Development and Investigation of an Innovative 3D Biohybrid Based on Collagen and Silk Sericin Enriched with Flavonoids for Potential Wound Healing Applications.

Skin tissue injuries necessitate particular care due to associated complex healing mechanisms. Current investigations in the domain of tissue engineering and regenerative medicine are focused on obtaining novel scaffolds adapted as potential delivery systems to restore lost tissue functions and properties. In this study, we describe the fabrication and evaluation of a novel 3D scaffold structure based on collagen and silk sericin (CollSS) enriched with microcapsules containing natural compounds, curcumin (C), and/or quercetin (Q). These 3D composites were characterized by FT-IR spectroscopy, water uptake, in vitro collagenase degradation, and SEM microscopy. Furthermore, they were biologically evaluated in terms of biocompatibility, cell adhesion, anti-inflammatory, and antioxidant properties. All tested materials indicated an overall suitable biocompatibility, with the best results obtained for the one containing both flavonoids. This study suggests the cumulative beneficial effect of C and Q, encapsulated in the same composite, as a potential non-invasive therapeutic strategy for skin tissue regeneration in patients suffering from chronic wounds.

Preparation of Fe@Fe3O4/ZnFe2O4 Powders and Their Consolidation via Hybrid Cold-Sintering/Spark Plasma-Sintering.

Our study is focused on optimizing the synthesis conditions for the in situ oxidation of Fe particles to produce Fe@Fe3O4 core-shell powder and preparation via co-precipitation of ZnFe2O4 nanoparticles to produce Fe@Fe3O4/ZnFe2O4 soft magnetic composites (SMC) through a hybrid cold-sintering/spark plasma-sintering technique. XRD and FTIR measurements confirmed the formation of a nanocrystalline oxide layer on the surface of Fe powder and the nanosized nature of ZnFe2O4 nanoparticles. SEM-EDX investigations revealed that the oxidic phase of our composite was distributed on the surface of the Fe particles, forming a quasi-continuous matrix. The DC magnetic characteristics of the composite compact revealed a saturation induction of 0.8 T, coercivity of 590 A/m, and maximum relative permeability of 156. AC magnetic characterization indicated that for frequencies higher than 1 kHz and induction of 0.1 T, interparticle eddy current losses dominated due to ineffective electrical insulation between neighboring particles in the composite compact. Nevertheless, the magnetic characteristics obtained in both DC and AC magnetization regimes were comparable to those reported for cold-sintered Fe-based SMCs.

Latest Research of Doped Hydroxyapatite for Bone Tissue Engineering.

Bone tissue engineering has attracted great interest in the last few years, as the frequency of tissue-damaging or degenerative diseases has increased exponentially. To obtain an ideal treatment solution, researchers have focused on the development of optimum biomaterials to be applied for the enhancement of bioactivity and the regeneration process, which are necessary to support the proper healing process of osseous tissues. In this regard, hydroxyapatite (HA) has been the most widely used material in the biomedical field due to its great biocompatibility and similarity with the native apatite from the human bone. However, HA still presents some deficiencies related to its mechanical properties, which are essential for HA to be applied in load-bearing applications. Bioactivity is another vital property of HA and is necessary to further improve regeneration and antibacterial activity. These drawbacks can be solved by doping the material with trace elements, adapting the properties of the material, and, finally, sustaining bone regeneration without the occurrence of implant failure. Considering these aspects, in this review, we have presented some general information about HA properties, synthesis methods, applications, and the necessity for the addition of doping ions into its structure. Also, we have presented their influence on the properties of HA, as well as the latest applications of doped materials in the biomedical field.

Structure-grain size-synthesis route of silver nanoparticles: a correlation with the cytotoxic effect.

Although engineered silver (Ag) nanopowders offer great promise in various fields of biomedical, industrial and ecological applications, insufficient data is known about their cytotoxicity. The purpose of the present study was the synthesis and then the determination of cytotoxicity effect of Ag powders using the pyrosol method, at various temperatures of 600°C, 650°C and 700°C, respectively by sol-gel method and heat treatments at 500°C, 600°C, 700°C and 800°C. From the structural, compositional and morphological point of view, Ag samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) techniques. There is an influence of the synthesis route on Ag particles, which is shown as their cytotoxicity, different sizes of micro and nanosilver synthesized powders, which were evaluated in comparison depending on the work methods. Their cytotoxicity was evaluated based on their influence on cellular morphology and proliferation rate, cell cycle and apoptosis of undifferential stem cells, endothelial cells and tumoral cells, assessed through flow cytometry, cloning and MTT assay. The results showed that the cytotoxicity of the obtained Ag nanoparticles (NPs) depends on the synthesis route, the pyrosol synthesized NPs exhibiting a higher cytotoxicity as compared to those obtained by the sol-gel method.

Photoluminescent Hydroxylapatite: Eu3+ Doping Effect on Biological Behaviour.

Luminescent europium-doped hydroxylapatite (EuXHAp) nanomaterials were successfully obtained by co-precipitation method at low temperature. The morphological, structural and optical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), UV-Vis and photoluminescence (PL) spectroscopy. The cytotoxicity and biocompatibility of EuXHAp were also evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)) assay, oxidative stress assessment and fluorescent microscopy. The results reveal that the Eu3+ has successfully doped the hexagonal lattice of hydroxylapatite. By enhancing the optical features, these EuXHAp materials demonstrated superior efficiency to become fluorescent labelling materials for bioimaging applications.

Mg-Zn alloys, most suitable for biomedical applications.

In this review are highlighted the corrosion and biocompatibility of biodegradable Mg alloys for their use in orthopedic applications. It was revealed that mixing with alloying elements, such as Mn and Zn, provides improved corrosion resistance to Mg alloys; this pursuit is built on the fact that Mg and its alloys are degradable through their time in the human body. Furthermore, Mg alloys afford a characteristic profile that is very close or even almost identical to that of human bone. Minimizing the rate of corrosion of Mg is the most adequate method, because a low corrosion rate of an Mg implant involves a decrease in the extent of hydrogen evolution and alkalization, which allow the human body to gradually absorb or consume the corrosion products.

Eu3+-doped ZnO nanostructures: advanced characterizations, photoluminescence and cytotoxic effect.

In this work, several nanostructures (nanopowders and nanostars) of undoped and 1%, 3% and 5% europium (Eu3+)-doped ZnO have been synthesized via coprecipitation method using oxalic acid and sodium hydroxide as precipitation agents. Starting from zinc acetate and europium acetate, nanopowders were obtained by coprecipitation with oxalic acid. ZnO based nanostars were synthesized by coprecipitation of Zn2+ and Eu3+ with hydroxide ions (HO-), when zinc chloride and europium acetate were used as reagents. The structure and morphology of the as-prepared ZnO nanopowders and nanostars were investigated by X-ray diffraction and electron microscopy. Only würtzite structure of ZnO was identified in all the samples based on ZnO. Transmission electron microscopy (TEM) investigations have shown an average particle÷crystallite size range from 23 to 29 nm and polyhedral and spherical morphology with tendency to form aggregates for nanopowders. Cytotoxicity tests on MG-63 cell lines was also performed. Photocatalytic activity of ZnO nanopowders have reached higher values compared to ZnO nanostars. The photocatalytic test indicates that the ZnO nanopowders have better activity than the nanostars, most probably because of the higher specific surface. Doping the ZnO with Eu2O3 does not seem to alter it in a decisive manner. The toxicity results indicated that ZnO nanoparticles (NPs) high toxicity on tumoral cells is also induced by particle size and, consequently, the dissolution of Zn2+ ions is dependent on the size of the particles, increasing with the particles size.