Porous Microspheres Research Articles

Enhancing Lithium-Ion Batteries with a 3D Conductive Network Silicon-Carbon Nanotube Composite Anode.

To meet the rising demand for energy storage, high-capacity Si anode-based lithium-ion batteries (LIBs) with extended cycle life and fast-charging capabilities are essential. However, Si anodes face challenges such as significant volume expansion and low electrical conductivity. This study synthesizes a porous spherical Si/Multi-Walled Carbon Nanotube (MWCNT)@C anode material via spray drying, combining Si nanoparticles, MWCNT dispersion, sucrose, and carboxymethyl cellulose (CMC). The MWCNT incorporation creates a robust 3D conductive network within the porous microspheres, enhancing Li+ diffusion and improving fast-charging/discharging performance. After 300 cycles at 1 A g-1, the material achieved a discharge capacity of 536.6 mA h g-1 with 80.5% capacity retention. Additionally, integrating a 3D network of Single-Walled Carbon Nanotubes (SWCNTs) further enhanced capacity retention in a binder-free, self-supporting electrode created through vacuum filtration. The Si/MWCNT@C//LiFePO4 full cell exhibited an initial Coulombic efficiency (ICE) exceeding 80%, with a specific capacity of 72.4 mA h g-1 and 79.8% capacity retention after 400 cycles at 1 A g-1. This study offers a promising strategy for improving the performance and structural design of Si anodes.

Negative Pressure Smart Patch to Sense and Heal the Wound.

Negative pressure wound therapy (NPWT) offers significant advantages in terms of rate and time for healing through generating sub-vacuum to draw out inflammatory exudate and promote wound closure. However, continuous drainage probably leads to healing delay due to the lack of information about the real status of the wound bed and the potential risk of infection. To address this concern, printed Negative Pressure Smart Patch (NPSP) is reported by integrating smart real-time sensing acidity (infection) and glucose, and anti-infection into NPWT systems. In addition, NPSP delivers vancomycin through chitosan porous microspheres under negative pressure to modulate wound healing. Compared with NPWT, NPSP projects a promising approach to removing bacteria, reducing local inflammation, and accelerating healing in a short period of time.

A stunning sensitive isopropanol gas sensor based on ZnMn2O4 microspheres

The pure porous ZnMn2O4 microspheres were prepared by a one-step hydrothermal technique with different concentrations of Urea (ZU). Various techniques including XRD, FESEM, PL, UV–Vis, FT-IR and EDS were used to study the structural and morphological properties of the obtained samples. The results show that the obtained samples have high purity and by changing the concentration of urea, the microspheres have rough surfaces, which is useful for gas sensing properties. Then, the gas sensor properties of the fabricated sensor layers were investigated for isopropanol vapor with different concentrations at different working temperatures. Gas sensing results confirm that the ZU films exhibit a high response of 5.54 for ZU3 (500 ppm isopropanol), a very fast response time of 2.5 s for ZU2 (400 ppm) and ZU3 (300 ppm), and excellent selectivity with a difference of approximately 107 % compared to DMF at a relatively low temperature. In addition, the gas sensing mechanism was also thoroughly discussed.

Engineered dECM-based microsystem promotes cartilage regeneration in osteoarthritis by synergistically enhancing chondrogenesis of BMSCs and anti-inflammatory effect

The cartilage defects in osteoarthritis (OA) often result in loss of supporting and cushioning functionalities. Along this line, tissue engineering strategies for microfluidics based on high-precision control capabilities have been developed as promising long-term therapeutic solutions for cartilage regeneration in OA towards implementing anti-inflammatory effects and subsequent chondroprotective regeneration. In this study, an engineered microcarrier comprising composite porous microspheres based on decellularized extracellular matrix (dECM) and poly(lactic-co-glycolic acid) (PLGA) encapsulating icariin (ICA) was fabricated by microfluidic technology. This microcarrier, co-cultured with bone marrow mesenchymal stem cells (BMSCs), was developed as an injectable engineered microsystem for cartilage regeneration in OA. Mechanistically, dECM effectively repaired cartilage defects by inducing the differentiation of encapsulated stem cells to a cartilage phenotype through microenvironmental effects. In addition to enhanced secretion of active anti-inflammatory substances from BMSCs by dECM, the gradual release of ICA from the degraded PLGA PMs synergized anti-inflammatory effects in vivo, resulting in effective cartilage regeneration in OA. In short, the engineered microsystem indicated favorable effects in protecting and repairing cartilage, highlighting their potential as a promising therapeutic intervention for effectively ameliorating OA.

Phytic Acid Functionalized Hierarchical Porous Metal-Organic Framework Microspheres for Efficient Extraction of Uranium from Seawater.

Uranium is a critical resource in the development of nuclear energy, and its extraction from natural seawater has been identified as a potential solution to address uranium resource shortages. In this study, hierarchical meso-/micro- porous metal-organic framework functionalized with phytic acid (PA) microspheres (denoted H-UiO-66-PA) are rationally synthesized for efficient uranium extraction. This unique design allowed for a large adsorption capacity and fast adsorption kinetics, making it a promising material for uranium extraction. Due to the hierarchically porous structure, H-UiO-66-NH2 materials not only provide more sites for grafting PA, and thus enhance the adsorption capacity, but also facilitate the rapid diffusion of uranyl ions which can quickly and effectively access the interior of the H-UiO-66-PA adsorbent. Therefore, the obtained H-UiO-66-PA can achieve an impressive absorption efficiency of 6.76mgg-1 in actual seawater within 15 days. Meanwhile, the H-UiO-66-PA possesses a good adsorption capacity for uranyl ions in the five adsorption/desorption cycles. This work proposes a feasible strategy for constructing functional hierarchical porous MOFs for uranium removal.

Ultrasensitive Acetone Gas Sensor Based on a K/Sn-Co3O4 Porous Microsphere for Noninvasive Diabetes Diagnosis.

The detection of acetone in human exhaled breath is crucial for the noninvasive diagnosis of diabetes. However, the direct and reliable detection of acetone in exhaled breath with high humidity at the parts per billion level remains a great challenge. Here, an ultrasensitive acetone gas sensor based on a K/Sn-Co3O4 porous microsphere was reported. The sensor demonstrates a detection limit of up to 100 ppb, along with excellent repeatability and selectivity. Remarkably, without the removal of water vapor from exhaled breath, the sensor can accurately distinguish diabetic patients and healthy individuals according to the difference in acetone concentrations, demonstrating its great potential for diabetes diagnosis. The enhanced sensitivity of the sensor is attributed to the increased oxygen adsorption on the material surface due to K/Sn codoping and the stronger coadsorption of Sn-K atoms to acetone molecules. These findings shed light on the mechanisms underlying the sensor's improved performance.

Engineering Injectable and Highly Interconnected Porous Silk Fibroin Microspheres for Tissue Regeneration.

Injectable porous microspheres represent a promising therapeutic platform for cell delivery, drug delivery, and tissue regeneration. Yet, the engineering of silk fibroin microspheres with a highly interconnected porous structure remains an unsolved challenge. In this study, a simple and efficient method is developed that does not require the use of organic solvents to prepare silk fibroin microspheres with a predictable structure. Through extensive screening, the addition of glucose is found to direct the formation of a highly interconnected porous structure from the interior to the surface of silk fibroin microspheres. Compared to silk fibroin microspheres (SF microspheres) produced through a combination of electro-spray, cryopreservation, and freeze drying, silk fibroin-glucose microspheres (SF-Glu microspheres) demonstrates enhanced capabilities in promoting cell adhesion and proliferation in vitro. Both SF-Glu and SF microspheres exhibit the capacity to maintain the sustained release kinetics of the loaded model drug. Furthermore, SF-Glu microspheres facilitate the recruitment of endogenous cells, capillary migration, and macrophage phenotype switch following subcutaneous injection in the rats. This study opens a new avenue for the construction of porous silk fibroin microspheres, which could lead to a broader range of applications in regenerative medicine.

Synergy of engineered gelatin methacrylate-based porous microspheres and multicellular assembly to promote osteogenesis and angiogenesis in bone tissue reconstruction

One of the key challenges in bone defects treatment is providing adequate and stable blood supply during new tissue regeneration. Mesenchymal stem cells (MSCs) and endothelial cells (ECs) have great potential to promote osteogenesis and angiogenesis during bone defect repair through paracrine effects, but their therapeutic efficacy depends on effective cellular assembly and delivery. In this work, we developed various microspheres with different pore sizes for multi-cellular delivery to enhance the angiogenic and osteogenic capability via combining microfluidic and gradient freeze-drying techniques. The particle and pore size of fabricated porous gelatin methacrylate (GelMA)-based hydrogel microspheres (PGMS) could be controllable through adjusting the freezing time of hydrogel microspheres, the range of particles and pores size are 150–250 μm and 10–100 μm with different freezing time from 0 min to 30 min. The optimized particle size (200.8 ± 14.2 μm) and pore size (11.2 ± 1.9 μm) were explored to promote cell assemble, adhesion, growth, and proliferation in the PGMS. Furthermore, the co-assembly and delivery of bone marrow mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) on the PGMS was achieved and an optimal cellular ratio of BMSCs to HUVECs (20:2) was established for co-culturing of them to achieve optimal paracrine effects, further promoting osteogenic differentiation and angiogenesis. Finally, results from both in vitro and in vivo experiments showed that the developed PGMS with co-assembly of BMSCs to HUVECs contributed to accelerate bone regeneration and vascularization process daringly, exhibited great potential in vascularized bone tissue reconstruction.

Cell-microsphere based living microhybrids for osteogenesis regulating to boosting biomineralization.

Biomineralization-based cell-material living composites ex vivo showed great potential for living materials construction and cell regulation. However, cells in scaffolds with unconnected pores usually induce confined nutrient transfer and cell-cell communications, affecting the transformation of osteoblasts into osteocytes and the mineralization process. Herein, the osteoblast-materials living hybrids were constructed with porous PLLA microspheres using a rational design, in which cell-based living materials presented an improved osteoblast differentiation and mineralization model using rationally designed cell-microsphere composites. The results indicated that the microfluidic-based technique provided an efficient and highly controllable approach for producing on-demand PLLA microspheres with tiny pores (<5 μm), medium pores (5-15 μm) and large pores (>15 μm), as well as further drug delivery. Furthermore, the simvastatin (SIM)-loaded porous PLLA microsphere with ε-polylysine (ε-PL) modification was used for osteoblast (MC3T3-E1) implantation, achieving the cell-material living microhybrids, and the results demonstrated the ε-PL surface modification and SIM could improve osteoblast behavior regulation, including cell adhesion, proliferation, as well as the antibacterial effects. Both in vitro and in vivo results significantly demonstrated further cell proliferation, differentiation and cascade mineralization regulation. Then, the quantitative polymerase chain reaction or histological staining of typical markers, including collagen type I, alkaline phosphatase, runt-related transcription factor 2 and bone morphogenetic protein 2, as well as the calcium mineral deposition staining in situ, reconfirmed the transformation of osteoblasts into osteocytes. These achievements revealed a promising boost in osteogenesis toward mineralization at the microtissue level by cell-microsphere integration, suggesting an alternative strategy for materials-based ex vivo tissue construction and cell regulation, further demonstrating excellent application prospects in the field of biomineralization-based tissue regeneration.

Ultrawhite and ultrablack asymmetric coatings for radiative cooling and solar heating

Passive daytime radiative cooling, a zero-energy and zero‑carbon cooling technology, has significant potential to substantially reduce reliance on compression-based cooling systems, combat the urban heat island effect, and mitigate global warming. However, current radiative cooling materials either exhibit low efficiency or are susceptible to overcooling, resulting in cooling penalties on winter days. In this work, we designed and fabricated the ultrawhite and ultrablack asymmetric coatings. The top-layer, designed for efficient radiative cooling, consists of a porous polymethyl methacrylate and hollow silica microspheres composite. The underlayer, tailored for solar heating, is composed of a carbon nanotubes and carbon black composite. The cooling side with an exceptional solar reflectivity of 0.98 and a mid-infrared emissivity of 0.97 achieves a comparable daytime subambient cooling of 7.6 °C, with a theoretical net cooling power of 98.8 W/m2. Conversely, the heating side with a solar absorptivity of 0.96, a ultra-high visible light absorptivity of 0.985, and a mid-infrared emissivity of 0.97, results in a daytime above-ambient heating of 12.8 °C, corresponding to a theoretical net heating power of 745 W/m2. Promisingly, our ultrawhite and ultrablack asymmetric coatings hold the promise of addressing the long-standing challenge of all-season temperature regulation, offering significant potential for electricity savings and CO2 emission reduction.

Mn-Zr promoted CaCO3 porous microspheres for enhanced performance in direct solar-driven calcium looping

The Calcium looping thermochemical reaction directly driven by solar energy effectively addresses the problem of efficient energy storage of concentrated solar power plants (CSP) by shortening the energy conversion path. But new requirements are put forward for energy storage materials, including high solar radiation absorption, high cycling stability and fast kinetics. To meet these challenges, we have designed porous microsphere structures for the purpose of enhancing mass transfer and the capture of solar radiation. Additionally, Zr and Mn oxides with elevated Tammann temperatures were incorporated to stabilize the morphology and prevent sintering. The synthesized porous microspheres retained abundant mesoporous channels on the surface even after undergoing 20 cycles. The addition of Mn oxide significantly enhances solar spectral absorptivity, achieving an impressive 82.88 % absorbance. The incorporation of Mn and Zr oxides increased the sintering resistance, specific surface area and porosity of CaO/CaCO3, especially in the 10–100 nm range, which accelerated the CO2 transport during carbonation. These enhancements significantly improve the chemical control stage of the carbonation reaction, as further supported by kinetic models. After 50 cycle experiments at 800 °C, the energy storage density of the sample remains at 1074 kJ/kg, which is 1.86 times that of the undoped CaCO3. This study provides a new way to design CaCO3 materials suitable for CSP applications.

Regulating the Electronic Structure of Cu Single-Atom Catalysts toward Enhanced Electro-Fenton Degradation of Organic Contaminants via 1O2 and •OH.

Heterogeneous electro-Fenton degradation with 1O2 and •OH generated from O2 reduction is cost-effective for the removal of refractory organic pollutants from wastewater. As 1O2 is more tolerant to background constituents such as salt ions and a high pH value than •OH, tuning the production of 1O2 and •OH is important for efficient electro-Fenton degradation. However, it remains a great challenge to selectively produce 1O2 and improve the species yield. Herein, the electronic structure of atomically dispersed Cu-N4 sites was regulated by doping electron-deficient B into porous hollow carbon microspheres (CuBN-HCMs), which improved *O2 adsorption and significantly enhanced 1O2 selectivity in electro-Fenton degradation. Its 1O2 yield was 2.3 times higher than that of a Cu single-atom catalyst without B doping. Meanwhile, •OH was simultaneously generated as a minor species. The CuBN-HCMs were efficient for the electro-Fenton degradation of phenol, sulfamethoxazole, and bisphenol A with a high mineralization efficiency. Its kinetic constants showed insignificant changes under various anions and a wide pH range of 1-9. More importantly, it was energy-efficient for treating actual coking wastewater with a low energy consumption of 19.0 kWh kgCOD-1. The superior performance of the CuBN-HCMs was contributed from 1O2 and •OH and its high 1O2 selectivity.

Soft-templating of biomass derivatives into edge-N doped 3D-interconnected hierarchical porous carbon for multi-scenario supercapacitive energy storage

Rational design of the pore structure for carbon materials is of great significance for solving the low specific capacitance and poor rate capability of supercapacitors. A novel soft-templating strategy is proposed by using biomass-derived sodium lignosulphonate as a carbon precursor and sublimable hexamethylenetetramine as a soft template. The hexamethylenetetramine nanoparticles are formed in the confined spaces of the precursor, and then these templates sublime to leave mesopores after the lignosulfonate transformed from linear structure to bulk structure by thermostabilization treatment. A high nitrogen content of 40 wt% in hexamethylenetetramine is also beneficial for the subsequent in-situ N-doping. The as-obtained nitrogen-doped hierarchical porous carbon microspheres possess a high specific surface area of 1416 m2 g−1 with an N-doping content of 4.32 % (86.26 % edge-N). In a two-electrode system, the soft-templating carbon exhibits a decent specific capacitance of 234 F g−1 at 0.1 A g−1, an excellent rate capability of 62.4 % at 50 A g−1, and a high energy density of 8.1 Wh kg−1 at 15.0 kW kg−1 in 6 M KOH aqueous electrolyte. Moreover, advanced additive manufacturing technology of direct ink writing was applied to construct a quasi-solid-state in-plane interdigital microsupercapacitor by using the soft-templating carbon, and it presents a superior areal/volumetric capacitance, rate performance, mechanical stability, and flexibility with PVA/H2SO4 gel electrolyte. This work broadens the pore structure engineering methodology by novel soft-templating biocarbon for multi-functional and multi-scenario energy storage systems.

Porous TiO2 microspheres containing MgO nanoparticles/epoxy composite with superior thermal conductivity, EMI shielding, and electrical insulation

With the continuous advancement of electronic devices, the amounts of heat as well as electromagnetic (EM) waves generated have increased. Materials with high thermal conductivity and excellent EM interference shielding effectiveness (EMI SE) can be utilized to address this issue. In this work, we synthesized hollow anatase TiO2 microspheres. Through a reaction, MgO nanoparticles were incorporated into the interior of TiO2 microspheres. (H-TiO2/MgO). The heterostructure of the fillers contributed to performance enhancement. TiO2 and MgO particles formed a dual thermal-conduction pathway. H-TiO2/MgO effectively weakened the energy of EM waves upon contact. Additionally, TiO2, MgO, and epoxy all exhibited hydrophilicity. Consequently, the interfacial compatibility between H-TiO2/MgO and epoxy was excellent. They formed strong interfacial interactions by hydrogen bonding. Because of the excellent electrical insulation properties of H-TiO2 and MgO, the composites exhibited superior insulation performance (over 1010 Ω·cm). Our H-TiO2/MgO/Epoxy composites exhibited a maximum thermal conductivity of 7.52 W/m·K, an EMI SE of 64.92 dB, and a tensile strength of 79.10 MPa. Our composites are expected to effectively manage heat and EM waves generated by electronic devices.

Porous microsphere LiNi0.8Co0.15Al0.05O2 electrode modified by Na2CO3: Enhanced performance of low temperature solid oxide fuel cells

LiNi0.8Co0.15Al0.05O2 (NCAL) has been extensively adopted as symmetric electrode for low temperature solid oxide fuel cells (SOFCs) based on oxide semiconductor electrolytes. However, the performance of NCAL electrode depend on material source, morphology and operating conditions. In this study, commercial microsphere NCAL is successfully modified with Na2CO3 by a wet chemical method. The crystal structure, surface morphology, elemental analysis, surface chemistry and electrochemical properties of NCAL modified by Na2CO3 (NCALN) are characterized by various techniques. When Na2CO3 content in NCALN is 5 wt% and 10 wt%, the CeO2 electrolyte SOFCs with NCALN symmetric electrode show significantly superior performance to that with NCAL symmetric electrode. The optimal heterostructure electrode NCALN5 exhibits a peak power density of 805 mW cm−2 and a polarization resistance of 0.237 Ω cm2 at 550 °C, which is 17 % higher and 21 % lower than those of NCAL electrode. Compared with NCAL electrode, NCALN5 electrode enhances the catalytic activities to both hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) but contributes more to ORR than HOR, especially at low temperatures. These results clearly demonstrate NCALN heterostructure composites are promising electrode materials for low temperature SOFCs.

Highly porous polycaprolactone microspheres for skeletal repair promote a mature bone cell phenotype in vitro.

Improving our ability to treat skeletal defects is a critical medical challenge that necessitates the development of new biomaterials. One promising approach involves the use of degradable polymer microparticles with an interconnected internal porosity. Here, we employed a double emulsion to generate such round microparticles (also known as microspheres) from a polycaprolactone-based polymerised high internal phase emulsion (polyHIPE). These microspheres effectively supported the growth of mesenchymal progenitors over a 30-day period, and when maintained in osteogenic media, cells deposited a bone-like extracellular matrix, as determined by histological staining for calcium and collagen. Interestingly, cells with an osteocyte-like morphology were observed within the core of the microspheres indicating the role of a physical environment comparable to native bone for this phenotype to occur. At later timepoints, these cultures had significantly increased mRNA expression of the osteocyte-specific markers dentin matrix phosphoprotein-1 (Dmp-1) and sclerostin, with sclerostin also observed at the protein level. Cells pre-cultured on porous microspheres exhibited enhanced survival rates compared to those pre-cultured on non-porous counterparts when injected. Cells precultured on both porous and non-porous microspheres promoted angiogenesis in a chorioallantoic membrane (CAM) assay. In summary, the polycaprolactone polyHIPE microspheres developed in this study exhibit significant promise as an alternative to traditional synthetic bone graft substitutes, offering a conducive environment for cell growth and differentiation, with the potential for better clinical outcomes in bone repair and regeneration.

A controllable self-template synthesis strategy for hierarchical porous carbon microspheres with cavity structures for supercapacitor applications

Herein, we introduce a novel and controllable self-template approach for fabricating hierarchical porous carbon microspheres with cavities (CPCMs). This approach uses polyacrylonitrile (PAN) and acrylamide (AM) microspheres as templates, which feature small anisotropic bumps on their surface. These bumps are encapsulated by divinylbenzene (DVB) during the coating polymerization process. The subsequent hydrolysis of PAN and AM led to the formation of a hierarchical porous structure. Specifically, mesopores mainly arose from PAN hydrolysis, whereas AM contributed additional micropores and macropores, generating an intricate pore structure within the DVB shell. This method differs from traditional pore-making approaches. Additionally, in situ doping of nitrogen (N) and oxygen (O) atoms was achieved. The amount of DVB coating can be adjusted to vary the shell thickness, allowing for the modulation of the pore size distribution and surface micromorphology. Owing to the synergistic effects of an ultrahigh specific surface area (1151.9 m2 g−1), extensive pore volume (1.2575 m3 g−1), and well-structured micro-meso-macropore hierarchy, along with N/O codoping, the resulting carbon material exhibited outstanding electrochemical energy storage performance. Notably, the optimal CPCMs-2 electrode achieves an exceptional specific capacitance of 377 F g−1 at a current density of 0.5 A g−1. This study proposes a novel avenue for designing hierarchical porous carbon materials, and CPCMs could be expanded to a wide range of applications.

Template synthesis of MgMn2O4 graded porous microspheres and electrochemical properties

Porous materials are more popular in electrochemical applications. In this study, MgMn2O4 microspheres with graded porous structure were prepared at lower temperature using a convenient template method, and MnCO3 microspheres were used as self-sacrificial templates. MgMn2O4 spinel microspheres were also prepared by template free method for comparison. The MgMn2O4 graded porous microspheres obtained by template method were assembled from nanoparticles with size of 20–50 nm, and have larger specific surface area (twice that of MgMn2O4 prepared by template free method). XPS studies show that both materials have mixed spinel structure with Mn present in multivalent states, and the material prepared by template method exhibits lower inversion degree. The electrochemical test results indicate that MgMn2O4 graded porous microspheres prepared by template method exhibit more excellent cycling and rate performance compared to materials prepared by template free method. The initial discharge capacity is up to 1429.5 mAh g−1 at a current density of 100 mA g−1, and discharge capacity remains 778.0 mAh g−1 after 150 cycles. Even at high rates (1000 mA g−1), it can stably output a cycling capacity of 295.5 mAh g−1. The MgMn2O4/LiCoO2 full cell delivers an initial discharge capacity of 83.4 mAh g−1 at a current of 100 mA g−1. The excellent electrochemical performance of MgMn2O4 microspheres prepared by template method may be related to their graded porous structure and low inversion degree. This study indicates that the electrochemical performance of MgMn2O4 materials can be greatly improved by adjusting the microstructural morphology.

In Situ Synthesis and Characterizations of a Strontium-Substituted Dicalcium Phosphate Anhydrous/Hydroxyapatite Biphasic Whisker and Its Properties Evaluation.

Dicalcium phosphate anhydrous (DCPA) presents good biomineralization ability, the strontium element is known for superior bone affinity, and a whisker possesses good mechanical strength; all these are beneficial for improving the drawbacks of hydroxyapatite (HAP) like weaker mechanical properties, poor biomineralization, and slower degradation/absorption. Therefore, a homogeneous precipitation was adopted to synthesize Sr-substituted and DCPA and HAP coexisting whiskers. The composition, structure, and morphology based on urea dosage and substitution content were characterized, and the roles of DCPA, Sr, and whisker shape were investigated. It turned out that Sr-DCPA/HAP biphasic products contained about 19% DCPA and 81% HAP, and both phases occupied the outer and inner parts of the whisker, respectively. Increasing the urea dosage made the morphology transform from a sea urchin shape to fiber clusters and then whiskers, while Sr substitution brought the whisker back to the porous microsphere shape. Only 5% of Sr content and 15 g of urea could maintain the whisker shape. Sr could promote the proliferation of MC3T3-E1 cells even at a higher extract concentration of 10 mg/mL. The cells stayed in a healthy state whether cocultured with the whisker or the microsphere. The unstable DCPA combined with the decreased crystallinity brought by Sr doping contributed to shortening the apatite deposition period to within 7 days. The whisker morphology enhanced the compressive strength of acrylic resin, and the apatite layer helped to reduce the strength loss during soaking. The Sr-DCPA/HAP biphasic whisker with enhanced overall properties possessed more promising potential for biomedical application.

Metal nanoparticles encapsulation within multi-shell spongy-core porous microspheres for efficient tandem catalysis

The “one-pot” cascade process involves multiple catalytic conversions followed by a single workup stage. This method has the capability to optimize catalytic efficiency by reducing chemical processes. The key to achieving cascade reactions lies in designing cascade catalysts with well-dispersed, stably immobilized, and accessible noble metal nanoparticles for multiple catalytic conversions. This work presents a strategy for creating long-lasting cascade catalysts by encapsulating Ru and Pd nanoparticles within multi-shell spongy-core porous microspheres (MS-SC-PMs). This cascade catalyst strategy enables the continuous hydrogenation of nitrobenzene to aniline and further to cyclohexylamine, demonstrating both high selectivity and conversion rates. Notably, this approach overcomes the typical challenges associated with noble metal nanoparticles, such as poor stability and recyclability, as it maintains its performance over ten consecutive cycles. Additionally, the MS-SC-PMs have the versatility to encapsulate various metal nanoparticles, providing catalytic versatility, scalability, and a promising avenue for designing long-lasting catalysts loaded with nanoparticles.