Engineering 3D Scaffold-Free Nanoparticle-Laden Stem Cell Constructs for Piezoelectric Enhancement of Human Neural Tissue Formation and Function.

Electrical stimulation (ES) of cellular systems can be utilized for biotechnological applications and electroceuticals (bioelectric medicine). Neural cell stimulation especially has a long history in neuroscience research and is increasingly applied for clinical therapies. Application of ES via conventional electrodes requires external connectors and power sources, hindering scientific and therapeutic applications. Here engineering novel 3D scaffold-free human neural stem cell constructs with integrated piezoelectric nanoparticles for enhanced neural tissue induction and function is described. Tetragonal barium titanate (BaTi03) nanoparticles are employed as piezoelectric stimulators prepared as cytocompatible dispersions, incorporated into 3D self-organizing neural spheroids, and activated wirelessly by ultrasound. Ultrasound delivery (low frequency; 40 kHz) is optimized for cell survival, and nanoparticle activation enabled ES throughout the spheroids during differentiation, tissue formation, and maturation. The resultant human neural tissues represent the first example of direct tissue loading with piezoelectric particles for ensuing 3D ultrasound-mediated piezoelectric enhancement of human neuronal induction from stem cells, including augmented neuritogenesis and synaptogenesis. It is anticipated that the platform described will facilitate advanced tissue engineering and in vitro modeling of human neural (and potentially non-neural) tissues, with modeling including tissue development and pathology, and applicable to preclinical testing and prototyping of both electroceuticals and pharmaceuticals.

Effect of BaTiO3 Filler Modification with Multiwalled Carbon Nanotubes on Electric Properties of Polymer Nanocomposites.

Two ranges of dielectric permittivity (k) increase in polymer composites upon the modification of BaTiO3 filler with multiwalled carbon nanotubes (MWCNTs) are shown for the first time. The first increase in permittivity is observed at low MWCNT content in the composite (approximately 0.07 vol.%) without a considerable increase in dielectric loss tangent and electrical conductivity. This effect is determined by the intensification of filler-polymer interactions caused by the nanotubes, which introduce Brønsted acidic centers on the modified filler surface and thus promote interactions with the cyanoethyl ester of polyvinyl alcohol (CEPVA) polymer binder. Consequently, the structure of the composites becomes more uniform: the permittivity increase is accompanied by a decrease in the lacunarity (nonuniformity) of the structure and an increase in scale invariance, which characterizes the self-similarity of the composite structure. The permittivity of the composites in the first range follows a modified Lichtenecker equation, including the content of Brønsted acidic centers as a parameter. The second permittivity growth range features a drastic increase in the dielectric loss tangent and conductivity corresponding to the percolation effect with the threshold at 0.3 vol.% of MWCNTs.

Preparation of High-Performance Barium Titanate Composite Hydrogels by Deep Eutectic Solvent-Assisted Frontal Polymerization.

This study aimed to develop composite hydrogels with exceptional piezoelectric properties and pressure sensitivity. To achieve the objective, this study created a deep eutectic solvent (DES) by mixing choline chloride (ChCl), acrylamide (AM), and acrylic acid (AA). Barium titanate nanoparticles (BTNPs) were incorporated as fillers into the deep eutectic solvents (DES) to synthesize the composite hydrogels using frontal polymerization (FP). The mechanical and piezoelectric properties of the resulting composite hydrogels were analyzed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). This study found that the BTNPs/P(AM-co-AA) composite hydrogels exhibited excellent mechanical and piezoelectric properties. This is attributed to the high dielectric constant of BTNPs and the electrode polarization phenomenon when subjected to pressure. With a BTNPs content of 0.6 wt%, the maximum compressive strength increased by 3.68 times compared with the hydrogel without added BTNPs. Moreover, increasing the BTNPs content to 0.6 wt% resulted in a 1.48 times increase in generated voltage under the same pressure, compared with the hydrogel with only 0.2 wt% BTNPs. This study provides a method for preparing composite hydrogels with outstanding piezoelectric properties and pressure sensitivity.

The Influence of Measurement Conditions on the Electrocaloric Effect in Ferroelectric Ceramics of Modified Barium Titanate.

In this work, the electrocaloric effect (ECE) and electrocaloric strength (ΔT/E) were measured and thermal and dielectric studies were performed on Pb-modified BaTiO3 (BPT). The saturated hysteresis loops and normal ferroelectric behavior of the ferroelectric ceramics allow the utilization of the indirect method to estimate the electrocaloric properties. The electrocaloric measurements were performed under high (18 kV/cm) versus low (8 kV/cm) electric field conditions. These conditions were chosen to notice and then eliminate an artificial negative electrocaloric effect in the tested ceramics. At the same time, relatively high values of positive electrocaloric temperature change ΔT (~ 2.19 K) and electrocaloric strength ΔT/E (~0.27-0.11 K·cm/kV) were obtained.

Ferroelectric Texture of Individual Barium Titanate Nanocrystals.

Ferroelectric materials display exotic polarization textures at the nanoscale that could be used to improve the energetic efficiency of electronic components. The vast majority of studies were conducted in two dimensions on thin films that can be further nanostructured, but very few studies address the situation of individual isolated nanocrystals (NCs) synthesized in solution, while such structures could have other fields of applications. In this work, we experimentally and theoretically studied the polarization texture of ferroelectric barium titanate (BaTiO3, BTO) NCs attached to a conductive substrate and surrounded by air. We synthesized NCs of well-defined quasicubic shape and 160 nm average size that conserve the tetragonal structure of BTO at room temperature. We then investigated the inverse piezoelectric properties of such pristine individual NCs by vector piezoresponse force microscopy (PFM), taking particular care to suppress electrostatic artifacts. In all of the NCs studied, we could not detect any vertical PFM signal, and the maps of the lateral response all displayed larger displacement amplitude on the edges with deformations converging toward the center. Using field phase simulations dedicated to ferroelectric nanostructures, we were able to predict the equilibrium polarization texture. These simulations revealed that the NC core is composed of 180° up and down domains defining the polar axis that rotate by 90° in the two facets orthogonal to this axis, eventually lying within these planes forming a layer of about 10 nm thickness mainly composed of 180° domains along an edge. From this polarization distribution, we predicted the lateral PFM response, which was revealed to be in very good qualitative agreement with the experimental observations. This work positions PFM as a relevant tool to evaluate the potential of complex ferroelectric nanostructures to be used as sensors.

Tuning Exciton Emission via Ferroelectric Polarization at a Heterogeneous Interface between a Monolayer Transition Metal Dichalcogenide and a Perovskite Oxide Membrane.

We demonstrate the integration of a thin BaTiO3 (BTO) membrane with monolayer MoSe2 in a dual-gate device that enables in situ manipulation of the BTO ferroelectric polarization with a voltage pulse. While two-dimensional (2D) transition metal dichalcogenides (TMDs) offer remarkable adaptability, their hybrid integration with other families of functional materials beyond the realm of 2D materials has been challenging. Released functional oxide membranes offer a solution for 2D/3D integration via stacking. 2D TMD excitons can serve as a local probe of the ferroelectric polarization in BTO at a heterogeneous interface. Using photoluminescence (PL) of MoSe2 excitons to optically read out the doping level, we find that the relative population of charge carriers in MoSe2 depends sensitively on the ferroelectric polarization. This finding points to a promising avenue for future-generation versatile sensing devices with high sensitivity, fast readout, and diverse applicability for advanced signal processing.

Microsphere lens array embedded microfluidic chip for SERS detection with simultaneous enhancement of sensitivity and stability.

Surface enhanced Raman spectroscopy (SERS) utilizes the fingerprint features of molecular vibrations to identify and detect substances. However, in traditional single focus excitation scenarios, its signal collection efficiency of the objective is restricted. Furthermore, the uneven distribution of samples on the SERS substrate would result in poor signal stability, while the excitation power is limited to avoid sample damage. SERS detection system always requires precise adjustment of focal length and spot size, making it difficult for point-of-care testing applications. Here, we proposed a SERS microfluidic chip with barium titanate microspheres array (BTMA) embedded using vacuum self-assembled hot-pressing method for SERS detection with simultaneous enhancement of sensitivity and stability. Due to photonic nano-jets and directional antenna effects, high index microspheres are perfect micro-lens for effective light focusing and signal collecting. The BTMA can not only disperse excitation beam into an array of focal points covering the target uniformly with very low signal fluctuation, but enlarge the power threshold for higher signal intensity. We conducted a proof-of-principle experiment on chip for the detection of bacteria with immuno-magnetic tags and immuno-SERS tags. Together with magnetic and ultrasonic operations, the target bacteria in the flow were evenly congregated on the focal plane of BTMA. It demonstrated a limit of detection of 5 cells/mL, excellent signal reproducibility (error∼4.84%), and excellent position tolerance of 500 µm in X-Y plane (error∼5.375%). It can be seen that BTMA-SERS microfluidic chip can effectively solve the contradiction between sensitivity and stability in SERS detection.

Effects of Calcination Temperature on the Synthesis of One-Pot Sol-Gelled Barium Titanate Powder and Its Performance as an Endodontic Radiopacifier.

Barium titanate (BaTiO3, BTO), conventionally used for dielectric and ferroelectric applications, has been assessed for biomedical applications, such as its utilization as a radiopacifier in mineral trioxide aggregates (MTA) for endodontic treatment. In the present study, BTO powders were prepared using the sol-gel process, followed by calcination at 400-1100 °C. The X-ray diffraction technique was then used to examine the as-prepared powders to elucidate the effect of calcination on the phase composition and crystalline size of BTO. Calcined BTO powders were then used as radiopacifiers for MTA. MTA-like cements were investigated to determine the optimal calcination temperature based on the radiopacity and diametral tensile strength (DTS). The experimental results showed that the formation of BTO phase was observed after calcination at temperatures of 600 °C and above. The calcined powders were a mixture of BaTiO3 phase with residual BaCO3 and/or Ba2TiO4 phases. The performance of MTA-like cements with BTO addition increased with increasing calcination temperature up to 1000 °C. The radiopacity, however, decreased after 7 days of simulated oral environmental storage, whereas an increase in DTS was observed. Optimal MTA-like cement was obtained by adding 40 wt.% 1000 °C-calcined BTO powder, with its resulting radiopacity and DTS at 4.83 ± 0.61 mmAl and 2.86 ± 0.33 MPa, respectively. After 7 days, the radiopacity decreased slightly to 4.69 ± 0.51 mmAl, accompanied by an increase in DTS to 3.13 ± 0.70 MPa. The optimal cement was biocompatible and verified using MG 63 and L929 cell lines, which exhibited cell viability higher than 95%.

The effect of dental material type and masticatory forces on periodontitis-derived subgingival microbiomes.

Restorative dental materials can frequently extend below the gingival margin, serving as a potential haven for microbial colonization, and altering the local oral microbiome to ignite infection. However, the contribution of dental materials on driving changes of the composition of the subgingival microbiome is under-investigated. This study evaluated the microbiome-modulating properties of three biomaterials, namely resin dental composites (COM), antimicrobial piezoelectric composites (BTO), and hydroxyapatite (HA), using an optimized in vitro subgingival microbiome model derived from patients with periodontal disease. Dental materials were subjected to static or cyclic loading (mastication forces) during biofilm growth. Microbiome composition was assessed by 16S rRNA gene sequencing. Dysbiosis was measured in terms of subgingival microbial dysbiosis index (SMDI). Biomaterials subjected to cyclic masticatory loads were associated with enhanced biofilm viability except on the antibacterial composite. Biomaterials held static were associated with increased biofilm biomass, especially on HA surfaces. Overall, the microbiome richness (Chao index) was similar for all the biomaterials and loading conditions. However, the microbiome diversity (Shannon index) for the HA beams was significantly different than both composites. In addition, beta diversity analysis revealed significant differences between composites and HA biomaterials, and between both loading conditions (static and cyclic). Under static conditions, microbiomes formed over HA surfaces resulted in increased dysbiosis compared to composites through the enrichment of periopathogens, including Porphyromonas gingivalis, Porphyromonas endodontalis, and Fretibacterium spp., and depletion of commensals such as Granulicatella and Streptococcus spp. Interestingly, cyclic loading reversed the dysbiosis of microbiomes formed over HA (depletion of periopathogenes) but increased the dysbiosis of microbiomes formed over composites (enrichment of Porphyromonas gingivalis and Fusobacterim nucleatum). Comparison of species formed on both composites (control and antibacterial) showed some differences. Commercial composites enriched Selenomonas spp. and depleted Campylobacter concisus. Piezoelectric composites effectively controlled the microbiome viability without significantly impacting the species abundance. Findings of this work open new understandings of the effects of different biomaterials on the modulation of oral biofilms and the relationship with oral subgingival infections.

Biomimetic-inspired piezoelectric ovalbumin/BaTiO3 scaffolds synergizing with anisotropic topology for modulating Schwann cell and DRG behavior.

The treatment of peripheral nerve injury is a clinical challenge that tremendously affected the patients' health and life. Anisotropic topographies and electric cues can simulate the regenerative microenvironment of nerve from physical and biological aspects, which show promising application in nerve regeneration. However, most studies just unilaterally emphasize the effect of sole topological- or electric- cue on nerve regeneration, while rarely considering the synergistic function of both cues simultaneously. In this study, a biomimetic-inspired piezoelectric topological ovalbumin/BaTiO3 scaffold that can provide non-invasive electrical stimulation in situ was constructed by combining piezoelectric BaTiO3 nanoparticles and surface microtopography. The results showed that the incorporation of piezoelectric nanoparticles could improve the mechanical properties of the scaffolds, and the piezoelectric output of the scaffolds after polarization was significantly increased. Biological evaluation revealed that the piezoelectric topological scaffolds could regulate the orientation growth of SCs, promote axon elongation of DRG, and upregulate the genes expression referring to myelination and axon growth, thus rapidly integrated chemical-mechanical signals and transmitted them for effectively promoting neuronal myelination, which was closely related to peripheral neurogenesis. The study suggests that the anisotropic surface topology combined with non-invasive electronic stimulation of the ovalbumin/BaTiO3 scaffolds possess a promising application prospect in the repair and regeneration of peripheral nerve injury.

Enhanced Piezocatalytic Performance of Li-doped BaTiO3 Through a Facile Sonication-Assisted Precipitation Approach.

Piezocatalysis-induced dye degradation has garnered significant attention as an effective method for addressing wastewater treatment challenges. In our study, we employed a room-temperature sonochemical method to synthesize piezoelectric barium titanate nanoparticles (BaTiO3: BTO) with varying levels of Li doping. This approach not only streamlined the sample preparation process but also significantly reduced the overall time required for synthesis, making it a highly efficient and practical method. One of the key findings was the exceptional performance of the Li-doped BTO nanoparticles. With 20 mg of Li additive, we achieved 90 % removal of Rhodamine B (RhB) dye within a relatively short timeframe of 150 minutes, all while subjecting the sample to ultrasonic vibration. This rapid and efficient dye degradation was further evidenced by the calculated kinetic rate constant, which indicated seven times faster degradation rate compared to pure BTO. The enhanced piezoelectric performance observed in the Li-doped BTO nanoparticles can be attributed to the strategic substitution of Li atoms, which facilitated a more efficient transfer of charge charges at the interface. Overall, our study underscores the potential of piezocatalysis coupled with advanced materials like Li-doped BTO nanoparticles as a viable and promising solution for wastewater treatment, offering both efficiency and environmental sustainability.

Direct Observation of Trace Elements in Barium Titanate of Multilayer Ceramic Capacitors Using Atom Probe Tomography.

Accurately controlling trace additives in dielectric barium titanate (BaTiO3) layers is important for optimizing the performance of multilayer ceramic capacitors (MLCCs). However, characterizing the spatial distribution and local concentration of the additives, which strongly influence the MLCC performance, poses a significant challenge. Atom probe tomography (APT) is an ideal technique for obtaining this information, but the extremely low electrical conductivity and piezoelectricity of BaTiO3 render its analysis with existing sample preparation approaches difficult. In this study, we developed a new APT sample preparation method involving W coating and heat treatment to investigate the trace additives in the BaTiO3 layer of MLCCs. This method enables determination of the local concentration and distribution of all trace elements in the BaTiO3 layer, including additives and undesired impurities. The developed method is expected to pave the way for the further optimization and advancement of MLCC technology.

Improving the Performance of Pd for Formic Acid Dehydrogenation by Introducing Barium Titanate.

Formic acid, a safe and widely available organic compound, produces hydrogen under mild conditions, with the existence of Pd-based catalysts. Efficiently generating hydrogen via formic acid decomposition (FAD) is restricted by the cleavage of the C-H bond in adsorbed HCOO* and strong adsorption of hydrogen on the Pd surface. Herein, tetragonal-phase barium titanate (TBT) was in situ grown on reduced graphene oxide (rGO) to support Pd (Pd/TBT/rGO) for FAD. The internal electric field exists around TBT owing to its spontaneous polarization capacity. The physical characterizations illustrate that the introduction of barium titanate affects the catalytic performance of the catalyst by decreasing the particle size of Pd nanoparticles (NPs) and forming electron-rich Pd. The as-synthesized Pd/TBT/rGO exhibited excellent catalytic activity and hydrogen selectivity for FAD with a high initial turnover frequency up to 3019.72 h-1 at 333 K. The reason for this enhancement is not only the small-size Pd NPs but also the internal electric field from TBT, which promotes the desorption of adsorbed hydrogen on the Pd surface. Additionally, the electron-rich Pd is favorable to the cleavage of the C-H bond in HCOO*. This work will improve the understanding of the characterization of barium titanate and provide a new design strategy for the FAD catalyst.

Nanoimprinting Solution-Derived Barium Titanate for Electro-Optic Metasurfaces.

Electro-optic metasurfaces have demonstrated significant potential in enhancing the modulation speed and efficiency for fast and large-scale free-space optical devices. Barium titanate has a strong electro-optic Pockels coefficient, but its availability in thin-film form is restricted due to costly growth processes or low thickness. Here, we fabricated active metasurfaces using an etch-free bottom-up process with sol-gel-based polycrystalline barium titanate with a large electro-optic coefficient similar to bulk lithium niobate. We achieve strong hybrid Mie/surface lattice resonances with a quality-factor of 200 at 633 nm wavelength, enhancing the light-matter interaction and therefore the Pockels effect. The metasurface transmission is electro-optically modulated with up to 5 MHz driving frequency at low voltages of less than 1 V thanks to resonant enhancement of the modulation amplitude by 2 orders of magnitude. This successful demonstration of electro-optic modulation in nanoimprinted barium titanate structures paves the way for low-cost and large-scale free-space modulators or tunable metalenses.

Bioactive Hydroxyapatite Aerogels with Piezoelectric Particles.

Open-cell foams based on hydroxyapatite (HAp) can mimic the extracellular matrix (ECM) to better replace damaged hard tissues and assist in their regeneration processes. Aerogels of HAp nanowires (NW) with barium titanate (BT) particles were produced and characterized regarding their physical and chemical properties, bioactivity, and in vitro cytotoxicity. Considering the role of piezoelectricity (mainly due to collagen) and surface charges in bone remodeling, all BT particles, of size 280 nm and 2 and 3 µm, contained BaTiO3 in their piezoelectric tetragonal phase. The synthesized nanowires were verified to be AB-type carbonated hydroxyapatite. The aerogels showed high porosity and relatively homogeneous distribution of the BT particles. Barium titanate proved to be non-cytotoxic while all the aerogels produced were cytotoxic for an extract concentration of 1 mg/mL but became non-cytotoxic at concentrations of 0.5 mg/mL and below. It is possible that these results were affected by the higher surface area and quicker dissolution rate of the aerogels. In the bioactivity assays, SEM/EDS, it was not easy to differentiate between the apatite deposition and the surface of the HAp wires. However, a quantitative EDS analysis shows a possible CaP deposition/dissolution cycle taking place.

Ferroelectric Phase Transition in Barium Titanate Revisited with Ab Initio Molecular Dynamics.

The ferroelectric phase transition of the perovskite barium titanate as well as its technical importance regarding the switching of respective polar properties is well known and has been thoroughly studied, both experimentally and on theoretical grounds. While details about the phase diagram as well as transition temperatures are experimentally well known, the theoretical approaches still face difficulties in contributing a detailed description of these phase transitions. Within this work, a new methodological approach is introduced to revisit the ferroelectric phase transition with first-principles methods. With the chosen ab initio molecular dynamics (AIMD) method in combination with the applied NpT ensemble, we are able to join the accuracy of density functional theory (DFT) with ambient conditions, realized using a thermostat and barostat in an MD simulation. The derived phase diagram confirms recent corrections in the theoretical models and reproduces the phase boundary pressure dependence of TC. In conclusion of the statistical atomistic dynamics, the nature of the transition can be described in a more detailed way. In addition, this work paves the way towards locally patterned piezoelectrica by means of acoustic standing waves as well as piezoelectrically induced acoustic resonators.

Horizontally-oriented barium titanate@polydomine/polyimide nanocomposite films for high-temperature energy storage.

High-temperature ceramics polymer dielectric nanocomposite materials have broad application prospects in energy storage. The barium titanate (BT) plays an important role as one of outstanding representative ceramics in the dielectric nanocomposite materials. However, there is little known for the effects of two-dimensional (2D) BT morphology and layout on the properties of high-temperature nanocomposite materials. Hence, 2D scale-like BT ceramic fillers were prepared from layered K0.8Li0.27Ti1.73O4 crystals as precursors using a combined solid-state and hydrothermal process. 2D scale-like BT@polydopamine (PDA) core-shell nanocomposites were prepared via coating PDA on the BT. BT@PDA/polyimide(PI) nanocomposite films were fabricated by horizontally oriented distribution of BT@PDA in the PI matrix. The BT@PDA/PI nanocomposite films exhibit a high energy density (3.34 J/cm3) and high charge-discharge efficiency (83.68 %) at 150 °C. It is currently the highest energy storage performance in the BT/PI nanocomposite films at 150 °C. The excellent properties are due to preventing upward breakdown of electrical pathways and promoting dispersion and entanglement of the electrical pathway routes. Additionally, strong electrostatic interactions between the different polymer chains (PDA and PI) restricts the movement of space charges. This work demonstrates that introducing horizontally oriented, organically shell-modified and 2D small-sized BT nanoparticles into a PI matrix is an effective method for improving energy storage performance.

Stretchable Magneto-Mechanical Configurations with High Magnetic Sensitivity Based on "Gel-Type" Soft Rubber for Intelligent Applications.

"Gel-type" soft and stretchable magneto-mechanical composites made of silicone rubber and iron particles are in focus because of their high magnetic sensitivity, and intelligence perspective. The "intelligence" mentioned here is related to the "smartness" of these magneto-rheological elastomers (MREs) to tune the "mechanical stiffness" and "output voltage" in energy-harvesting applications by switching magnetic fields. Hence, this work develops "gel-type" soft composites based on rubber reinforced with iron particles in a hybrid with piezoelectric fillers such as barium titanate. A further aspect of the work relies on studying the mechanical stability of intelligence and the stretchability of the composites. For example, the stretchability was 105% (control), and higher for 158% (60 per 100 parts of rubber (phr) of barium titanate, BaTiO3), 149% (60 phr of electrolyte iron particles, EIP), and 148% (60 phr of BaTiO3 + EIP hybrid). Then, the magneto-mechanical aspect will be investigated to explore the magnetic sensitivity of these "gel-type" soft composites with a change in mechanical stiffness under a magnetic field. For example, the anisotropic effect was 14.3% (60 phr of EIP), and 4.4% (60 phr of hybrid). Finally, energy harvesting was performed. For example, the isotropic samples exhibit ~20 mV (60 phr of BaTiO3), ~5.4 mV (60 phr of EIP), and ~3.7 mV (60 phr of hybrid). However, the anisotropic samples exhibit ~5.6 mV (60 phr of EIP), and ~8.8 mV (60 phr of hybrid). In the end, the composites prepared have three configurations, namely one with electro-mechanical aspects, another with magnetic sensitivity, and a third with both features. Overall, the experimental outcomes will make fabricated composites useful for different intelligent and stretchable applications.

Silver doped barium titanate nanoparticles for enhanced visible light photocatalytic degradation of dyes.

Due to the rapid growth of global population, new, fast and reliable methods must be developed to purify contaminated water. Various photocatalysts have been developed to remove organic dyes from water. Herein, Ag doped BaTiO3 has been synthesized using a facile solvothermal method and its excellent photocatalytic activities were demonstrated in degradation of both anionic and cationic dyes under visible light illumination. Ag doped BaTiO3 nanoparticles showed greater efficacy in the degradation of methylene blue (MB) and eosin yellow (EY) than undoped BaTiO3 nanoparticles, which makes them a better candidate for photocatalysis. 1.0 AgBT sample showed the highest photocatalytic activity for MB (99.1 % in 100 min) and EY (99.3 % in 60 min) dye degradation compared with those of other samples. Further, the trapping experiments revealed that hydroxyl radicals and holes are the active species in the photocatalytic process of MB and EY dye degradation and recycle test showed excellent stability of the synthesized material.

3D printed barium titanate/calcium silicate composite biological scaffold combined with structural and material properties.

In the case of a large bone defect, the human endogenous electrical field is no longer sufficient. Therefore, it is necessary to support structural electrical bone scaffolds. Barium titanate (BT) has received much attention in bone tissue engineering applications due to its biocompatibility and ability to maintain charged surfaces. However, its processability is poor and it does not have the biological activity to promote mineralization, which limits its use in bone repair. In this paper, a composite bone scaffold with excellent piezoelectric properties was prepared by combining 20 wt% calcium silicate. The influence of the light curing process on the properties of the piezoelectric biological scaffold was investigated by comparing it with the traditional piezoelectric ceramic molding method (dry pressing). Despite the structural features of 3D printing (layered structure, pore features), the piezoelectric and mechanical properties of the scaffold are weakened. However, 3D-printed scaffolds can combine structural and piezoelectric properties, which makes the 3D-printed scaffold more effective in terms of degradation and antibacterial performance. In terms of cell activity, piezoelectric properties attract proteins and nutrients into the scaffold, promoting cell growth and differentiation. Besides, it is undeniable that the pore structure of the scaffolds plays an important role in the biological properties. Finally, the 3D printed scaffolds have excellent antimicrobial properties due to the redox reaction under piezoelectric effect as well as structural characterization.