Facile synthesis, microstructure, formation mechanism, in vitro biocompatibility, and drug delivery property of novel dendritic TiO2 nanofibers with ultrahigh surface area

Fabrication and in vitro biocompatibility of hierarchical cellulose acetate/polyvinylpyrrolidone@titania nanowire hollow microfibers

In this study, hierarchical cellulose acetate/polyvinylpyrrolidone hollow microfibers (CA/PVP HMFs) were first prepared via a dip coating method using a steel wire as tubular template and then supported a sol-gel deposition of titania nanoparticles (NPs) to derive CA/PVP@titania NP HMFs. After hydrothermally treated in NaOH solution, CA/PVP@titania NP HMFs were transformed to CA/PVP@titania nanowire (NW) HMFs. SEM observation showed that CA/PVP@titania NW HMFs had a hollow structure with diameters of 450-600 μm and exhibited a hierarchical and nanofibrous structure. Their surfaces were constructed by numerous titania NWs with diameters of 10-30 nm and lengths of 1-5 μm. The incorporation of PVP not only caused a significant change in surface wettability from hydrophobic CA HMFs to hydrophilic CA/PVP HMFs, but also promoted the sol-gel deposition of titania NPs on CA/PVP HMFs. CA/PVP@titania NW HMFs exhibited the highest hydrophilicity with water contact angle of 32° and the largest specific surface area of 86.1 m2/g. In vitro biocompatible evaluation indicated that CA/PVP@titania NW HMFs exhibited much higher cell adhesion and proliferation than CA/PVP@titania NP HMFs and CA/PVP HMFs within 7 days due to the presence of nanofibrous surface architecture. Thus, the present CA/PVP titania NW HMFs have potential as biocompatible cell supporting matrices.

Titanium Dioxide Nanomaterials: Progress in Synthesis and Application in Drug Delivery

Background: Recent developments in nanotechnology have provided efficient and promising methods for the treatment of diseases to achieve better therapeutic results and lower side effects. Titanium dioxide (TiO2) nanomaterials are emerging inorganic nanomaterials with excellent properties such as low toxicity and easy functionalization. TiO2 with special nanostructures can be used as delivery vehicles for drugs, genes and antigens for various therapeutic options. The exploration of TiO2-based drug delivery systems shows great promise for translating nanotechnology into clinical applications; Methods: Comprehensive data on titanium dioxide were collected from reputable online databases including PubMed, GreenMedical, Web of Science, Google Scholar, China National Knowledge Infrastructure Database, and National Intellectual Property Administration; Results: In this review, we discuss the synthesis pathways and functionalization strategies of TiO2. Recent advances of TiO2 as a drug delivery system, including sustained and controlled drug release delivery systems were introduced. Rigorous long-term systematic toxicity assessment is an extremely critical step in application to the clinic, and toxicity is still a problem that needs to be closely monitored; Conclusions: Despite the great progress made in TiO2-based smart systems, there is still a great potential for development. Future research may focus on developing dual-reaction delivery systems and single-reaction delivery systems like redox and enzyme reactions. Undertaking thorough in vivo investigations is necessary prior to initiating human clinical trials. The high versatility of these smart drug delivery systems will drive the development of novel nanomedicines for personalized treatment and diagnosis of many diseases with poor prognosis.

Measuring Physical Properties of Electrospun Nanofiber Mats for Different Biomedical Applications

Electrospun nanofiber mats are nowadays often used for biotechnological and biomedical applications, such as wound healing or tissue engineering. While most studies concentrate on their chemical and biochemical properties, the physical properties are often measured without long explanations regarding the chosen methods. Here, we give an overview of typical measurements of topological features such as porosity, pore size, fiber diameter and orientation, hydrophobic/hydrophilic properties and water uptake, mechanical and electrical properties as well as water vapor and air permeability. Besides describing typically used methods with potential modifications, we suggest some low-cost methods as alternatives in cases where special equipment is not available.

Enhancing mechanical and photocatalytic properties by surface microstructure regulation of TiO2 nanofiber membranes

In this work, TiO₂ nanofiber membrane (NFM) with a complete surface microstructure was prepared through regulating the surface microstructure of TiO₂ NFM by doping Zr. The crystal structures and morphological analyses indicated that the nanofiber membranes were consisted by disordered accumulation of Zr-doped TiO₂ nanofibers with a crack-free surface, small grain size and high aspect ratio. When the doping amount of Zr was 0.8 mL, the tensile strength of the doped membranes reached 1.27 MPa, which was 60.7% higher than that of pure TiO₂ NFM. The photocatalytic performance of Zr-doped TiO₂ NFM was evaluated by the degradation performance of Methylene orange (MO) under simulated sunlight irradiation. Compared with the undoped TiO₂ NFM, the 0.8-Zr/TiO₂ NFM presented a higher catalytic degradation efficiency (improved by 69.6%), and the photocatalytic performance maintained stable after five circulating. It was found that the doping of Zr ions effectively limited the surface crack size and grain size of TiO₂ nanofibers, thereby improving the tensile strength, and enhanced the surface area effect and carrier transfer efficiency of TiO₂ NFM. On the other hand, a narrow band-gap was obtained by doping a small amount of Zr ions, which expanded the visible light response range to improve the photocatalytic performance of TiO₂ nanofibers.

A Short Review on Various Engineering Applications of Electrospun One-Dimensional Metal Oxides

The growing scientific interest in one-dimensional (1D) nanostructures based on metal-oxide semiconductors (MOS) resulted in the analysis of their structure, properties and fabrication methods being the subject of many research projects and publications all over the world, including in Poland. The application of the method of electrospinning with subsequent calcination for the production of these materials is currently very popular, which results from its simplicity and the possibility to control the properties of the obtained materials. The growing trend of industrial application of electrospun 1D MOS and the progress in modern technologies of nanomaterials properties investigations indicate the necessity to maintain the high level of research and development activities related to the structure and properties analysis of low-dimensional nanomaterials. Therefore, this review perfectly fits both the global trends and is a summary of many years of research work in the field of electrospinning carried out in many research units, especially in the Department of Engineering Materials and Biomaterials of the Faculty of Mechanical Engineering and Technology of Silesian University of Technology, as well as an announcement of further activities in this field.

Synthesis of hierarchical and flower-like TiO2 nanowire microspheres as biocompatible cell carriers

Fibrous materials are of great interest in the development of tissue regenerative matrix. However, synthesis of inorganic fibrous microspheres as cell carriers is a great challenge. In this study, we for the first time report on the synthesis of novel hierarchical and flower-like TiO₂ nanowire (NW) microspheres as biocompatible cell carriers. TiO₂ NW microspheres were synthesized through in situ alkali hydrothermal treatment of the TiO₂ nanoparticle (NP) microspheres and their microstructure, formation mechanism and in vitro biocompatibility were evaluated. SEM observations show that the resulting TiO₂ NW microspheres were constructed by a large number of NWs with the diameter of 10-20 nm and exhibited a flower-like and hierarchical morphology with the diameter of 400-600 μm. XRD patterns indicate that TiO₂ NW microspheres were constructed by both rutile and anatase phase of TiO₂. FT-IR spectra reveal that Ti-O-Ti bonds were involved in TiO₂ NW microspheres. In vitro biocompatibility was evaluated by seeding the fibroblast L929 cells on the microspheres. A conventional MTT assay quantitatively indicates that the TiO₂ NW microspheres favored adhesion and proliferation of cells and were biocompatible, while SEM observations qualitatively confirmed that the cells were well grown on the surface of TiO₂ NW microspheres. Thus, the as-synthesized TiO₂ NW microspheres would be applicable to novel and biocompatible cell carriers.