No abstract

Curcumin (CCM) is one of the most frequently explored plant compounds with various biological actions such as antibacterial, antiviral, antifungal, antineoplastic, and antioxidant/anti-inflammatory properties. The laboratory data and clinical trials have demonstrated that the bioavailability and bioactivity of curcumin are influenced by the feature of the curcumin molecular complex types. Curcumin has a high capacity to form molecular complexes with proteins (such as whey proteins, bovine serum albumin, β-lactoglobulin), carbohydrates, lipids, and natural compounds (e.g., resveratrol, piperine, quercetin). These complexes increase the bioactivity and bioavailability of curcumin. The current review provides these derivatization strategies for curcumin in terms of biological and physico-chemical aspects with a strong focus on different type of proteins, characterization methods, and thermodynamic features of protein–curcumin complexes, and with the aim of evaluating the best performances. The current literature review offers, taking into consideration various biological effects of the CCM, a whole approach for CCM-biomolecules interactions such as CCM-proteins, CCM-nanomaterials, and CCM-natural compounds regarding molecular strategies to improve the bioactivity as well as the bioavailability of curcumin in biological systems.

Pure nano-crystalline hydroxyapatite (Hap) and Hap doped with magnesium, zinc and silicon, namely Hap-0.25wt%Mg: Hap01, Hap-0.25wt%Mg-0.47wt%Si: Hap02, Hap-1.50wt%Mg-0.47wt%Si: Hap03, Hap-0.67wt%Mg-0.2wt%Zn-0.13wt%Si: Hap04, were synthesized using aqueous precipitation method. The pure and doped Hap were calcined individually at 400, 650 and 850 �C for 2h, and investigated by Brunauer-Emmett-Teller (BET) specific surface area and porosity measurements, as well as by X-ray powder diffraction (XRD). The morphology and particle size of nano-crystalline powders were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal stability of the obtained nanoceramics from 30�C to 1000�C and the effect of calcination temperatures (400, 650 and 850 �C) on their composition and structure were also determined by using TG, DTG, TGA and DTA techniques coupled with SEM-EDX. Results analysis shows a high thermal stability (up to 1000 �C) of these nanomaterials, including the triple-substituted Hap with Mg, Zn and Si (Hap04). Simultaneous incorporation of Mg, Zn and Si into Hap lattice represents a novelty and promotes a new generation of synthetic porous nanoceramics with unique Hap structure, and high thermal stability. Due to their chemical composition and structure rather similar to those characteristic for the inorganic component of bone, these nanoceramics can have multiple applications in biomedicine, as bone substitutes, for metal coatings and in drug delivery systems.

ABSTRACT. HAP powder of a low crystallinity and rather large specific surface area was synthesized by an environmentally friendly, cost effective precipitation method, and characterized by XRD, FTIR, and BET isotherms. TEM and AFM are used to envisage the surface of HAP nano particles, showing a high porosity of this ceramic powder. It was used for the removal of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) from mine wastewater. Metal contents in the initial and treated samples were quantified by inductively coupled plasma atomic emission spectrometry and high-resolution continuum source atomic absorption spectrometry. By the use of HAP, an efficient removal of all metals was ensured. The increase of Ca 2+ ions content in the treated water suggests an ion exchange mechanism.

The goal of this investigation is related to the development of nanostructured biomaterials based on hydroxyapatite (HAP) and multi-doped hydroxyapatites (HAPs), with essential physiological elements, like Mg, Zn, Sr, and Si, for bone repair and regeneration. Nano hydroxyapatites pastes and powders were obtained by wet chemical method using innovative nanotechnology and advanced processing of biomaterials at various temperatures to control the crystallite size and crystallinity degree. The prepared HAPs were analysed by various physical and chemical methods, like SEM, SEM-EDX, AFM, XRD, TG and DSC analysis. The results showed that these biomaterials both in pastes and in powders contained a unique phase, characterized by the HAP structure, which was substantially preserved even at 1000 oC, indicating a high thermal stability of these biomaterials. To enhance their usage, we have prepared HAP and multi-doped HAPs in the form of pastes with controlled humidity (moisture) and powders with controlled crystallinity, which were lyophilized or lyophilized calcined at 300 oC for 1 h. Preliminary biological tests showed that the adhesion and proliferation of human osteoblasts depended on the heat treatment of HAPs used for building the scaffolds. The findings suggest that these biomaterials based on HAPs may have a wide range of medical applications as bone substitute and coatings on metallic implants.