Synthesis, Spectroscopic Characterization and Antibactrial Activities of Co(II) Complex of Ofloxacin Drug Mixed with Ascorbic Acid as secondary ligand

Ofloxacin is a quinolone antibiotic that is considered an efficient antibacterial drug with a broad spectrum of activity against anaerobic and aerobic bacteria and has strong antibacterial activity in vitro against many bacteria species by inhibiting their DNA-gyrase. In this study, the synthesis, physicochemical and spectroscopic characterization of Cobalt (II) metal complex with ofloxacin as primary ligand and ascorbic acid as the secondary ligand have been carried out. The complex was prepared by reflux method for four hours in methanol. The complex, with the molecular formula [Co(Ofl)(Asc)], was characterized by its color, solubility, melting point, FTIR, UV/Visible, 1H NMR, and 13C NMR spectroscopy. The color and the melting point suggest that complexation occurred. The Fourier Transform Infrared data for both the primary ligand (Ofl) and the secondary ligand (Asc) acted as tridentate ligands. Ofl coordinated to the Co(II) metal ion via the two carbonyl oxygen atoms and the oxygen atom of the hydroxyl group, whereas Asc coordinated to the metal through the carbonyl and enolic C-2 and C-3 hydroxyl groups. The electronic data suggests octahedral geometry for the complex. The ligands and the novel Co (II) complex were tested for in vitro antibacterial activity against gram-negative and gram-positive bacterial species using the filter paper disc agar diffusion method. Significant antibacterial activities were observed for the complex compared to the ligands. This research will aid in the development of more potent drugs that are resistant to organisms.

The use of nanobodies in a sensitive ELISA test for SARS-CoV-2 Spike 1 protein

Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in the fluid has important uses in biotechnology, and is integral to many point-of-care SARS-CoV-2 diagnostics. Sandwich enzyme-linked immunosorbent assays (ELISAs) are a sensitive, well-established method of measuring antigens in solutions. They use one ligand to capture and the other ligand to detect the target analyte. Detection is commonly achieved using colorimetric readout obtained upon the reaction of a substrate with HRP-conjugated secondary ligand. Nanobodies, the V H H domain of camelid antibodies, have expanded the repertoire of molecules used in antigen detection. Nanobodies' high affinity for target antigens, their compact structure, their high stability and ease of production has driven research into their use as diagnostic reagents. Guided by a structural understanding of epitopes on the receptor-binding domain of the SARS-CoV-2 Spike protein, we investigated various combinations of engineered nanobodies in a sandwich ELISA to detect the Spike protein of SARS-CoV-2. We have identified an optimal combination of nanobodies. These were selectively functionalized to further improve antigen capture, enabling the measurement of sub-picomolar amounts of SARS-CoV-2 Spike protein in solution. With this combination, the routine detection limit in samples inactivated by heat and detergent corresponded to less than seven focus-forming units of infectious SARS-CoV-2.

Homoleptic Quasilinear Metal(I/II) Silylamides of Cr – Co with Phenyl and Allyl Functions – Impact of Oxidation State on Secondary Ligand Interactions

Herein we describe the synthesis and characterization of a variety of new quasilinear metal(I/II) silylamides of the type [M(N(Dipp)SiR3)2]0,− (M = Cr − Co) with different silyl substituents (SiR3 =...

Chemical sensors based on a Eu (III)-centered Periodic Mesoporous Organosilica hybrid material using picolinic acid as an efficient secondary ligand

Through a series of post synthetic modification methods applied to the 100% trans ethenylene-bridged Periodic Mesoporous Organosilica (ePMO), the lanthanide-functionalized hybrid nanomaterial ePMO@Eu_PA (PA= picolinic acid) has been prepared. The...

Introduction of Secondary Ligand in Titanium-Based Metal-Organic Frameworks for Visible-Light-Driven Photocatalytic Hydrogen Peroxide Production from Dioxygen Reduction

Introduction of multiple components with specific properties in metal–organic frameworks (MOFs) is an attractive strategy to modify their catalytic properties. Herein, through the introduction of ligand 4,4’,4’’,4’’’-(pyrene-1,3,6,8-tetrayl)tetrabenzoic acid (L2) in...