Potential toxicity of superparamagnetic iron oxide nanoparticles (SPION)

Superparamagnetic iron oxide nanoparticles (SPION) are being widely used for various biomedical applications, for example, magnetic resonance imaging, targeted delivery of drugs or genes, and in hyperthermia. Although, the potential benefits of SPION are considerable, there is a distinct need to identify any potential cellular damage associated with these nanoparticles. Besides focussing on cytotoxicity, the most commonly used determinant of toxicity as a result of exposure to SPION, this review also mentions the importance of studying the subtle cellular alterations in the form of DNA damage and oxidative stress. We review current studies and discuss how SPION, with or without different surface coating, may cause cellular perturbations including modulation of actin cytoskeleton, alteration in gene expression profiles, disturbance in iron homeostasis and altered cellular responses such as activation of signalling pathways and impairment of cell cycle regulation. The importance of protein-SPION interaction and various safety considerations relating to SPION exposure are also addressed

Interaction of two imidazolium gemini surfactants with two model proteins BSA and HEWL

Gemini surfactants and their interactions with proteins have gained considerable scientific interest, especially when amyloidogenic proteins are taken into account. In this work, the influence of two selected dicationic (gemini) surfactants (3,3′-[1,8-(2,7-dioxaoctane)]bis(1-dodecylimidazolium) chloride and 3,3′-[1,12-(2,11-dioxadodecane)]bis(1-dodecylimidazolium) chloride) on two model proteins, bovine serum albumin (BSA) and hen egg white lysozyme (HEWL), have been investigated. A pronounced and sophisticated influence on BSA structure has been revealed, including a considerable change of protein radius of gyration as well as substantial alteration of its secondary structure. Radius of gyration has been found to rise significantly with addition of surfactants and to fall down for high surfactants concentration. Similarly, a remarkable fall of secondary structure (α-helix content) has been observed, followed by its partial retrieval for high surfactants concentration. A strong aggregation of BSA has been observed for a confined range of surfactants concentrations as well. In case of HEWL-gemini system, on the other hand, the protein-surfactant interaction was found to be weak. Molecular mechanisms explaining such behaviour of protein-surfactant systems have been proposed. The differences of properties of both studied surfactants have also been discussed

Antibakterielle Aktivität von Opferanodensystemen durch Kombination von Platingruppen-Metallen mit Silber

Antibakterielle Oberflächen sind zentrales Thema aktueller Biomaterialforschung. Zuletzt sind Silberbeschichtungen wieder in den Vordergrund gerückt. Opferanoden-Systeme, durch die Kombination von Silber mit Metallen der Platingruppe, können die Silberfreisetzung potenzieren. Durch Magnetron-Sputter-Deposition wurden Probekörper hergestellt, die Dünnschichten von jeweils Platin, Palladium, Iridium und Titan (Kontrolle) mit Silber-Dots kombinierten. Die hergestellten Probekörper wurden bakteriellen, zytologischen und elektrochemischen Tests unterworfen. Alle Opferanoden-Paare wiesen eine erhöhte antibakterielle Aktivität im Vergleich zu Titan-Silber auf. Das Iridium-Silber-System zeigte dabei die stärkste antibakterielle Aktivität. Analog dazu zeigten Iridium-Silber-Proben die höchste Silberionen-Freisetzung. Die Machbarkeit eines Opferanoden-Systems konnte in dieser Arbeit bestätigt werden. Ein solches System ist für die klinische Anwendung vielversprechend