In this study, hybrid carbon dots-plasmonic nanostructures including carbon dots/polyethyleneimine/gold (C-dots/PEI/Au), and carbon dots/polyethyleneimine/silver (C-dots/PEI/Ag) have been prepared using a microwave irradiation method. The prepared hybrid nanostructures have been characterized via optical spectroscopy, high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD).A remarkable enhancement in the optical parameters, such as absorptivity and quantum yield (QY), has been observed for the hybrid nanostructure compared to pure carbon dots. This plasmonic enhancement was more pronounced in the presence of silver (C-dots/PEI/Ag nanohybrid) than that of gold (C-dots/PEI/Au nanohybrid). This is referred to the low intrinsic loss and the degree of the overlap between the absorption spectra of silver nanoparticles and carbon dots. Furthermore, the biocompatibility assay and cellular response on epithelial kidney (Vero) normal cell has been investigated.The results showed that the optimal dose of treatment is about $200 mg ml À1 using both C-dots/PEI/Au or C-dots/PEI/Ag, nano-hybrids could be used safely in diagnostic bioimaging applications.

The use of bone grafts permits the filling of a bone defect without risk of virus transmission. In this work, pure bioactive glass (46S6) and zinc-doped bioactive glass (46S6Zn10) with 0.1 wt% zinc are used to elaborate highly bioactive materials by melting and rapid quenching. Cylinders of both types of glasses were soaked in a simulated body fluid (SBF) solution with the aim of determining the effect of zinc addition as a trace element on the chemical reactivity and bioactivity of glass. Several physico-chemical characterization methods such as x-ray diffraction, Fourier transform infrared spectroscopy and nuclear magnetic resonance methods, with particular focus on the latter, were chosen to investigate the fine structural behaviour of pure and Zn-doped bioactive glasses as a function of the soaking time of immersion in SBF. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to measure the concentrations of Ca and P ions in the SBF solution after different durations of immersion. The effect of the investigated samples on the proliferation rate of human osteoblast cells was assessed by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, and tested on two different sizes of pure and zinc-doped glasses in powder form, with particle sizes that ranged between 40 to 63 µm and 500 to 600 µm. The obtained results showed the delay release of ions by Zn-doped glass (46S6Zn10) and the slower CaP deposition. Cytotoxicity and cell viability were affected by the particle size of the glass. The release rate of ions was found to influence the cell viability.

Synthetic multi-substituted hydroxyapatite nano powders containing silicon and or carbonate prepared by a wet chemical method. The process parameters are set up to allow the simultaneous substitution of carbonate and silicon ions in the place of phosphorus. The chemical and structural characterizations of the prepared powders are determined with the aid of; XRF, ICP, XRD and FTIR. The results show that, the ion substitution in the crystal lattice of HA caused a change in the unit cell dimensions and affected the degree of crystallization of the produced powders. The apatite formation abilityy of the prepared discs from the synthesized powders is determined by immersing in SBF solution for different periods. The degree of ion release was determined in the obtained solutions. The examined surface of the immersed discs under SEM and analyzed by CDS showed a more dense HA layer than those of un-substituted ones. The HA with the substituted silicon and carbonate ions, showed the highest solubility with greater rate of ion release, compared with carbonate-free powder. All prepared powders took sodium ion from the SBF solution during immersion, which was not recorded before.

Scaffolds are implants used to deliver cells, drugs, and genes into the body in a local controlled release pattern which offers many advantages over systematic drug delivery. Composite scaffolds of polyvinyl alcohol (PVA) and quaternary bioactive glass (46S6 system) with different ratios of glass contents were prepared by lyophilisation technique. The broad spectrum antibiotic ciprofloxacin (Cip) was impregnated to the scaffold during the fabrication in a concentration of 5, 10 and 20%. Biodegradation rate and in-vitro mineralization of the prepared scaffolds were performed by soaking the scaffolds in simulated body fluid (SBF). Phase identification, microstructure, porosity, bioactivity, mechanical properties and drug release pattern in PBS were characterized by XRD, SEM coupled with EDS, Hg-porosimeter, inductively coupled plasma-optical emission spectroscopy (ICP-OES), universal testing machine, fourier transform infrared (FTIR) and UV-spectrophotometer, respectively. A porous scaffold has been obtained with porosity up to 85%. By increasing the glass contents in the prepared scaffold the porosity and the degradation rate decrease however, the compressive strength was enhanced. A sustained drug release pattern was observed with a quasi-Fickian diffusion mechanism. The formulated ciprofloxacin loaded porous polyvinyl alcohol scaffold gave an acceptable physicochemical properties and was able to deliver the drug in a prolonged release pattern which offers a distinguish treatment for osteomylitis as well as local antibacterial effect.

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