Facile Synthesis and X-ray Attenuation Properties of Ultrasmall Platinum Nanoparticles Grafted with Three Types of Hydrophilic Polymers.

Ultrasmall platinum nanoparticles (Pt-NPs) grafted with three types of hydrophilic and biocompatible polymers, i.e., poly(acrylic acid), poly(acrylic acid-co-maleic acid), and poly(methyl vinyl ether-alt-maleic acid) were synthesized using a one-pot polyol method. Their physicochemical and X-ray attenuation properties were characterized. All polymer-coated Pt-NPs had an average particle diameter (davg) of 2.0 nm. Polymers grafted onto Pt-NP surfaces exhibited excellent colloidal stability (i.e., no precipitation after synthesis for >1.5 years) and low cellular toxicity. The X-ray attenuation power of the polymer-coated Pt-NPs in aqueous media was stronger than that of the commercial iodine contrast agent Ultravist at the same atomic concentration and considerably stronger at the same number density, confirming their potential as computed tomography contrast agents.

Robust Copper Metal-Organic Framework-Embedded Polysiloxanes for Biomedical Applications: Its Antibacterial Effects on MRSA and In Vitro Cytotoxicity.

Polysiloxanes (PSs) have been widely utilized in the industry as lubricants, varnishes, paints, release agents, adhesives, and insulators. In addition, their applications have been expanded to include the development of new biomedical materials. To modify PS for application in therapeutic purposes, a flexible antibacterial Cu-MOF (metal-organic framework) consisting of glutarate and 1,2-bis(4-pyridyl)ethane ligands was embedded in PS via a hydrosilylation reaction of vinyl-terminated and H-terminated PSs at 25 °C. The bactericidal activities of the resulting Cu-MOF-embedded PS (PS@Cu-MOF) and the control polymer (PS) were tested against Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus. PS@Cu-MOF exhibited more than 80% bactericidal activity toward the tested bacteria at a concentration of 100 µg⋅mL-1 and exhibited a negligible cytotoxicity toward mouse embryonic fibroblasts at the same concentration. Release tests of the Cu(II) ion showed PS@Cu-MOF to be particularly stable in a phosphate-buffered saline solution. Furthermore, its physical and thermal properties, including the phase transition, rheological measurements, swelling ratio, and thermogravimetric profile loss, were similar to those of the control polymer. Moreover, the low cytotoxicity and bactericidal activities of PS@Cu-MOF render it a promising candidate for use in medicinal applications, such as in implants, skin-disease treatment, wound healing, and drug delivery.

One-dimensional lead iodide hybrid stabilized by inorganic hexarhenium cluster cations as a new broad-band emitter.

A novel one-dimensional (1D) hybrid {[Re6S8(PzH)6][Pb3I8(DMF)2]}·6(DMF) with hexarhenium cluster cations has been synthesized and characterized by means of single-crystal X-ray diffraction. Two DMF oxygen atoms bridge three lead iodides to form a set of lead iodides, {[PbI4/2I(ODMF)1/2][PbI4/2(ODMF)2/2][PbI4/2I(ODMF)1/2]}2-, and these sets of lead iodide share edges to form a 1D lead iodide chain, [Pb3I8(DMF)2]2- which has never been reported before and is different from the typical edge sharing of octahedral PbI6 units. 1D lead iodide chains are stacked along the a axis, and [Re6S8(PzH)6]2+ cations with H-bonded DMF molecules to pyrazole N-H reside between 1D lead iodide chains. This 1D lead iodide hybrid shows strong broad-band emission with a peak at 634 nm. The excellent photoluminescent properties of the new lead iodide hybrid exhibit great potential for optoelectronic applications in photonic devices with broad-band emission and stability. This study introduces a new class of lead iodide hybrid compounds having new inorganic cluster cations rather than the organic amine cations that have been used in numerous studies to date. This work opens a promising path to overcome the instability of perovskites including of organic amine cations.