To fix the bone in orthopedics, it is almost always necessary to use implants. Metals provide the needed physical and mechanical properties for load-bearing applications. Although widely used as biomedical materials for the replacement of hard tissue, metallic implants still confront challenges, among which the foremost is their low biocompatibility. Some of them also suffer from excessive wear, low corrosion resistance, infections and shielding stress. To address these issues, various coatings have been applied to enhance their in vitro and in vivo performance. When merged with the beneficial properties of various bio-ceramic or polymer coatings remarkable bioactive, osteogenic, antibacterial, or biodegradable composite implants can be created. In this review, bioactive and high-performance coatings for metallic bone implants are systematically reviewed and their biocompatibility is discussed. Updates in coating materials and formulations for metallic implants, as well as their production routes, have been provided. The ways of improving the bioactive coating performance by incorporating bioactive moieties such as growth factors, osteogenic factors, immunomodulatory factors, antibiotics, or other drugs that are locally released in a controlled manner have also been addressed.

/pdf/advances-in-multifunctional-bioactive-coatings-for-metallic-mide6pg0.pdf

Advances in Multifunctional Bioactive Coatings for Metallic Bone Implants

The contribution of AuIII species to catalysis is still debated due to the limited number of characterized intermediates with this oxidation state. In particular, the coordination of alkenes and alkynes to AuIII followed by insertion into AuIII–X bonds has been suggested but rarely proven experimentally. Here, these reactions are explored by means of DFT and CCSD(T) calculations considering [AuX3(L)] and [AuX2(L)2]+ complexes. In these complexes, L = ethylene and acetylene have been chosen as substrates of high interest and representative of any unsaturated organic substrate, whereas X is Cl, Me or H, as found in metal salts and as model for intermediates involved in catalysis. Isoelectronic PtII complexes are also considered for comparison. Ethylene coordination occurs preferentially perpendicular for all X except H, whereas for acetylene, coordination takes place in-plane for all X except Cl. These coordination isomers can represent either minima (intermediates) or saddle points (transition states) on the potential energy surface, depending on X. NBO analysis shows how this variety of structures results from the combination of electronic (M–L donation and back-donation) and steric (cis L–X repulsion) effects. With the sole exception of [AuMe2(ethylene)2]+, rotation of the unsaturated ligand and insertion into a cis Au–X bond involve low to moderate energy barriers, ΔG‡ = 2.5 to 23.5 kcal mol−1, and are thermodynamically feasible, ΔG = 4.3 to −47.2 kcal mol−1. The paucity of experimental observations for such reactions should thus be caused by other factors, like the participation of the intermediates and products in competitive side reactions including the reductive elimination of XCHnCHnX (n = 1 or 2).

/pdf/coordination-and-insertion-of-alkenes-and-alkynes-in-au-iii-4xi5g86wpp.pdf

Coordination and insertion of alkenes and alkynes in Au(III) complexes: nature of the intermediates from a computational perspective.

A DFT conformational and vibrational analysis of a single molecule of cisplatin (cis-[Pt(NH3)2Cl2]) was performed by means of PW91 functional and LANL08 ECP basis set for the Pt atom. 3-21G and 3-21G* Basis sets were used for the remaining atoms. All the initially chosen conformations were found to converge to the global minimum conformation of C2v symmetry with H atoms lying in the coordination plane and pointing to the Cl atoms. The computational results were compared with the newest experimental structural data and with the vibrational spectroscopic data for cisplatin, obtained by other workers. The chosen level of theory was found to describe satisfactory the molecular structure (r. m. s. of the relative deviations ≤ 6%) and the harmonic vibrational frequencies (r. m. s. of the relative deviations ≤ 5%) of cisplatin.

/pdf/a-dft-ecp-small-basis-set-modelling-of-cisplatin-molecular-humrptyr5a.pdf

A DFT/ECP-Small Basis Set Modelling of Cisplatin: Molecular Structure and Vibrational Spectrum

Three new platinum(II) complexes bearing a eugenol and a pyridine derivative, namely (η2-2-allyl-4-meth­oxy-5-{[(propan-2-yl­oxy)carbon­yl]meth­oxy}phenyl-κC1)chlorido­(pyridine-κN)platinum(II), [Pt(C15H19O4)Cl(C5H5N)], (I), (η2-2-allyl-4-meth­oxy-5-{[(propan-2-yl­oxy)carbon­yl]meth­oxy}phenyl-κC1)chlorido­(4-methyl­pyridine-κN)platinum(II), [Pt(C15H19O4)Cl(C6H7N)], (II), and (η2-2-allyl-4-meth­oxy-5-{[(propan-2-yl­oxy)carbon­yl]meth­oxy}phenyl-κC1)chlorido(pyridine-4-carb­oxy­lic acid-κN)platinum(II), [Pt(C15H19O4)Cl(C6H5NO2)], (III), have been synthesized and further characterized by single-crystal X-ray diffraction. The PtII atoms exhibit the usual distorted square-planar coordination and are surrounded by one Cl atom, one N atom, and a C atom and C=C double bond of the eugenol ligand. The donor N atom of the pyridine ligand occupies a cis position with respect to the double bond. Complexes (I) and (II) crystallize isomorphously in space group P\overline{1} and display a similar crystal packing characterized by C—H⋯O hydrogen bonding, C—H⋯π and π–π inter­actions. However, the presence of the additional methyl group in the 4-methyl­pyridine ligand in (II) disturbs the π–π inter­actions. The crystal packing of (III) is characterized by O—H⋯O hydrogen bonding, resulting in the formation of chains of mol­ecules connected in a head-to-tail fashion and running in the [101] direction. The IC50 values for the HepG2 and KB cell lines are 150.9, 122.3 µM for (I) and 138.9, 93.2 µM for (II), respectively.

https://journals.iucr.org/e/issues/2020/07/00/mw2159/mw2159.pdf

Crystal structures of three platinacyclic complexes bearing isopropyl eugenoxyacetate and pyridine derivatives.

The organometallic complex, trans-[PtCl2(η 2-C2H4)(PMSA)] (1), where PMSA = N-3-pyridinylmethanesulfonamide, has been synthesized and characterized by elemental analysis, molar electric conductivity, IR, electronic, and NMR (1H, 13C, and 195Pt) spectroscopy, and thermal analysis. X-ray crystallography revealed that in 1 [monoclinic, P21 c, a = 5.1260(1), b = 19.1600(4), c = 12.7990(3) A, β = 97.242(2)°, Z = 4] Pt(II) shows planar coordination geometry with PMSA coordinated via the pyridine. The ethylene is virtually perpendicular to the PtCl2N plane with the pyridine ring twisted relative to this plane by 47°. In in vitro assays, PMSA, K[PtCl3(η 2-C2H4)] · H2O, and 1 do not exhibit appreciable cytotoxic activity against human K562 and HepG2 tumor cell lines.

trans-Dichloro(η 2-ethylene) (N-3-pyridinylmethanesulfonamide)platinum(II). Crystal structure, spectroscopic, and thermoanalytical characterization, and cytotoxicity assays

Osteoporosis – the commonest age-related skeletal chronic disorder– is characterized by loss of bone mass, alterations of bone micro-architecture, and increased fracture risk. It has, however, received much less attention than most chronic diseases. Osteoporotic fractures are expensive to treat, and cause significant mortality, morbidity, and loss of independence in an ever broader population of patients. As we have said, osteoporosis is a disease in which the mineral density of the bone (BMD) is reduced, its microarchitecture disrupted, and the expression profile of non-collagenous proteins altered. All these factors predispose bones to fractures, particularly the hip, spine and wrist, and are a major cause of disability, severe back pain and deformity. The World Health Organization estimates that approximately 70 million people worldwide have osteoporosis (Penrod J. et al., 2008). The total cost of osteoporosis is difficult to calculate because it includes in-patient and outpatient medical care, loss of working days, chronic nursing-home costs, and medication. The direct costs of osteoporosis arise mainly from the management of patients with hip fractures. Hip fractures also account for 40% of all deaths from trauma in patients over 75, with 68% of all patients not returning to their former level of activity following an osteoporotic hip fractures. The annual worldwide incidence of hip fracture is 1.5 million, a number projected to grow to 2.6 million by 2025 and to 4.5 million by 2050 (Penrod J. et al., 2008). For these reasons, it is necessary to pay a special attention to these health problems which disturb the quality of life.

/pdf/osteoporosis-a-look-at-the-future-3lderd1z8t.pdf

Osteoporosis: A Look at the Future

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trans-Dichloro(η 2-ethylene) (N-3-pyridinylmethanesulfonamide)platinum(II). Crystal structure, spectroscopic, and thermoanalytical characterization, and cytotoxicity assays

Osteoporosis: A Look at the Future