Electrostatic and covalent contributions in the coordination bonds of transition metal complexes

Green synthesis of novel stable biogenic gold nanoparticles for breast cancer therapeutics via the induction of extrinsic and intrinsic pathways

Biosynthesis of gold nanoparticles (AuNPs) using algal polysaccharides is a simple, low-cost, and an eco-friendly approach. In the current study, different concentrations of Arthospira platensis exopolysaccharides (EPS) were used to synthetize AuNPs via the reduction of gold ions. The biologically synthesized AuNPs (AuNPs1, AuNPs2, AuNPs3) were prepared in 3 different forms through the utilization of three different ratios of EPS-reducing agents. AuNPs analysis confirmed the spherical shape of the EPS-coated AuNPs. Furthermore, AuNPs prepared by EPS and l-ascorbic acid (AuNPs3) showed more stability than the AuNPs colloidal solution that was prepared using only l-ascorbic acid. Analysis of the antimicrobial effects of AuNPs showed that E. coli was the most sensitive bacterial species for AuNPs3 and AuNPs1 with inhibition percentages of 88.92 and 83.13%, respectively. Also, safety assay results revealed that AuNPs3 was the safest biogenic AuNPs for the tested noncancerous cell line. The anticancer assays of the biogenic AuNPs1, AuNPs2, and AuNPs3 against MCF-7 cell line indicated that this cell line was the most sensitive cell line to all treatments and it showed inhibition percentages of 66.2%, 57.3%, and 70.2% to the three tested AuNPs, respectively. The AuNPs also showed abilities to arrest MCF-7 cells in the S phase (77.34%) and increased the cellular population in the sub G0 phase. Gene expression analysis showed that AuNPs3 down regulated Bcl2, Ikapα, and Survivn genes in MCF-7 treated-cells. Also, transmission electron microscopy (TEM) analysis of MCf-7 cells revealed that AuNPs 3 and AuNPs2 were localized in cell vacuoles, cytoplasm, and perinuclear region.

Plasmonic gold nanostars for multi-modality sensing and diagnostics

Gold nanostars (AuNSs) are unique systems that can provide a novel multifunctional nanoplatform for molecular sensing and diagnostics. The plasmonic absorption band of AuNSs can be tuned to the near infrared spectral range, often referred to as the "tissue optical window", where light exhibits minimal absorption and deep penetration in tissue. AuNSs have been applied for detecting disease biomarkers and for biomedical imaging using multi-modality methods including surface-enhanced Raman scattering (SERS), two-photon photoluminescence (TPL), magnetic resonance imaging (MRI), positron emission tomography (PET), and X-ray computer tomography (CT) imaging. In this paper, we provide an overview of the recent development of plasmonic AuNSs in our laboratory for biomedical applications and highlight their potential for future translational medicine as a multifunctional nanoplatform.