Antibacterial adhesive based on oxidized tannic acid-chitosan for rapid hemostasis.

Currently, bacterial infections and bleeding interfere with wound healing, and multifunctional hydrogels with appropriate blood homeostasis, skin adhesion, and antibacterial activity are desirable. In this study, chitosan-based hydrogels were synthesized using oxidized tannic acid (OTA) and Fe3+ as cross-linkers (CS-OTA-Fe) by forming covalent, non-covalent, and metal coordination bonds between Fe3+ and OTA. Our results demonstrated that CS-OTA-Fe hydrogels showed antibacterial properties against Gram-positive bacteria (Staphylococcus aureus)and Gram-negative bacteria (Escherichia coli), low hemolysis rate (< 2 %), rapid blood clotting ability, in vitro (< 2 min), and in vivo (90 s) in mouse liver bleeding. Additionally, increasing the chitosan concentration from 3 wt% to 4.5 wt% enhanced cross-linking in the network, leading to a significant improvement in the strength (from 106 ± 8 kPa to 168 ± 12 kPa) and compressive modulus (from 50 ± 9 kPa to 102 ± 14 kPa) of hydrogels. Moreover, CS-OTA-Fe hydrogels revealed significant adhesive strength (87 ± 8 kPa) to the cow's skin tissue and cytocompatibility against L929 fibroblasts. Overall, multifunctional CS-OTA-Fe hydrogels with tunable mechanical properties, excellent tissue adhesive, self-healing ability, good cytocompatibility, and fast hemostasis and antibacterial properties could be promising candidates for biomedical applications.

Amorphous magnesium phosphate-graphene oxide nano particles laden 3D-printed chitosan scaffolds with enhanced osteogenic potential and antibacterial properties.

The utilization of 3D printing technology for the fabrication of graft substitutes in bone repair holds immense promise. However, meeting the requirements for printability, bioactivity, mechanical strength, and biological properties of 3D printed structures concurrently poses a significant challenge. In this study, we introduce a novel approach by incorporating amorphous magnesium phosphate-graphene oxide (AMP-GO) into a thermo-crosslinkable chitosan/ß glycerol phosphate (CS/GP) ink. We fabricated thermo-crosslinkable CS inks containing varying concentrations (10 %, 20 %, or 30 % weight) of AMP-GO. The 3D printed scaffolds incorporating 20 % AMP-GO exhibited significantly improved mechanical properties, with compressive strengths of 4.5 ± 0.06 MPa compared to 0.5 ± 0.03 MPa for CS printed scaffolds. Moreover, the CS/AMP-GO inks demonstrated enhanced antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, attributed to the release of magnesium cations and the performance of GO. Additionally, CS/20AMP-GO ink facilitated increased adhesion, viability, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs), as evidenced by the upregulation of ALP, COL1, and Runx2 expression, which were elevated 9.8, 6.5, and >22 times, respectively, compared to pure CS scaffolds. Considering its exceptional in vivo osteogenic potential, we anticipate that the CS/20AMP-GO ink holds great potential for 3D printing of bone grafts.

Kappa-carrageenan based hybrid hydrogel for soft tissue engineering applications.

Biological materials such as cell-derived membrane vesicles have emerged as alternative sources for molecular delivery systems, owing to multicomponent features, the inherent functionalities and signaling networks, and easy-to-carry therapeutic agents with various properties. Herein, red blood cell membrane (RBCM) vesicle-laden methacrylate kappa-carrageenan (KaMA) composite hydrogel is introduced for soft tissue engineering. Results revealed that the characteristics of hybrid hydrogels were significantly modulated by changing the RBCM vesicle content. For instance, the incorporation of 20% (v/v) RBCM significantly enhanced compressive strength from 103 ± 26 kPa to 257 ± 18 kPa and improved toughness under the cyclic loading from 1.0 ± 0.4 kJ m-3to 4.0 ± 0.5 kJ m-3after the 5thcycle. RBCM vesicles were also used for the encapsulation of curcumin (CUR) as a hydrophobic drug molecule. Results showed a controlled release of CUR over three days of immersion in PBS solution. The RBCM vesicles laden KaMA hydrogels also supportedin vitrofibroblast cell growth and proliferation. In summary, this research sheds light on KaMA/RBCM hydrogels, that could reveal fine-tuned properties and hydrophobic drug release in a controlled manner.

Synthesis and characterization of gentamicin loaded ZSM-5 scaffold: Cytocompatibility and antibacterial activity.

Porous structure, biocompatibility and biodegradability, large surface area, and drug-loading ability are some remarkable properties of zeolite structure, making it a great possible option for bone tissue engineering. Herein, we evaluated the potential application of the ZSM-5 scaffold encapsulated GEN with high porosity structure and significant antibacterial properties. The space holder process has been employed as a new fabrication method with interconnected pores and suitable mechanical properties. In this study, for the first time, ZSM-5 scaffolds with GEN drug-loading were fabricated with the space holder method. The results showed excellent open porosity in the range of 70-78% for different GEN concentrations and appropriate mechanical properties. Apatite formation on the scaffold surface was determined with Simulation body fluid (SBF), and a new bone-like apatite layer shaping on all samples confirmed the in vitro bioactivity of ZSM-5-GEN scaffolds. Also, antibacterial properties were investigated against both gram-positive and gram-negative bacteria. The incorporation of various amounts of GEN increased the inhibition zone from 24 to 28 (for E. coli) and 26 to 37 (for S. aureus). In the culture with MG63 cells, great cell viability and high cell proliferation after 7 days of culture were determined.

Antibacterial amorphous magnesium phosphate/graphene oxide for accelerating bone regeneration.

Magnesium phosphates (MgP)s have attracted interest as an alternative biomaterial compared to the calcium phosphate (CaP)s compounds in the bone regeneration application in terms of their prominent biodegradability, lack of cytotoxicity, and ability of bone repair stimulation. Among them, amorphous magnesium phosphates (AMP)s indicated a higher rate of resorption, while preserving high osteoblasts viability and proliferation, which is comparable to their CaP peers. However, fast degradation of AMP leads to the initial fast release of Mg2+ ions and adverse effects on its excellent biological features. It seems that the addition of graphene oxide (GO) to magnesium phosphate can moderate its degradation rate. Hence, a novel in situ synthesized AMP powders containing 0.05, 0.25, 0.5, and 1 wt% of graphene oxide (AMP/GO) were developed to achieve a favorable degradation rate, desirable antibacterial properties against both Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) accompanying with proper cell viability and proliferation. The incorporation of 0.5 wt% of graphene oxide into the AMP ceramic led to reduce the release of Mg2+ ions from 571.2 ± 12.9 mg/L to 372.8 ± 14.7 mg/L and P ions from 354.8 ± 11.9 mg/L to 245.3 ± 9.9 mg/L, at day 10 of immersion in PBS. Besides, AMP/0.5 GO bioceramics were capable of eradicating all bacterial colonies of both strains. On the other hand, MG63 cells viability went up from 143.46% ± 7.54 to 184.46% ± 11.54 on the 7th day of culture in the presence of 0.5 wt% of GO compared to pure AMP ceramic. Furthermore, alizarin red staining and alkaline phosphatase (ALP) activity demonstrated the ability of AMP/GO to maintain the osteogenic phenotype of MG63 cells during 7 days culture. Therefore, it can be concluded that well distributed and in situ synthesized AMP/0.5GO powders can be a promising biomaterial for bone tissue regeneration.

Antibacterial Activity and Cell Responses of Vancomycin-Loaded Alginate Coating on ZSM-5 Scaffold for Bone Tissue Engineering Applications.

Despite the significant advancement in bone tissue engineering, it is still challenging to find a desired scaffold with suitable mechanical and biological properties, efficient bone formation in the defect area, and antibacterial resistivity. In this study, the zeolite (ZSM-5) scaffold was developed using the space holder method, and a novel vancomycin-loaded alginate coating was developed on it to promote their characteristics. Our results demonstrated the importance of alginate coating on the microstructure, mechanical, and cellular properties of the ZSM-5 scaffold. For instance, a three-fold increase in the compressive strength of coated scaffolds was observed compared to the uncoated ZSM-5. After the incorporation of vancomycin into the alginate coating, the scaffold revealed significant antibacterial activity against Staphylococcus aureus (S. aureus). The inhibition zone increased to 35 mm. Resets also demonstrated 74 ± 2.5% porosity, 4.3 ± 0.07 MPa strength in compressive conditions, acceptable cellular properties (72.3 ± 0.2 (%control) cell viability) after 7 days, good cell attachment, and calcium deposition. Overall, the results revealed that this scaffold could be a great candidate for bone tissue engineering.

Polysaccharides-based nanofibrils: From tissue engineering to biosensor applications.

Carbohydrate-based nanofibrils, including cellulose nanofibrils (CNFs) and chitin nanofibrils (ChNFs) are highly ordered architectures which are the basis of various biological components with hierarchical features, low-cost, biocompatibility, and biofunctionality. To preserve these exceptional structural topographies and to directly use these natural nanofibrils assembly, different approaches have been introduced to exfoliate these nanofibrils from their origin. In this review, we aim to summarize the recent progress on the isolation methods of CNFs and ChNFs and their relation to their physical and chemical properties. In addition, recent studies on their biomedical applications, focusing on tissue engineering, wound dressing, biomedical implants, drug delivery, and biosensors are emphasized. After short evaluation of the toxicity and immunogenicity of these nanofibrils, the outlooks and current challenges of CNFs and ChNFs-based constructs for biomedical applications are summarized. This study shows that CNFs and ChNFs-based constructs have significant potential for a widespread biomedical application in the future.

Inspiring biomimetic system based on red blood cell membrane vesicles for effective curcumin loading and release.

The aim of this study is to introduce an inspiring biomimetic system based on the red blood cell membrane (RBCM) vesicles for improved encapsulation efficiency and release of curcumin (Cur). Here, the role of the sonication time (0.5, 1.5, 3 and 5 min) on the properties of RBCM-CUR vesicles is investigated. It is determined that the hydrodynamic vesicle size, zeta potential, and release behavior are tunable by changing the sonication time. Noticeably, the average size of vesicles decreased from 163.0 ± 21 nm to 116.3 ± 16 nm by increasing the sonication time from 0.5 to 5 min. Moreover, the drug release value, after 24 h incubation, enhances from 57 to 99% with the expansion of sonication from 0.5 to 5 min. Additionally, the entrapment efficiency of Cur as a model drug is high in whole sonication time, owing to the amphiphilic nature of RBCM. Finally, the RBCM-CUR vesicles are not only cytocompatible, but also could support the attachment and proliferation of fibroblast cells in vitro. The RBCM based system for delivery of Cur could be a promising system for the wound healing applications.

Shear-thinning and self-healing nanohybrid alginate-graphene oxide hydrogel based on guest-host assembly.

The study aims to develop a novel nanohybrid shear-thinning hydrogel with fast gelation, and variable mechanical and biological properties. This nanohybrid hydrogel was developed via self-assembly guest-host interaction between ß-cyclodextrin modified alginate (host macromere, Alg-CD) and adamantine modified graphene oxide (guest macromere, Ad-GO) and subsequent ionic crosslinking process. We found that the rheological and mechanical properties of hydrogels were controlled via macromere concentration and the host: guest macromere ratio, due to the modulation of crosslinking density and network structure. Noticeably, 12%(1:2) dual-crosslinked hydrogel (2DC12) significantly improved the strength (1.3-folds) and toughness compared to 10%(1:4) dual-crosslinked hydrogel (4DC10). Furthermore, the hydrogel erosion and cytocompatibility relied on the designed parameters. Remarkably, 2DC12 showed less than 20% weight loss after 20 days of incubation in physiological solution and more than 200% cell survival after five days. In conclusion, the nanohybrid Alg-GO hydrogel could be used as an injectable hydrogel for soft tissue engineering applications.

CNT and rGO reinforced PMMA based bone cement for fixation of load bearing implants: Mechanical property and biological response.

Polymethyl methacrylate (PMMA) bone cements (BCs) have some drawbacks, including limited bioactivity and bone formation, as well as inferior mechanical properties, which may result in failure of the BC. To deal with the mentioned issues, novel bioactive polymethyl methacrylate-hardystonite (PMMA-HT) bone cement (BC) reinforced with 0.25 and 0.5 wt% of carbon nanotube (CNT) and reduced graphene oxide (rGO) was synthesized. In this context, the obtained bone cements were evaluated in terms of their mechanical and biological characteristics. The rGO reinforced bone cement exhibited better mechanical properties to the extent that the addition of 0.5 wt% of rGO where its compressive and tensile strength of bioactive PMMA-HT/rGO cement escalated from 92.07 ± 0.72 MPa, and 40.02 ± 0.71 MPa to 187.48 ± 5.79 MPa and 64.92 ± 0.75 MPa, respectively. Besides, the mechanisms of toughening, apatite formation, and cell interaction in CNT and rGO encapsulated PMMA have been studied. Results showed that the existence of CNT and rGO in BCs led to increase of MG63 osteoblast viability, and proliferation. However, rGO reinforced bone cement was more successful in supporting MG63 cell attachment compared to the CNT counterpart due to its wrinkled surface, which made a suitable substrate for cell adhesion. Based on the results, PMMA-HT/rGO can be a proper bone cement for the fixation of load-bearing implants.

Triboelectric nanogenerators based on graphene oxide coated nanocomposite fibers for biomedical applications.

A high demand for green and eco-friendly triboelectric nanogenerators (TENGs) has multiplied the importance of their degradability for biomedical applications. However, the charge generation of current eco-friendly TENGs is generally limited. In this research, a flexible TENG based on a silk fibroin (SF) fibrous layer and a polycaprolactone (PCL)/graphene oxide (GO) fibrous layer was developed. Moreover, the PCL/GO layer was surface modified using various concentrations of GO (0, 1.5, 3, 6, and 9 wt%). We demonstrated that surface modification using GO nanosheets significantly improved the output of the TENG. Notably, the optimized GO modified layer resulted in a voltage of 100 V, a current of 3.15 mA [Formula: see text], and a power density of 72 mW[Formula: see text]. Moreover, a thin PCL layer applied as an encapsulation layer did not significantly modulate the performance of the TENG. Furthermore, during 28 d of soaking in a phosphate buffer solution, the proposed TENG was able to successfully generate electricity. The TENG was also proposed to be used for the electrical stimulation of PC12 cells. The results confirmed that this self-powered electrical stimulator could promote the attachment and proliferation of PC12 cells. Therefore, we have shown the potential for an eco-friendly and cost-effective TENG based on GO modified PCl/GO and silk fibrous layers to be used as a power source for biomedical applications.

Biomimetic Nylon 6-Baghdadite Nanocomposite Scaffold for Bone Tissue Engineering.

Nature creates soft and hard ingredients revealing outstanding properties by adjusting the ordered assembly of simple primarily components from the nano- to the macro-scale. To simulate the important features of native tissue architecture, wide researches are being performed to develop new biomimetic custom-made composite scaffolds for tissue engineering. Here, we introduced a three-dimensional (3D) biomimetic scaffold based on the cuttlefish bone (CB) as a sacrificial template for bone tissue engineering. By combination of nylon 6 (N6), various amounts of baghdadite (BG) nanopowder and sacrificial template CB, a novel nanocomposite scaffolds was successfully developed with hierarchical microstructure and open pores in the range size in long and minor axis of 153-253 µm and 39-70 µm, respectively, depending on the BG content. In addition, incorporation of BG improved the mechanical properties of the scaffolds. Noticeably, the compressive strength and compressive modulus enhanced from 0.47 ± 0.05 to 1.41 ± 0.25 MPa and from 3.16 ± 0.14 to 6.23 ± 0.3 MPa, respectively. Moreover, results demonstrated that the incorporation of BG nanoparticles in the N6 matrix significantly improved bioactivity in simulated body fluid and increased degradation rate of N6 scaffold. Additionally, 3D nanocomposite scaffolds disclosed meaningfully excellent cellular responses. It is envisioned that the provided N6-BG nanocomposite scaffold might be a promising candidate for bone tissue engineering applications.

TiO2 nanotubes/reduced GO nanoparticles for sensitive detection of breast cancer cells and photothermal performance.

In this study, we developed a simple and cost effective aptasensor based on TiO2 nanotubes-reduced graphene oxide (TiO2 nanotube-rGO) linked to MUC1 aptamers for ultrasensitive electrochemical detection of breast cancer cell (MCF-7). Moreover, the photothermal performance of nanohybrid TiO2-rGO was investigated for cancer treatment. In this regard, after synthesize of TiO2 nanotubes via anodization process, TiO2 nanotubes-rGO hybrid was synthesized by UV assisted reduction of GO and subsequent TiO2 nanotubes attachment to rGO sheets. The resultant hybrid could provide an excellent large surface area leading to improvement of suitable sites for MUC1 aptamer immobilization. Our results revealed that TiO2-rGO aptasensor exhibited superior analytical performance for MCF-7 cell detection with the detection limit of 40 cells.ml-1 within the detection range of 103-107 cells. ml-1. In addition, the designed aptasensor was effectively applied to detect MUC1 marker in a real sample. Moreover, the TiO2 nanotube-rGO hybrid nanoparticles revealed great photothermal performance exposed to NIR laser. It could be concluded that nanohybrid TiO2-rGO would be a useful and beneficial platform for detection and treatment of breast cancer.

Electrophoretic deposition of chitosan reinforced graphene oxide-hydroxyapatite on the anodized titanium to improve biological and electrochemical characteristics.

Chitosan reinforced hydroxyapatite-graphene oxide (CS-GO-HA) nanocomposite coatings were developed using electrophoretic deposition process in order to improve the biological and electrochemical properties of Ti surface. Moreover, the role of anodized layer on the physical and electrochemical properties of the CS-GO-HA nanocomposite coating was evaluated. After synthesize of HA-GO nanopowder using a sol-gel process, nanocomposite coatings with various concentrations of chitosan (0.5, 1 and 1.5 mg/ml) were produced. Increasing the chitosan content lowered the deposition rate of HA-GO nanoparticles, reduced the coating thickness and diminished apatite-formation ability and biocompatibility. Noticeably, MG63 cell viability significantly reduced form 119.3 ±â€¯5.1 (% control) to 51.9 ±â€¯14.8 (% control), when the chitosan concentration increased from 0.5 to 1.5 mg/ml. In addition, the CS-GO-HA coating containing 0.5 mg/ml chitosan revealed the best barrier property owing to the less crack formation. Furthermore, anodizing of titanium substrate and formation of TiO2 nanotube (TiNT) resulted in the formation of crack-free and homogeneous CS-GO-HA coatings without any observable defect. Moreover, the TiNT formation noticeably improved barrier resistance of the coating (6.7 times) due to better adhesion governed between coating and substrate. Our results confirmed that the surface modification using both anodizing of Ti substrate and electrophoretic deposition of ternary CS-GO-HA nanocomposite coating with 0.5 mg/ml chitosan successfully improves electrochemical properties, bioactivity and cell function, which makes it promising for bone implant applications.

Nanohybrid hydrogels of laponite: PVA-Alginate as a potential wound healing material.

The aim of this study was to develop a novel nanohybrid interpenetrating network hydrogel composed of laponite:polyvinyl alcohol (PVA)-alginate (LAP:PVA-Alginate) with adjustable mechanical, physical and biological properties for wound healing application. Results demonstrated that compared to PVA-Alginate, mechanical strength of LAP:PVA-Alginate significantly enhanced (upon 2 times). Moreover, incorporation of 2wt.% laponite reduced swelling ability (3 times) and degradation ratio (1.2 times) originating from effective enhancement of crosslinking density in the nanohybrid hydrogels. Furthermore, nanohybrid hydrogels revealed admirable biocompatibility against MG63 and fibroblast cells. Noticeably, MTT assay demonstrated that fibroblast proliferation significantly enhanced on 0.5wt.% LAP:PVA-alginate compared to PVA-alginate. Moreover, hemolysis and clotting tests indicated that the nanohybrid hydrogels promoted hemostasis which could be helpful in the wound dressing. Therefore, the synergistic effects of the nanohybrid hydrogels such as superior mechanical properties, adjustable degradation rate and admirable biocompatibility and hemolysis make them a desirable candidate for wound healing process.

Nano­calcium phosphate bone cement based on Si-stabilized α-tricalcium phosphate with improved mechanical properties.

This study aimed to develop nano­calcium phosphate cement (nCPC) and evaluate the effect of nanosized precursors on mechanical, physical and handling properties (injectability and setting time) as well as conversion rate of nano-reactants into nano-hydroxyapatite (nHA). In this study, while alpha tricalcium phosphate (α-TCP, 98wt%) and HA (2wt%) were applied as the powder phase, 2.5wt% NaH2PO4 solution was used as liquid phase of cement. Before nano-CPC preparation, Si-stabilized α-TCP nanopowder with particle size of 10±3.6nm was firstly synthesized in a two-step process of sol-gel followed by mechanical alloying. Moreover, HA nanopowder with particle size of 32±3.6nm was synthesized using sol-gel process. Our results revealed that after 3days of immersion in ringer's solution, reactants almost completely converted to nHA. Moreover, the initial and final setting time of nano-CPC was obtained 6.3±2.1min and 14.3±4.0min, respectively. Furthermore, injectability of this formulation was reached 87.90±2.60%. In addition, our results confirmed that the compressive strength and modulus of nano-CPC enhanced with increasing immersion time in ringer's solution from 9.50±1.27MPa and 0.38±0.07GPa (at 1day) to 18.70±2.23MPa and 0.57±0.15GPa (at 5days), respectively. Finally, in order to evaluate cellular responses to nano-CPC, MG63 cells were cultured on it and cell morphology and cytotoxicity were evaluated. Results revealed that nano-CPC enhanced proliferation and spreading of osteoblast like cells compared to control (tissue culture plate) which could be due to both appropriate physical and chemical properties of nano-CPC which stimulate cell proliferation. Our findings suggest the formation of an injectable nano-CPC with appropriate mechanical, physical and degradation rate which can potentially utilized for filling bone defects.

Polyethylenimine/kappa carrageenan: Micro-arc oxidation coating for passivation of magnesium alloy.

The aim of this study was to combine micro-arc oxidation (MAO) and self-assembly technique to improve corrosion resistivity of AZ91 alloy. While a silicate-fluoride electrolyte was adopted for MAO treatment, polyethylenimine (PEI)/kappa carrageenan (KC) self-assembly coating was applied as the second coating layer. Resulted demonstrated the formation of forsterite-fluoride containing MAO coating on AZ91 alloy depending on the voltage and time of anodizing process. Addition of the second PEI/KC coating layer on MAO treated sample effectively enhanced the adhesive strength of MAO coated sample due to filling the pores with polymers and increase in the mechanical interlocking of coating to the substrate. Moreover, the corrosion evaluation considered by potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that double layered PEI/KC:MAO coating presented superior resistance to corrosion attack. It is envisioned that the proposed double layered PEI/KC:MAO coating could be useful for biomedical applications.

pH sensitive dexamethasone encapsulated laponite nanoplatelets: Release mechanism and cytotoxicity.

The purpose of this study was to develop an efficient strategy to use laponite (LAP) nanoplates as a platform for the efficient release of anionic dexamethasone (DEX). Results revealed that DEX was encapsulated into the interlayer space of LAP nanodisks through an intercalation process with a high loading efficiency of 95.10±0.80%. X-Ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the hybrid LAP/DEX nanoplates (LD-NPs) indicated that DEX molecules could successfully adsorb into the LAP nanoplates depending on the pH value. Moreover, in vitro drug release study showed that the release of DEX from LD-NPs was pH-dependent, and DEX released at a faster rate at acidic pH (pH=5.4) than physiological one. Importantly, the results of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay confirmed that the released DEX from LD-NPs not only did not show cytotoxic effect but also improved the viability of MG63 cells compared to LAP-free samples (DEX enriched medium). Our work indicated that LAP nanoplates could be a promising candidate for release of anionic DEX in the controlled manner depending on the pH environment. Moreover, the merits of LD-NPs such as good cytocompatibility, excellent physiological stability and sustained pH-responsive release properties, make them a promising platform for the delivery of other therapeutic agents beyond DEX.

Effects of surface modification on the mechanical and structural properties of nanofibrous poly(ε-caprolactone)/forsterite scaffold for tissue engineering applications.

Composite scaffolds consisting of polymers reinforced with ceramic nanoparticles are widely applied for hard tissue engineering. However, due to the incompatible polarity of ceramic nanoparticles with polymers, they tend to agglomerate in the polymer matrix which results in undesirable effects on the integral properties of composites. In this research, forsterite (Mg2SiO4) nanoparticles was surface esterified by dodecyl alcohol and nanofibrous poly(ε-caprolactone)(PCL)/modified forsterite scaffolds were developed through electrospinning technique. The aim of this research was to investigate the properties of surface modified forsterite nanopowder and PCL/modified forsterite scaffolds, before and after hydrolytic treatment, as well as the cellular attachment and proliferation. Results demonstrated that surface modification of nanoparticles significantly enhanced the tensile strength and toughness of scaffolds upon 1.5- and 4-folds compared to unmodified samples, respectively, due to improved compatibility between matrix and filler. Hydrolytic treatment of scaffolds also modified the bioactivity and cellular attachment and proliferation due to greatly enhanced hydrophilicity of the forsterite nanoparticles after this process compared to surface modified samples. Results suggested that surface modification of forsterite nanopowder and hydrolytic treatment of the developed scaffolds were effective approaches to address the issues in the formation of composite fibers and resulted in development of bioactive composite scaffolds with ideal mechanical and structural properties for bone tissue engineering applications.

Development of novel aligned nanofibrous composite membranes for guided bone regeneration.

The ability to mimic the structure of the natural extracellular matrix is a successful key for guided bone regeneration (GBR). For the regeneration of highly organized structures such as heart and bone, aligned fibrous membranes could provide anisotropic mechanical and biological properties which are adequate topographic guidance to cells. Here, novel nanofibrous membranes were developed through electrospinning of PCL-forsterite nanopowder. The membranes were characterized with regard to structural and mechanical properties, degradation, bioactivity and cellular interactive responses. Results showed that optimized nanofibrous composite membrane with significantly improved tensile strength and elastic modules was achieved through addition of 10 wt% forsterite nanopowder into PCL membrane. Addition of forsterite nanopowder decreased the average fiber diameters from 872±361 nm (pure PCL membrane) to 258±159 nm (PCL-10 wt% forsterite membrane). At higher forsterite contents (>10 wt%), the agglomeration of nanoparticles was observed which resulted in reduced mechanical properties. Aligned fibrous membranes revealed smaller fiber sizes and significantly enhanced and anisotropic mechanical properties compared to random ones suggesting that fiber alignment has a profound effect on the structural properties of membranes. Forsterite nanopowder increased the degradation rate showing enhanced hydrophilicity and induced apatite formation in simulated body fluid. Furthermore, composite nanofibrous membranes possessed significantly improved cellular responses in terms of attachment, proliferation and mineralization of pre-osteoblasts compared to PCL membrane. Thus, the currently developed nanofibrous composite membranes embedded in forsterite nanopowder expected to be attractive in GBR membrane applications.