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Silver nanomaterials have been produced by chemical or biological methods requiring room to higher temperatures resulting in poor stable particles. Only a couple of reports use low temperature for their synthesis but, in these cases, nanoparticles aggregated in a short time. We hypothesized that psychrophilic bacteria could be found that produce stable nanoparticles at low temperature with antimicrobial activity that can be of use in biomedicine against pathogenic bacteria. Isolation of several bacteria from Antarctica was performed to obtain different psychrophilic bacteria, and their capability to extracellularly synthesize silver nanoparticles tested. Different conditions, including presence of sodium chloride and a low (4 °C) and a medium (30 °C) temperature, were used and the structure of the nanoparticles physicochemically characterized. The antimicrobial activity of freshly prepared and aged nanoparticles was determined against Gram-negative and Gram-positive bacteria. Nanoparticles were synthesized by all four psychrophilic bacteria at 4 °C and 30 °C. NaCl highly decreased the synthesis of nanosilver particles. Depending on the bacteria and temperature used, nanoparticles were spherical with sizes 5.0–11.1 nm, and stable after several months of incubation under light. The most stable nanoparticles were those kept at 4 °C and the highest detected activity was against Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

To solve the traditional radiotherapy obstacles, and also to enhance the radiation therapy efficacy various radiosensitizers have been developed. Radiosensitizers are promising agents that under X-ray irradiation enhance injury to tumor tissue by accelerating DNA damage. In this report, silver-silver sulfide nanoparticles (Ag-Ag2S NPs) were synthesized via a facile, one-pot and environmentally friendly biomineralization method. Ag-Ag2S was coated with bovine serum albumin (BSA) in situ and applied as an X-ray sensitizer to enhance the efficiency of radiotherapy. Also, folic acid (FA) was conjugated to Ag-Ag2S@BSA to impart active targeting capability to the final formulation (Ag-Ag2S@BSA-FA). Prepared NPs were characterized by transmission electron microscopes (TEM), scanning electron microscope (SEM), dynamic light scattering (DLS), ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. Results show that most of the NPs have well-defined uniform Janus structures. The biocompatibility of the NPs was then evaluated both in vitro and in vivo. A series of in vitro assays were performed on 4T1 cancer cells to evaluate the therapeutic efficacy of the designed NPs. In addition, the radio-enhancing ability of the NPs was tested on the 4T1 breast cancer murine model. MTT, live and dead cell staining, apoptosis, ROS generation, and clonogenic in vitro assays demonstrated the efficacy of NPs as radiosensitizers in radiotherapy. In vivo results as well as H&E staining tumor tissues confirmed tumor destruction in the group that received Ag-Ag2S@BSA-FA NPs and exposed to X-ray. The results showed that prepared tumor-targeted Ag-Ag2S@BSA-FA NPs could be potential candidates as radiosensitizers for enhanced radiotherapy. [ABSTRACT FROM AUTHOR]

To solve the traditional radiotherapy obstacles, and also to enhance the radiation therapy efficacy various radiosensitizers have been developed. Radiosensitizers are promising agents that under X-ray irradiation enhance injury to tumor tissue by accelerating DNA damage. In this report, silver-silver sulfide nanoparticles (Ag-Ag2S NPs) were synthesized via a facile, one-pot and environmentally friendly biomineralization method. Ag-Ag2S was coated with bovine serum albumin (BSA) in situ and applied as an X-ray sensitizer to enhance the efficiency of radiotherapy. Also, folic acid (FA) was conjugated to Ag-Ag2S@BSA to impart active targeting capability to the final formulation (Ag-Ag2S@BSA-FA). Prepared NPs were characterized by transmission electron microscopes (TEM), scanning electron microscope (SEM), dynamic light scattering (DLS), ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. Results show that most of the NPs have well-defined uniform Janus structures. The biocompatibility of the NPs was then evaluated both in vitro and in vivo. A series of in vitro assays were performed on 4T1 cancer cells to evaluate the therapeutic efficacy of the designed NPs. In addition, the radio-enhancing ability of the NPs was tested on the 4T1 breast cancer murine model. MTT, live and dead cell staining, apoptosis, ROS generation, and clonogenic in vitro assays demonstrated the efficacy of NPs as radiosensitizers in radiotherapy. In vivo results as well as H&E staining tumor tissues confirmed tumor destruction in the group that received Ag-Ag2S@BSA-FA NPs and exposed to X-ray. The results showed that prepared tumor-targeted Ag-Ag2S@BSA-FA NPs could be potential candidates as radiosensitizers for enhanced radiotherapy. [ABSTRACT FROM AUTHOR]

[Display omitted] This study aimed to develop a novel radiosensitizer consisting of platinum nanoparticles (Pt NPs) as a high-atomic-number element in order to maximize the generation of ROS under ionizing radiation at the tumor site. Pt NPs were produced via a green and facile method in the presence of gelatin (Gel) as both reducing and stabilizing agent. After determining the physical structure and chemical composition of Pt@Gel NPs by STEM, FeSEM, EDS, DLS, XRD and FTIR, in vitro cytotoxicity on human umbilical vein endothelial cells (HUVEC) and breast cancer cell line (4T1) was evaluated by MTT assay. Finally, ROS generation assay, calcein AM/PI staining assay and clonogenic test were performed on 4T1 cells under X-Ray irradiation to evaluate the radioenhancment efficiency of Pt@Gel. The prepared NPs exhibited spherical and uniform shapes and narrowly distributed sizes in addition to an acceptable radiosensitization capability. The nanosystem provided higher levels of intracellular ROS in malignant cells and enhanced cancer cell death rate under X-Ray irradiation. Overall, the findings suggested that Pt@Gel could be a safe and effective alternative to existing radiosensitizers and potentially be employed for the treatment of breast cancer. [ABSTRACT FROM AUTHOR]