Bone Healing Applications Research Articles

State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques

Atmospheric pressure microplasma is a simple, cost-effective, efficient, and eco-friendly procedure, which is superior to the traditional nanomaterials synthesis techniques. It generates high yields and allows for a controlled growth rate and morphology of nanomaterials. The silver (Ag) nanomaterials, with their unique physical and chemical properties, exhibit outstanding antibacterial and antifungal properties. Similarly, zinc oxide (ZnO) nanomaterials, known for their low toxicity and relatively lower cost, find wide applications in wound repair, bone healing, and antibacterial and anticancer applications. The use of core–shell nanomaterials in certain situations where some nanoparticles can cause serious harm to host tissues or organs is a testament to their potential. A benign material is coated over the core to reduce toxicity in these cases. This review compares the numerous configurations of microplasma systems used for synthesizing nanomaterials and their use in producing Ag, ZnO, and their core–shell (Ag-ZnO) nanomaterials for biomedical applications. The summary also includes the effect of control parameters, including cathode diameter, gas flow rate, precursor concentration, voltage, and current, on the nanomaterial’s characteristics and applications. In addition, it provides a research gap in the synthesis of Ag, ZnO, and core–shell nanomaterials by this technique, as well as the development and limitations of this technique and the use of these nanoparticles for biomedical applications.

Injectable hydrogel scaffold incorporating microspheres containing cobalt-doped bioactive glass for bone healing.

Injectable in situ-forming scaffolds that induce both angiogenesis and osteogenesis have been proven to be promising for bone healing applications. Here, we report the synthesis of an injectable hydrogel containing cobalt-doped bioactive glass (BG)-loaded microspheres. Silk fibroin (SF)/gelatin microspheres containing BG particles were fabricated through microfluidics. The microspheres were mixed in an injectable alginate solution, which formed an in situ hydrogel by adding CaCl2. The hydrogel was evaluated for its physicochemical properties, in vitro interactions with osteoblast-like and endothelial cells, and bone healing potential in a rat model of calvarial defect. The microspheres were well-dispersed in the hydrogel and formed pores of >100 μm. The hydrogel displayed shear-thinning behavior and modulated the cobalt release so that the optimal cobalt concentration for angiogenic stimulation, cell proliferation, and deposition of mineralized matrix was only achieved by the scaffold that contained BG doped with 5% wt/wt cobalt (A-S-G5Co). In the scaffold containing higher cobalt content, a reduced biomimetic mineralization on the surface was observed. The gene expression study indicated an upregulation of the osteogenic genes of COL1A1, ALPL, OCN, and RUNX2 and angiogenic genes of HIF1A and VEGF at different time points in the cells cultured with the A-S-G5Co. Finally, the in vivo study demonstrated that A-S-G5Co significantly promoted both angiogenesis and osteogenesis and improved bone healing after 12 weeks of follow-up. These results show that incorporation of SF/gelatin microspheres containing cobalt-doped BG in an injectable in situ-forming scaffold can effectively enhance its bone healing potential through promotion of angiogenesis and osteogenesis.

Poloxamer 407 modified collagen/β-tricalcium phosphate scaffold for localized delivery of alendronate.

Systemic administration of alendronate is associated with various adverse reactions in clinical settings. To mitigate these side effects, poloxamer 407 (P-407) modified with cellulose was chosen to encapsulate alendronate. This drug-loaded system was then incorporated into a collagen/β-tricalcium phosphate (β-TCP) scaffold to create a localized drug delivery system. Nuclear magnetic resonance spectrum and rheological studies revealed hydrogen bonding between P-407 and cellulose as well as a competitive interaction with water that contributed to the delayed release of alendronate (ALN). Analysis of the degradation kinetics of P-407 and release kinetics of ALN indicated zero-order kinetics for the former and Fickian or quasi-Fickian diffusion for the latter. The addition of cellulose, particularly carboxymethyl cellulose (CMC), inhibited the degradation of P-407 and prolonged the release of ALN. The scaffold's structure increased the contact area of P-407 with the PBS buffer, thereby, influencing the release rate of ALN. Finally, biocompatibility testing demonstrated that the drug delivery system exhibited favorable cytocompatibility and hemocompatibility. Collectively, these findings suggest that the drug delivery system holds promise for implantation and bone healing applications.

Synthesis, Characterizations and Optimization of Magnesium Oxide Scaffold for Bone Healing Applications

In this work, the structural properties of Magnesium oxide nanoparticles (MgONPs) are synthesized by a simple chemical technique. X-ray diffraction pattern (XRD) pattern showed the crystalline nature of MgO NPs. The average diameter of MgO NPs calculated by SEM and XRD was around 19 nm. Energy dispersive X-ray spectroscopy (EDS) spectrum and XRD pattern suggested that prepared MgO NPs were highly pure. The viability of cells in a medium containing MgO-AV composite scaffold was nearly equal to that of MgO, AV, and control, with no statistically significant difference (p>0.05). The Runx2-mediated modulation of gene expressions of the bone biomarkers ALP and OCN was investigated to determine the mechanism of scaffold-induced improvement in bone repair. ALP was immunodetected in the injured site of the right femur twenty-one days after the bone defects were created. The implantation of scaffolds into the bone defect region of the left femur, on the other hand, resulted in a noticeable increase in ALP levels. Similarly, OCN was immunodetected in the right femur's bone defect site. The implantation of scaffolds into the bone defect location of the left femur, on the other hand, resulted in a significant increase in OCN levels. The low-level diode laser therapy (LLLT) promotes the partially bony incorporation of the xeno bony implantation with the recipient femoral bone, and can successfully fill the space, and support the weight after removing the internal fixation methods, with no body rejection. The histopathological finding at the end of the 6th week post-operation in treatment groups the trabecular bone is mature and wide with little cavity. The control group showed immature and thin trabecular bone, with large cavities, and an area of connective tissues not organized. At the end of 12th weeks, post-operation the treatment groups revealed mature trabecular bone surrounding the bony device and lamellar bone formation with partial bony incorporation, the lacuna and haversian canals of the bony device filled with osteocyte and blood vessels, while in control groups the trabecula bone not mature, and many lucana and havesan canal still empty in the bony device

Fabrication and application of salicin-polycaprolactone 3D-printed scaffold in the healing of femur bone defects

Polycaprolactone (PCL) is a suitable material for bone repair due to good biocompatibility and mechanical properties. However, low bioactivity and hydrophobicity pose major challenges for its biomedical applications. To overcome these limitations, PCL-based scaffolds loaded with bioactive agents have been developed. Salicin (Sal) is an anti-inflammatory and analgesic herbal glycoside with osteogenic potential. In the present study, we aimed to produce a Sal-laden PCL (PCL–Sal) scaffold for bone healing applications. Three-dimensional scaffolds were produced and their biocompatibility, and physical-chemical characteristics were determined. The osteogenic potential of the PCL (PCL) and PCL–Sal scaffolds was evaluated using bone marrow mesenchymal stem cells (BMSCs). Scaffolds were implanted into a 5 mm bone defect created in the femur of adult rats, and the new bone fraction was determined using micro-computed tomography scanning at one-month follow-up. PCL–Sal scaffold had a structure, porosity, and fiber diameter suitable for bone construction. It also possessed a higher rate of hydrophilicity and bioactivity compared to the PCL, providing a suitable surface for the proliferation and bone differentiation of BMSCs. Furthermore, PCL–Sal scaffolds showed a higher capacity to scavenge free radicals compared to PCL. The improved bone healing potential of the PCL–Sal scaffold was also confirmed according to in vivo implantation results. Our findings revealed that the Sal-laden implant could be considered for bone repair due to desirable characteristics of Sal such as hydrophilicity, surface modification for cell attachment, and antioxidant properties.

ZnO-doped β-TCP ceramic-based scaffold promotes osteogenic and antibacterial activity

β-Tricalcium phosphate (β-TCP) scaffolds, which are synthetic bone graft materials, have been explored as a potential solution in the healing of bone deformities due to their acceptable degradation rate and ability to support bone growth. However, these scaffolds have limitations such as poor mechanical properties, to stimulate bone growth, which increases the risk of infection after implantation. To overcome these issues, a new type of biomedical scaffold was developed that incorporated zinc oxide (ZnO) particles into β-TCP using wet chemical techniques. The scaffolds were created using sintering to produce porous β-TCP scaffolds with good connectivity. The addition of zinc oxide as a dopant significantly improved the biophysical properties of the scaffolds, with higher concentrations of zinc oxide, leading to better cell adhesion and proliferation. The scaffolds placed in simulated body fluid demonstrated exceptional ability to promote bone growth and regeneration by developing a bone-like apatite layer on their surfaces. The mechanical and physical properties of the scaffolds were effectively assessed using X-ray diffraction and scanning electron microscopy analyses. To validate the efficacy of the specimen in preventing microbial growth and promoting bone growth, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test and gene expression investigation were conducted. Zinc oxide-doped β-TCP scaffolds are envisaged to show enormous potential for use in future bone-healing applications.

Blend Electrospinning of Nigella sativa-Incorporating PCL/PLA/HA Fibers and Its Investigation for Bone Healing Applications.

One of the well-known postoperative complications that requires a number of prophylactic and curative treatments is infection. The implications of postsurgical infections are further exacerbated by the emergence of antibiotic-resistant strains. Reduced effectiveness of synthetic antibiotics has led to an interest in plant-based substances. Extracts obtained from Nigella sativa have been shown to possess effective anti-infectious agents against bacteria frequently seen in bone infections. In this study, a fiber-based bone scaffold containing polycaprolactone, poly(lactic acid), and hydroxyapatite with N. sativa oil at varying concentrations was developed. Solvent electrospinning was used to fabricate the fibers with the specified composition. According to FE-SEM analysis, fibers with average diameters of 751 ± 82, 1000 ± 100, 1020 ± 90, and 1223 ± 112 nm were formed and successful integration of N. sativa oil into the fiber's structure was confirmed via FTIR. Staphylococcus aureus showed moderate susceptibility against the fibers with a maximum inhibition zone diameter of 11.5 ± 1.6 mm. MTT assay analysis exhibited concentration-dependent cell toxicity against fibroblast cells. In short, the antibacterial fibers synthesized in this study possessed antibacterial properties while also allowing moderate accommodation of CDD fibroblast cells at low oil concentrations, which can be a potential application for bone healing and mitigating postsurgical infections.

Comparative Analysis of Stromal Vascular Fraction and Alternative Mechanisms in Bone Fracture Stimulation to Bridge the Gap between Nature and Technological Advancement: A Systematic Review.

Various stimulation methods, including electrical, ultrasound, mechanical, and biological interventions, are explored, each leveraging intricate cellular and molecular dynamics to expedite healing. The advent of stromal vascular fraction (SVF) marks a significant stride, offering multifarious benefits in bone healing, from enhanced bone formation to optimal vascular integration, drawing a harmonious balance between innate mechanisms and scientific advancements. This systematic review was conducted focusing on literature from 2016 to 2023 and encompassing various bone healing stimulation mechanisms like SVF, electrical, ultrasound, and mechanical stimulation. The extracted data underwent meticulous synthesis and analysis, emphasizing comparative evaluations of mechanisms, applications, and outcomes of each intervention. The reviewed studies reveal the potential of SVF in bone fracture healing, with its regenerative and anti-inflammatory effects. The purification of SVF is crucial for safe therapeutic use. Characterization involves flow cytometry and microscopy. Studies show SVF's efficacy in bone regeneration, versatility in various contexts, and potential for clinical use. SVF appears superior to electrical, ultrasound, and mechanical stimulation, with low complications. This review compares bone healing methods, including SVF. It provides valuable insights into SVF's potential for bone regeneration. However, due to limited human studies and potential bias, cautious interpretation is necessary. Further research is essential to validate these findings and determine the optimal SVF applications in bone healing.

Platelet-derived extracellular vesicles formulated with hyaluronic acid gels for application at the bone-implant interface: An animal study.

Platelet derived extracellular vesicles (pEV) are promising therapeutical tools for bone healing applications. In fact, several in vitro studies have already demonstrated the efficacy of Extracellular Vesicles (EV) in promoting bone regeneration and repair in various orthopedic models. Therefore, to evaluate the translational potential in this field, an in vivo study was performed. Here, we used hyaluronic acid (HA) gels formulated with pEVs, as a way to directly apply pEVs and retain them at the bone defect. In this study, pEVs were isolated from Platelet Lysate (PL) through size exclusion chromatography and used to formulate 2% HA gels. Then, the gels were locally applied on the tibia cortical bone defect of New Zeland White rabbits before the surgical implantation of coin-shaped titanium implants. After eight weeks, the bone healing process was analyzed through biomechanical, micro-CT, histological and biochemical analysis. Although no biomechanical differences were observed between pEV formulated gels and non-formulated gels, biochemical markers of the wound fluid at the interface presented a decrease in Lactate dehydrogenase (LDH) activity and alkaline phosphatase (ALP) activity for pEV HA treated implants. Moreover, histological analyses showed that none of the treatments induced an irritative effect and, a decrease in the fibrotic response surrounding the implant for pEV HA treated implants was described. In conclusion, pEVs improve titanium implants biocompatibility at the bone-implant interface, decreasing the necrotic effects of the surgery and diminishing the fibrotic layer associated to the implant encapsulation that can lead to implant failure.

A 3D printed polylactic acid-Baghdadite nanocomposite scaffold coated with microporous chitosan-VEGF for bone regeneration applications

Three-dimensional (3D) printing technology has become an advanced approach for fabricating patient-specific scaffolds with complex geometric shapes to replace damaged or diseased tissue. Herein, polylactic acid (PLA)-Baghdadite (Bgh) scaffold were made through the fused deposition modeling (FDM) 3D printing method and subjected to alkaline treatment. Following fabrication, the scaffolds were coated with either chitosan (Cs)-vascular endothelial growth factor (VEGF) or lyophilized Cs-VEGF known as PLA-Bgh/Cs-VEGF and PLA-Bgh/L.(Cs-VEGF), respectively. Based on the results, it was found that the coated scaffolds had higher porosity, compressive strength and elastic modulus than PLA and PLA-Bgh samples. Also, the osteogenic differentiation potential of scaffolds following culture with rat bone marrow-derived mesenchymal stem cells (rMSCs) was evaluated through crystal violet and Alizarin-red staining, alkaline phosphatase (ALP) activity and calcium content assays, osteocalcin measurements, and gene expression analysis. The release of VEGF from the coated scaffolds was assessed and also the angiogenic potential of scaffolds was evaluated. The sum of results presented in the current study strongly suggests that the PLA-Bgh/L.(Cs-VEGF) scaffold can be a proper candidate for bone healing applications.

Chitosan/Hydroxyapatite Scaffolds with P28 as a Promising Osteoinductive Scaffold for Bone Healing Applications

Despite bone’s inherent ability to heal, large bone defects remain a major clinical concern. This study proposes an off-the-shelf treatment combining chitosan/hydroxyapatite (CS/HAp) scaffolds, covalently linked with either bone morphogenetic protein-2 (BMP-2) or its related peptide P28 via a UV crosslinking process. Although covalently binding the growth factors was reported as a great alternative to the conventionally physical adsorption and encapsulation methods, this method presents the risk of altering the molecular activity and interaction of the growth factors. Therefore, alkaline phosphatase (ALP) activity and alizarin red staining (ARS) with a quantitative cetylpyridinium chloride (CPC) assay were conducted to validate that our photo-crosslinking fabrication method did not interfere with the functionality of the growth factors. The ALP activity of C2C12 with 100 µg/mL P28 was found to be comparable to 0.5 µg/mL BMP-2 after two weeks, where 0.001 U/mL was recorded for both treatments. The C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds also showed an increased ALP activity compared to the negative control. ARS-CPC assay presented the highest optical density in 0.3 µg/mL BMP-2 and 50 µg/mL P28, while the highest intensity of ARS was observed in C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds compared to the negative controls. The osteoconductive capability of this delivery system was then investigated through a rat femoral condyle defect model, where the new bone mineral density and the bone volume increased for all CS/HAp scaffolds compared to the collagen sponge control treatment. The histological assessment showed a favourable bone regeneration efficacy of the CS/HAp/P28 compared to the CS/HAp/BMP-2 treatment, thus showing the use of CS/HAp scaffolds with P28 as a promising osteoinductive scaffold for bone healing applications.

Recent advances in gene therapy for bone tissue engineering.

Autografting, a major treatment for bone fractures, has potential risks related to the required surgery and disease transmission. Bone morphogenetic proteins (BMPs) are the most common osteogenic factors used for bone-healing applications. However, BMP delivery can have shortcomings such as a short half-life and the high cost of manufacturing the recombinant proteins. Gene delivery methods have demonstrated promising alternative strategies for producing BMPs or other osteogenic factors using engineered cells. These approaches can also enable temporal overexpression and local production of the therapeutic genes in the target tissues. This review addresses recent progress on engineered viral, non-viral, and RNA-mediated gene delivery systems that are being used for bone repair and regeneration. Advances in clustered regularly interspaced short palindromic repeats/Cas9 genome engineering for bone tissue regeneration also is discussed.

Investigation of structural, spectroscopic, dielectric, magnetic, and in vitro biocompatibility properties of Sr/Ni co-doped hydroxyapatites

In this study, the changes caused by Ni and Sr additives on the structural, thermal, dielectric, and magnetic properties of hydroxyapatite (HAp) samples were examined and reported for the first time in detail.Some effects of the Sr/Ni site disorder on the crystallographic, dielectric, and magnetic properties in Sr/Ni-HAp have been examined, as well as their cytotoxicity effects. The addition of Ni affected the morphology of nanoparticles with a low agglomeration increase. Our results showed that the dielectric constant (ε′) and dielectric loss (ε′′) have greater values at low frequencies than at higher frequencies for all the samples.It can be concluded that Ni and Sr additions to the HAp structure contribute to the development of thermal, magnetic, and dielectric properties required to mimic natural HAp in the study conducted with the idea of creating a medical application area for bone healing and regeneration. The cytotoxicity test of the produced nanoparticles and the evaluation of the results were also performed using human foreskin fibroblasts (HFF). The viability of cells after treatment for 48 h ranged between 50 and 75%. While 0.37Ni-0.37Sr-HAp and 1.11Ni-0.37Sr-HAp were similar to 0.37Sr-HAp, 0.74Ni-0.37Sr-HAp had the highest cellular viability. At 0.1 mg/mL, 0.74Ni-0.37Sr-HAp had a viability of 79.97% compared to the untreated control cells. Our Sr/Ni-HAp nanoparticles have promising medical applications in bone healing and regeneration.

Improved corrosion resistance on Mg-2Ca alloy with TiO2 nanoparticles embedded in a polycaprolactone (PCL) coating

When seeking bone healing applications, calcium (Ca) is the preferred element for Magnesium (Mg) alloying. Unfortunately, the fast degradation rate of these alloys limits their applicability as bioresorbable implants. Biodegradable polymeric coatings based on polycaprolactone (PCL) were prepared to overcome this limitation. TiO2 nanoparticles (NPs) were further embedded in the polymeric matrix to increase the protectiveness and biocompatibility of such coatings. The degradation rate, assessed by electrochemical impedance technique (EIS) in cell culture medium, proved the superior protectiveness of the PCL-TiO2 coating. The corrosion layer was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In the bare and PCL coated samples, the corrosion layer was composed of brucite, carbonates, and magnesium oxychloride, whereas in the PCL-TiO2 coated sample, the additional precipitation of apatites occurred. This data advances important insights on Mg-2Ca alloys and discusses the role of bioactive coatings on the degradation of this alloy.

Inorganic Nanoparticles in Bone Healing Applications.

Modern biomedicine aims to develop integrated solutions that use medical, biotechnological, materials science, and engineering concepts to create functional alternatives for the specific, selective, and accurate management of medical conditions. In the particular case of tissue engineering, designing a model that simulates all tissue qualities and fulfills all tissue requirements is a continuous challenge in the field of bone regeneration. The therapeutic protocols used for bone healing applications are limited by the hierarchical nature and extensive vascularization of osseous tissue, especially in large bone lesions. In this regard, nanotechnology paves the way for a new era in bone treatment, repair and regeneration, by enabling the fabrication of complex nanostructures that are similar to those found in the natural bone and which exhibit multifunctional bioactivity. This review aims to lay out the tremendous outcomes of using inorganic nanoparticles in bone healing applications, including bone repair and regeneration, and modern therapeutic strategies for bone-related pathologies.

Optimized consolidation process at a near-room temperature of nano-hydroxyapatite and sodium silicate glass composites for bone healing applications

ABSTRACT Hydroxyapatite nanoparticles (nHap) with chemical and structural characteristics similar to the bone mineral are widely used for orthopaedic applications. However, conventional sintering methods applied to consolidate nHap alter significantly their properties. Recently, a near-room temperature process was developed to consolidate nHap using a sodium silicate solution (SS) as a mineral binder to produce highly reactive composites. In this work, a central composite design is employed to determine the best parameters to elaborate nHap/SSG with optimized mechanical properties. The studied factors were the molar ratio of SS (n), liquid-to-solid ratio (Ls) and drying temperature (T°C). A maximum compressive strength of 24.01 MPa was achieved when composites were formulated using SS with a ratio of 1, Ls of 0.4 cm3/g and drying temperatures below 50 °C. In vitro biocompatibility of bone cells (MG-63) revealed that the optimized composite enhanced cellular proliferation and differentiation which make them a promising candidate for bone regeneration.

Mineralized Polyvinyl Alcohol/Sodium Alginate Hydrogels Incorporating Cellulose Nanofibrils for Bone and Wound Healing.

Bio sustainable hydrogels including tunable morphological and/or chemical cues currently offer a valid strategy of designing innovative systems to enhance healing/regeneration processes of damaged tissue areas. In this work, TEMPO-oxidized cellulose nanofibrils (T-CNFs) were embedded in alginate (Alg) and polyvinyl alcohol (PVA) solution to form a stable mineralized hydrogel. A calcium chloride reaction was optimized to trigger a crosslinking reaction of polymer chains and mutually promote in situ mineralization of calcium phosphates. FTIR, XRD, SEM/EDAX, and TEM were assessed to investigate the morphological, chemical, and physical properties of different mineralized hybrid hydrogels, confirming differences in the deposited crystalline nanostructures, i.e., dicalcium phosphate dehydrate (DCPDH) and hydroxyapatite, respectively, as a function of applied pH conditions (i.e., pH 4 or 8). Moreover, in vitro tests, in the presence of HFB-4 and HSF skin cells, confirmed a low cytotoxicity of the mineralized hybrid hydrogels, and also highlighted a significant increase in cell viability via MTT tests, preferentially, for the low concentration, crosslinked Alg/PVA/calcium phosphate hybrid materials (<1 mg/mL) in the presence of hydroxyapatite. These preliminary results suggest a promising use of mineralized hybrid hydrogels based on Alg/PVA/T-CNFs for bone and wound healing applications.

3D-printable chitosan/silk fibroin/cellulose nanoparticle scaffolds for bone regeneration via M2 macrophage polarization

Biopolymers-induced immune microenvironment exhibited prominent effects on bone regeneration. Osteo-immunomodulatory responses of cellulose nanoparticles incorporated chitosan hydrogel scaffolds have not yet been reported. The objective of this study was to monitor the synergistic effects of silk fibroin and cellulose nanoparticles on the immune-modulatory behavior of chitosan biopolymer scaffolds. 3D-printed biodegradable cellulose nanoparticles-reinforced chitosan/silk fibroin (CS/SF/CNPs) scaffolds were fabricated and characterized by different spectroscopic techniques. The improved rheological and recovery strength was observed in CS/SF/CNPs hydrogels than pure polymer hydrogels. A significant shift from M1 → M2 macrophages polarization occurred in the CS/SF/CNPs scaffolds treated groups than the control after 3 days of incubation, showing its immune-modulatory potential. Osteo-immunomodulatory effects of the fabricated scaffolds were analyzed on human bone marrow-derived mesenchymal stem cells (hBMSCs), with macrophages-derived conditioned media (M-CM). Enhanced bone regeneration was observed in the calvaria defect rat model, indicating that the fabricated scaffolds are promising materials for bone-healing applications.

Natural Polymer-Based Micronanostructured Scaffolds for Bone Tissue Engineering.

Although bone tissue allografts and autografts aremoften used as a regenerative tissue during the bone healing, their availability, donor site morbidity, and immune response to grafted tissue are limiting factors their more common usage. Tissue engineered implants, such as acellular or cellular polymeric structures, can be an alternative solution. A variety of scaffold fabrication techniques including electrospinning, particulate leaching, particle sintering, and more recently 3D printing have been used to create scaffolds with interconnected pores and mechanical properties for tissue regeneration. Simply combining particle sintering and molecular self-assembly to create porous microstructures with imbued nanofibers to produce micronanostructures for tissue regeneration applications. Natural polymers like polysaccharides, proteins and peptides of plant or animal origin have gained significant attention due to their assured biocompatibility in tissue regeneration. However, majority of these polymers are water soluble and structures derived from them are in the form of hydrogels and require additional stabilization via cross-linking. For bone healing applications scaffolds are required to be strong, and support attachment, proliferation and differentiation of osteoprogenitors into osteoblasts. Our ongoing work utilizes plant polysaccharide cellulose derivatives and collagen to create mechanically stable and bioactive micronanostructured scaffold for bone tissue engineering. Scaffold microstructure is essentially solvent sintered cellulose acetate (CA) microspheres in the form of a negative template for trabecular bone with defined pore and mechanical properties. Collagen nanostructures are imbued into the 3D environment of CA scaffolds using collagen molecular self-assembly principles. The resultant CA-collagen micronanostructures provide the benefits of combined polymers and serve as an alternative material platform to many FDA approved polyesters. Our ongoing studies and published work confirm improved osteoprogenitor adhesion, proliferation, migration, differentiation, extracellular matrix (ECM) secretion in promoting bone healing. In this chapter we will provide a detailed protocol on the creation of micronanostructured CA-collagen scaffolds and their characterization for bone tissue engineering using human mesenchymal stem cells.

Biomedical potential of 3D Zn and ZnCu foams produced by dynamic hydrogen bubble template

New biomaterials for bone healing applications are crucial for our ageing populations. Three-dimensional (3D) Zn and ZnCu architectures on stainless steel were reinvented through dynamic hydrogen bubble template (DHBT) deposition. 3D Zn was formed by porous pure Zn structures, whereas an interconnected architecture composed of CuxZny was detected in ZnCu foams, with the preferential deposition of Cu on the top and Zn on the bottom. These materials, with pore diameters ranging from 0.4 to 5 µm in 3D Zn and from 60 to 270 µm in ZnCu foams, have applications in drug delivery or scaffold systems, respectively. To evaluate the biomedical usage of these materials, their degradation in different biological media was assessed. Both materials were stable in cell culture medium and active in simulated body fluid solution, where typical Cu- and Zn-derived corrosion products were formed. The bioactivity of the degradation products formed, namely Zn and Cu oxides, hydrozincite, simonkolleite and hydroxyapatite, all most likely doped with Cu in the ZnCu foams, was related to their applicability in the biomedical field. Based on these findings, 3D Zn and ZnCu foams produced by DHBT proved their biomedical potential, an original approach reported herein for the first time.