on polymeric microneedle patches, and it is expected to be used in the broader biomedical field with potential applications.

Biomimetic Scaffolds Regulating the Iron Homeostasis for Remolding Infected Osteogenic Microenvironment

The treatment of infected bone defects (IBDs) needs simultaneous elimination of infection and acceleration of bone regeneration. One mechanism that hinders the regeneration of IBDs is the iron competition between pathogens and host cells, leading to an iron deficient microenvironment that impairs the innate immune responses. In this work, an in situ modification strategy is proposed for printing iron-active multifunctional scaffolds with iron homeostasis regulation ability for treating IBDs. As a proof-of-concept, ultralong hydroxyapatite (HA) nanowires are modified through in situ growth of a layer of iron gallate (FeGA) followed by incorporation in the poly(lactic-co-glycolic acid) (PLGA) matrix to print biomimetic PLGA based composite scaffolds containing FeGA modified HA nanowires (FeGA-HA@PLGA). The photothermal effect of FeGA endows the scaffolds with excellent antibacterial activity. The released iron ions from the FeGA-HA@PLGA help restore the iron homeostasis microenvironment, thereby promoting anti-inflammatory, angiogenesis and osteogenic differentiation. The transcriptomic analysis shows that FeGA-HA@PLGA scaffolds exert anti-inflammatory and pro-osteogenic differentiation by activating NF-κB, MAPK and PI3K-AKT signaling pathways. Animal experiments confirm the excellent bone repair performance of FeGA-HA@PLGA scaffolds for IBDs, suggesting the promising prospect of iron homeostasis regulation therapy in future clinical applications.

Initial solution pH value for the construction of a 3D hydroxyapatite via the trisodium citrate-assisted hydrothermal route

In this study, a trisodium citrate (TSC)-assisted hydrothermal method is utilized to prepare three-dimensional hydroxyapatite (3D HA). Understanding the role of TSC in the preparation of 3D HA crystals may provide valuable methods to design advanced biomaterials. As one of the indexes of solution supersaturation, the initial pH (ipH) value can not only directly affect the nucleation rate, but also affect the growth of HA crystals. In this work, the effect of the ipH on the microstructure, particle size distribution, and specific surface area of the 3D HA is explored. Results showed that the morphology of 3D HA transformed from a bundle to a dumbbell ball and then a dumbbell with an increase in the ipH. A corresponding mechanism of such a structural evolution was proposed, providing inspiration for the fabrication of innovative 3D HA structures with enhanced biological functionality and performance.