Search

Due to the abuse of antibiotics, the sensitivity of patients to antibiotics is gradually reduced. This work develops a Fe3O4@SiO2@Au/PDA nanochain which shows an interesting magnetic-field-induced improvement of its photothermal antibacterial property. First, SiO2 was wrapped on Fe3O4 nanospheres assembled in a chain to form a Fe3O4@SiO2 nanocomposite with a chain-like nanostructure. Then, the magnetic Fe3O4@SiO2@Au/PDA nanochains were prepared using in situ redox-oxidization polymerization. Under the irradiation of an 808 nm NIR laser, the temperature rise of the Fe3O4@SiO2@Au/PDA nanochain dispersion was obvious, indicating that they possessed a good photothermal effect. Originating from the Fe3O4, the Fe3O4@SiO2@Au/PDA nanochain showed a typical soft magnetic behavior. Both the NIR and magnetic field affected the antimicrobial performance of the Fe3O4@SiO2@Au/PDA nanochains. Escherichia coli and Staphylococcus aureus were used as models to verify the antibacterial properties. The experimental results showed that the Fe3O4@SiO2@Au/PDA nanochains exhibited good antibacterial properties under photothermal conditions. After applying a magnetic field, the bactericidal effect was further significantly enhanced. The above results show that the material has a broad application prospect in inhibiting the growth of bacteria. [ABSTRACT FROM AUTHOR]

Antimicrobial materials are expected to be alternatives for antibiotics against multidrug-resistant bacteria. In this paper, non-spherical α-Fe2O3@Au/PDA core/shell nanoparticles with tunable shapes are synthesized by a one-step in situ oxidation-redox polymerization method toward near infrared light-responsive antibacterial therapy. The thickness and composition of the Au/PDA hybrid shell can be controlled by varying the concentration of HAuCl4 and the dopamine precursor. Owing to the wonderful photothermal characteristics originating from the Au/PDA shell, the spindle α-Fe2O3@Au/PDA core shell nanoparticles exhibit excellent photothermal sterilization effects against both Escherichia coli and Staphylococcus aureus at low concentrations. Meanwhile, the NIR photothermal induced bactericidal performance indicates that α-Fe2O3@Au/PDA hybrid particles with tunable non-spherical shapes possess unique controllable antibacterial effects. As a result, this finding provides a simple strategy for fabricating high performance photothermal antibacterial agents and the final products possess high potential in synergistic antimicrobial therapy. [ABSTRACT FROM AUTHOR]

Infectious diseases associated with drug-resistant bacteria increasingly threaten public health. Effective antibacterial nanoplatforms are of special importance for treating bacterial infections. In this work, a novel magnetic Fe3O4–Au–PDA hybrid microcapsule with both photothermal (PTT) and photodynamic (PDT) anti-bacterial functions was developed. First, the Fe3O4@Au/PDA core/shell microspheres with hollow nature were obtained by a simple in situ redox–oxidize polymerization method. Then, they were etched in acid to improve the hollow interior and porous shell. Finally, the tetracarboxyzinc phthalocyanine (ZnPc) was used as the photosensitizer to be loaded into the above Fe3O4–Au–PDA hybrid microcapsule. Owing to the dual-mode photothermal Au–PDA hybrid shell and the ZnPc photosensitizer, the final Fe3O4–Au–PDA/ZnPc hybrid microcapsule serves as a wonderful photothermal/photodynamic (PTT/PDT) synergistic therapy agent. The experimental results show that the Fe3O4–Au–PDA/ZnPc microcapsule possesses excellent photothermal sterilization effect (808 nm laser irradiation) against Escherichia coli, and the experimental results further demonstrate good photodynamic behavior under Xenon lamp irradiation. The product exhibits much higher antibacterial performance by combining the PTT/PDT treatment, which demonstrates that this work provides a novel dual-mode phototheranostic nano-agent for an effective treatment of bacterial infections. [ABSTRACT FROM AUTHOR]

Due to the abuse of antibiotics, the sensitivity of patients to antibiotics is gradually reduced. This work develops a Fe 3 O 4 @SiO 2 @Au/PDA nanochain which shows an interesting magnetic-field-induced improvement of its photothermal antibacterial property. First, SiO 2 was wrapped on Fe 3 O 4 nanospheres assembled in a chain to form a Fe 3 O 4 @SiO 2 nanocomposite with a chain-like nanostructure. Then, the magnetic Fe 3 O 4 @SiO 2 @Au/PDA nanochains were prepared using in situ redox-oxidization polymerization. Under the irradiation of an 808 nm NIR laser, the temperature rise of the Fe 3 O 4 @SiO 2 @Au/PDA nanochain dispersion was obvious, indicating that they possessed a good photothermal effect. Originating from the Fe 3 O 4 , the Fe 3 O 4 @SiO 2 @Au/PDA nanochain showed a typical soft magnetic behavior. Both the NIR and magnetic field affected the antimicrobial performance of the Fe 3 O 4 @SiO 2 @Au/PDA nanochains. Escherichia coli and Staphylococcus aureus were used as models to verify the antibacterial properties. The experimental results showed that the Fe 3 O 4 @SiO 2 @Au/PDA nanochains exhibited good antibacterial properties under photothermal conditions. After applying a magnetic field, the bactericidal effect was further significantly enhanced. The above results show that the material has a broad application prospect in inhibiting the growth of bacteria.

Antimicrobial materials are expected to be alternatives for antibiotics against multidrug-resistant bacteria. In this paper, non-spherical α-Fe 2 O 3 @Au/PDA core/shell nanoparticles with tunable shapes are synthesized by a one-step in situ oxidation-redox polymerization method toward near infrared light-responsive antibacterial therapy. The thickness and composition of the Au/PDA hybrid shell can be controlled by varying the concentration of HAuCl 4 and the dopamine precursor. Owing to the wonderful photothermal characteristics originating from the Au/PDA shell, the spindle α-Fe 2 O 3 @Au/PDA core shell nanoparticles exhibit excellent photothermal sterilization effects against both Escherichia coli and Staphylococcus aureus at low concentrations. Meanwhile, the NIR photothermal induced bactericidal performance indicates that α-Fe 2 O 3 @Au/PDA hybrid particles with tunable non-spherical shapes possess unique controllable antibacterial effects. As a result, this finding provides a simple strategy for fabricating high performance photothermal antibacterial agents and the final products possess high potential in synergistic antimicrobial therapy.

The bacteria, which usually contaminate water environment, often cause terrible infectious diseases thus seriously threaten people's health. To meet the increasing requirement of the public health care, an easily separable nanomaterial with sustainable anti-bacteria performance is required. This work reports a Fe 3 O 4 @PDA/Ag/PDA core-shell nanosphere in which the Ag nanocrystals immobilized on the magnetic carrier are protected by an external polydopamine (PDA) layer. The magnetic hybrid nanospheres are constructed by a tunable coating method and the particle parameters can be effectively controlled by the experimental condition. The antibacterial potential of the nanospheres is evaluable by using the Staphylococcus aureus and Escherichia coli as the models. The results indicate the Fe 3 O 4 @PDA/Ag/PDA core-shell nanospheres have a high antibacterial performance by measuring the minimum inhibitory concentration and the minimum bactericidal concentration. Finally, the product is expected to have a sustainable activity because the protecting PDA layer reduce the releasing rate of the Ag + ions and the materials can be magnetically recovered from the media after the disinfection procedure.