Pore Structure Of Scaffolds Research Articles

Mineralized Biopolymers-Based Scaffold Encapsulating with Dual Drugs for Alveolar Ridge Preservation.

Mineralization of scaffolds is essential for alveolar ridge preservation and bone tissue engineering, enhancing the mechanical strength and bioactivity of scaffolds, and promoting better integration with natural bone tissue. While the in situ mineralization method using concentrated SBF solutions is promising, there is limited comprehensive research on its effects. In this study, it is demonstrate that soaking gelatin/alginate scaffolds (GAS) in fivefold concentrated SBF significantly reduces the mineralization time to 3-7 days but also leads to considerable degradation and loss of the scaffold's original microstructure. The ratio of gelatin to alginate is optimized to improve the properties of GAS. The optimized GAS sample, when soaked in concentrated SBF to form GAS/HAp, exhibited hydroxyapatite (HAp) crystal formation starting from day 3, with mature hexagonal crystals forming by day 7. However, this process also caused significant decomposition and deformation of the scaffold's pore structure. Additionally, the biocompatibility of GAS and GAS/HAp is evaluated through in vitro, in ovo, haemolysis, and anti-ROS assays. The findings highlight the impact of SBF5× on the mineralization of GAS, laying the groundwork for further research in alveolar ridge preservation and bone tissue engineering.

Research on Dual-Phase Composite Forming Process and Platform Construction of Radial Gradient Long Bone Scaffold.

The structure and composition of natural bone show gradient changes. Most bone scaffolds prepared by bone tissue engineering with single materials and structures present difficulties in meeting the needs of bone defect repair. Based on the structure and composition of natural long bones, this study proposed a new bone scaffold preparation technology, the dual-phase composite forming process. Based on the composite use of multiple biomaterials, a bionic natural long bone structure bone scaffold model with bone scaffold pore structure gradient and material concentration gradient changes along the radial direction was designed. Different from the traditional method of using multiple nozzles to achieve material concentration gradient in the scaffold, the dual-phase composite forming process in this study achieved continuous 3D printing preparation of bone scaffolds with gradual material concentration gradient by controlling the speed of extruding materials from two feed barrels into a closed mixing chamber with one nozzle. Through morphological characterization and mechanical property analysis, the results showed that BS-G (radial gradient long bone scaffolds prepared by the dual-phase composite forming process) had obvious pore structure gradient changes and material concentration gradient changes, while BS-T (radial gradient long bone scaffolds prepared by printing three concentrations of material in separate regions) had a discontinuous gradient with obvious boundaries between the parts. The compressive strength of BS-G was 1.00 ± 0.19 MPa, which was higher than the compressive strength of BS-T, and the compressive strength of BS-G also met the needs of bone defect repair. The results of in vitro cell culture tests showed that BS-G had no cytotoxicity. In a Sprague-Dawley rat experimental model, blood tests and key organ sections showed no significant difference between the experimental group and the control group. The prepared BS-G was verified to have good biocompatibility and lays a foundation for the subsequent study of the bone repair effect of radial gradient long bone scaffolds in large animals.

A multi-scale porous scaffold fabricated by a combined additive manufacturing and chemical etching process for bone tissue engineering

It is critical to develop a fabrication technology for precisely controlling an interconnected porous structure of scaffolds to mimic the native bone microenvironment. In this work, a novel combined process of additive manufacturing (AM) and chemical etching was developed to fabricate graphene oxide/poly(L-lactic acid) (GO/PLLA) scaffolds with multiscale porous structure. Specially, AM was used to fabricate an interconnected porous network with pore sizes of hundreds of microns. And the chemical etching in sodium hydroxide solution constructed pores with several microns or even smaller on scaffolds surface. The degradation period of the scaffolds was adjustable via controlling the size and quantity of pores. Moreover, the scaffolds exhibited surprising bioactivity after chemical etching, which was ascribed to the formed polar groups on scaffolds surfaces. Furthermore, GO improved the mechanical strength of the scaffolds.

Micro-Computed Tomography Analysis and Histological Observation of the Screw-Bone Interface of Novel Porous Scaffold Core Pedicle Screws and Hollow Lateral Hole Pedicle Screws: A Comparative Study in Bama Pigs

Screw loosening is a common complication of pedicle screw internal fixation surgery. This study aimed to investigate whether the application of a porous scaffold structure can increase the contact area between screws and bone tissue by comparing the bone ingrowth and screw-bone interface of porous scaffold core pedicle screws (PSCPSs) and hollow lateral hole pedicle screws (HLHPSs) in the lumbar spine of Bama pigs. Sixteen pedicle screws of both types were implanted into the bilateral pedicles of the L1-4 vertebrae of 2 Bama pigs. All Bama pigs were sacrificed and the lumbar spine was freed into individual vertebrae at 16weeks postoperatively. After the vertebrae were made into screw-centered specimens, micro-computed tomography analysis and histological observation were performed to assess the screw-bone interface and bone growth around and within the screws. We found that the bone condition around PSCPSs and HLHPSs did not show significant differences on micro-computed tomography three-dimensional reconstruction images. CT transverse views showed different bone growth inside the 2 screws. In PSCPSs, bone tissue was seen to fill the internal pores and was evenly distributed around each strut. Inside HLHPSs, bone growth was confined to 1 side of the screw and did not fill the entire cavity. Osteometric analysis showed that bone volume fraction and trabecular number, the parameters representing bone mass, were higher in PSCPSs than in HLHPSs. These differences were not statistically significant (P > 0.05). Histological observations visualized that the osseointegration within PSCPSs was superior to that of HLHPSs, and the tight integration of bone tissue with the porous scaffold resulted in a larger screw-bone integration area in PSCPSs than in HLHPSs. Compared with HLHPSs, PSCPSs possessing a porous scaffold core could promote bone ingrowth and osseointegration, resulting in an effective enhancement of the combined area of the screw-bone interface.

Tailored edible 3D porous scaffolds constructed by Pickering emulgel templating for cell-cultured fish meat

Cell-cultured fish meat have emerged as an innovative approach to resolving the issues in response to consumer demand. Food-grade scaffolds, which not only serve as the “comfortable home” for stem cells but also endow the final product with meat-like texture, play a vital role in the construction of cell-cultured fish meat. In this study, pea protein, an abundant and inexpensive plant protein, is used to construct edible three-dimensional (3D) porous scaffolds, which exhibit desirable stem cell proliferation and differentiation performance. Our findings demonstrate that it is feasible to apply the Pickering emulgel templating combined with double-crosslinking to the preparation of cell-cultured fish meat scaffolds. The pore structure of 3D porous scaffolds can be altered by varying the emulsification parameters on demand. The Pickering emulgels with large droplet size (around 40 μm) are conducive to the formation of 3D porous scaffolds with large enough pore size for the growth of stem cells. The now available result help to explore the plant protein-derived scaffolds, provide insights into the development of Pickering emulgel-based 3D porous scaffolds and illuminate the relationship between the structural characteristics of scaffolds and the biological functions of stem cells.

Fishwaste Derived Hydroxyapatite Nanostructure Combined with Black Rice Wine for Potential Antioxidant and Antimicrobial Response.

Hospital-acquired infection remains a serious threat globally, due to development of resistance to conventional antibiotics, which necessitates the urge for alternative therapy. Green nanotechnology has emerged as a holistic approach to address antibiotic resistance by combining environmental sustainability with improved therapeutic outcome. Nanostructure hydroxyapatite (HAP) has received significant attention in therapeutic and regenerative purposes due to its porous scaffold structure and biocompatible nature. In the present study, hydroxyapatite (HAP) nanoparticle was fabricated from the fish scale waste of red snapper fish. Black rice wine (BRW) was extracted from black rice commonly termed as Karupu kavuni/forbidden rice known for its nutritious effects. The present study focused on encapsulation of BRW within HAP nanoparticles (HAP@BRW) and evaluated its potential against nosocomial infections. Spectral and microscopic characterization of HAP@BRW revealed uniform encapsulation of BRW in HAP nanoparticles, aggregated irregular-shaped morphology of size 117.6nm. Maximum release of BRW (72%) within 24h indicates HAP as suitable drug delivery system suitable for biomedical applications. Antimicrobial studies revealed that HAP@BRW exhibited potent bactericidal effect against MRSA, MSSA, and Pseudomonas aeruginosa. Furthermore, HAP@BRW significantly inhibited the biofilm forming ability of MSSA and P. aeruginosa. Rich antioxidant property of HAP@BRW might be due to the presence of rich source of total polyphenolic, flavonoid, and anthocyanin content in BRW. In vitro and in vivo toxicity studies revealed biocompatible nature of HAP@BRW. Antibiofilm, antimicrobial, antioxidant, and biocompatible nature of HAP@BRW makes it a promising candidate for coating medical implants to avoid implant-associated infections and nosocomial infections.

Mechanical and in vitro study of 3D printed silk fibroin and bone-based composites biomaterials for bone implant application.

When treating orthopaedic damage or illness and accidental fracture, bone grafting remains the gold standard of treatment. In cases where this approach does not seem achievable, bone tissue engineering can offer scaffolding as a substitute. Defective and fractured bone tissue is extracted and substituted with porous scaffold structures to aid in the process of tissue regeneration. 3D bioprinting has demonstrated enormous promise in recent years for producing scaffold structures with the necessary capabilities. In order to create composite biomaterial inks for 3D bioprinting, three different materials were combined such as silk fibroin, bone particles, and synthetic biopolymer poly (ε-caprolactone) (PCL). These biomaterials were used to fabricate the two composites scaffolds such as: silk fibroin + bovine bone (SFB) and silk fibroin + bovine bone + Polycaprolactone (SFBP). The biomechanical, structural, and biological elements of the manufactured composite scaffolds were characterized in order to determine their suitability as a possible biomaterial for the production of bone tissue. The in vitro bioactivity of the two composite scaffolds was assessed in the simulated body fluids, and the swelling and degradation characteristics of the two developed scaffolds were analyzed separately over time. The results showed that the mechanical durability of the composite scaffolds was enhanced by the bovine bone particles, up to a specific concentration in the silk fibroin matrix. Furthermore, the incorporation of bone particles improved the bioactive composite scaffolds' capacity to generate hydroxyapatite in vitro. The combined findings show that the two 3D printed bio-composites scaffolds have the required mechanical strength and may be applied to regeneration of bone tissue and restoration, since they resemble the characteristics of native bone.

Mechanical Characterisation of 3D-Printed Porous PLA Scaffolds with Complex Microarchitectures for Bone Tissue Engineering Applications

Bone transplantation remains the leading approach in addressing orthopaedic trauma or disease. In cases where this option is not viable, bone tissue engineering offers an alternative through the use of scaffolding. This approach involves the removal of damaged bone tissue and its replacement with porous scaffold structures to support the regeneration process. Recently, additive manufacturing has emerged as a promising technology for producing scaffold structures that satisfy the necessary performance criteria. In this study, PLA scaffolds with tortuous pore network designs were fabricated using fused deposition modelling. Scaffolds were fabricated with four different porosity values by changing the pore diameter in the range of 840–1732 µm. Sixteen specimens were tested under monotonic compression testing. Result shows the elastic moduli generated by each sample with 25%, 45%, 60% and 75% porosity: 545.21 ± 109.76, 446.82 ± 57.12, 312.55 ± 82.64 and 123.81 ± 23.95 MPa, respectively. Finite element simulation showed good correlation with experimental results, thereby effectively assessing the scaffold mechanical behaviour. Accordingly, the proposed finite element model can predict the mechanical behaviour of fabricated bone scaffolds accurately. The results demonstrate that the numerically predicted elastic modulus of complex scaffold is not closer to experimental outcomes in comparison with as-built samples. Overall, these findings suggest the potential of 3D-printed PLA scaffolds with tuneable porosity for cancellous bone replacement applications.

Biomechanical Properties of Novel Porous Scaffold Core and Hollow Lateral Hole Pedicle Screws: A Comparative Study in Bama Pigs.

Screw loosening is a common complication of internal fixation of pedicle screw. Therefore, the development of a pedicle screw with low loosening rate and high biosafety is of great clinical significance. This study aimed to investigate whether the application of a porous scaffold structure can improve the stability of pedicle screws by comparing the biomechanical properties of novel porous scaffold core pedicle screws (PSCPSs) with those of hollow lateral hole pedicle screws (HLHPSs) in a porcine lumbar spine. Thirty-two pedicle screws of both types were implanted bilaterally into the L1-4 vertebrae of four Bama pigs, with our newly designed PSCPSs on the right and HLHPSs on the left. All the Bama pigs were sacrificed 16 weeks postoperatively, and the lumbar spine was freed into individual vertebrae. Biomechanical properties of both the pedicle screws were evaluated using pull-out tests, as well as cyclic bending and pull-out tests, while the mechanical properties were assessed using three-point bending tests. The data generated were statistically analyzed using paired-sample t-tests and two independent sample t-tests. We found that the maximal pull-out forces before and after cyclic bending of the PSCPSs (1161.50 ± 337.98 N and 1075.25 ± 223.33 N) were significantly higher than those of the HLHPSs (948.38 ± 194.32 N and 807.13 ± 242.75 N) (p < 0.05, p < 0.05). In 800 cycles of the bending tests, neither PSCPS nor HLHPS showed loosening or visible detachment, but their maximal pull-out forces after cyclic bending tests decreased compared to those in cycles without cyclic bending tests (7.43% and 14.89%, respectively), with no statistical significance (p > 0.05 and p > 0.05, respectively). Additionally, both screws buckled rather than broke in the three-point bending tests, with no statistically significant differences between the maximal bending load and modulus of elasticity of the two screws (p > 0.05 and p > 0.05, respectively). Compared with the HLHPSs, the PSCPSs have greater pull-out resistance and better fatigue tolerance with appropriate mechanical properties. Therefore, PSCPSs theoretically have significant potential for clinical applications in reducing the incidence of loosening after pedicle screw implantation.

Indirect 3D printing CDHA scaffolds with hierarchical porous structure to promote osteoinductivity and bone regeneration

Hierarchical porous structure, which include macropores, minor pores, and micropores in scaffolds, are essential in the multiple biological functions of bone repair and regeneration. In this study, patient-customized calcium-deficient hydroxyapatite (CDHA) scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method. The sacrificial template scaffolds were fabricated using a photo-curing 3D printer, which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds. Additionally, 20 wt% pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds, and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former. The obtained CDHA-2 scaffolds exhibited interconnected macropores (300–400 μm), minor pores (∼10–100 μm), and micropores (< 10 μm) distributed throughout the scaffolds, which could promote bone tissue ingrowth, increase surface roughness, and enhance protein adsorption of scaffolds. In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains, high specific surface area, and outstanding protein adsorption capacity, which could provide a microenvironment for cell adhesion, spreading, and proliferation. In addition, the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors. The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration. In conclusion, these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration, and CDHA-2 scaffolds were potential candidates for bone regeneration.

Achieving Long Cycle Life of Zn-Ion Batteries through Three-Dimensional Copper Foam.

Metallic zinc anodes in aqueous zinc-ion batteries (ZIBs) suffer from dendritic growth, low Coulombic efficiency, and high polarization during cycling. To mitigate these challenges, current collectors based on three-dimensional (3D) commercial copper foam (CCuF) are generally preferred. However, their utilization is constrained by their thickness, low electroactive surface area, and increased manufacturing expenses. In this study, the synthesis of cost-effective current collectors with exceptionally large surface areas designed for ZIBs that can be cycled hundreds of times is reported. A zinc-coated CuF anode (Zn/CuF) was prepared with a 3D porous CuF current collector produced by the dynamic hydrogen bubble template (DHBT) method. Electrochemically generated copper foam could be obtained within seconds while offering a thickness as low as 30-40 μm (CuF5 achieved a thickness of ∼38 μm in 5 s) via the DHBT method. The excellent electrical conductivity and open pore structure of the 3D porous copper scaffold ensured the uniform deposition/stripping of Zn during cycling. During the 500 h Zn deposition/stripping process, the as-synthesized CuF5 current collector offered fast electrochemical kinetics and low polarization as well as a relatively high average Coulombic efficiency of 99% (at a current density of 5 mA cm-2 and a capacity of 1 mAh cm-2). Furthermore, the symmetric cell exhibited low voltage polarization and a stable voltage profile for 1000 h at a current density of 0.1 mA cm-2. In addition, full cells containing the Zn/CuF anode coupled with an as-synthesized α-MnO2 nanoneedle cathode in aqueous electrolyte were also prepared. Capacities of 266 mAh g-1 at 0.1 A g-1 and 94 mAh g-1 at 2 A g-1 were achieved after 200 charge/discharge cycles with a stable Coulombic efficiency value close to 99.9%.

Three-dimensional printed silk fibroin and fenugreek based bio-composites scaffolds

When treating orthopaedic damage or illness and accidental fracture, bone grafting remains the gold standard of treatment. In cases where this approach doesn't seem achievable, bone tissue engineering can offer scaffolding as a substitute. Defective and fractured bone tissue is extracted and substituted with porous scaffold structures to aid in the process of tissue regeneration. Three-dimensional bioprinting has demonstrated enormous promise in recent years for producing scaffold structures with the necessary capabilities. In order to create composite biomaterial inks for three-dimensional bioprinting, four different materials were combined such as silk fibroin, bone particles (B), synthetic biopolymer poly (ε-caprolactone), and Fenugreek (F). These biomaterials were mixed together in certain proportion to develop a silk fibroin + bovine bone + polycaprolactone + fenugreek powder composites biomaterial which was later three-dimensional bioprinted to fabricated composite bio-scaffold. The biomechanical, structural, and biological elements of the manufactured composite scaffolds were characterized in order to determine their suitability as a possible biomaterial for the production of bone tissue. The in vitro bioactivity of the composite scaffolds was assessed in the simulated body fluids, and the swelling and degradation characteristics of the two developed scaffolds were analyzed separately over time. The results showed that the mechanical durability of the composite scaffolds was enhanced by the bovine bone particles, up to a specific concentration in the silk fibroin matrix. Furthermore, the incorporation of bone particles improved the bioactive composite scaffolds’ capacity to generate hydroxyapatite in vitro. The combined findings show that the three-dimensional printed bio-composites scaffolds have the required mechanical strength and may be applied to regeneration of bone tissue and restoration, since they resemble the characteristics of native bone.

Effect of porogen agent on the size, shape, and structure of porous hydroxyapatite scaffolds

Effect of porogen agent on the size, shape, and structure of porous hydroxyapatite scaffolds

3D printing technology and its combination with nanotechnology in bone tissue engineering.

With the graying of the world's population, the morbidity of age-related chronic degenerative bone diseases, such as osteoporosis and osteoarthritis, is increasing yearly, leading to an increased risk of bone defects, while current treatment methods face many problems, such as shortage of grafts and an incomplete repair. Therefore, bone tissue engineering offers an alternative solution for regenerating and repairing bone tissues by constructing bioactive scaffolds with porous structures that provide mechanical support to damaged bone tissue while promoting angiogenesis and cell adhesion, proliferation, and activity. 3D printing technology has become the primary scaffold manufacturing method due to its ability to precisely control the internal pore structure and complex spatial shape of bone scaffolds. In contrast, the fast development of nanotechnology has provided more possibilities for the internal structure and biological function of scaffolds. This review focuses on the application of 3D printing technology in bone tissue engineering and nanotechnology in the field of bone tissue regeneration and repair, and explores the prospects for the integration of the two technologies.

Synergistic Amelioration of Osseointegration and Osteoimmunomodulation with a Microarc Oxidation-Treated Three-Dimensionally Printed Ti-24Nb-4Zr-8Sn Scaffold via Surface Activity and Low Elastic Modulus.

Biomaterial scaffolds, including bone substitutes, have evolved from being primarily a biologically passive structural element to one in which material properties such as surface topography and chemistry actively direct bone regeneration by influencing stem cells and the immune microenvironment. Ti-6Al-4V(Ti6Al4V) implants, with a significantly higher elastic modulus than human bone, may lead to stress shielding, necessitating improved stability at the bone-titanium alloy implant interface. Ti-24Nb-4Zr-8Sn (Ti2448), a low elastic modulus β-type titanium alloy devoid of potentially toxic elements, was utilized in this study. We employed 3D printing technology to fabricate a porous scaffold structure to further decrease the structural stiffness of the implant to approximate that of cancellous bone. Microarc oxidation (MAO) surface modification technology is then employed to create a microporous structure and a hydrophilic oxide ceramic layer on the surface and interior of the scaffold. In vitro studies demonstrated that MAO treatment enhances the proliferation, adhesion, and osteogenesis capabilities on the scaffold surface. The chemical composition of the MAO-Ti2448 oxide layer is found to enhance the transcription and expression of osteogenic genes in bone mesenchymal stem cells (BMSCs), potentially related to the enrichment of Nb2O5 and SnO2 in the oxide layer. The MAO-Ti2448 scaffold, with its synergistic surface activity and low stiffness, significantly activates the anti-inflammatory macrophage phenotype, creating an immune microenvironment that promotes the osteogenic differentiation of BMSCs. In vivo experiments in a rabbit model demonstrated a significant improvement in the quantity and quality of the newly formed bone trabeculae within the scaffold under the contact osteogenesis pattern with a matched elastic modulus. These trabeculae exhibit robust connections to the external structure of the scaffold, accelerating the formation of an interlocking structure between the bone and implant and providing higher implantation stability. These findings suggest that the MAO-Ti2448 scaffold has significant potential as a bone defect repair material by regulating osteoimmunomodulation and osteogenesis to enhance osseointegration. This study demonstrates an optional strategy that combines the mechanism of reducing the elastic modulus with surface modification treatment, thereby extending the application scope of β-type titanium alloy.

Multifunctional DNA scaffold mediated gap plasmon resonance: Application to sensitive PD-L1 sensor

The introduction of noble metal nanoparticles with good LSPR characteristics can greatly improve the sensitivity of SPR through resonance coupling effect. The plasma resonance response and optical properties of film coupling nanoparticle systems largely depends on the ingenious design of gap structures. Nucleic acid nanostructures have good stability, flexibility, and high biocompatibility, making them ideal materials for gap construction. 2D MOF (Cu-Tcpp) has a large conjugated surface similar to graphene, which can provide a stable substrate for the directional fixation of nucleic acid nanostructures. However, research on gap coupling plasmon based on nucleic acid nanostructures and 2D MOF is still rarely reported. By integrating the advantages of Cu-Tcpp assembled film and DNA tetrahedron immobilization, a nano gap with porous scaffold structure between the gold film and gold nanorod was build. The rigidity of DNA tetrahedron can precisely control the gap size, and its unique programmability allows us to give the coupling structure greater flexibility through the design of nucleic acid chain. The experimental results and FDTD simulation show that the film coupling nanoparticle systems constructed with DNA tetrahedrons greatly enhance the electric field strength near the chip surface and effectively improve the sensitivity of SPR. This research shows the huge potential of nucleic acid nanomaterials in the construction of SPR chip surface microstructures.

Silver-doped hydroxyapatite laden chitosan–gelatin nanocomposite scaffolds for bone tissue engineering: an in-vitro and in-ovo evaluation

Despite the advancements in bone tissue engineering, the majority of implant failures are caused due to microbial contamination. So, efforts are being made to develop biomaterial with antimicrobial property enhancing the regeneration of damaged bone tissue. In the present study, chitosan–gelatin (CG) scaffolds containing silver-doped hydroxyapatite (AgHAP) nanoparticles at 0.5%, 1.0% and 1.5% (w/v) were fabricated by lyophilization technique. The results confirmed the synthesis of AgHAP nanoparticles and showed interconnected porous structure of the nanocomposite scaffolds with 89%–75% porosity. Similarly, the swelling percentage, degradation behavior and compressive modulus of CG-AgHAP nanocomposite scaffolds were 1666%, 40% and 0.7 MPa, respectively. The developed nanocomposite scaffolds revealed better antimicrobial properties and bioactivity. The cell culture studies showed favorable viability of Wharton’s jelly stem cells on CG-AgHAP nanocomposite scaffolds. CAM (chorioallantoic membrane) assay determined the angiogenic potential with better visualization of blood vessels in the CAM area. Hence, the obtained results confirmed that CG-AgHAP3 nanocomposite scaffold was the most suitable for bone tissue engineering applications among all scaffolds.

Adhesion and morphology of mammalian cells on nanoporous and nonporous spherical carbon substrates

Three spherical activated carbons (SACs) were used as substrates for mammalian cell proliferation. SACs were obtained by carbonizing styrene-co-divinylbenzene ion exchangers 35WET, XAD4, or 1200H. The new materials (XAD_C, WET_C, and H_C) were characterized by adsorption–desorption nitrogen isotherms and mercury intrusion porosimetry. XAD_C and WET_C exhibited well-developed BET surface areas, similar total pore volumes, and highly different pore size distributions. H_C was nonporous spherical material—reference material. The XAD_C was meso-macroporous, but the WET_C was micro-mesoporous. All SACs were not cytotoxic toward Leydig TM3 cells. The differences in porous structure and morphology of the carbon scaffolds led to morphological differences in adhered cells. The monolayer of cells was distributed flat over the entire WET_C and H_C surfaces. Leydig TM3 cells adhered to nonporous SAC but were easily washed out due to weak adhesion. The cells adhered in clusters to XAD_C and proliferated in clusters. As microscopic techniques and viability tests demonstrated, only nanoporous carbons provided a good surface for the attachment and proliferation of eukaryotic cells.

Sustainable Porous Scaffolds with Retained Lignin as An Effective Light-absorbing Material for Efficient Photothermal Energy Conversion.

Organic phase change materials (PCMs) are promising to utilize thermal energy from solar radiation for photothermal energy conversion. However, the issues of poor photo absorption and liquid leakage greatly restrict their practical application. Herein, a sustainable porous scaffold comprising periodate oxidized wood (POW) as the supporting material and in situ retains lignin as the light-absorber dopant are demonstrated. The π-π stacking ability of lignin molecules endows the retained lignin with efficient photonic energy harvesting characteristics for fast thermal conductivity to reach a higher maximal energy storage volume. The inherently porous structure of the POW scaffold enables excellent shape-stability, which bypasses the liquid leakage problem. The resulting POW/PCM composites exhibit superior comprehensive performance, including enhanced light absorption capacity, high photothermal conversion efficiency (≈86.7%), and high latent heat of 151 J g-1 . Furthermore, the POW/PCM composites also possess the ability to maintain a relatively constant indoor temperature when fixed atop the model house roof, showing great potential for their practical applications in the thermal regulation of intelligent buildings. This work not only paves a new way to obtain sustainable and effective porous scaffolds for sufficient photothermal energy conversion but also provides more possibilities for their practical application in the future.

Mechanical Properties Directionality and Permeability of Fused Triply Periodic Minimal Surface Porous Scaffolds Fabricated by Selective Laser Melting.

Titanium alloy porous scaffolds possess excellent mechanical properties and biocompatibility, making them promising for applications in bone tissue engineering. The integration of triply periodic minimal surface (TPMS) with porous scaffolds provides a structural resemblance to the trabecular and cortical bone structures of natural bone tissue, effectively reducing stress-shielding effects, enabling the scaffold to withstand complex stress environments, and facilitating nutrient transport. In this study, we designed fused porous scaffolds based on the Gyroid and Diamond units within TPMS and fabricated samples using selective laser melting technology. The effects of the rotation direction and angle of the inner-layer G unit on the elastic modulus of the fused TPMS porous scaffold were investigated through quasi-static compression experiments. Furthermore, the influence of the rotation direction and angle of the inner-layer G unit on the permeability, pressure, and flow velocity of the fused TPMS porous scaffold structure was studied using computational fluid dynamics (CFD) based on the Navier-Stokes model. The quasi-static compression experiment results demonstrated that the yield strength of the fused TPMS porous scaffold ranged from 367.741 to 419.354 MPa, and the elastic modulus ranged from 10.617 to 11.252 GPa, exhibiting stable mechanical performance in different loading directions. The CFD simulation results indicated that the permeability of the fused TPMS porous scaffold model ranged from 5.70015 × 10-8 to 6.33725 × 10-8 m2. It can be observed that the fused porous scaffold meets the requirements of the complex stress-bearing demands of skeletal structures and complies with the permeability requirements of human bone tissue.