Graphene (G) and graphene oxide (GO) nano-sized powders with loadings ranging from 0.1 to 1.0wt% were investigated as reinforced agents for polymethyl methacrylate (PMMA) bone cements. The mechanical properties (i.e. bend strength, bend modulus, compression strength, fracture toughness and fatigue performance) and the thermal properties (i.e. maximum temperature, setting time, curing heat and residual monomer) of the resultant nanocomposites were characterised. The mechanical performance of G-PMMA and GO-PMMA bone cements has been improved at low loadings (≤0.25wt%), especially the fracture toughness and fatigue performance. These improvements were attributed to the fact that the G and GO induced deviations in the crack fronts and hampered crack propagation. The high functionalisation of GO compared with G resulted in greater enhancements because it facilitated the creation of a stronger interfacial adhesion between the GO and PMMA. The use of loadings ≥0.25wt% showed a detriment in the mechanical performance as consequence of the formation of agglomerates as well as to an increase in the porosity. The increase in the residual monomer and the decrease in the curing heat, observed with the increase in the level of G and GO added, suggests that such materials retard and inhibit the curing reaction at high levels of loading by interfering in the radical reaction.

Graphene oxide versus graphene for optimisation of PMMA bone Cement for orthopaedic applications

α-Terpineol (CAS No. 98-55-5) is a tertiary monoterpenoid alcohol widely and commonly used in the flavors and fragrances industry for its sensory properties. It is present in different natural sources, but its production is mostly based on chemical hydration using α-pinene or turpentine. Moreover, many bioprocesses for the microbial production of α-terpineol via biotransformation of monoterpenes (limonene, α- and β-pinenes) are also available in the literature. In addition to its traditional use, α-terpineol has also been evaluated in other application fields (e.g., medical), since some biological properties other than aroma, such as antioxidant, anti-inflammatory, antiproliferative, antimicrobial, and analgesic effects, among others, have been attributed to this compound. Therefore, this review presents an original compilation of data regarding the production (extraction directly from nature; chemical synthesis; via biotechnological process), the chemical and biological properties, and the current market and novel applications of α-terpineol to guide further research in this area. Considering the information presented, we believe that α-terpineol applications may transcend the flavors and fragrances industry in the future.

Production, Properties, and Applications of α-Terpineol

A comparison of chitosan properties after extraction from shrimp shells by diluted and concentrated acids.

Developing a biopolymeric chitosan supported Schiff-base and Cu(II), Ni(II) and Zn(II) complexes and biological evaluation as pro-drug

Tannins are eco-friendly, bio-sourced, natural, and highly reactive polyphenols. In the past decades, the understanding of their versatile properties has grown substantially alongside a continuously broadening of the tannins' application scope. In particular, recently, tannins have been increasingly investigated for their interaction with other species in order to obtain tannin-based hybrid systems that feature advanced and/or novel properties. Furthermore, in virtue of the tannins' chemistry and their high reactivity, they either physicochemically or physically interact with a wide variety of different compounds, including metals and ceramics, as well as a number of organic species. Such hybrid or hybrid-like systems allow the preparation of various advanced nanomaterials, featuring improved performances compared to the current ones. Consequently, these diverse-shaped materials have potential use in wastewater treatment or catalysis, as well as in some novel fields such as UV-shielding, functional food packaging, and biomedicine. Since these kinds of tannin-based hybrids represent an emerging field, thus far no comprehensive overview concerning their potential as functional chemical building blocks is available. Hence, this review aims to provide a structured summary of the current state of research regarding tannin-based hybrids, detailed findings on the chemical mechanisms as well as their fields of application.

https://www.mdpi.com/1420-3049/25/21/4910/pdf

Tannin-Based Hybrid Materials and Their Applications: A Review.

The development of systems for transport and release of drugs, also known as Drug delivery system (DDS), and are being used as strategies to combat cancer. These systems can maintain drug delivery at therapeutic levels and protect it from premature degradation in the biological environment, minimizing adverse effects. Based on this, α-terpineol was encapsulated in the polymer matrix of Poly(methyl methacrylate) (PMMA) in the form of nanoparticles. Preliminarily the computational analysis of parameters such as administration, distribution, metabolism, excretion, and toxicity (PreADMET and SwissADME) for the α-terpineol molecule was performed. Afterward, the synthesis of polymeric nanoparticles of PMMA, encapsulating α-terpineol, through the miniemulsion technique was carried out. The proposed system was characterized by the techniques of FT-IR, TGA, Gel Permeation Chromatography (GPC), Scanning Electron Microscopy (SEM), Atomic Force Microscopy and Nuclear Magnetic Resonance (NMR). Characterization results that α-terpineol-loaded PMMA nanoparticles with sizes between 50 and 150 nm were synthesized. The toxicological profile of PMMA containing 400 mg of α-terpineol was assessed in Artemia salina (LC50 698.8 ± 74.6, 24 h incubation), erythrocytes and normal animal cells like macrophages and fibroblasts (MRC-5), suggesting the high pharmacological security of this drug. The cytotoxic effects of PMMA containing 400 mg of α-terpineol (5–500 μg/mL) were demonstrated against melanoma cell lines from mice (B16- F10) and human (SK-MEL-28) suggesting the potential of these nanoparticles for melanoma therapy.

Synthesis, characterization of α-terpineol-loaded PMMA nanoparticles as proposed of therapy for melanoma

Biological properties of chitosan derivatives associated with the ceftazidime drug.

Synthesis, characterization and electrochemical properties of composites synthesized from silver-tannic acid hybrid nanoparticles and different clays

Alpha-terpineol is a monoterpene alcohol found in essential oils from medicinal plants with some well-known pharmacological activities and widely used in cosmetics. However, the toxicological effects and additional pharmacological activities need to be clarified. Thus, the study evaluated the toxic, cytotoxic, genotoxic, hemolytic, and oxidative potential of alpha-terpineol in non-clinical bioassays. Different concentrations of alpha-terpineol were used in bioassays, including MTT (50, 100, 200, and 400 μg/mL), Artemia salina (6.25-400 μg/mL), Allium cepa (10, 50, and 100 μg/mL), comet assay (100, 200, and 500 μg/mL), cytokinesis-block micronucleus (100, 250, and 500 μg/mL), confocal microscopy for apoptosis quantification (100 and 500 μg/mL), hemolysis and Saccharomyces cerevisiae central disk test (10, 35, and 75 μg/mL). For the MTT test, alpha-terpineol was more cytotoxic on melanoma murine B16-F10 cells rather than macrophages. For A. salina test, alpha-terpineol showed LC50 of 68.29 and 76.36 μg/mL for 24 h and 48 h of exposure time, respectively. Meanwhile, alpha-terpineol was also cytotoxic to meristematic cells, which revealed inhibition of cellular division and mutagenic action by formation of bridges and delayed anaphases. The compound increased damage index and frequency of damage corroborated by the presence of micronuclei, bridges and nuclear buds at 500 μg/mL, but it caused neither hemolysis, oxidative damage on the S. cerevisiae nor cell death in normal fibroblasts. The findings indicate alpha-terpineol has cytotoxic potential by cytogenetic and molecular mechanisms associated with apoptosis and probable target effects against melanoma cells.

Felipe Alves Batista

Papers

Synthesis, characterization of α-terpineol-loaded PMMA nanoparticles as proposed of therapy for melanoma

Biological properties of chitosan derivatives associated with the ceftazidime drug.

Synthesis, characterization and electrochemical properties of composites synthesized from silver-tannic acid hybrid nanoparticles and different clays

Toxicogenetic profile of the monoterpene alpha-terpineol on normal and tumor eukaryotic cells.