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Gold nanoparticles (GNPs), usually fabricated through reduction and stabilization two steps, have been widely used in biomedical field. Here, the six-armed star copolymer was synthesized and self-assembled into crosslinked micelles for the in-situ preparation of GNPs in one-step without external reductant.The copolymer and their precursors were synthesized by a combination of ring-opening polymerization (ROP), activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), and Michael addition reaction. Their molecular weights and structures were measured by gel permeation chromatography (GPC) and 1 H NMR. The diselenide bond of crosslinked micelles reduced AuCl 4 À to GNPs, and the crosslinked micelles stabilized the GNPs in-situ. Through increasing AuCl 4 À concentration, the collision probability between the GNPs increased, with particle diameters of 1.5, 2.3, and 3.0 nm. Moreover, the GNPs showed good stability, and the wavelength of maximum absorbance (λ max ) did not change under different dilution, temperature, and storage conditions. Furthermore, integrating dissipative particle dynamics (DPD) simulations and scripts with experiments, the formation process of crosslinked micelles, the stabilization process, and the size regulation of GNPs at mesoscopic scale were revealed. Therefore, this stable crosslinked micelles/GNPs hybrid material is expected to be used as a nanocarrier in an integrated diagnosis and treatment system.

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Silver nanoparticles (AgNPs) were synthesised using banana flower extract (BFE) as a reducing and stabilising agent. Spherical, well-dispersed, and stable AgNPs were formed and characterised by ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and zeta potential. The in vitro antimicrobial properties of AgNPs against Staphylococcus aureus and Escherichia coli were then investigated. The minimum inhibitory concentration (MIC) of AgNPs against S. aureus and E. coli were 32 and 16 μg/mL, respectively. E. coli was more sensitive to AgNPs than S. aureus due to differences in cell wall structures of the bacteria. Regarding the bactericidal mechanisms of AgNPs, an increase in cell permeability and a distinctive deformation in cellular morphology was observed. The antibacterial effect decreased with the addition of the antioxidant N-acetyl-l-cysteine (NAC) which acted as ROS scavenger. In summary, the antibacterial mechanism was likely a combination of cell membrane damage and ROS induction.