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We report a modified synthesis route of colloidal gold nanorods (AuNRs) by combining the thermal re-shaping treatment and bi-surfactant modification using hexadecyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL). Aspect ratios down to 1.3 ± 0.1 can be achieved in addition to good monodispersity, uniformity, and chemical stability of the materials. Furthermore, without needing post-treatment, metal ions directly interact with the AuNRs efficiently, allowing rapid and sensitive colorimetric detection of heavy metal ions such as Pb2+ and Cu2+ with a low concentration down to 2.5 μM. The detection performance in terms of selectivity, sensitivity and stability is systematically evaluated. The AuNRs with tunable aspect ratios as well as chemical stability have potential in surface-plasmon-based applications such as biochemical sensing, biochemical imaging, medical diagnostics, and cancer therapy. [ABSTRACT FROM AUTHOR]

Bacterial infection and inferior osseointegration are major complications associated with titanium (Ti) based implants. Although surface-engineered zinc oxide (ZnO) nanorods exhibit remarkable antibacterial ability, their potential biomedical applications are hampered by their pronounced cytotoxicity. Herein, inspired by the in vivo degradation process of znic, ZnO nanorods are converted into thermodynamically more stable zinc phosphate (Zn3(PO4)2 )through a simple hydrothermal treatment in a hydrogen phosphate solution. By adjusting the conversion ratio, the surface morphology, release of zinc ions (Zn2+), and generation of reactive oxygen species can be finely tailored to overcome the cytotoxicity of ZnO nanorods while preserving their antibacterial capability. Furthermore, an optimized amount of Zn2+ released from the ZnO/Zn3(PO4)2 hybrid coating enhances osteogenic differentiation and extracellular matrix mineralization of human bone marrow mesenchymal stem cells by reprogramming their metabolic configuration. An implant-related infection model in rabbit femurs indicates that the hybrid ZnO/Zn3(PO4)2 coating can even promote osseointegration in the presence of pathogenic bacteria. This surface modification strategy which endows Ti-based implants with superior anti-bacterial and pro-osteogenic properties holds great clinical potential for orthopedic and dental applications. [ABSTRACT FROM AUTHOR]