Photodynamic and antibacterial studies of template-assisted Fe2O3-TiO2 nanocomposites.

Fe2O3-TiO2 (FT) nanocomposites were successfully synthesized by template-assisted precipitation reaction using Polyvinylpyrrolidone-Polyethylene glycol (PVP-PEG), Tween-80 (T-80) and Cetyltrimethylammomium bromide (CTAB) as templates. The prepared nanocomposites were characterized by XRD, SEM, EDX, UV-DRS, FT-IR, and FT-Raman spectroscopic analysis. The photohemolysis studies were done in human erythrocytes and the cell viability studies were done in HeLa cell lines under the irradiation of an LED light source. The photodynamic studies were performed under two different experimental conditions, such as varying concentrations as well as a time of irradiation. The nanocomposites exhibit significant photodynamic activity via the generation of reactive oxygen species (ROS) under the light source. The results show that the PVP-PEG-assisted Fe2O3-TiO2 (FT-PVP-PEG) nanocomposite has more potential for photodynamic activity in the presence of an LED light source. Also, the antibacterial effect of the samples was investigated against gram-negative bacteria (Escherichia coli). Among all nanocomposites, FT-PVP-PEG shows remarkable antibacterial activity against E. coli. Moreover, the template-assisted nanocomposites protect the biomolecules from the toxicity generated by the magnetic nanoparticles (NPs). The template-assisted FT nanocomposites for the field of photodynamic activity have been experimentally shown for the first time.

Photodynamic cancer therapy: role of Ag- and Au-based hybrid nano-photosensitizers.

The utilization of photodynamic therapy (PDT) has been rapidly increasing due to its advantage as an effective treatment modality for cancer. The organic photosensitizers employed for PDT have some disadvantages, including high toxicity, non-selectivity toward tumors and poor absorption of light. The low light penetration into the tumor sites resulting from low wavelength of absorption and long-term skin photosensitivity. Hence, the attention toward non-toxic inorganic photosensitizers like noble metal nanoparticles (NPs) has been increasing nowadays. In bioscience, NPs are replacing organic dyes since they have photostability and non-toxicity. Generally, nanomaterials can easily form compounds with other substances as well as organic materials and the modified NPs surface enhances the chemical activity. Among the metal NPs, noble metals, especially gold and silver are attractive because of their size and shape-dependent unique optoelectronic properties. The coating of inorganic/organic materials on top of the noble metal makes the NPs bio-compatible and less toxic. Furthermore, Ag- and Au-based inorganic/organic complex NPs could offer a new possibility because of their unique structures. Meanwhile, the coating of inorganic/organic complex NPs protects the noble metals and stabilizes them against chemical corrosion and enhances the production of reactive oxygen species. Thus, in this review, we have highlighted the role of Ag- and Au-based inorganic/organic hybrid nano-photosensitizers in photodynamic therapy.Communicated by Ramaswamy H. Sarma.

Enhanced photocatalytic and photodynamic activity of chitosan and garlic loaded CdO-TiO2 hybrid bionanomaterials.

Herein, the work addresses the synthesis of biomaterials (chitosan and garlic) loaded CdO-TiO2 hybrid nanocomposites for photocatalytic water treatment and photodynamic cancer therapeutic applications that were reported the first time. CdO-TiO2 (CT) nanocomposites were synthesized and loaded with the biomaterials such as chitosan and garlic by simple sol-gel method. The nanomaterials were characterized and the photodegradation of three model pollutants, Methylene blue (MB), Methyl orange (MO) and Rhodamine B (Rh-B) was opted to investigate the efficiency of the synthesized photocatalyst under the solar light. From the results, the garlic-loaded CdO-TiO2 (AS-CT) hybrid nanocomposites exhibit a superior photocatalytic activity than the chitosan-loaded CdO-TiO2 (CS-CT) and CdO-TiO2 (CT) nanocomposites under the irradiation of solar light. Additionally, the cell viability of the synthesized nanocomposites was carried out in HeLa cell lines under different concentrations, light doses and incubation periods using an LED light source. Compared to the CS-CT and CT nanocomposites, an efficient photodynamic activity was achieved in the case of AS-CT hybrid nanocomposites. Actually, the end-use properties required for both processes in AS-CT nanocomposites appear similar due to the presence of organo sulphurus compounds.

Preparation and characterization of core-shell type Ag@SiO2 nanoparticles for photodynamic cancer therapy.

With recent scientific developments, Photodynamic therapy (PDT) offers the promisie to become incorporated into the mainstream of cancer therapy. Noble metal based nano-PDT is increasing due to its advantages in the field of biomedicine. In this study, noble metal based Ag@SiO2 core-shell nanoparticles were synthesized and to confirm the core-shell structure they were characterized by UV-vis, XRD, FTIR, TEM, and EDX. Our data confirm that core-shell type Ag@SiO2 nanoparticles maintain its ability to kill cancer cells upon light irradiation. This shows that SiO2 shell may not only prevent aggregation but it also may enhance the photodynamic activity of Ag nanoparticles.

Photodynamic activity and DNA binding studies of Pd@SiO2 core-shell nanoparticles in vitro.

Metal-semiconductor core-shell type Pd@SiO2 nanoparticles (NPs) were successfully synthesized by Stober's method and the product was characterized by UV-vis, XRD, FT-IR, SEM, HR-TEM and EDX techniques. In vitro Photodynamic activity and DNA binding studies of Pd@SiO2 core shell nanoparticles were studied. Cell viability of the core-shell nanoparticles against HeLa cell line was screened by MTT assay after exposing at different light doses. The outcome of the present study indicates that the core-shell Pd@SiO2 NPs are highly stable and exhibited strong photodynamic efficiency under LED light illumination in HeLa cells. The results indicated that SiO2 supported on the surface of Pd NPs not only prevented the aggregation in addition exhibited remarkable photodynamic activity.