Narrow Results

Cancer threatens the life and well-being of human beings. Millions of newly diagnosed cancer cases and a large number of deaths caused by cancer are reported each year in the world. Early detection and effective treatment are key to reduce cancer mortality, which can be potentially realized by using “theranostics”. Theranostics are a group of hybrid nanoparticles that perform in cancer patients to provide both diagnostic and therapeutic functions through a single nano-sized structure. In particular, core-shell structured theranostics have shown unique physicochemical properties, allowing them to facilitate molecular/cell targeting, bio-imaging, and drug delivery functions. This review, therefore, aims to present and discuss the recent development of research on core-shell structured theranostics. Specifically, it focuses on core-shell structured theranostics made of metals, silica and polymers. Different aspects, such as synthesis and structure, of core-shell structured theranostics are discussed in this review. This review helps readers to have a good understanding of the design and fabrication of core-shell structured theranostics.

Due to their distinct structural, electrical, and electrochemical properties, macrocyclic complexes have been recognized as potential models in a variety of areas, including electrocatalysis, biology, and medicine. In this study, two hexa-aza-macrocyclic complexes of Ni(II) and Cu(II) transition metals (denoted as [NiL] and [CuL]) were synthesized via template procedure. Based on the results of multiple spectroscopic characterization, a distorted octahedral geometry was proposed for both the complexes. The electrochemical results showed that the macrocyclic framework can stabilize the unusual oxidation states of Ni(II) and Cu(II) transition metal ions, as evidenced by the corresponding quasi-reversible Ni(II)/(III) and Cu(II)/(III) redox couples. Additionally, both the complexes were found to be promising antibacterial agents against the B. subtilis, S. aureus, P. aeruginosa, and E. coli pathogens. The Cu(II) complex had the largest inhibition zone (22mm) against B. subtilis, while the Ni(II) complex had the smallest (15mm).

Synthetic protocols for the preparation of nanomaterials chemically are expensive, too much time taking and unfriendly to the environment, therefore, phyto-assisted approach has the potential to be a promising alternative strategy for the synthesis of nanomaterials. Herein, Fe₂O₃ with nanoflower-like architecture (Fe₂O₃ NFs) was prepared using Moringa oleifera leaf extract, and characterized by employing several analytical techniques. The antimicrobial activity of the prepared Fe₂O₃ NFs was evaluated against the bacteria viz. Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Escherichia coli by using the serial dilution method. The results suggested that Fe₂O₃ NFs possess comparable antimicrobial activity comparable with streptomycin against the used pathogens.

The tailoring of the coordination environment around a central metal ion by changing ligands in macrocyclic complexes is one of the key approaches to monitoring their functions in various applications. Herein, two macrocyclic complexes of Co(II) transition metal ion, tetra-aza and penta-aza, were synthesized using a condensation reaction between different diamine and dicarboxylic precursors. The prepared complexes were analyzed using various characterization techniques. Further, the electrochemical behavior of both the tetra-aza and penta-aza complexes was investigated using cyclic voltammetry. The Co(II)-penta-aza-complex exhibited a quasi-reversible redox couple for Co(III)/Co(II) transition in the more anodic region as compared to Co(II)-tetra-aza-complex. According to theoretical calculations, the fifth N-coordination transferred a high electron density in the eg-orbital of Co-atom of penta-aza-complex, resulting in an anodic shift in the Co(III)/Co(II) redox potential when compared to the Co(II)-tetra-aza-complex. Furthermore, both complexes were tested for antimicrobial activity against P. aeruginosa, E. coli, S. aureus, and B. subtilis, with the results indicating that Co(II)-penta-aza-complex had higher antimicrobial activity against these bacteria than Co(II)-tetra-aza-complex. This study offers new insight into tailoring the electrochemical and biological features of macrocyclic complexes by tuning the coordination environment around the central metal ion.