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In this study, bioactive glass (BG) and copper metal nanoparticles (Cu NPs)-doped poly(Ɛ-caprolactone) (PCL) nanofiber membranes were produced by electrospinning method. Box–Behnken design was used to evaluate the effect of formulation variables including PCL concentration, Cu NPs ratio and BG ratio on nanofiber diameter, and cytotoxicity studies on mouse fibroblasts (L-929) were performed to evaluate the formulation suitable for tissue engineering applications. Membranes containing BG showed enhanced cytocompatibility. It was determined that the toxic properties of the membranes increased with the increase of the Cu NPs ratio. In light of these studies, it was determined that 10% w/v PCL concentration, 15% w/w BG ratio and 0.025% w/w Cu NPs ratio were biocompatible with L929 fibroblast cells. The stability and mineralization ability of the obtained membrane in simulated body fluid were determined by scanning electron microscope and X-ray diffraction analysis. This proved the osteogenic potential of the obtained membrane. Copper ions release from the nanofiber mat was detected by inductively coupled plasma-optical emission spectrometry, and it was found that this membrane had an angiogenic potential. Therefore, this study provides an overview of the effect of formulation variables to fabricate PCL nanofiber scaffolds with BG and Cu NPs for tissue engineering applications.

This is the first study that investigates the crystallization behavior of strontium- and copper-doped bioactive glasses by both isothermal and nonisothermal methods using differential thermal analysis (DTA) data. DTA results showed that bioactive glasses are suitable for glass-ceramic production. Isothermal and nonisothermal DTA experiments indicated that the crystallization activation energies of strontium-doped bioactive glasses are in the range of 304.1-327.7 kJ/mol, whereas the activation energies of copper-doped bioactive glasses change in the range of 219.13-263.20 kJ/mol. It was found that crystallization activation energies of strontium-doped glasses are higher than those of the copper-doped glasses. Avrami exponent, n, values of bioactive glasses showed that the bulk crystallization was found to predominate in all samples. Results revealed that isothermal and nonisothermal crystallization kinetics of strontium- and copper-doped bioactive glasses are in agreement within the experimental error.

This review focuses on recent advances in the development and use of nanoscale silicate bioactive glasses for medical applications. In the context of materials for bone substitution, dental applications, and bone tissue engineering, nanoscale bioactive glasses have been gaining attention due to their expected superior osteoconductivity when compared with conventional (micrometer-sized) bioactive glass materials. A detailed overview of recent developments in the field of nanoscale bioactive glasses will be given, including a summary of common fabrication methods and diverse application areas which include tissue engineering scaffolds and coatings, drug delivery devices, and dentistry. The nanofeatures characteristic of this type of bioactive glasses and the possibilities to expand their use in biomedical applications (nanomedicine) are highlighted.

Extended Abstract Tissue damage and degenerative diseases such as large bone defects are among the most human health issues which lead to organ failure and death all over the world [1-3]. Bone tissue engineering emerges a promising approach to repair bone defects, especially large bone defects resulting from trauma, infections, tumors or genetic malformations [2-4]. The development of scaffolds and their processing into structures are becoming increasingly important in bone tissue engineering applications. Three-dimensional (3D) scaffolds should show a highly porous, open structure to allow a proper vascularisation of the implant, as well as the flow of nutrients and waste products through the scaffold. Major issues of bone tissue engineering scaffolds include the use of appropriate matrix materials for scaffolds, control of porosity and pore characteristics of scaffolds, mechanical strength of scaffolds as well as scaffold degradation properties [5]. Ideal bioactive porous scaffolds, which are used in bone tissue engineering applications, should meet multifunctional properties such as angiogenesis, osteostimulation and antibacterial properties for the treatment of large bone defects [2]. Among these properties, angiogenesis plays an important role for the formation and repair of new tissue because blood vessels provide for newly formed tissues to receive nutrients and oxygen. The stimulation of angiogenesis by the delivery of inorganic ions from biomaterial scaffolds provide to reduce cost of treatments and also prevent biological side effects when compared to the use of growth factors and so it has been attracting considerable interest in recent years [6]. The focus of this study is on advanced bioactive scaffolds enabling internal growth of tissue and controlled delivery of therapeutic ion. To be able to achieve this goal, in the first stage bioactive glass (composition in weight; 45% SiO2, 24.5% Na2O, 6% P2O5, 24.5% CaO, 2% CuO) were developed which have antibacterial and angiogenic properties. After the production of bioactive glass, bioactive glass/polymer 3D composite multifunctional scaffolds were fabricated by using foam replication technique. Then, they were coated with alginate at different percentages (in weight; 1, 2, 3 %) to improve the properties of them. The obtained scaffolds were immersed in simulated body fluid (SBF) at different time points (1, 7, 14 and 28 day) to investigate the bioactivity and biodegradability behavior of the samples. Physical and micro structural properties of the obtained scaffolds were determined by using different characterization techniques. Scanning electron microscopy investigations showed that scaffolds have highly porous structure with a good pore interconnectivity. After immersion in SBF for 28 days, the hydroxyapatite layer formation was observed significantly on the surface of the scaffolds. X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis also verified the bioactivity of the obtained scaffolds. Characteristic chemical bonds which belongs to hydroxyapatite were obtained with FTIR and degree of hydroxyapatite was detected from the result of XRD analysis. Physical and mechanical properties of the composite scaffolds were studied and compared with each other. Inductively Coupled Plasma (ICP) analysis was also applied to investigate the copper release behavior of the scaffolds in SBF and the results indicated that the alginate coated scaffolds allowed controlled release of copper ions but in low amounts compared to uncoated ones. The overall results showed that three dimensional composite scaffolds could be promising candidates for bone tissue engineering applications.

The current research was conducted to propose a nanocomposite material, which could be suitable to be used as a scaffold for bone tissue engineering applications. For this purpose, nanocomposite fibers of gelatin, poly(e-caprolactone) (PCL), and bioactive glass were successfully fabricated via electrospinning process. In this context, response surface methodology based on a three-level, four-variable Box-Behnken design was adopted as an optimization tool to choose the most appropriate parameter settings to obtain the desired fiber diameter. The investigation, based on a second order polynomial model, focused on the analysis of the effect of both solution and processing parameters on the fiber diameter and its standard deviation. In optimum conditions (bioactive glass content of 7.5% (w/v), applied voltage of 25kV, tip-to-collector distance of 12.5cm, and flow rate of 1mL/h), the fiber diameter was found to be 584±337nm which was in good agreement with the predicted value by the developed models (523±290nm). Analytical tools such as scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and differential thermal analyzer were used for further evaluation of the optimized nanocomposite mat. The overall results showed that nanocomposite scaffolds could be promising candidates for tissue engineering applications.

This study intends to design magnetite (Fe3 O4 )-based magnetic fingerprint powders with different particle size distributions. It also investigates the influence of particle size distribution on the visualization of latent fingermarks with as little background staining as possible on the surfaces with various porosities in a systematic way. Two strategies were used to prepare the magnetic fingerprint formulations for this study: milling of coarse magnetite particles for different durations, and mixing of sieved fine particles with different size ranges with coarse particles. Particle size analyses of the prepared magnetic powders, optical microscopy-based roughness analysis of the surfaces and SEM measurements of the visualized fingerprints and representative powders were performed. Mag2 of the formulations prepared through milling and Mag5 and Mag6 of the formulations prepared through sieving and mixing were more successful in the development of latent prints than the rest of the solutions.