Oguzhan Gunduz

Electrohydrodynamic Preparation of Nanomedicines

The preparation of nanomedicines can be achived using a host of methods ranging from wet-chemical approaches to more engineering related techniques. As a maturing branch of nanotechnology, nanomedcines are being tailored to serve multiple pharmaceutic and biomedical related funcitons (e.g. targeted delivery, imaging, healing, sensing which may require the utilisaiton of one or more actives or excipients. In some instances, handling of materials (such as sensitive biomolecules or active pharmaceutical ingredient) becomes a limiting factor along with issues related to fabrication steps (loss or degradation of active components and functional materials, deposition location & procedure (removal of formed structures, process environment sensitivity and scale-up potential. This short review focuses on the electrohydrodynamic preparation of emerging nanomedicines that have potential to serve as therapeutic platforms. An insight into the underpinning process (jet-formation, related paramerts (material and process and strucutral outcomes (particles and fibres is given in relation to highlighted research. The ambient temperature processing, user friendly preparation and present industrial scale up potential (now in kg/hr make such processes valuable in the preparation of future nano-scaled and sensitive dosage forms.

Mesoporous materials used in medicine and environmental applications.

Mesoporous materials synthesized in the presence of templates, are commonly used for environment and medical applications. Due to the properties it holds, mesoporous silica nanoparticles is an excellent material for use in medical field, biomaterials, active principles delivery systems, enzyme immobilization and imaging. Their structure allows embedding large and small molecules, DNA adsorption and genetic transfer. Using mesoporous silica nanoparticles for delivery of bioactive molecules can protect them against degradation under physiological conditions, allow controlled drugs release and minimize side effects on healthy tissues. Cellular tests performed on mesoporous silica nanoparticles demonstrate that MSNs cytotoxicity is dependent on the size and concentration and suggests the use of larger size nanoparticles is optimal for medical applications. Mesoporous materials possess high biological compatibility, are non-toxic and can be easily modified by functionalizing the surface or inside the pores by grafting or co-condensation method. The structure, composition and pores size of this material can be optimized during synthesis by varying the stoichiometric reactants, reaction conditions, nature of the templates molecules or by functionalization method.

MAGNETIC CORE SHELL STRUCTURES: from 0D to 1D assembling

Material research and development studies are focused on different techniques of bringing out nanomaterials with desired characteristics and properties. From the point of view of materials development, nowadays scientists are strongly focused on obtaining materials with predefined characteristics and properties. The morphology control seems to be a determinant factor and increasing attention is devoted to this aspect. At this moment it is possible to engineer the materials features by using different methods and materials combination for both medical and industrial applications. In the applications of chemistry and synthesis, biology, mechanics, optics solar cells and microelectronics tailoring the adjustable parameters of stoichiometry, chemical structure, shape and segregation are evaluated and opens new fields. Because of the magnetic features of nanoparticles and durable particle size, less than 100 nm, this study is aiming to describe their uses in practical applications. Thats why the whole hydrodynamic magnetic core shell topic will be reviewed on this paper. Additionally, the properties acting in general sight in solid-state physics are utilized for material selection and for defining issue connecting the core, shell structure and their producing properties. Here, in the study of core/shell nanoparticle various physical and chemical synthesis routes and the effect of electrospun method are briefly discussed. Starting from a real void of the scientific literature, the existent data related to the 1D magnetic electrospun materials are reviewed. The perspectives in the medical, environmental or energetic sector is great and bring some real advantages related to the 0D core@shell structures because both mechanical and biological properties are dependent on the morphology of the materials.

Part 2: biocompatibility evaluation of hydroxyapatite-based clinoptilolite and Al2O3 composites

The biocompatibility of clinoptilolite/alumina/bovine hydroxyapatite (Cp - A12O3 - BHA) composite, at different ratio obtained by powder pressing process, were investigated studying the behavior of osteosarcoma (SAOS-2) cells. The biocompatibility was examined by means of cytotoxicity and cytocompatibility tests. The structure and morphology of bioceramic composites were studied by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) technique. The results showed that these materials have no toxic effects. The natural composite that fabricated in this study may be a promising approach for bone-engineering applications.

Electrospun Poly(ε-Caprolactone)/Bovine Hydroxyapatite (BHA) Composite Nanofibers for Bone Tissue Engineering

Tissue engineering applications have opened a different future-promising era for critical injuries, defects and diseases. Bone tissue engineering is the part of tissue engineering which aims to stir up new practical bone re-formation via the interactive combination of biomaterials and cells. Poly (e-caprolactone) (PCL) is a unique semi crystalline polymer material which handles several important features such as biocompatibility, high biomedical durability and degradation properties. Bovine hydroxyapatite (BHA) is another biocompatible material which provides to get ultimate mechanical behavior in composite designs. Because of their high biocompatibility, PCL and BHA were integrated the electrospinning system together. The system was revised for multi-feeding needle equipment. Eight dissimilar tissue scaffolds were produced and investigated for this recent work.

Novel Bioceramic Production via Mechanochemical Conversion from Plate Limpet (Tectura scutum) - Shells

Calcium phosphates are very important biomaterials for orthopaedic and dental applications. Hydroxyapatite (HA) is one of the important phases used for grafting. Those are produced from synthetic and natural sources with various methods. Especially nano-bioceramics can be produced through calcitic and aragonitic structures (i.e. mussel shells, sea snail shells, land snail shells and sea urchin shells). The plate limpet shells were used. The plate limpet is a gastropod, a soft-bodied invertebrate (an animal without a backbone) that is protected by a very hard, flattened conical shell. In this study the Plate Limpet (Tectura scutum) shells were obtained from a local gift store in Istanbul. The habitation of these limpets broadens from south Alaska down to California - Mexico. First the exact CaCO3 content was measured with thermal analysis (DTA/TGA). Here in this study agitation was carried out on a hot-plate (i.e. mechano-chemical processing). First the temperature was set at 80 °C for 15 min. Then equivalent amount to CaO H3PO4 was added dropwise for HA phase formation and the reaction was set on a hotplate for 8 hours. The dried sediments HA part was divided into 2 groups. One group was sintered to 835 °C and second group to 855 °C. Here x-ray diffraction and scanning electron microscope (SEM) studies were performed. From the study various HA phases and TCP phases were obtained. A previous study done with Atlantic Deer Cowrie encourages nanobioceramic production from natural sources. This study proposes that mechanochemical agitation with very simple way for producing nano-sized calcium phosphates for future bioengineering scaffold applications.

Can European Sea Bass (Dicentrarchus labrax) Scale Be a Good Candidate for Nano-Bioceramics Production?

Bioceramics are commonly used biomaterials for orthopedic and dental applications. Among these bioceramics, hydroxyapatite (HA) and tricalcium phosphate (TCP) are of interest and are used in various biomedical applications. Production of bioceramics from natural materials such as bovine and sheep bones with calcination method, is possible. Lately, fish scales become an alternative biological source for bioceramic production. The present study proposes an approach to obtain HA bone-scaffolds from European Sea Bass (Dicentrarchus labrax) scales aiming to provide nano-biomaterials via calcination method. Untreated fish scales are obtained and are carefully cleaned from their meat and grease. They are washed with alkaline water several times and calcinated at 850°C for 4 hours. Energy Dispersive Spectroscopy (EDS), X-ray diffraction analysis, Scanning Electron Microscopy (SEM) studies are performed. Various calcium phosphate species (HA, TCP) are identified in the study. SEM images prove the presence of the nano-scale structures. This study indicates calcination as a simple way of nano-scale bioceramic production for drug delivery and tissue engineering applications. Being produced from wastes of a sustainable and cheap source, these bioceramics can be good candidates for future clinical applications.

Mechanical and Physical Properties of Dentine-Glass Composites

Hydroxyapatite (HA) is one of the most widely used bioceramics to reconstruct most parts of the skeleton. HA biomaterials are nontoxic and biocompatible with bony tissues. It can be derived from natural sources like bovine bone and other original sources. Also it can be produced synthetically from reagent materials. Due to the fact that HA is not able to be used in biomedical applications cause of bear loadings. It has to be reinforced with materials such as whiskers, metallic oxides, glasses and others. In this study, sintering effects on physical and mechanical properties, such as density (gr/cm3), compression strength (MPa) and Vickers microhardness (HV) of the commercial inert glass (CIG) added human dentine HA (DHA) composite investigated. HA source material is dentine material which is obtained from extracted human teeth. After calcinations enamel and dentine parts were separated (850°C - 4 hours). DHA particles were ball milled and sieved through 100µm sieve. DHA is mixed with 5 and 10 % CIG. Then, this composite material is pressed with a steel mould and sintered in the temperature range of 1000°C to 1300°C with 100°C increments. After scanning electron microscope (SEM) and x-ray diffraction (XRD) studies, both physical and mechanical characterization for DHA – CIG composites are completed by performing density, micro and macro-mechanical test procedures, i.e., HV and compression testing. Briefly, density measurements are conducted corresponding to the Archimedes principle. HV measurements are obtained under a 200g load. Compression test is performed at a rate of 2 mm/min. Here the densest structure was obtained as 2.48 gr/cm3 at 1300°C with 5 wt.% CIG addition. The HV values are increasing with temperature (1082 HV at 1300°C with 10 wt.% CIG addition). The toughest MPa value is 118MPa with 10%CIG addition, sintered at 1300°C. Inert glass addition to dentine HA sounds promising with increasing values of microhardness and compression properties. It can be described as a very hard and a strong biomaterial.