Electrospun titanium dioxide nanofibers containing hydroxyapatite and silver nanoparticles as future implant materials

Fabrication of multifunctional cellulose/TiO2 /Ag composite nanofibers scaffold with antibacterial and bioactivity properties for future tissue engineering applications

In the present work, a novel strategy was explored to fabricate nanofiber scaffolds consisting of cellulose assimilated with titanium dioxide (TiO₂ ) and silver (Ag) nanoparticles (NPs). The concentration of the TiO₂ NPs in the composite was adjusted to 1.0, 1.5, and 2.0 wt % with respect to polymer concentration used for the electrospinning of colloidal solutions. The fabricated composite scaffolds were dispensed to alkaline deacetylation using 0.05 M NaOH to remove the acetyl groups in order to generate pure cellulose nanofibers containing TiO₂ NPs. Moreover, to augment our nanofiber scaffolds with antibacterial activity, the in situ deposition approach of using Ag NPs was utilized with varied molar concentrations of 0.14, 0.42, and 0.71 M. The physicochemical properties of the nanofibers were identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and contact angle meter studies. This demonstrated the presence of both TiO₂ and Ag NPs and complete deacetylation of nanofibers. The antibacterial efficiency of the nanofibers was scrutinized against Escherichia coli and Staphylococcus aureus, revealing proper in situ deposition of Ag NPs and confirming the nanofibers are antibacterial in nature. The biocompatibility of the scaffolds was accustomed using chicken embryo fibroblasts, which confirmed their potential role to be used as wound-healing materials. Furthermore, the fabricated scaffolds were subjected to analysis in simulated body fluid at 37°C to induce mineralization for future osseous tissue integration. These results indicate that fabricated composite nanofiber scaffolds with multifunctional characteristics will have a highest potential as a future candidate for promoting new tissues artificially.

Size effect of nano-hydroxyapatite on proliferation of odontoblast-like MDPC-23 cells

Nano-hydroxyapatite (nano-HAP) is supposed to be a promising candidate for apatite substitute in hard tissue engineering. We aimed to investigate the effect of nano-HAP particles on the proliferation of odontoblast-like MDPC-23 cells compared with conventional hydroxyapatite (c-HAP). HAP in diameter of ~20 nm (np20), ~70 nm (np70) and ~200 nm (c-HAP) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Inverted microscope and MTT assay were used to detect the morphology and proliferation rate of MDPC-23 cells; TEM was used to reveal the internalization of HAP. We found that nano-HAP (np20 and np70), especially np20 expressed obvious growth-promoting effect on MDPC-23 cells compared with c-HAP, which caused the most vacuole in MDPC-23 cells. These results suggest that nano-HAP may be an optimal choice of apatite substitute for MDPC-23 cells on the aspect of cell proliferation.

Nanoparticles used in dentistry: A review

Nanotechnology is widely used in our day to day life including its use in medicine. Using nanotechnology, it is easy to analyze and manipulate atoms, chemical bonds and molecules present between various compounds. Nanotechnology is used in the dental field as nano dentistry. While choosing the nanoparticle for the use in the field of nano dentistry its chemical, physical, along with the biological aspect of nanostructures are taken into account. Often various atoms or molecules are added to form the functional structure. Nanostructures are used in innovations or diagnosis of dentistry. Some nanoparticles are used for oral disease preventive drugs, prostheses and for teeth implantation. Nanomaterials further deliver oral fluid or drugs, preventing and curing some oral disease (oral cancer) and maintain oral health care up to a high extent. This review summarises the use of various widely used nanoparticle in the field of dentistry.

Radiopacity of Mineral Trioxide Aggregate with and without Inclusion of Silver Nanoparticles

AIM

The aim of this study was to investigate the inclusion of silver nanoparticles (Ag NPs) in the mineral trioxide aggregate (MTA) composition to know which changes will result in the radiopacity of the material.

MATERIALS AND METHODS

The experiment was performed according to the American National Standard Institute/American Dental Association specification no. 57/2000 and ISO 6876/2001. Five plates with five holes measuring 1 mm in depth and 5 mm in internal diameter were filled according to the different experimental groups as follows: white mineral trioxide aggregate (WMTA) + NP50 - W MTA with liquid Ag NP 50 ppm, WMTA + NP30 - W MTA with liquid Ag NP 30 ppm, WMTA + NP22 - W MTA with liquid Ag NP 22 ppm, WMTA + NPP - white MTA with liquid Ag NP and powder 1%, WMTA (control). After filling the plates, they were kept in an incubator at 37°C in relative humidity for setting. Each sample was positioned along an aluminum step-wedge placed above the Opteo digital sensor system. The image was divided into four quadrants, and three readings were made for each quadrant to render the average of each quadrant. The resulting data were submitted to Kruskal-Wallis and Dunn's tests.

RESULTS

The results showed statistically significant differences between WMTA + NP30, WMTA + NP22, and WMTA + NPP interactions compared with WMTA (control) (p < 0.05). The radiopacity was in descending order: WMTA + NPP, WMTA + NP22, WMTA + NP30, MTA + NP50, and WMTA.

CONCLUSION

Silver NPs changed the radiopacity of WMTA, being more evident in WMTA + NP powder at 1% weight.

CLINICAL SIGNIFICANCE

The low radiopacity of MTA makes it difficult for any radiographic observation. The Ag NPs appear as an alternative, being an excellent radiopacifier as they have excellent antimicrobial property and relatively low toxicity.

Green synthesis and characterization of Ag nanoparticles from Mangifera indica leaves for dental restoration and antibacterial applications

Green synthesis has gained a wide recognition as clean synthesis technique in the recent years. In the present investigation, silver nanoparticles were prepared by a novel green synthesis technique using Mangifera indica (Mango leaves) and found to be successfully used in dental applications. The prepared samples were spectroscopically characterized by XRD, PSA, SEM with EDS, and UV-Vis spectroscopy. The crystalline size and lattice strain were analyzed from the XRD data which were counter-verified by W-H plots and particle size analyzer. The XRD peaks revealed that average crystalline size of the as-synthesized Ag nanoparticles was of 32.4 nm with face-centered cubic structure. This was counter-verified by particle size analyzer and Williamson-Hall plots and found to be 31.7 and 33.21 nm in the former and latter, and the crystalline size of Ag NPs could be concluded as 32 ± 2 nm. The morphological structure of the prepared sample was studied through SEM images and the chemical composition was analyzed by the EDS data. The band energy was calculated as 393 nm from UV-Vis, which confirmed the synthesized sample as Ag nanoparticles. To improve the mechanical bonding and hardness of the dentally used glass ionomer cement (GIC), the synthesized silver nanoparticles were incorporated into GIC in 2% weight ratio. The morphology of the prepared specimens was studied using optical microscope images. Vickers microhardness and Monsanto hardness tests were performed on GIC, GIC reinforced with microsilver particles and GIC reinforced with nanosilver particles and the latter derived a promising results. The results of the Monsanto tests confirmed the increase in hardness of the GIC reinforced with AgNps as 14.2 kg/cm2 compared to conventional GIC and GIC reinforced with silver microparticle as 11.7 and 9.5 kg/cm2. Similarly the Vickers hardness results exhibited the enhanced hardness of GIC-reinforced AgNps as 82 VHN compared to GIC as 54 and GIC-reinforced silver microparticles as 61 VHN. The antibacterial activity of AgNPs was tested by a well-diffusion method on Escherichia coli and Staphylococcus aureus bacteria, and the obtained results exhibited a promising antibacterial activity of the as-synthesized nanoparticles.

Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process

This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned.

Titanium Dioxide Nanofibers and Microparticles Containing Nickel Nanoparticles

The present study reports on the introduction of various nanocatalysts containing nickel (Ni) nanoparticles (NPs) embedded within TiO₂ nanofibers and TiO₂ microparticles. Typically, a sol-gel consisting of titanium isopropoxide and Ni NPs was prepared to produce TiO₂ nanofibers by the electrospinning process. Similarly, TiO₂ microparticles containing Ni were prepared using a sol-gel syntheses process. The resultant structures were studied by SEM analyses, which confirmed well-obtained nanofibers and microparticles. Further, the XRD results demonstrated the crystalline feature of both TiO₂ and Ni in the obtained composites. Internal morphology of prepared nanofibers and microparticles containing Ni NPs was characterized by TEM, which demonstrated characteristic structures with good dispersion of Ni NPs. In addition, the prepared structures were studied as a model for hydrogen production applications. The catalytic activity of the prepared materials was studied by in situ hydrolysis of NaBH₄, which indicated that the nanofibers containing Ni NPs can lead to produce higher amounts of hydrogen when compared to other microparticles, also reported in this paper. Overall, these results confirm the potential use of these materials in hydrogen production systems.

Next generation of electrosprayed fibers for tissue regeneration

Electrospinning is a widely established polymer-processing technology that allows generation of fibers (in nanometer to micrometer size) that can be collected to form nonwoven structures. By choosing suitable process parameters and appropriate solvent systems, fiber size can be controlled. Since the technology allows the possibility of tailoring the mechanical properties and biological properties, there has been a significant effort to adapt the technology in tissue regeneration and drug delivery. This review focuses on recent developments in adapting this technology for tissue regeneration applications. In particular, different configurations of nozzles and collector plates are summarized from the view of cell seeding and distribution. Further developments in obtaining thick layers of tissues and thin layered membranes are discussed. Recent advances in porous structure spatial architecture parameters such as pore size, fiber size, fiber stiffness, and matrix turnover are summarized. In addition, possibility of developing simple three-dimensional models using electrosprayed fibers that can be utilized in routine cell culture studies is described.

Silver nanoparticles: synthesis through chemical methods in solution and biomedical applications

Chemical methods provide an easy way to synthesize silver nanoparticles (Ag NPs) in solution. These metal nanoparticles have a great potential for biomedical applications as an antibacterial, antifungal, and antiviral agent or in wound healing. The adjustment of the parameters involved in these reactions permits a precise control over the size, shape, monodispersity, and the surfaces of the nanoparticles. These nanoparticles are being used in the design of new hybrid organic-inorganic or inorganic nanomaterials for biomedical applications.