Organic-inorganic Composite Materials Research Articles

Promoting neurovascularized bone regeneration with a novel 3D printed inorganic-organic magnesium silicate/PLA composite scaffold

Critical-size bone defect repair presents multiple challenges, such as osteogenesis, vascularization, and neurogenesis. Current biomaterials for bone repair need more consideration for the above functions. Organic-inorganic composites combined with bioactive ions offer significant advantages in bone regeneration. In our work, we prepared an organic-inorganic composite material by blending polylactic acid (PLA) with 3-aminopropyltriethoxysilane (APTES)-modified magnesium silicate (A-M2S) and fabricated it by 3D printing. With the increase of A-M2S proportion, the hydrophilicity and mineralization ability showed an enhanced trend, and the compressive strength and elastic modulus were increased from 15.29MPa and 94.61MPa to 44.30MPa and 435.77MPa, respectively. Furthermore, A-M2S/PLA scaffolds not only exhibited good cytocompatibility of bone marrow mesenchymal stem cells (BMSCs), human umbilical vein endothelial cells (HUVECs), and Schwann cells (SCs), but also effectively promoted osteogenesis, angiogenesis, and neurogenesis in vitro. After implanting 10% A-M2S/PLA scaffolds in vivo, the scaffolds showed the most effective repair of cranium defects compared to the blank and control group (PLA). Additionally, they promoted the secretion of proteins related to bone regeneration and neurovascular formation. These results provided the basis for expanding the application of A-M2S and PLA in bone tissue engineering and presented a novel concept for neurovascularized bone repair.

Effects of germanium content on the optical properties of GeO2-based organic-inorganic composite films doped with azobenzene

Organic-inorganic composite materials have great applications in integrated optics due to their good optical performance. In this study, GeO2-based organic-inorganic composite films doped with azobenzene were prepared by combining the solgel technique and the spin-coating method. The optical waveguide properties including the refractive index and film thickness and the optical response properties of the composite films with different germanium contents have been investigated. The results indicate that the refractive index of the film increases, but the film thickness decreases as the germanium content increases. The composite film with 0.2 mol of germanium exhibits the best optical response properties. Further, the optical switching characteristics of the optimal composite film shows good stability and reversibility. The photochemical and structural properties of the film were also investigated by using Fourier transform infrared spectroscopy and thermo-gravimetric analysis. Finally, hexagonal microlens arrays were built in the film by using the UV nanoimprint technique, resulting in neatly arranged structures with good optical imaging performance.

Novel organic-inorganic composite pea protein silica food-grade aerogel materials: Fabrication, mechanisms, high oil-holding property and curcumin delivery capacity

The fragility of the skeleton and poor bioaccessibility limit Silica aerogel's application in the food industry. In this study, composite gels were obtained by cross-linking pea proteins isolate (PPI) with Tetraethoxysilane (TEOS)to improve the bioavailability of silica-derived aerogels. It indicated that TEOS first condensed with H+ to form secondary particles and then complexed with PPI via hydroxyl groups to form a composite aerogel. Meanwhile, the PPI-Si composite aerogel formed a dense mesoporous structure with a specific surface area of 312.5 g/cm3. This resulted in a higher oil holding percentage of 89.67 % for the PPI (10 %)-Si aerogel, which was 34.1 % higher than other studies, leading to a more stable oleogel. Finally, as a delivery system, the composite oleogel not only could significantly increase the bioaccessibility rate by 27.4 % compared with silica aerogel, but also could efficiently inhibit the premature release of curcumin in the simulated gastric fluids, while allowed sustainably release in the simulated intestinal fluids. These results provided a theoretical basis for the application of silica-derived aerogels in food and non-food applications.

Quantifying the interfacial triboelectricity in inorganic-organic composite mechanoluminescent materials

Mechanoluminescence (ML) sensing technologies open up new opportunities for intelligent sensors, self-powered displays and wearable devices. However, the emission efficiency of ML materials reported so far still fails to meet the growing application requirements due to the insufficiently understood mechano-to-photon conversion mechanism. Herein, we propose to quantify the ability of different phases to gain or lose electrons under friction (defined as triboelectric series), and reveal that the inorganic-organic interfacial triboelectricity is a key factor in determining the ML in inorganic-organic composites. A positive correlation between the difference in triboelectric series and the ML intensity is established in a series of composites, and a 20-fold increase in ML intensity is finally obtained by selecting an appropriate inorganic-organic combination. The interfacial triboelectricity-regulated ML is further demonstrated in multi-interface systems that include an inorganic phosphor-organic matrix and organic matrix-force applicator interfaces, and again confirmed by self-oxidization and reduction of emission centers under continuous mechanical stimulus. This work not only gives direct experimental evidences for the underlying mechanism of ML, but also provides guidelines for rationally designing high-efficiency ML materials.

Double-inverse-opal structured films of a hydrogel framework and mobile inorganic particles

Double-inverse-opal (DIO) structured assemblies are three-dimensionally ordered porous materials containing core particles inside. In this work, DIO structured films composed of mobile inorganic colloidal particles within an organic polymer gel framework were developed. As the organic backbone, a poly(N-isopropylacrylamide) gel (PNIPAM gel) was employed to enhance the flexibility and processability of the films. A three-dimensional periodic structure of fluorescent-labelled silica core particles in the film was observed with confocal microscopy. Thermally induced volume transitions of the PNIPAM gels were observed, which showed the potential for stimuli-responsive optical materials. By selective etching of the sacrificial shell layers surrounding the core particles, cavities formed around the cores, and they exhibited random Brownian motion inside these pockets in the film. As a new type of organic-inorganic composite material, the proposed DIO structured films possessed unique characteristics originating from the combination of a flexible backbone and mobile cores, applicable to stimuli-responsive photonic devices, reusable catalytic particle assemblies, etc.

Abundant nucleation sites-available liquid crystal hydrogel mimics bone ECM mineralization to boost osteogenesis

Bone extracellular matrix (ECM) is a unique organic-inorganic composite material derived from highly mineralized liquid crystal (LC) organic substrate. However, it remains a substantial challenge to design bone ECM-like LC materials with sufficient available nucleation sites to mimic the mineralization process of natural bone. Herein, we designed a bioinspired hydrogel with bone ECM-like LC organic substrate and inorganic phosphate mineralization nucleation sites for robust cell biomineralization and bone regeneration. Black phosphorus (BP) nanosheet was firstly loaded by bioactive layered double hydroxide (LDH) based on electrostatic attraction to improve the stability and photothermal performance of BP. Then, the LDH@BP was creatively added into chitin whisker/poly (ethylene glycol) diacrylate (CHW/PEGDA) LC hydrogel, abbreviated as LCgel, to fabricate LCgel/LDH@BP to highly mimic the mineralization microenvironment of bone ECM. The bone ECM-like LC topology of LCgel/LDH@BP is conducive to facilitating cell adhesion, proliferation and osteogenic differentiation. More importantly, the in-situ phosphate mineralization nucleation sites combined with mild hyperthermia induced by BP can further synergistically reinforce biomineralization of cells adhered on bone ECM-like LC substrate, thus substantially promoting cell biomineralization-mediated osteogenesis in vitro and in vivo. This study opens a new insight for the design of bioinspired hydrogel for cell biomineralization-mediated osteogenesis.

In Situ Construction of Morphologically Different Hydroxyapatite-Mineralized Structures on a Three-Dimensional Bionic Chitin Scaffold.

Slow healing at the tendon-bone interface is a prominent factor in the failure of tendon repair surgeries. The development of functional biomaterials with 3D gradient structures is urgently needed to improve tendon-bone integration. The crystalline form of hydroxyapatite (HAP) has a crucial impact on cell behavior, which directly influences protein adsorption, such as bone morphogenetic protein 2, the adhesion, proliferation, and osteogenic differentiation with cells. This work aimed to generate gradient mineral structures in situ by stabilizing calcium and phosphate ions using a polymer-induced liquid precursor process. To regulate the crystalline growth of HAP at the interface of β-chitin, this work made use of the surface properties of the organic matrix found in cuttlefish bone. These techniques allowed us to prepare an organic-inorganic composite gradient scaffold comprising plate-like HAP mineralized in situ on the surface of the scaffold and fibrous HAP in the scaffold's interior. Organic-inorganic composite gradient materials are anticipated for use in tendon-bone healing produced via the in situ construction of gradient-distributed HAP mineralization layers having varying crystalline morphologies on chitin scaffolds that possess a three-dimensional bionic structure.

DFT Study on the Spin States of Polyaniline-3d Transition-Metal (Sc-Zn) Composites and Their Sensing Application to Detect Chemical Warfare Agents.

Organic-inorganic composite materials, combining polymers with transition metal (TM) atoms based on PAni and 3d TMs, have been designed and investigated in various spin states by performing density functional calculations. These designed composites were analyzed for their stability in different spin states as well as for their calculated electronic properties, including binding energies, frontier molecular orbitals, and dipole moments. Additionally, 3D isosurfaces and 2D scattered plots of reduced density gradient as a function of (sign λ2)ρ provide insights into the noncovalent interactions between the composite units. The most stable Mn@PAni composite has been assessed as a sensing material for chemical warfare blood agents (HCN, NCCl, NCBr, NCCN, and AsH3) using density functional-based calculations. The reduced band gap and significant red/blue shift in the UV-vis spectra obtained through TDDFT calculations underline the selectivity and efficiency of the Mn@PAni composite toward different analytes.

Dioctylsulfosuccinate Functionalized NiAl-Layered Double Hydroxide for Sensitive Fenuron Electroanalysis Using a Carbon Paste Electrode.

Environmental pollution resulting from the use of pesticides such as fenuron poses significant health risks due to the carcinogenic and teratogenic properties of these compounds. There is an urgent need to develop rapid and cost-effective detection methods for quantifying fenuron. In this study, an inorganic-organic composite material was obtained by intercalating sodium dioctylsulfosuccinate (DSS) within the interlayer space of a nickel-aluminum-layered double hydroxide (NiAl-LDH). The pristine and modified LDHs (NiAl-LDH) were characterized using Fourier transform infrared, X-ray diffraction, and thermogravimetric analysis, confirming the successful intercalation of DSS in the mineral structure. The modified LDH was used to elaborate a sensor for detecting fenuron herbicide via differential pulse voltammetry (DPV) employing a carbon paste electrode (CPE). The electrochemical procedure for fenuron analysis consisted of immersing the working electrode in an electrolytic solution containing the appropriate amount of fenuron, followed by voltammetry detection without any preconcentration step. Compared to CPE modified by pristine LDH, the peak current obtained on the organo-LDH-modified CPE was twice as high. The increase in the fenuron signal was attributed to the high organophilic feature of this composite material induced by DSS modification. To optimize the sensitivity of the organo-LDH modified electrode, the effects of several experimental parameters such as pH of the medium and proportion of the modifier in the paste on the stripping response were examined. Linear calibration curves were obtained for the fenuron concentrations ranging from 0.5 × 10-6 to 1 × 10-6 mol.L-1 and 1 × 10-6 to 5 × 10-6 mol.L-1. The limit of detection (LOD) calculated on the basis of a signal-to-noise ratio of 3 was found to be 1.8 × 10-8 mol.L-1 for the low concentration range with a limit of quantification (LOQ) which was 6 × 10-8 mol.L-1. Furthermore, the interference effect of several inorganic ions and other pesticides potentially affecting fenuron stripping was explored, and the method's applicability was confirmed by determining fenuron levels in a river sample taken from down-town Yaoundé.

Photoelectrochemical signal polarity transition mediated by quercetin for the detection of neuron-specific enolase.

A photoelectrochemical (PEC) biosensor with a wide linear detection range was developed for the sensitive detection of neuron-specific enolase (NSE), which was achieved by applying a photocurrent polarity transition strategy mediated by quercetin. The coupling reaction between Cr(VI) and quercetin drives the signal polarity from anodic to cathodic. When only quercetin is present in the test solution, photogenerated electrons are transferred to the electrode to generate anodic photocurrent. However, in the presence of the target, the signal probe released Cr(VI), which interacted with quercetin, and the electron transfer direction was changed to achieve signal polarity conversion. Meanwhile, protoporphyrin-sensitized Bi:SrTiO3 nanocubes were used as matrix photoactive materials to provide basic photocurrent. The doping of Bi element would adjust the bandgap of SrTiO3, and the organic-inorganic composite material exhibits good photostability and chemical stability that can maintain stable photoelectric properties over a long period of time. Such a novel signal polarity transition strategy greatly broadened the sensor detection to the range of 0.00007-170 ng mL-1 and obtained a relatively low detection limit (25 fg mL-1), which greatly improved the detection sensitivity and accuracy of the biosensor.

Synthesis of organic-inorganic composite materials by sol-gel method

Synthesis of organic-inorganic composite materials by sol-gel method

A novel synthesis of β-CD@SA@Ag composite hydrogel microspheres with high catalytic activity and environmental adaptability

The composite of hydrogels and noble metal nanoparticles has wide applications in the field of functional materials. In this paper, we developed a novel and green strategy to synthesize a kind of composite hydrogel microspheres containing silver nanoparticles and β-cyclodextrin (β-CD) modified sodium alginate (β-CD@SA@Ag) without use of strong reducing reagent. First, β-CD was chemical linked to SA by epichlorohydrin (ECH) to form the β-CD modified polymer (β-CD@SA). then AgNO3 was added to the as-prepared polymer solution, in which silver nanoparticles were formed by the reducing power of β-CD units. Subsequently, by reversed-phase emulsion method and ionic cross-linking, a kind of β-CD@SA@Ag hydrogel microspheres were obtained. The structure and morphology of the composite material were characterized in detail by Fourier infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Test data indicated that silver nanoparticles evenly dispersed in the composite material. On the basis, the adsorption and catalytic performances of the β-CD@SA@Ag hydrogel microspheres were studied towards to the reduction of aromatic nitro compounds. Research results showed that the β-CD@SA@Ag hydrogel microspheres had excellent catalytic activity along with high environmental adaptability. whether in pure water, tap water or river water, aromatic nitro compounds can be completely reduced within 2–13 min. Moreover, the morphology of microspheres of the composite material endows the composite material with high stability and reusability. We believe that our work would provide a new idea for the green synthesis of organic-inorganic composite functional materials.

Prediction of Electrophysical Properties of Organic-Inorganic Composite Materials

Prediction of Electrophysical Properties of Organic-Inorganic Composite Materials

Self-Assembly of Atomically Precise Silver Nanoclusters in Crowded Colloids into Ultra-Long Ribbons with Tunable Supramolecular Chirality.

Atomically precise metal nanoclusters (NCs) emerge as fascinating synthons in self-assembled materials. The self-assembly of metal NCs are highly sensitive to the environment because they have an inorganic-organic hybridized structure and a relatively complicated conformation. Here, it is shown that when confined in crowded colloids, a water-soluble Ag9 -cored nanocluster (Ag9 -NC) can self- assemble into ultra-long (up to millimeters) and photoluminescent ribbons with high flexibility. The ribbon contains rectangularly organized columns of Ag9 -NCs and can undergo secondary self-assembly to form bundled and branched structures. Formation of ribbons is observed in all the tested colloids, including lyotropic liquid crystals and disordered, three-dimensional network. The high viscosity/elasticity of the crowded colloids weakens gravity-induced sedimentation of the ribbons, leading to the formation of an interesting class of inorganic-organic composite materials where the hard Ag-containing skeleton strengthens the soft matter. The simultaneously occurring symmetry breaking during the self-assembly of Ag9 -NCs gives uncontrolled supramolecular chirality, which can be tuned through the majority rule and soldier-and-sergeant rule by the introduction of chiral seeds. The regulated chirality and the intrinsic photoluminescence of the Ag9 -NCs ribbons impart the composite material circularly polarized luminescence, opening the door for a variety of potential applications.

Electron-rich active sites created by fine-tuning the electronic structure of Co(II) porphyrin frameworks for high-performance CO2 electroreduction

Electrochemical reduction of CO2 for sustainable production of carbon-based chemicals and fuels is a promising approach to solve environmental and energy problems. However, the development of electrocatalysts with satisfactory catalytic activity and product selectivity is still a considerable challenge. Porphyrin organic frameworks (POFs) are considered one of the most promising models for regulating the structure at the molecular level. In this work, we propose a strategy that integrates nanoscale and molecular scale to synthesize several organic-inorganic composite materials by the template-oriented polymerization of isolated Co(II) porphyrin (CoPor-) on the carbon nanotube (CNT) scaffold. The electronic structure of CoPor-active sites in the POFs for electrocatalytic CO2 reduction was tuned by modification of the substituents. Remarkably, the optimal sample CoPOF-(Me)4@CNT was found to reduce CO2 to CO with a high Faradaic efficiency for CO production (FECO) of 93 % at the overpotential of 600 mV and a remarkable turnover frequency (TOF) value of 9720 h−1 at −1.0 V vs reversible hydrogen electrode (RHE), surpassing the performance of most recently reported CoPOFs in terms of selectivity and efficiency. Moreover, this electrocatalyst is stable for more than 42 h without a loss in reactivity. In-depth experimental research suggests that the electron-rich active sites created by methyl substituents with an electron-donating effect and the synergy between POF nanolayers and CNT scaffold successfully modulate the electronic structure of Co sites in this reticular framework, thereby enhancing the electrocatalytic performance.

Bioinspired Mechanical Materials—Development of High-Toughness Ceramics through Complexation of Calcium Phosphate and Organic Polymers

Inspired by the process of bone formation in living organisms, many studies have been conducted to develop organic–inorganic composite materials by preparing calcium phosphate crystals within solutions or dispersions of polymers with appropriate functional groups. Bones are composite materials consisting of organic polymers (mainly type I collagen), carbonated apatite, and water, with volume fractions of 35–45%, 35–45%, and 15–25%, respectively. Carbonated apatite in bone contributes to rigidity, while organic polymers and water contribute to toughness. The inorganic crystal, carbonated apatite, is a plate-shaped crystal with dimensions of 50 nm × 25 nm × 1–4 nm, generating a significant organic–inorganic interface, due to its nanoscale size. This interface is believed to absorb externally applied forces to dissipate mechanical energy to thermal energy. Creating such nanometer-scale structures using top-down approaches is challenging, making bottom-up methods, such as the coprecipitation of polymer and inorganic crystals, more suitable. In this account, efforts to develop eco-friendly mechanical materials using biomass, such as cellulose and starch, based on the bottom-up approach to bone-like composites are described.

New Functional Groups Design toward High Performance Ultraviolet Nonlinear Optical Materials.

ConspectusThe invention of the laser is a pivotal milestone in the evolution of modern science and technology. Second-order nonlinear optical (NLO) crystals, which possess the ability to convert frequencies, have found widespread applications in laser science, information transmission, industrial Internet, and other cutting-edge fields within materials and optics. As modern science and technology continue to advance at a rapid pace, existing ultraviolet (UV) and deep ultraviolet (DUV) NLO crystals struggle to meet the ever-growing demands of various applications. Consequently, the development of novel UV and DUV NLO crystals has become an urgent necessity. For a UV NLO crystal to be considered outstanding in the UV/DUV range, it must exhibit three fundamental yet crucial properties: large second-order NLO coefficients, suitable birefringence, and short UV cutoff edge corresponding to a wide band gap. However, these key factors often conflict with one another, making it challenging to achieve a harmonious balance within a single crystal. It is widely believed that these mutually constrained optical properties are codetermined by microscopic NLO-active units and macroscopic structure features. Therefore, how to design high performance UV NLO-active groups to balance these three key properties is an essential scientifically question and serious challenge. In this Account, we present three strategies for designing high-performance UV NLO-active groups: (1) The "tetrahedron partial substitution" strategy by employing various substituents to replace one or more atoms in the traditional nonpolar tetrahedral groups, might achieve the aim of increasing the polarizability anisotropy and hyperpolarizability of the newly formed polar tetrahedral functional groups, such as from SO4 to SO3NH2 or SO3CH3 groups. (2) The "structure-analogue" strategy to develop a range of organic functional groups exhibiting more strong polarizability anisotropy and hyperpolarizability by using inorganic π-conjugated groups, such as BO3 and B3O6 groups, as templates. (3) The "two in one" strategy for integrating groups featuring planar triangle configurations and tetrahedrons to create NLO-active functional groups possessing large band gaps, strong hyperpolarizability, and moderate polarizability anisotropy. These three strategies successfully guide us to design and explore various kinds of organic-inorganic composite NLO crystal materials with excellent performances, like Ba(SO3CH3)2, M(SO3NH2)2 (M = Sr, Ba), C(NH2)3SO3F, KLi(HC3N3O3)·2H2O, KLi(C3H2O4)·H2O, and so on. Finally, we briefly conclude these strategies and propose some prospects for exploring new excellent UV/DUV NLO materials with practical applications. These findings could inspire novel thoughts for researchers designing new UV/DUV NLO materials and providing abundant materials used in UV/DUV regions.

Investigation of novel expandable polystyrene/alumina aerogel composite thermal insulation material

Expandable polystyrene (EPS) foam is one of the most commonly used building thermal insulation materials due to its low thermal conductivity, apparent density as well and low cost. However, its high flammability and the release of a large number of toxic gases during combustion hinder its application. In this paper, using EPS foam and alumina aerogel (Al2O3) as insulation components, epoxy resin (EP) as a binder, and expandable graphite (EG) and ammonium polyphosphate (APP) as composite flame-retardant, a novel organic-inorganic composite thermal insulation material (EPS-AEA) was designed and fabricated. Experiment results showed that adding Al2O3 to EPS could further reduce the thermal conductivity of the obtained composite, and improve its mechanical properties. The addition of EG and APP composite flame-retardant could markedly enhance flame-retardant performance. With the addition of 4.17% Al2O3, and 50% EG/APP (1/1 mass ratio), the obtained EPS-AEA-1/1 composite showed superior fire resistance (reaching UL-94 V-0 rating and limiting oxygen index (LOI of 40.6%), high thermal insulation (thermal conductivity of 0.0487 W/(m·K)and applicable mechanical properties. In addition, EPS-AEA had excellent anti-hygroscopic properties (moisture ab-desorption rate within 0.5%) and fairly low toxic gas emissions during combustion, indicating its potential in practical application.

Large-Area Flexible Electrochromic Devices with High-Performance and Low-Power Consumption Enabled by Hydroxyhexyl Viologen-Substituted Polyhedral Oligomeric Silsesquioxane

In this work, we prepared octa-hydroxyhexyl viologen-substituted polyhedral oligomeric silsesquioxane (OHHV-POSS) as an organic–inorganic composite material applicable for large-area flexible electrochromic devices (FECDs). The organic–inorganic hybrid structure supported by the POSS cage and the enhanced interaction between hydroxyl end-groups and lithium salts can effectively increase the ionic conductivity of the ion gel films, thereby improving the electrochromic performance capabilities. Homogeneous ion gel was obtained with polyvinyl butyral and a lithium salt, and outstanding electrochromic properties were observed during electrochromic device operations. The FECDs of various sizes were fabricated for systematic evaluation, and the device of up to 22.5 × 19.5 cm2 was successfully constructed using the simple doctor blade coating method. The prepared large-area FECDs achieved a large transmittance difference of 70.0% at 604 nm, fast switching times of 21.1 and 18.0 s, high coloration efficiency of 260.61 cm2/C, long-term cycling stability of up to 300 cycles, and low power consumption of about 250 μW/cm2. Furthermore, the device was maintained stably in various application tests for heat insulation and storage, UV resistance, and mechanical stability. High performance and low power consumption of OHHV-POSS prove suitable for large-area FECDs, suggesting promising potential for smart windows, wristbands, and eyewear products.

Study of the Possibility of Using Sol-Gel Technology to Obtain Magnetic Nanoparticles Based on Transition Metal Ferrites.

The article presents results for the magnetic nanoparticles sol-gel method synthesis of cobalt (II) ferrite and organic-inorganic composite materials based on it. The obtained materials were characterized using X-ray phase analysis, scanning and transmission electron microscopy, Scherrer, Brunauer-Emmett-Teller (BET) methods. A composite materials formation mechanism is proposed, which includes a gelation stage where transition element cation chelate complexes react with citric acid and subsequently decompose under heating. The fundamental possibility of obtaining an organo-inorganic composite material based on cobalt (II) ferrite and an organic carrier using the presented method has been proved. Composite materials formation is established to lead to a significant (5-9 times) increase in the sample surface area. Materials with a developed surface are formed: the surface area measured by the BET method is 83-143 m2/g. The resulting composite materials have sufficient magnetic properties to be mobile in a magnetic field. Consequently, wide possibilities for polyfunctional materials synthesis open up for various applications in medicine.