FUNCTIONAL COMPOSITE NANOFIBERS DERIVED FROM NATURAL EXTRACT OF SATUREJA HORTENSIS

Development of environmentally friendly and natural-based products with healing properties has become a popular trend for human health. Here, for the first time as far as known, we reported an efficient antibacterial composite nanofiber which was functionalized with the herbal extract of Satureja hortensis (SH) via electrospinning technique for wound care dressing applications. The plant which was used for this purpose is cultivated on a commercial scale in our country, Turkey, and it is relatively inexpensive and widely used. Investigation of the herbal extract demonstrated 227% higher antibacterial activity against Staphylococcus aureus and 141% higher for Pseudomonas aeruginosa when compared with a commonly used strong antibiotic of amoxicillin. Thermoplastic polyurethane (TPU)-based composite nanofibers including SH with a diameter of about 734 nm for the wound dressings also showed efficient antibacterial activity against these two pathogens which can lead significant health problems and deaths. FTIR characterization confirmed that there is no chemical change of SH when it was incorporated to the composite polymeric nanofibers by the electrospinning technique. We strongly believe that the obtained results suggest a potential natural-based eco-friendly approach for wound care dressing in contrast with synthetic and metal based-antibacterial agents, which have many negative effects on human body and the environment

Comparative study on structural and optical features of undoped and Eu3+ doped Pr6O11 synthesized via sol-gel and flame spray pyrolysis

© 2020 The AuthorsHerein, it was aimed to differentiate features of undoped and europium (Eu3+) doped Pr6O11 particles fabricated via the sol-gel (SG) and flame spray pyrolysis (FSP) methods. The crystal phase structure, morphological, chemical, and optical features of synthesized Pr6O11 particles were characterized using an X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL), and UV–vis spectrophotometer. The results show that, compared with SG-based samples, Eu-doped Pr6O11 synthesized by FSP has excellent structural integrity, optical and electrical features, and morphology. This study outlines the development of a compatibility strategy between the production method and the final Pr6O11 powders, and that the optical, and electrical features may be controlled by selecting the proper dopant

Investigation of the effect of catalyst type, concentration, and growth time on carbon nanotube morphology and structure

Different materials have been shown to "catalyze" carbon nanotube (CNT) growth in chemical vapor deposition (CVD) when they become nano-sized particles. Catalysts, which act as a kind of "seed" for CNT growth, show two types of behavior in the CVD method; precipitation of carbon atoms from the eutectic alloy forming a kind of alloy with carbon; the fact that the catalyst remains as a solid phase and forms a carbon surface layer during the CVD process. This study examines the relationship between the iron-group and non-iron-group catalyst types and the catalyst concentration and growth time of CVD-based CNT growth via emphasizing growth mechanisms. The novelty of this work is to compare and evaluate the effects of catalyst type, concentration, and growth time, which are three critical CVD parameters, on the final nanotube morphology. It was utilized five different catalysts (Fe2O3, Fe3O4, Nb2O5, Au, and Pt), three different growth durations (3, 5, and 7 min), and three different catalyst concentrations (2, 4, and 6 wt%) to explore the morphological differences on CNT synthesis by CVD under the same process parameters. The results demonstrated that catalyst type is the most influential parameter in CVD-based CNT synthesis, while catalyst concentration and growth time are indispensable elements for the uniformity and small diameter in the final morphology

Nano-carbons in biosensor applications: an overview of carbon nanotubes (CNTs) and fullerenes (C-60)

Recently, the use of carbon nanotubes (CNTs) and fullerenes in the design of new biosensors have attracted great interest in the development of carbon nanomaterials. Due to the superior properties of CNTs and fullerenes, the use of sensor components allows the development of reliable, accurate and fast biosensors. Depending on the types of target molecules, the development and application areas of the sensors vary. This review summarizes the role of CNTs and fullerenes in the development of biosensors in different application areas. Considering the difference between other members of the nano-carbon family, we explain why CNTs are used more widely in biosensor applications and why fullerenes have high potentials in these areas of application. Moreover, we focused on investigating the function of these nano-carbons in the detection of various analytes in bio-sensing. By discussing the challenges and future expectations, we have put forward a perspective that may help synthesize advanced composites in the development of new generation designs in biosensor applications

Synthesis, structural and optical characterization of Nd: YAG powders via flame spray pyrolysis

In this study, undoped Y3Al5O12 (YAG) and neodymium (Nd3+) doped (Nd: YAG) powders were synthesized by Flame Spray Pyrolysis (FSP) for the first time in literature. The synthesized powders were investigated about structural, morphological, elemental and optical properties by using Thermogravimetric - Differential Thermal Analysis (DTA-TG), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Fourier Transformed Infrared Spectroscopy (FTIR), and photoluminescence spectroscopy (PL). The particle size range of undoped and Nd doped YAG powders produced by the FSP method was determined around 200-1100 nm. After calcination at 1000 degrees C, cubic YAG crystalline phases were successfully observed. The luminescence results as excitation, emission, and upconversion properties have been investigated for both undoped YAG (YG) and Nd3+ doped YAG with different dopant ratios as 1% (YG1), 3% (YG3) and %5 (YG5). When synthesized powders excited at 460 nm, the emission maxima observed at 540 nm and 808 nm. All YAG powders yielded bi-exponential decay curves. The highest decay time value was 1% Nd: YAG particle at 277 mu s. Furthermore, these powder

An Overview on Recent Progress of Metal Oxide/Graphene/CNTs-Based Nanobiosensors

Nanobiosensors are convenient, practical, and sensitive analyzers that detect chemical and biological agents and convert the results into meaningful data between a biologically active molecule and a recognition element immobilized on the surface of the signal transducer by a physicochemical detector. Due to their fast, accurate and reliable operating characteristics, nanobiosensors are widely used in clinical and nonclinical applications, bedside testing, medical textile industry, environmental monitoring, food safety, etc. They play an important role in such critical applications. Therefore, the design of the biosensing interface is essential in determining the performance of the nanobiosensor. The unique chemical and physical properties of nanomaterials have paved the way for new and improved sensing devices in biosensors. The growing demand for devices with improved sensing and selectivity capability, short response time, lower limit of detection, and low cost causes novel investigations on nanobiomaterials to be used as biosensor scaffolds. Among all other nanomaterials, studies on developing nanobiosensors based on metal oxide nanostructures, graphene and its derivatives, carbon nanotubes, and the widespread use of these nanomaterials as a hybrid structure have recently attracted attention. Nanohybrid structures created by combining these nanostructures will directly meet the future biosensors' needs with their high electrocatalytic activities. This review addressed the recent developments on these nanomaterials and their derivatives, and their use as biosensor scaffolds. We reviewed these popular nanomaterials by evaluating them with comparative studies, tables, and charts