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This work introduces the synthesis of N-doped nanocomposite of ZrO2/TiO2 nanofibers (NFs) by use of both electrospinning and hydrothermal methods. The physicochemical properties of the introduced TiO2 NFs are investigated to describe the morphology, crystallinity and chemistry through FESEM, SEM-EDX, XRD, TEM and XPS. As the results, the investigated material can be described as N@ZrO2/TiO2 NFs. The crystal structure of the prepared TiO2 is only anatase structure. Then, the novel NFs are utilized to design novel photoanode and photo-electrochemical characterization such as current-potential response under light, incident photon-to-current efficiency (IPCE) and electrochemical impedance spectroscopy (EIS) of the dye-sensitized solar cell (DSC) are also investigated. The photovoltaic response showed that the efficiency of the DSCs employed N@ZrO2/TiO2 photoanode gave 4.95%, which was higher than those of DSCs designed with ZrO2/TiO2 NFs (4.51%) and N@TiO2 NFs (4.41%) photoanodes. The high photo-response of DSC by use of N@ZrO2/TiO2 NFs can be attributed to enhanced electrical conductivity, which is studied via EIS, and presence of active sites of N. These active sites can easily absorb dye-molecules in the step of dye-loading in the fabrication of DSC.

In the efforts to improve corrosion resistance and biocompatibility of magnesium alloys, polycarprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs) composite coatings were applied onto AZ31 Mg alloys via electrospinning technique in this study. The PCL/ZnO composite coatings on Mg alloys were characterized by using FE-SEM, EDX, XPS, and FT-IR. Moreover, coating adhesion test, electrochemical corrosion test, and biocompatibility test in vitro were performed to measure coating performance. Our results revealed that the increase in the content of ZnO NPs in the composite coatings not only improved the coating adhesion of composite coatings on Mg alloys, but also increased the corrosion resistance. Furthermore, the biocompatibility of MC3T3-E1 osteoblasts of the PCL/ZnO composite coated samples was superior to the biocompatibility of the bare samples. Such data suggest that applying PCL/ZnO composite coating to the magnesium alloys has suitable potential in biomedical applications.

Although, titanium dioxide (TiO2) is the most widely used photoanode material in the dye-sensitized solar cells, the low tendency for dye adsorption, fast electrons/holes recombination and the poor electrons transfer are considered important reasons for the corresponding low photovoltaic efficiency. To overcome these problems, combining the versatility of the hydrothermal and electrospinning processes was exploited to synthesize novel nitrogen doped & tin oxide (SnO2) co-incorporated good morphology TiO2 nanofibers to be used as photoanode material. Experimentally, compared to pristine, nitrogen-doped and nitrogen-freeS the best result was obtained at 10 wt%. Moreover, nitrogen doping enhances the cell efficiency based on both pristine and SnO2-incorporated TiO2 nanofibers. Typically, the estimated photovoltaic efficiencies for the fabricated cells based on pristine, nitrogen-doped, SnO2-incorportaed, and nitrogen-dopedS 8.74 mA/cm2, which can be attributed to the enhancement of the dye adsorption, improving in the charge transfer, and decreasing of the electrons/holes recombination. Secondly, SnO2 incorporation leads to creates new routes for transferring the electrons from LUMO state of photosensitizer to the external circuit through the conduction band of this hetero structure and also wider the band gap which retards the recombination reactions.

A highly electroactive bio-nanohybrid film of polypyrrole (PPy)-Nafion (Nf)-functionalized multi-walled carbon nanotubes (fMWCNTs) nanocomposite was prepared on the glassy carbon electrode (GCE) by a facile one-step electrochemical polymerization technique followed by chitosan-glucose oxidase (CH-GOx) immobilization on its surface to achieve a high-performance glucose biosensor. The as-fabricated nanohybrid composite provides high surface area for GOx immobilization and thus enhances the enzyme-loading efficiency. The structural characterization revealed that the PPy-Nf-fMWCNTs nanocomposite films were uniformly formed on GCE and after GOx immobilization, the surface porosities of the film were decreased due to enzyme encapsulation inside the bio-nanohybrid composite materials. The electrochemical behavior of the fabricated biosensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry measurements. The results indicated an excellent catalytic property of bio-nanohybrid film for glucose detection with improved sensitivity of 2860.3μAmM(-1)cm(-2), the linear range up to 4.7mM (R(2)=0.9992), and a low detection limit of 5μM under a signal/noise (S/N) ratio of 3. Furthermore, the resulting biosensor presented reliable selectivity, better long-term stability, good repeatability, reproducibility, and acceptable measurement of glucose concentration in real serum samples. Thus, this fabricated biosensor provides an efficient and highly sensitive platform for glucose sensing and can open up new avenues for clinical applications.

Magnesium (Mg) and its alloys have attracted much attention as a promising candidate for degradable implant applications however the rapid corrosion of magnesium inside the human body greatly limits its use as an implant material. Therefore, coating the alloy surface with a multifunctional film is a promising way to overcome the drawbacks. Here we propose for the first time a multifunction layer coating to enhance the cell viability, antibacterial property and decelerated corrosion rates to act as a novel material to be used for degradable implant Applications. For that, the magnesium alloy (AZ31) was first treated with hydrofluoric acid (HF) and then dopamine tris Hydrochloric acid (tris-HCL) solution. The reducing catechol groups in the polydopamine (PD) layer subsequently immobilize silver/gold ions in situ to form uniformly dispersed Ag/Au nanoparticles on the coating layer. The successful formation of Ag/Au nanoparticles on the HF-PD AZ31 alloy was confirmed using XPS and XRD, and the morphology of all the coated samples were investigated using SEM images. The alloy with HF-PDA exhibit enhanced cell attachment and proliferation. Moreover, the nanoparticle immobilized HF-PD alloy exhibited dramatic corrosion resistance enhancement with superior antibacterial properties and accountable biocompatibility. Thus the result suggest that HF-PD Ag/Au alloy has great potential in the application of degradable implant and the surface modification method is of great significance to determine its properties.

Due to its eco-friendly and low energy technique for removing salt ions from saline water, capacitive deionization (CDI) is highly recommended as a desalination process. Based on its good features, large surface area and good electric conductivity, graphene oxide is a promising electrode in the CDI technology if the specific capacitance could be enhanced. In this study, to improve the electrochemical performances, novel ZrO 2 nanoparticles-incorporated graphene oxide nanosheets with different concentrations were successfully synthesized by hydrothermal treatment, their electrosorption characteristics in CDI unit were examined. The morphology, structure and electrochemical performance of the fabricated materials were investigated by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry and electrochemical impedance spectroscopy. The capacitive and electrosorption performances in NaCl solution were studied. Moreover, the role of ZrO 2 loading was investigated. The introduced ZrO 2 -doped graphene oxide showed a distinct improvement in the electrosorption capacity and revealed higher specific capacitance compared to the pristine graphene oxide. The obtained results indicated that the synthesized ZrO 2 -doped graphene oxide nanocomposite having 10 wt.% ZrO 2 displayed a significant increase in the specific capacitance as the corresponding value (452.06 F/g) was nine folds more than that of the pristine GO at 10 mV/s. Moreover, the same electrode exhibits great cycling stability, excellent salt removal efficiency (93.03%), and distinct electrosorptive capacity (4.55 mg/g). Overall, the proposed GO/ZrO 2 nanoparticle composite electrode is appropriate for utilizing as optimum electrodes for the CDI technique.

In this study, Ni/Pd-decorated carbon nanofibers (NFs) were fabricated as an electrocatalyst for methanol oxidation. These NFs were synthesized based on carbonization of poly(vinyl alcohol), which has high carbon content compared to many polymers used to prepare carbon NFs. Typically, calcination of an electrospun mat composed of nickel acetate, palladium acetate, and poly(vinyl alcohol) can produce Ni/Pd-doped carbon NFs. The introduced NFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, line TEM energy dispersive x-ray spectrometry, field emission scanning electron microscopy, and x-ray powder diffraction. These physicochemical characterizations are acceptable tools to investigate the crystallinity and chemistry of the fabricated Ni/Pd-carbon NFs. Accordingly, the prepared NFs were tested to enhance the economic and catalytic behavior of methanol electrooxidation. Experimentally, the obtained onset potential was small compared to many reported materials; 0.32 V (versus Ag/AgCl as a reference electrode). At the same time, the current density changed from 5.08 mA/cm2 in free methanol at 0.6 V to 12.68 mA/cm2 in 0.1 mol/L methanol, which can be attributed to the MeOH oxidation. Compared to nanoparticles, the NFs have a distinct effect on the electrocatalytic performance of material due to the effect of the one-dimensional structure, which facilitates the electron transfer. Overall, the presented work opens a new way for non-precious one-dimensional nanostructured catalysts for direct methanol fuel cell technology.

Highly porous, hollow TiO 2 nanofibers (NFs) were fabricated through coaxial nozzle electrospinning using a polymer sol–gel solution of CaCO 3 and TiO 2 precursor. Hollow and porous TiO 2 NFs were obtained by etching CaCO 3 on calcined TiO 2 fibers using dilute HCl. Characterization of the as-synthesized materials were performed using FE-SEM and XRD before and after 24 h of bio-mineralization. The in vitro cell culture test was performed using MC3T3-E1 osteoblast cells to assess cell response of the different NFs. The results suggested that as-synthesized porous nanotubes have better biocompatibility for bone regeneration and implantations compared to other nonporous TiO 2 nanorods or NFs.

Third-generation biomaterials aim to stimulate specific cellular responses at the molecular level, these materials characterized with a resorbable and bioactivity that help body heal once they have been implanted. Here, a biomimetic method was used to generate hydroxyapatite (HA) nanoplates on the surface of AZ31B Mg alloy via anodization in simulated body fluid (SBF), followed by a hydrothermal (HT) process. The resulting nanoplates were characterized using FE-SEM, XRD, and FT-IR, surface hydrophobicity, in addition, corrosion was assessed electrochemically. The excellent bioactivity of the treated samples compared with naked ones were confirmed in vitro with MC3T3-E1 osteoblastic cells with significant growth and proliferation.

Bioactive films with a nanoplate structure were prepared on the surface of a biodegradable AZ31B magnesium (Mg) alloy via anodization in simulated body fluid (SBF) as an electrolyte to control Mg biodegradability and improve surface bioactivity. The effect of the electrolyte temperature and pH values on the formation of the biomimetic film were studied. The electrolyte was set at three different temperatures of 37, 50, and 80 °C, with pH values ranging from 7.4 to 8 for the lower electrolyte temperature and 11.5–12 for the two higher levels of temperature. The apatite films on the different samples were characterized using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), EDS element mapping, X-ray photon spectroscopy (XPS), and FTIR spectroscopy. The water contact angles of the different surfaces were evaluated, moreover, the corrosion behaviors of the different samples were studied using electrochemical potentiodynamic DC, electrochemical impedance spectroscopy (EIS), and immersion tests. The human fetal-osteoblast cell line hFOB 1.19 was used in a cell culture test, and the biological response and cell function were evaluated in vitro using DNA and PCR. The decomposition of the apatite film was affected by the anodization electrolyte temperature, resulting in an amorphous structure. It is observed that the apatite structure has nanoplates at electrolyte temperature (37 to 50) °C and these have a tendency to disappear at 80 °C.

Magnesium (Mg), and its alloys have good potential for using in biomedical applications due to its good mechanical properties and biodegradability. However, the poor corrosion resistance and insufficient mechanical stability of Mg in biological fluids have limited its clinical applicability. As a result, surface modification techniques are being investigated to improve corrosion resistance for biomedical applications. In this study, a bioactive CaP film were deposited on the surface of the AZ31B magnesium alloy via anodization with SBF solution used as the electrolyte with and without ZrO 2 Nanoparticles (NPs). The samples were evaluated and characterized in vitro to assess their degradation and cytocompatability behaviour via FE-SEM, electrochemical corrosion test, immersion test, and cell culture tests. The results indicate that the AZ31B Mg alloy surface anodized in SBF with and without ZrO 2 NPs consists of CaP nanoplate leaf-like apatite structures and porous 3-D structures, respectively. The nanomorphology showed uniform growth on the anodized surface that had created the porous layer on the surface of the samples three days after immersion in the SBF solution. The formation of such nanostructures on the anodized sample could provide the implant materials with extra biocompatibility. Moreover, this unique deposited layer can improve the corrosion resistance and cytocompatability of the Mg alloys, which make it a promising material for use in biomedical applications.

The aim of the present study was to develop a fibrous scaffold with unique physiochemical, mechanical and biocompatible characteristics with morphological structure similar to the native extracellular matrix (ECM). A dual non-woven ultrafine fibrous scaffold composed of polyurethane (PU)/Nylon 6 (N6) hybrid polymers mixed with natural gelatin (Gel) was fabricated by a dual syringe electrospinning technique. Pronounced dual composite fine fibers of PU/N6 (148 ± 43 nm) and (PU-Gel)/(N6-Gel) (161 ± 79 nm) with an interconnected porosity were obtained. The dual N6/Pu fibrous scaffold showed higher tensile strength and tensile modulus than a dual PU-Gel/N6-Gel scaffold, whereas the dual composite fibrous scaffold containing Gel induced the largest elongation at breaking load. Biomimetic mineralization characteristics observed at different time intervals showed the formation of a bone apatite like layer on the dual composite fibrous scaffold, indicating good bioactivity. The dual (PU-Gel)/(N6-Gel) nanofibers composite fibrous scaffold had better wettability compared to the other scaffolds, and supported high osteoblast cell proliferation. This suggests that the fabricated dual composite fibrous scaffolds containing gelatin may have the potential to be applied in bone tissue engineering.

The development of biocompatible patches that can provide adequate mechanical properties and mimicking the physiological relevance still has enormous challenges in the field of tissue engineering. In this study, the aim is to engineer and develop tri-layered nanofiber patches to synchronous the mechanical properties and mimic the complex structure of living cardiovascular tissues. The developed patches consisting of blended silk fibrin (SF) and polyvinyl alcohol (PVA) composite as a hydrophilic middle layer. The upper and lower layers were composed of polycaprolactone polymer (PCL) and Poly (Lactic Acid) (PLA), respectively. Layer by layer of the developed patches were fabricated by electrospinning technique. The patches characteristics such as morphology, surface topography, and physiochemical, biodegradable and mechanical stability were investigated. Furthermore, a human endothelial cell line (EA. hy926) was exploited to assess the biological properties of the fabricated patches. The results show that the patches had high endothelial cells biocompatibility, mechanical elasticity, and unique nanofibers structure.

A biodegradable polyvinyl alcohol/silk fibroin (PVA/SF) nanofibrous heart patch with unique tensile properties was fabricated by an electrospinning technique based on a water-solvent system. The fabricated heart patches were exposed to 2% Glutaraldehyde vapor to provide a cross-linkage and tune the degradation behavior. Numerous characterizations of the modified PVA/SF patches such as surface morphology, chemical bonding, mechanical behavior, biodegradation, and biological assessment of the crosslinked PVA/SF patches were performed. It was found that pronounced and interconnected PVA/SF composite fibrous patches had an average nanofiber diameter of 228 ± 49 nm. In addition, incorporation of SF into PVA nanofibers enhanced the mechanical properties (i.e. tensile strength and tensile modulus) and tuning the degradation rate of the PVA/SF patch. Human cardiac fibroblast cells (HCFC) were cultured on the cross-linked composite patches and the results showed good cell proliferation and attachment on the patches bio-interface.

In this study, for the first time, the degradation performance of AZ31B Mg alloy was tuned by an in situ deposition of apatite thin layer within a short time in one step. Using Taguchi method for experimental design, anodization process was designed under control conditions (time and voltage), and simulated body fluid (SBF) was used as the electrolyte to nucleate apatite-like compounds. The coated alloy was characterized through field emission scanning electron microscopy (FE-SEM), EDS, X-ray diffraction and XPS analysis. The results show that the applied voltage has a significant effect on the formation of apatite-like layers. Compared to the uncoated samples, microhardness and surface roughness of the coated samples showed remarkably different values. The potentiodynamic polarization results demonstrate that the polarization resistance of the anodized samples is higher than the substrate polarization resistance, thus improving the alloy corrosion resistant. Based on the experimental results, the proposed nanostructure apatite-like coating can offer a promising way to improve the biocompatibility and degradability properties of the Mg alloy for bone tissue regeneration.

Magnesium (Mg) as a biodegradable implant brings a revolution in medical field application, especially in bone implant and stent application. Biodegradability of Mg has attracted attentions of researchers to avoid secondary surgery to remove the implant materials after healing process. Various advantages of Mg make it suitable for medical application such as density, good mechanical properties and biodegradation. However, Mg biodegradability must be controlled to meet tissue-healing period of time because of the high degradation in a physiological environment. Fast corrosion and high alkalinity due to hydrogen release induce tissue inflammation, which limits its clinical applications. Many techniques are applied to the Mg surface to improve surface biocompatibility and control its biodegradability. This chapter focuses on anodization of Mg and its alloys to improve corrosion resistance and biocompatibility for orthopedic application. Mg coating with thin film apatite could enhance the biocompatibility and increase osseointegration formation in the bone fracture side. Evaluation of the required anodized film discussed in the chapter such as chemical composition, biodegradability and biocompatibility.