Binjie Li

Synthesis of silver nanoparticle-loaded sulfadiazine/polyvinyl alcohol nanorods and their antibacterial activities

Silver nanoparticle-loaded sulfadiazine/polyvinyl alcohol nanorods (Ag-SD/PVA NRs) were successfully synthesized in an ammonia solution, and were characterized by XRD, FT-IR, SEM and TEM. In the synthesis process, PVA was introduced to control the size of the silver sulfadiazine (SSD) precursor and further reduce SSD to produce Ag-SD/PVA NRs. The obtained Ag-SD/PVA NRs have an average width of 50 nm and a length of 300 nm, loaded with Ag NPs about 8 nm in size. As novel composite antibacterial agents, the Ag-SD/PVA NRs exhibited higher bactericidal efficacy in comparison to the Ag NPs and SSD microrods (MRs) alone. Additionally, these Ag-SD/PVA NRs showed concentration-dependent antibacterial behavior. At high concentrations, they displayed more effective antibacterial activity towards S. aureus than P. aeruginosa and E. coli, and at lower concentrations, they exhibited more effective antibacterial activity towards E. coli.

Highly water-dispersible silver sulfadiazine decorated with polyvinyl pyrrolidone and its antibacterial activities

Highly water-dispersible silver sulfadiazine (SSD) was prepared by liquid phase method with polyvinyl pyrrolidone (PVP) as a surface modification agent. The structure and morphology of the PVP-modified silver sulfadiazine (P-SSD) were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier-transform infrared (FT-IR) spectrometry. The produced particles are ginkgo leaf-like architecture with the sizes of micron-nanometer. Due to hydrophilic PVP decorated on the surface, the P-SSD has excellent dispersion in water over a period of 24h, which is obviously stable by comparison to that of the commercial silver sulfadiazine (C-SSD). In addition, the P-SSD exhibits good antibacterial activities against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus).

Synthesis of flower-like sulfadiazine copper/polyvinyl pyrrolidone composite and its antimicrobial activities

Flower-like sulfadiazine copper/polyvinyl pyrrolidone (SD-Cu/PVP) composite was synthesized at room temperature. Its structure and morphology were investigated by X-ray powder diffraction, scanning electron microscopy, thermo gravimetric analysis, Fourier transform infrared spectrometry, and the possible forming mechanism was discussed as well. In addition, its antibacterial activity toward the bacterial strains such as Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) was evaluated by the minimum inhibitory concentration, the minimum bactericidal concentration, and cup diffusion method. Results suggested that the SD-Cu/PVP composite displayed selectively antibacterial activity for E. coli and P. aeruginosa than S. aureus.

Antibacterial activities of polythionates enhanced by carbonates

Inorganic antibiotics, with low cost, low occurrence of antibacterial resistance, and long-term effects, have attracted great research interest and have been widely used in many fields. However, few investigations have focused on the antibacterial properties of polythionates due to their synthetic difficulty and commercial unavailability. In this work, the antibacterial properties of polythionates, prepared through a new and facile fabrication method, were measured by minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and cup diffusion methods. Moreover, we have proven for the first time that application of polythionates with different bases (carbonate, urea) exhibits enhanced antibacterial activity compared to application of pure polythionates. The increase in antibacterial activity is related to the formation of active sulfur species from the decomposition of polythionates that is promoted by the increase in pH. The MIC of potassium hexathionate against Gram-positive S. aureus and Gram-negative P. aeruginosa, enhanced by adding potassium carbonate, was 7.81 μg mL−1 and 0.98 μg mL−1, respectively. Therefore, the mixture of polythionate and carbonate is promising as a cheap and sustained antibacterial candidate.