No abstract

In this work, doxorubicin (Dox)-encapsulated poly(vinyl caprolactam) (PVCL)-based three-dimensional nanogel networks were developed and were crosslinked with disulfide linkages. The nanogels degrade rapidly to low molecular weight chains in the presence of the typical intracellular concentration of glutathione. Doxorubicin (Dox) was successfully encapsulated into these nanogels. The nanogels have a high drug loading of 49% and can be tailored to 182 nm to deliver themselves to the targeted cells and release Dox under dual stimuli conditions, such as redox and temperature. By evaluating cell viability in the HepG2 cell line, we observed that Dox-loaded nanogels effectively killed the cancer cell. Fluorescence microscopy results show that the nanogels could easily be internalized with HepG2 cells. The results confirm that the nanogels destabilized in intracellular cytosol via degradation of disulfide bonds in nanogels networks and release of the Dox nearby the nucleus. These carriers could be promising for cancer drug delivery.

The biological synthesis of nanoparticles has been emerging as an environmentally benign and eco-friendly method owing to its cost-effectiveness and high efficiency. Recently, the biological synthesis of semiconductor and metal-doped semiconductor nanoparticles with enhanced photocatalytic degradation efficiency and anticancer and antibacterial properties have gained tremendous attention. In pursuit of this purpose, for the first time, we biosynthesized zinc oxide (ZnO) and silver/ZnO nanocomposites (NCs) as semiconductor and metal-doped semiconductor nanoparticles, respectively, using the cell-free filtrate (CFF) of Lysinibacillus sphaericus bacterium. The biosynthesized ZnO and Ag/ZnO were characterized by various techniques such as ultraviolet-visible spectroscopy, X-ray diffraction, Fourier-transform Infrared spectroscopy, Field-emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The photocatalytic degradation potential of these semiconductor/metal-semiconductor nanoparticles was evaluated against the degradation of azo dye methylene blue (MB) under simulated solar irradiation. Ag/ZnO showed 90.7 ± 0.91% photocatalytic degradation of MB, compared to 50.7 ± 0.53% by ZnO in 120 min. The cytotoxicity of ZnO and Ag/ZnO on human cervical HeLa cancer cells was determined using an MTT assay. Both nanomaterials exhibited cytotoxicity in a concentration-dependent and time-dependent manner on HeLa cells. The antibacterial activity was also determined against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). Compared to ZnO, Ag/ZnO NPs showed higher antibacterial activity. Hence, the biosynthesis of semiconductor nanoparticles could be a promising strategy for developing hybrid metal/semiconductor nanomaterials for different biomedical and environmental applications.

The biological synthesis of nanocomposites has become cost-effective and environmentally friendly and can achieve sustainability with high efficiency. Recently, the biological synthesis of semiconductor and metal-doped semiconductor nanocomposites with enhanced photocatalytic degradation efficiency, anticancer, and antibacterial properties has attracted considerable attention. To this end, for the first time, we biosynthesized zinc oxide (ZnO) and silver/ZnO nanocomposites (Ag/ZnO NCs) as semiconductor and metal-doped semiconductor nanocomposites, respectively, using the cell-free filtrate (CFF) of the bacterium Lysinibacillus sphaericus. The biosynthesized ZnO and Ag/ZnO NCs were characterized by various techniques, such as ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The photocatalytic degradation potential of these semiconductor NPs and metal-semiconductor NCs was evaluated against thiazine dye, methylene blue (MB) degradation, under simulated solar irradiation. Ag/ZnO showed 90.4 ± 0.46% photocatalytic degradation of MB, compared to 38.18 ± 0.15% by ZnO in 120 min. The cytotoxicity of ZnO and Ag/ZnO on human cervical HeLa cancer cells was determined using an MTT assay. Both nanomaterials exhibited cytotoxicity in a concentration- and time-dependent manner on HeLa cells. The antibacterial activity was also determined against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). Compared to ZnO, Ag/ZnO NCs showed higher antibacterial activity. Hence, the biosynthesis of semiconductor nanoparticles could be a promising strategy for developing hybrid metal/semiconductor nanomaterials for different biomedical and environmental applications.