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Biomimetic calcium phosphate (CaP) systems mono-substituted with zinc (Zn2+) and magnesium (Mg2+) ions were prepared from a biogenic source (cuttlefish bone) by wet precipitation method. The results revealed that the as-prepared powders were composed of calcium-deficient carbonated hydroxyapatite (HAp), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP), while the heat-treated powders consisted of HAp, α -tricalcium phosphate (α -TCP), and β -tricalcium phosphate (β -TCP). In addition to Zn2+ and Mg2+ ions, the presence of CO 3 2−, Sr2+ and Na + ions was detected with elemental analysis, which can be attributed to the use of cuttlefish bone as a natural precursor of Ca2+ ions. The data obtained by XRD study demonstrated the decrease in lattice parameters in the OCP and β -TCP phases for Zn-substitution and Mg-substitution in the HAp, OCP, and β -TCP phases. Zn2+ occupies the Ca(1,3,4,6,7,8) sites in OCP and Ca(1,2,3,4) sites in β -TCP, while Mg2+ occupies the Ca(2) sites in HAp and the Ca(4,5) sites in β -TCP. Phase transformation study under simulated physiological conditions for 7 days showed the transformation of OCP and ACP into the thermodynamically more stable HAp. Characterization of the zeta-potential showed positively charged populations for all prepared CaP powders, while all samples showed high bovine serum albumin adsorption capacity. The culture of human embryonic kidney cells showed that the prepared CaPs are non-cytotoxic and that viability of the cells increases during the culture period. All powders obtained showed antibacterial activity towards Gram-negative Escherichia coli and low antibacterial effect against Gram-positive Staphylococcus aureus , as determined by viability analysis during 48 h. Inhibition zone analysis and observation of the morphology after 24 h showed no antibacterial properties. [ABSTRACT FROM AUTHOR]

The bioactive properties of hydroxyapatite (HAp) facilitate bone regeneration, however, its physico-chemical and bioactive properties can be further enhanced by ionic substitutions within the crystalline lattice. In this work, substitution with Sr2+ and Ag+ ions was investigated for the improvement of osseointegration and antibacterial activity in potential treatment of traumatic bone injuries. A series of single substituted HAp with Sr2+ or Ag+ ions and Ag/Sr-co-substituted HAp with different degrees of substitution (0, 1, 2.5, and 5 mol%) were obtained by wet precipitation from cuttlefish bone. Rietveld refinement indicated successful Ca2+ substitution by increasing cell parameters due to the larger ionic radii of Sr2+ and Ag+ compared to Ca2+, which was confirmed by elemental mapping showing uniform distribution of substituent cations. Characterization of the zeta-potential of Ag/Sr-co-substituted HAp showed negatively charged populations, at potentials not lower than −15 mV. Increasing the degree of substitution resulted in decreasing zeta-potential. The higher absorption capacity of bovine serum albumin was determined on Ag/Sr-co-substituted HAp powders as compared to non-substituted HAp. All Ag-substituted HAps have shown an antibacterial activity towards Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli , as determined by inhibition zone, viability analysis and scanning electron microscopy. In addition, non-cytotoxicity towards human cells was confirmed by in vitro tests with embryonic kidney 293 and mesenchymal stem cells. [ABSTRACT FROM AUTHOR]

Chemical analysis of plasma samples of wild fish from the Sava River (Croatia) revealed the presence of 90 different pharmaceuticals/illicit drugs and their metabolites (PhACs/IDrgs). The concentrations of these PhACs/IDrgs in plasma were 10 to 1000 times higher than their concentrations in river water. Antibiotics, allergy/cold medications and analgesics were categories with the highest plasma concentrations. Fifty PhACs/IDrgs were identified as chemicals of concern based on the fish plasma model (FPM) effect ratios (ER) and their potential to activate evolutionary conserved biological targets. Chemicals of concern were also prioritized by calculating exposure-activity ratios (EARs) where plasma concentrations of chemicals were compared to their bioactivities in comprehensive ToxCast suite of in vitro assays. Overall, the applied prioritization methods indicated stimulants (nicotine, cotinine) and allergy/cold medications (prednisolone, dexamethasone) as having the highest potential biological impact on fish. The FPM model pointed to psychoactive substances (hallucinogens/stimulants and opioids) and psychotropic substances in the cannabinoids category (i.e. CBD and THC). EAR confirmed above and singled out additional chemicals of concern - anticholesteremic simvastatin and antiepileptic haloperidol. Present study demonstrates how the use of a combination of chemical analyses, and bio-effects based risk predictions with multiple criteria can help identify priority contaminants in freshwaters. The results reveal a widespread exposure of fish to complex mixtures of PhACs/IDrgs, which may target common molecular targets. While many of the prioritized chemicals occurred at low concentrations, their adverse effect on aquatic communities, due to continuous chronic exposure and additive effects, should not be neglected. Image 1 • Ninety pharmaceuticals/illicit drugs and their metabolites were analyzed. • Fish plasma model and ToxCast data were used to identify chemicals of concern. • Nicotine, cotinine, prednisolone and dexamethasone: chemicals of concern. • Fish plasma model pointed psychoactive chemicals as potentially hazardous to fish. [ABSTRACT FROM AUTHOR]