Zinc and manganese substituted hydroxyapatite/CMC/PVP electrospun composite for bone repair applications

Synthesis of YFeO3-Y3Fe5O12 Heterogeneous Structure Magnetic Nanomaterials and Preparation of Nanofibers by Coprecipitation Method

The design and fabrication of yttrium iron oxide-based magnetic nanomaterials play an indispensable role in microelectronic-related fields. The bottleneck still remains, including limited reproducibility and the inability to control the size of the resulting material. In this study, a straightforward coprecipitation method was firstly used for the production of heterogeneous YFeO3-Y3Fe5O12 composite with (NH4)2CO3 as the precipitant. Under optimized conditions, the obtained YFeO3-Y3Fe5O12 nanoparticles exhibit high crystallinity and ferromagnetic properties at room temperature, and its saturation magnetization strength (Ms) reached 11.927 emu·g-1. Meanwhile, the particle size can be achieved at approximately 14.7 nm. The compact heterojunction between the yttrium iron oxide components gives rise to the obvious ferromagnetic property. Subsequently, YFeO3-Y3Fe5O12 nanoparticles were taken as the raw material for preparing flexible [(YFeO3-Y3Fe5O12)/PVP] nanofibers by electrospinning technology. By changing the proportion of magnetic particles in the nanofibers, the magnetic strength can be regulated. The integration between magnetism and the preparation of nanofiber membranes is realized. The encapsulation of magnetic particles in the nanofibers avoids not only aggregation but also the direct contact with the impurity, which promotes practicability and recycle life.

Advancements in nanoparticles-based therapeutic approaches for osteosarcoma: Insights from catechins-modified selenium-doped hydroxyapatite: A review

Osteosarcoma is common in all age groups, and a multifaceted strategy that includes radiation therapy, surgical intervention and chemotherapy remains the conventional treatment for osteosarcoma. Existing therapies typically result in recurring malignancies and postsurgical bone abnormalities, necessitating novel strategies for targeted drug administration and bone defects. The most significant components that are crucial for maintain strong bones include trace elements, calcium, selenium, and vitamins K and D. A deficiency in selenium advances the risk of cancer in many organs, including the bones. The progression of an effective technique such as a "local delivery system" is required to efficiently deliver the antioxidant to the targeted tissues for treatment as the circulatory system is unable to convey an adequate concentration of catechin to the regions of bone abnormalities. In this regard the combination of selenium and catechin with mesoporous hydroxyapatite nanoparticles displays promise as a nanoscale delivery method, offering an ideal approach to use it for the treatment and prevention of bone-related diseases. Therefore, this review mainly focusing in exploring the therapeutic potential of catechins-modified selenium-doped hydroxyapatite nanomaterials, chitosan-PEG-folate-Fe (III) complexes as nanocarriers for epigallocatechin-3-gallate, and catechin-conjugated mesoporous hydroxyapatite nanoparticle, highlighting their novel functions as nano-antioxidants with improved osteogenic characteristics in osteosarcoma treatment.

Zinc-doped hydroxyapatite loaded chitosan gelatin nanocomposite scaffolds as a promising platform for bone regeneration

The advancement in the arena of bone tissue engineering persuades us to develop novel nanocomposite scaffolds in order to improve antibacterial, osteogenic, and angiogenic properties that show resemblance to natural bone extracellular matrix. Here, we focused on the development of novel zinc-doped hydroxyapatite (ZnHAP) nanoparticles (1, 2 and 3 wt%; size: 50-60 nm) incorporated chitosan-gelatin (CG) nanocomposite scaffold, with an interconnected porous structure. The addition of ZnHAP nanoparticles decreases the pore size (∼30 µm) of the CG scaffolds. It was observed that with the increase in the concentration of ZnHAP nanoparticles (3 wt%) in CG scaffolds, the swelling ratio (1760% ± 2.0%), porosity (71% ± 0.98%) and degradation rate (35%) decreased, whereas mechanical property (1 MPa) increased, which was better as compared to control (CG) samples. Similarly, the high deposition of apatite crystals especially CG-ZnHAP3nanocomposite scaffold revealed the excellent osteoconductive potential among all other scaffolds. MC3T3-E1 osteoblastic cells seeded with CG-ZnHAP nanocomposite scaffolds depicted better cell adhesion, proliferation and differentiation to osteogenic lineages. Finally, the chorioallantoic membrane (CAM) assay revealed better angiogenesis of ZnHAP nanoparticles (3 wt%) loaded CG scaffolds supporting vascularization after 7th day incubation in the CAM area. Overall, the results showed that the CG-ZnHAP3nanocomposite scaffold could be a potential candidate for bone defect repair.

Hydroxyapatite/Silk Fibroin Composite Scaffold with a Porous Structure and Mechanical Strength Similar to Cancellous Bone by Electric Field-Induced Gel Technology

Repair and regeneration of bone tissue defects is a multidimensional process that has been highly challenging to date. The artificial bone scaffold materials, which play a core role, still face the conflict that a biofriendly porous structure will reduce the mechanical performance and accelerate degradation. Herein, a multistage porous structured hydroxyapatite (HA)/silk fibroin (SF) composite scaffold (e-HA/SF) was successfully constructed by cleverly utilizing electric field-induced gel technology. The results indicated that the prepared e-HA/SF scaffolds possess biomimetic hierarchical porous structures with a suitable porosity similar to that of cancellous bone. The HA nanocrystals were uniformly encapsulated in the three-dimensional space of the composite scaffold, thus endowing the e-HA/SF composite scaffolds with an enhanced mechanical performance. Notably, the maximum compression stress and Young's modulus of e-HA/SF-2 scaffolds can reach 24.66 ± 0.88 and 28.91 ± 3.19 MPa, respectively, which are equivalent to those of cancellous bone. Such mechanical performance enhancement was previously unattainable through conventional freeze-drying strategies. Moreover, the introduction of bioactive nano-HA can trigger the optimal cell response in both static and dynamic cell culture experiments in vitro. The e-HA/SF composite scaffold developed in this study can better balance the conflict between the porous structure and mechanical and degradation properties of porous scaffolds.

Novel Saccharomyces cerevisiae-Loaded Polyvinylpyrrolidone/SiO2 Nanofiber for Wound Dressing Prepared Using Electrospinning Method

Electrospun nanofibers have been used as wound dressings to protect skin from infection and promote wound healing. In this study, we developed polyvinylpyrrolidone (PVP)/silicon dioxide (SD) composite nanofibers for the delivery of probiotic Saccharomyces cerevisiae (SC), which potentially aids in wound healing. PVP/SD composite nanofibers were optimized through electrospinning, and bead-free nanofibers with an average diameter of 624.7 ± 99.6 nm were fabricated. Next, SC, a wound-healing material, was loaded onto the PVP/SD composite nanofibers. SC was encapsulated in nanofibers, and nanofibers were prepared using SC, PVP, SD, water, and ethanol in a ratio of 3:4:0.1:4.8:1.2. The formation of smooth nanofibers with protrusions around SC was confirmed using SEM. Nanofiber dressing properties were physicochemically and mechanically characterized by evaluating SEM, DSC, XRD, and FTIR images, tensile strength, and elongation at break. Additionally, a release test of active substances was performed. The absence of interactions between SC, PVP, and SD was confirmed through physicochemical evaluation, and SEM images showed that the nanofiber dressing contained SC and had a porous structure. It also showed a 100% release of SC within 30 min. Overall, our study showed that SC-loaded PVP/SD composite nanofibers prepared using the electrospinning method are promising wound dressings.

Enhanced bone regeneration by osteoinductive and angiogenic zein/whitlockite composite scaffolds loaded with levofloxacin

Promoting angiogenesis following biomaterial implantation is essential to bone tissue regeneration. Herein, the composite scaffolds composed of zein, whitlockite (WH), and levofloxacin (LEVO) were fabricated to augment bone repair by facilitating osteogenesis and angiogenesis. First, three-dimensional composite scaffolds containing zein and WH were prepared using the salt-leaching method. Then, as a model antibiotic drug, the LEVO was loaded into zein/WH scaffolds. Moreover, the addition of WH enhanced the adhesion, differentiation, and mineralization of osteoblasts. The zein/WH/LEVO composite scaffolds not only had significant osteoinductivity but also showed excellent antibacterial properties. The prepared composite scaffolds were then implanted into a calvarial defect model to evaluate their osteogenic induction effects in vivo. Micro-CT observation and histological analysis indicate that the scaffolds can accelerate bone regeneration with the contribution of endogenous cytokines. Based on amounts of data in vitro and in vivo, the scaffolds present profound effects on improving bone regeneration, especially for the favorable osteogenic, intensive angiogenic, and alleviated inflammation abilities. The results showed that the synthesized scaffolds could be a potential material for bone tissue engineering.

Synthesis of pure and doped nano-calcium phosphates using different conventional methods for biomedical applications: a review

The applications of calcium phosphates (hydroxyapatite, tetracalcium phosphate, tricalcium phosphate (alpha and beta), fluorapatite, di-calcium phosphate anhydrous, and amorphous calcium-phosphate) are increasing day by day. Calcium hydroxyapatite, commonly known as hydroxyapatite (HAp), represents a mineral form of calcium apatite. Owing to its close molecular resemblance to the mineral constituents of bones, teeth, and hard tissues, HAp is often employed in the biomedical domain. In addition, it is extensively employed in various sectors such as the remediation of water, air, and soil pollution. The key advantage of HAp lies in its potential to accommodate a wide variety of anionic and cationic substitutions. Nevertheless, HAp and tricalcium phosphate (TCP) syntheses typically involve the use of chemical precursors containing calcium and phosphorus sources and employ diverse techniques, such as solid-state, wet, and thermal methods or a combination of these processes. Researchers are increasingly favoring natural sources such as bio-waste (eggshells, oyster shells, animal bones, fish scales, etc.) as viable options for synthesizing HAp. Interestingly, the synthesis route significantly influences the morphology, size, and crystalline phase of calcium phosphates. In this review paper, we highlight both dry and wet methods, which include six commonly used synthesis methods (i.e. solid-state, mechano-chemical, wet-chemical precipitation, hydrolysis, sol-gel, and hydrothermal methods) coupled with the variation in source materials and their influence in modifying the structural morphology from a bulky state to nanoscale to explore the applications of multifunctional calcium phosphates in different formats.

Trends in the Incorporation of Antiseptics into Natural Polymer-Based Nanofibrous Mats

Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.

Manganese Enhances the Osteogenic Effect of Silicon-Hydroxyapatite Nanowires by Targeting T Lymphocyte Polarization

Biomaterials encounter considerable challenges in extensive bone defect regeneration. The amelioration of outcomes may be attainable through the orchestrated modulation of both innate and adaptive immunity. Silicon-hydroxyapatite, for instance, which solely focuses on regulating innate immunity, is inadequate for long-term bone regeneration. Herein, extra manganese (Mn)-doping is utilized for enhancing the osteogenic ability by mediating adaptive immunity. Intriguingly, Mn-doping engenders heightened recruitment of CD4+ T cells to the bone defect site, concurrently manifesting escalated T helper (Th) 2 polarization and an abatement in Th1 cell polarization. This consequential immune milieu yields a collaborative elevation of interleukin 4, secreted by Th2 cells, coupled with attenuated interferon gamma, secreted by Th1 cells. This orchestrated interplay distinctly fosters the osteogenesis of bone marrow stromal cells and effectuates consequential regeneration of the mandibular bone defect. The modulatory mechanism of Th1/Th2 balance lies primarily in the indispensable role of manganese superoxide dismutase (MnSOD) and the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). In conclusion, this study highlights the transformative potential of Mn-doping in amplifying the osteogenic efficacy of silicon-hydroxyapatite nanowires by regulating T cell-mediated adaptive immunity via the MnSOD/AMPK pathway, thereby creating an anti-inflammatory milieu favorable for bone regeneration.

Zinc-based biomaterials for bone repair and regeneration: mechanism and applications

Zinc (Zn) is one of the most important trace elements in the human body and plays a key role in various physiological processes, especially in bone metabolism. Zn-containing materials have been reported to enhance bone repair through promoting cell proliferation, osteogenic activity, angiogenesis, and inhibiting osteoclast differentiation. Therefore, Zn-based biomaterials are potential substitutes for traditional bone grafts. In this review, the specific mechanisms of bone formation promotion by Zn-based biomaterials were discussed, and recent developments in their application in bone tissue engineering were summarized. Moreover, the challenges and perspectives of Zn-based biomaterials were concluded, revealing their attractive potential and development directions in the future.

Biomineralized tetramethylpyrazine-loaded PCL/gelatin nanofibrous membrane promotes vascularization and bone regeneration of rat cranium defects

Conventional electrospinning produces nanofibers with smooth surfaces that limit biomineralization ability. To overcome this disadvantage, we fabricated a tetramethylpyrazine (TMP)-loaded matrix-mimicking biomineralization in PCL/Gelatin composite electrospun membranes with bubble-shaped nanofibrous structures. PCL/Gelatin membranes (PG), PCL/Gelatin membranes containing biomineralized hydroxyapatite (HA) (PGH), and PCL/Gelatin membranes containing biomineralized HA and loaded TMP (PGHT) were tested. In vitro results indicated that the bubble-shaped nanofibrous surface increased the surface roughness of the nanofibers and promoted mineralization. Furthermore, sustained-release TMP had an excellent drug release efficiency. Initially released vigorously, it reached stabilization at day 7, and the slow-release rate stabilized at 61.0 ± 1.8% at 28 days. All membranes revealed an intact cytoskeleton, cell viability, and superior adhesion and proliferation when stained with Ghost Pen Cyclic Peptide, CCK-8, cell adhesion, and EdU. In PGHT membranes, the osteogenic and vascularized gene expression of BMSCs and human vascular endothelial cells was significantly upregulated compared with that in other groups, indicating the PGHT membranes exhibited an effective vascularization role. Subsequently, the membranes were implanted in a rat cranium defect model for 4 and 8 weeks. Micro-CT and histological analysis results showed that the PGHT membranes had better bone regenerative patterns. Additionally, the levels of CD31 and VEGF significantly increased in the PGHT membrane compared with those in other membranes. Thus, PGHT membranes could accelerate the repair of cranium defects in vivo via HA and TMP synergistic effects.

Mechanical, biocompatibility and antibacterial studies of gelatin/polyvinyl alcohol/silkfibre polymeric scaffold for bone tissue engineering

The current study focuses on the incorporation of natural polymers (gelatin, silk fibre) and synthetic (polyvinyl alcohol) polymer towards the fabrication of a novel composite for bone tissue engineering. The Electrospinning method was used to fabricate the novel gelatin/polyvinyl alcohol/silk fibre scaffold. XRD, FTIR and SEM-EDAX analysis was performed to characterize the composite. The characterized composite was investigated for its physical properties (porosity and mechanical studies) and biological studies (antimicrobial activity, hemocompatibility, bioactivity). The fabricated composite showed high porosity and the highest tensile strength of 34 MPa, with elongation at a break of 35.82 for the composite. The antimicrobial activity of the composite was studied and the zone of inhibition was measured around 51 ± 0.54 for E. coli, 48 ± 0.48 for S. aureus and 50 ± 0.26 for C. albicans. The hemolytic % was noted around 1.36 for the composite and the bioactivity assay revealed the formation of apatite on composite surfaces.

AZ63/Ti/Zr Nanocomposite for Bone-Related Biomedical Applications

Considering the unique properties of magnesium and its alloy, it has a vast demand in biomedical applications, particularly the implant material in tissue engineering due to its biodegradability. But the fixing spares must hold such implants till the end of the biodegradation of implant material. The composite technology will offer the added benefits of altering the material properties to match the requirements of the desired applications. Hence, this experimental investigation is aimed at developing a composite material for manufacturing fixing spares like a screw for implants in biomedical applications. The matrix of AZ63 magnesium alloy is reinforced with nanoparticles of zirconium (Zr) and titanium (Ti) through the stir casting-type synthesis method. The samples were prepared with equal contributions of zirconium (Zr) and titanium (Ti) nanoparticles in the total reinforcement percentage (3%, 6%, 9%, and 12%). The corrosive and tribological studies were done. In the corrosive study, the process parameters like NaCl concentration, pH value, and exposure time were varied at three levels. In the wear study, the applied Load, speed of sliding, and the distance of the slide were considered at four levels. Taguchi analysis was employed in this investigation to optimize the reinforcement and independent factors to minimize the wear and corrosive losses. The minimum wear rate was achieved in the 12% reinforced sample with the input factor levels of 60 N of load on the pin, 1 m/s of disc speed at a sliding distance was 1500 m, and the 12% reinforce samples also recorded a minimum corrosive rate of 0.0076 mm/year at the operating environment of 5% NaCl-concentrated solution with the pH value of 9 for 24 hrs of exposure. The prediction model was developed based on the experimental results.

Electrosprayed Particles Loaded with Kartogenin as a Potential Osteochondral Repair Implant

The restoration of cartilage damage is a slow and not always successful process. Kartogenin (KGN) has significant potential in this space-it is able to induce the chondrogenic differentiation of stem cells and protect articular chondrocytes. In this work, a series of poly(lactic-co-glycolic acid) (PLGA)-based particles loaded with KGN were successfully electrosprayed. In this family of materials, PLGA was blended with a hydrophilic polymer (either polyethyleneglycol (PEG) or polyvinylpyrrolidone (PVP)) to control the release rate. Spherical particles with sizes in the range of 2.4-4.1 µm were fabricated. They were found to comprise amorphous solid dispersions, with high entrapment efficiencies of >93%. The various blends of polymers had a range of release profiles. The PLGA-KGN particles displayed the slowest release rate, and blending with PVP or PEG led to faster release profiles, with most systems giving a high burst release in the first 24 h. The range of release profiles observed offers the potential to provide a precisely tailored profile via preparing physical mixtures of the materials. The formulations are highly cytocompatible with primary human osteoblasts.

Cellulose-based composite scaffolds for bone tissue engineering and localized drug delivery

Natural bone constitutes a complex and organized structure of organic and inorganic components with limited ability to regenerate and restore injured tissues, especially in large bone defects. To improve the reconstruction of the damaged bones, tissue engineering has been introduced as a promising alternative approach to the conventional therapeutic methods including surgical interventions using allograft and autograft implants. Bioengineered composite scaffolds consisting of multifunctional biomaterials in combination with the cells and bioactive therapeutic agents have great promise for bone repair and regeneration. Cellulose and its derivatives are renewable and biodegradable natural polymers that have shown promising potential in bone tissue engineering applications. Cellulose-based scaffolds possess numerous advantages attributed to their excellent properties of non-toxicity, biocompatibility, biodegradability, availability through renewable resources, and the low cost of preparation and processing. Furthermore, cellulose and its derivatives have been extensively used for delivering growth factors and antibiotics directly to the site of the impaired bone tissue to promote tissue repair. This review focuses on the various classifications of cellulose-based composite scaffolds utilized in localized bone drug delivery systems and bone regeneration, including cellulose-organic composites, cellulose-inorganic composites, cellulose-organic/inorganic composites. We will also highlight the physicochemical, mechanical, and biological properties of the different cellulose-based scaffolds for bone tissue engineering applications.

Evaluation of Trace Element and Heavy Metal Levels of Some Ethnobotanically Important Medicinal Plants Used as Remedies in Southern Turkey in Terms of Human Health Risk

Heavy metal accumulation in medicinal plants has increased dramatically in recent years due to agricultural and industrial activities leading to pollution of natural sources. This study is focused on the concentration of trace elements and heavy metals in aboveground parts of 33 medicinal plants from the Eastern Mediterranean of Turkey. Results showed that the Al concentrations varied between 4.368 and 1104.627, the B level varied between 47.850 and 271.479, Ca values ranged between 1971.213 and 22,642.895, Cd concentrations ranged between 0.011 and 0.651, Cr contents varied between 1.371 and 41.692, Cu values varied between 13.278 and 42.586, Fe concentrations varied between 20.705 and 1276.783, K levels ranged between 652.143 and 14,440.946, Mg concentrations varied from 336.871 to 1869.486, Mn contents varied between 46.383 and 849.492, Na concentrations varied between 167.144 and 3401.252, Ni values varied between 0.065 and 9.968, Pb levels ranged between 1.311 and 16.238, and Zn concentrations ranged between 67.250 and 281.954 mg kg-1, respectively. Furthermore, Recommended Dietary Allowance (RDA) values for trace elements and estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) for heavy metals were calculated. The concentrations of heavy metals in some studied plants distributed in industrial and mining regions were found as slightly higher than the acceptable limits determined by WHO. Consequently, in order to prevent this heavy metal accumulation, when collecting medicinal aromatic plants, rural areas, close to clean rivers, or mountainous areas should be preferred, away from highway, mining, and industrial areas.

Synergistic cellulose-based nanocomposite packaging and cold plasma decontamination for extended saffron preservation

Sterilization of saffron packaging and maintaining the quality of saffron content are the main priorities in saffron preservation. Common modalities do not offer lasting saffron preservation and it is urgent to develop novel packaging approaches from renewable resources and prevent packaging waste. Here, simultaneous decontamination and quality maintenance of saffron is demonstrated, for the first time, through the synergistic application of nano-clay-loaded carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) nanocomposites (CNCs) and cold plasmas (CP). Compared to the separate uses of CP and CMC/PVA/nano clay, our results confirm the synergies between CP and CMC/PVA/nano clay cause complete inactivation of Escherichia coli bacteria, while not significantly affecting the concentrations of the essential saffron components (safranal, crocin, and picrocrocin). Overall, the CP-treated CMC/PVA/nano clay fosters saffron preservation, through contamination removal and quality maintenance of the food product. The synergistic application of CP and CMC/PVA/nano clay thus represents a promising strategy for packaging, sterilization, and preservation of high-value food products.

Enhanced anti-biofilm and biocompatibility of Zn and Mg substituted β-tricalcium phosphate/functionalized multiwalled carbon nanotube composites towards A. baumannii and Methicillin-Resistant Staphylococcus aureus, and MG-63 cells

In this work, Zn and Mg substituted β-tricalcium phosphate/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposites were prepared by the co-precipitation method. The structural, vibrational, morphological and biological properties of the prepared nanocomposites were studied. The structural study revealed that the increase of Zn concentration shifts the β-tricalcium phosphate planes towards higher angle. Morphological analysis confirmed the formation of hexagonal-shaped particles after substitution of Zn. The particle size of the nanoparticles decreased with the increase of Zn concentration. XPS analysis clearly showed the presence of Zn, Mg, P, Ca, O and C. The Zn (5%) rich nanocomposites have better antibiofilm activity compared to 2% of zinc substituted composite. Also, it has been proven that the prepared nanocomposites have the ability to enhance the bioactivity of commercial antibiotics by means of a decrease in drug resistance. Finally, this study acted as a pioneer to improve drug efficiency and reduced the biofilm formation of certain medically important bacteria. The in-vitro cell viability and anti-biofilm results of zinc (5%) rich nanocomposite confirmed that prepared nanocomposite has biocompatible and enhanced anti-biofilm property, which will be beneficial candidate for biomedical applications.

Zinc substituted hydroxyapatite/silk fiber/methylcellulose nanocomposite for bone tissue engineering applications

Fibrous bio-composite based on silk fiber (SF), methylcellulose (MC) and zinc substituted hydroxyapatite (Zn_xCa_5-x (PO₄)₃(OH) (x = 0.1, 0.2, 0.5 and 1.0)) were obtained with the use of electrospinning (E-Spin) method. XRD, FTIR, SEM-EDAX, swelling, porosity and mechanical properties of the composites were analyzed. The elongation at break (%) (20.97-317.20 %) and tensile strength (29.85-110.92 MPa) of nanocomposites was increased with an increase in the wt% of Zn-HAP in SF/MC. An increase in the zone of inhibition with an increase in the wt% of Zn-HAP into the SF/MC was observed against E. coli (34 ± 0.33 to 47 ± 1.15), S. aureus (28 ± 0.24 to 38 ± 1.32) and C. albicans (24 ± 0.36 to 39 ± 2.36). The in-vitro biomineralization study using SBF (simulated body fluid) showed apatite layer formation on the nano-composite. In addition, the optimized (20 wt % of Zn₁.₀Ca_4.0(PO₄)₃(OH)/SF/MC) nano-composite showed good cell viability against human bone osteosarcoma (MG-63) cells.

Current Advances and Future Perspectives of Advanced Polymer Processing for Bone and Tissue Engineering: Morphological Control and Applications

Advanced polymer processing has received extensive attention due to its unique control of complex force fields and customizability, and has been widely applied in various fields, especially in preparation of functional devices for bioengineering and biotechnology. This review aims to provide an overview of various advanced polymer processing techniques including rotation extrusion, electrospinning, micro injection molding, 3D printing and their recent progresses in the field of cell proliferation, bone repair, and artificial blood vessels. This review dose not only attempts to provide a comprehensive understanding of advanced polymer processing, but also aims to guide for design and fabrication of next-generation device for biomedical engineering.

The impact of Zn-doped synthetic polymer materials on bone regeneration: a systematic review

Introduction

To repair bone defects, a variety of bone substitution materials have been used, such as ceramics, metals, natural and synthetic polymers, and combinations thereof. In recent decades, a wide range of synthetic polymers have been used for bone regeneration. These polymers have the advantages of biocompatibility, biodegradability, good mechanical properties, low toxicity, and ease of processing. However, when used alone, they are unable to achieve ideal bone formation. Incorporating zinc (Zn) into synthetic polymers has been considered, as previous studies have shown that Zn²⁺ promotes stem cell osteogenesis and mineral deposition. The purpose of this systematic review was to provide an overview of the application and effectiveness of Zn in synthetic polymers for bone regeneration, whether used alone or in combination with other biomaterials. This study was performed according to the PRISMA guidelines.

Materials and methods

A search of the PubMed, Embase, and the Cochrane Library databases for articles published up to June 2020 revealed 153 relevant studies. After screening the titles, abstracts, and full texts, 13 articles were included in the review; 9 of these were in vitro, 3 were in vivo, and 1 included both in vitro and in vivo experiments.

Results

At low concentrations, Zn²⁺ promoted cell proliferation and osteogenic differentiation, while high-dose Zn²⁺ resulted in cytotoxicity and inhibition of osteogenic differentiation. Additionally, one study showed that Zn²⁺ reduced apatite formation in simulated body fluid. In all of the in vivo experiments, Zn-containing materials enhanced bone formation.

Conclusions

At appropriate concentrations, Zn-doped synthetic polymer materials are better able to promote bone regeneration than materials without Zn.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02195-y.

Acceleration of Bone Formation and Adhesion Ability on Dental Implant Surface via Plasma Electrolytic Oxidation in a Solution Containing Bone Ions

The present study examined the in vitro and in vivo bone formation and adhesion ability on the surface of a titanium dental implant made by plasma electrolytic oxidation (PEO) in electrolytes containing bioactive ions. To achieve this goal, screw-shaped fabricated Ti-6Al-4V alloy implants were processed via PEO using an electrolyte solution containing calcium (Ca), phosphorous (P), magnesium (Mg), zinc (Zn), strontium (Sr), silicon (Si), and manganese (Mn) species. The screw implants doped with bioactive elements via PEO were placed in rabbit tibia, and the results were compared to the sand-blasted Ti-6Al-4V alloy implants. At eight-week post-surgery, there was no significant difference in the values of removal torque between sand-blasted and PEO-treated implants. However, it was observed that the PEO treatment of dental implants led to the formation of more periphery bone as compared to the case of sand-blasted implants. Accordingly, the PEO-treated implants have the potential to be used as promising materials for dental applications.

Biodegradable materials for bone defect repair

Compared with non-degradable materials, biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects, and have attracted extensive attention from researchers. In the treatment of bone defects, scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role, which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue. Traditional biodegradable materials include polymers, ceramics and metals, which have been used in bone defect repairing for many years. Although these materials have more or fewer shortcomings, they are still the cornerstone of our development of a new generation of degradable materials. With the rapid development of modern science and technology, in the twenty-first century, more and more kinds of new biodegradable materials emerge in endlessly, such as new intelligent micro-nano materials and cell-based products. At the same time, there are many new fabrication technologies of improving biodegradable materials, such as modular fabrication, 3D and 4D printing, interface reinforcement and nanotechnology. This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing, especially the newly emerging materials and their fabrication technology in recent years, and look forward to the future research direction, hoping to provide researchers in the field with some inspiration and reference.

Recent Advances in Applications of Cellulose Derivatives-Based Composite Membranes with Hydroxyapatite

The development of novel polymeric composites based on cellulose derivatives and hydroxyapatite represents a fascinating and challenging research topic in membranes science and technology. Cellulose-based materials are a viable alternative to synthetic polymers due to their favorable physico-chemical and biological characteristics. They are also an appropriate organic matrix for the incorporation of hydroxyapatite particles, inter and intramolecular hydrogen bonds, as well as electrostatic interactions being formed between the functional groups on the polymeric chains surface and the inorganic filler. The current review presents an overview on the main application fields of cellulose derivatives/hydroxyapatite composite membranes. Considering the versatility of hydroxyapatite particles, the hybrid materials offer favorable prospects for applications in water purification, tissue engineering, drug delivery, and hemodialysis. The preparation technique and the chemical composition have a big influence on the final membrane properties. The well-established membrane fabrication methods such as phase inversion, electrospinning, or gradual electrostatic assembly are discussed, together with the various strategies employed to obtain a homogenous dispersion of the inorganic particles in the polymeric matrix. Finally, the main conclusions and the future directions regarding the preparation and applications of cellulose derivatives/hydroxyapatite composite membranes are presented.

Synthesis, DFT studies, fabrication, and optical characterization of the [ZnCMC]TF polymer (organic/inorganic) as an optoelectronic device

A novel carboxymethyl cellulose zinc thin film [ZnCMC]^TF was fabricated using the sol–gel technique.