Novel Silver-Platinum Nanoparticles for Anticancer and Antimicrobial Applications.

BACKGROUND: Cancer is a disease with an enormous worldwide impact. One of the fatal complications in cancer patients are bacterial opportunistic infections. The use of chemotherapeutic drugs made cancer remission more frequent and prolonged patient survival, but, increased the risk of infections. PURPOSE: Address the current problem with growing pandemic cancer and considering high risks of complications with bacterial infections, the present study synthesized novel dendritic assembly of silver (Ag)-platinum (Pt) nanoparticles. METHODS: Nanoparticles were characterized by TEM analysis, and the composition was confirmed by EDX. Bacterial studies were performed for Gram-positive Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa and Gram-negative multi-drug resistant Escherichia coli. Cell experiments were performed with two different cancer cell lines, glioblastoma and melanoma to determine anticancer activity. Finally, cytotoxicity with fibroblast was tested. RESULTS: The TEM analysis of silver-platinum (AgPt) nanoparticles showed dendrimer shape nanoparticles with a mean size of 42 ± 11nm. Elemental composition was analyzed by EDX, confirming the presence of both Ag and Pt metals. The synthesized nanoparticles significantly inhibited the growth of medically important pathogenic, Gram-positive Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa and Gram-negative multi-drug resistant Escherichia coli. Bactericidal effect of AgPt nanoparticles had greater effectiveness than silver nanoparticles. MTS assay revealed a selective and dose-dependent anticancer activity of AgPt nanoparticles over cancer cell lines glioblastoma and melanoma in the 10-250 µg/mL concentration range. Cytotoxicity experiments with fibroblast cells showed no side effects of nanoparticles against healthy cells at a range of concentrations from 10-50 µg/mL. CONCLUSION: The newly synthesized AgPt nanoparticles have a promising future as a potent anticancer agent with antibacterial properties.

Hydrothermal treatment of etched titanium: A potential surface nano-modification technique for enhanced biocompatibility.

Nanoengineering the topology of titanium (Ti) implants has the potential to enhance cytocompability and biocompatibility properties as implant surfaces play a decisive role in determining clinical success. Despite developments in various surface engineering strategies, antibacterial properties of Ti still need to be enhanced. Here a facile, cost-effective hydrothermal route was used to develop nano-patterned structures on a Ti surface. Changing hydrothermal treatment parameters such as temperature, pressure, and time, resulted in various topographies, crystal phases, and hydrophobicity. Specifically, hydrothermal treatment performed at 225 °C for 5 h, presented a novel topography with nanoflower features, exhibited no mammalian cell cytotoxicity for a time period of 14 days, and increased calcium deposition from osteoblasts. Treated samples also demonstrated antibacterial properties (without resorting to the use of antibiotics) against Staphylococcus aureus and methicillin resistant Staphylococcus aureus. In conclusion, hydrothermal oxidation on an etched Ti surface can generate surface properties that have excellent prospects for the biomedical field.

Tat-functionalized liposomes for the treatment of meningitis: an in vitro study.

Bacterial meningitis has become a global concern, because of the emergence of antibiotic-resistant bacteria. It has been demonstrated that liposomes can enter bacteria, thus providing a possible treatment for numerous infections, including meningitis. Fusogenic liposomes are pH-sensitive with a high capacity to fuse with the bacteria membrane and promote intracellular drug release. Moreover, this ability can be improved by using cell-penetrating peptides (such as Tat47-57, which is a peptide derived from the Tat protein of HIV). The purpose of this in vitro study was to demonstrate for the first time the ability of the presently prepared fusogenic liposomes, which were spherical particles with a diameter of 100 nm loaded with antibiotics and functionalized with-cell penetrating peptides (Tat47-57), to fight the main bacteria that cause meningitis. For this, vancomycin, methicillin, and ampicillin antibiotics were loaded inside fusogenic liposomes to fight Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Antibacterial activity of Tat-functionalized and nonfunctionalized liposomes loaded with antibiotics was tested by determining bacteria colony-forming units and growth-curve assays coupled with live/dead assays using fluorescence microscopy. Results showed a remarkable decrease in antibiotic minimum inhibitory concentration when all of the bacteria were treated with these novel liposomes, especially for the functionalized liposomes loaded with methicillin. With antibiotic concentrations of 1.7-3 µg/mL for Tat-functionalized liposomes loaded with methicillin, the bacteria population was totally eradicated. Cytotoxicity tests with astrocytes and endothelial cells, major cellular components of the blood-brain barrier, were also performed for all of the liposomes, including free antibiotic and the Tat peptide. Results showed much promise for the further study of the presently formulated liposomes to treat meningitis.