Adsorption of bovine serum albumin onto synthetic Fe-doped geomimetic chrysotile.

Synthetic stoichiometric and Fe-doped geomimetic chrysotile nanocrystals represent a reference standard to investigate the health hazard associated with mineral asbestos fibres. Experimental evidence suggests that the generation of reactive oxygen species and other radicals, catalysed by iron ions at the fibre surface, plays an important role in asbestos-induced cytotoxicity and genotoxicity. In this study, structural modification of bovine serum albumin (BSA) adsorbed onto synthetic chrysotile doped with different amounts of Fe has been investigated by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and analytical pyrolysis coupled with gas chromatography-mass spectrometry.

Cuttlefish bone scaffold for tissue engineering: a novel hydrothermal transformation, chemical-physical, and biological characterization.

Purpose: Natural resources are receiving growing interest because of their possible conversion from a cheap and easily available material into a biomedical product. Cuttlefish bone from Sepia Officinalis was investigated in order to obtain an hydroxyapatite porous scaffold using hydrothermal transformation.

Methods: Complete conversion of the previous calcium carbonate (aragonite) phase into a calcium phosphate (hydroxyapatite) phase was performed with an hydrothermal transformation at 200 °C (~ 15 atm), for four hours, with an aqueous solution of KH2PO4 in order to set the molar ratio Ca/P = 10/6 in a reactor (Parr 4382).

Conformational modifications of serum albumins adsorbed on different kinds of biomimetic hydroxyapatite nanocrystals.

Nanosized carbonate-hydroxyapatite represents a suitable material for bone substitution and delivery of biomolecules. Its interaction with serum proteins plays a central role in the process of implantation of a device. Herein, surface interactions of human (HSA) and bovine (BSA) serum albumin with two biomimetic carbonate-hydroxyapatites (CHA) differing for size, surface area, crystallinity degree and surface properties have been investigated.

Spectroscopic characterization of Fe-doped synthetic chrysotile by EPR, DRS and magnetic susceptibility measurements.

Fe-doped synthetic geomimetic chrysotile nanocrystals represent a reference standard to investigate the health hazard associated with asbestos fibers and constitute interesting inorganic nanotubes for specific technological applications in light harvesting systems, optoelectronics and photonics. As the fiber toxicity is catalyzed by iron ions in specific crystallographic sites and the mechanical behaviour of synthetic chrysotile nanotubes is strongly affected by the iron doping extent, the characterization of Fe substitution to Mg and/or Si sites in the chrysotile structure appears highly important. By EPR, DRS spectroscopic analyses and magnetic investigations, Mg and/or Si ion replacement by Fe(3+) in a synthetic geomimetic chrysotile structure has been investigated.

Asbestos health hazard: a spectroscopic study of synthetic geoinspired Fe-doped chrysotile.

The chrysotile fibres toxicity appears correlated to the redox activity of iron present in the chrysotile structure. In fact the generation of reactive oxygen species and other radicals appears catalyzed by iron ions and closely related to Fe ions organization in specific crystallographic sites having a capability to activate free radical generation. The Fe substitution to Mg and/or Si in the chrysotile structure appears important for asbestos health hazard investigation.

Adsorption of human serum albumin on the chrysotile surface: a molecular dynamics and spectroscopic investigation.

The human serum albumin (HSA) secondary structure modifications induced by the chrysotile surface have been investigated via computational molecular dynamics (MD) and experimental infrared spectroscopy (FTIR) on synthetic chrysotile nanocrystals coated with different amount of HSA. MD simulations, conducted by placing various albumin subdomains close to the fixed chrysotile surface, show an initial adsorption phase, accompanied by local rearrangements of the albumin motifs in contact with the chrysotile layer. Next, large-scale rearrangements follow with consequent secondary structure modifications.

Synthetic chrysotile nanocrystals as a reference standard to investigate surface-induced serum albumin structural modifications.

Geoinspired synthetic chrysotile, which represents an ideal asbestos reference standard, has been utilized to investigate homomolecular exchange of bovine serum albumin (BSA), the major plasma protein, between the adsorbed and dissolved state at the interface between asbestos fibers and biological medium. FTIR spectroscopy has been used to quantify BSA structural modifications due to surface adhesion on chrysotile fibers as a function of the surface coating extent. Circular dichroism spectroscopy has been used to investigate the adsorption/desorption equilibrium through analysis of the BSA structural perturbations after protein desorption from chrysotile surface.

Iron-loaded synthetic chrysotile: a new model solid for studying the role of iron in asbestos toxicity.

The generation of reactive oxygen species and other radicals, catalyzed by iron ions at the fiber surface, is thought to play an important role in asbestos-induced cytotoxicity and genotoxicity, but a direct confirmation of this statement needs the availability of asbestos samples differing only for their iron content, without the interference of other physicochemical features. Synthetic stoichiometric chrysotile nanofibers, devoid of iron or any other contaminant, did not exert genotoxic and cytotoxic effects nor elicited oxidative stress in a murine alveolar macrophage cell line; on the contrary, the same nanofibers, loaded with 0.57% and 0.

Different cellular responses evoked by natural and stoichiometric synthetic chrysotile asbestos.

The carcinogenic potency of asbestos, including chrysotile, is well established. Several physico-chemical features of the fibers appear implied, such as fibrous habit, size, crystallinity, morphology, and surface active metal ions, where free radical generation may take place. In contrast to other asbestos forms, iron is not a stoichiometric component of chrysotile, but is only present together with other extraneous ions as a magnesium- and silicon-replacing contaminant.