Iron Sulfide Nanoparticles: Synthesis, Characterization, and Molecular Docking Studies of Its Interaction with Bovine Serum Albumin and Human Serum Albumin

Nano-sized iron sulfides have garnered great scientific interest as they possess a wide range of varieties, topologies, and physiochemical qualities. Particularly, iron sulfides (FeS) in the nanometer range size demonstrate enzyme-like activity by imitating organic enzymes that require an iron-sulfur cluster as a cofactor, increasing their potential for use in biomedicine. Here, sodium dithionite was used as the sulfur source and iron chloride (FeCl3·3H2O) as the iron source to create iron sulfide nanoparticles through the chemical precipitation method. The synthesis of the prepared FeS nanoparticles was confirmed by using various spectroscopic studies, i.e., TEM, SEM, DLS, VSM, XRD, and EDX, validating their size, shape, hydrodynamic diameter, magnetic properties, phase composition, and elemental composition respectively. The average particle size obtained from TEM was around 83 nm, and quasi-shaped morphology was observed from SEM. The presence of iron and sulfur within the synthesized nanoparticles was confirmed by EDX. Molecular docking is an effective tool to model the interactions between a protein and small molecules at the atomic level. The ability of a nanoparticle (ligand) to interact with proteins to form a protein–ligand complex plays a crucial role in the dynamics of proteins. The binding of nanoparticles with protein may inhibit or enhance (or have no effect) the biological function of the protein. Thus, it becomes necessary/important to know whether a particular nanoparticle should be used for drug delivery or not. The binding information obtained from the molecular docking of nanoparticles and proteins may be used to decide about the same. We have studied the interaction of ferrous/iron sulfide (FeS) with bovine serum albumin (BSA) and human serum albumin (HSA) proteins through molecular docking. The binding of ferrous/iron sulfide was studied separately with both the selected proteins. Findings demonstrated that four hydrogen bonds involving hydrogen atoms from four distinct amino acid residues of BSA protein (Arg194, Ser343, Asp450, and Ser453) are predicted by the preferential binding of FeS nanoparticles to BSA protein. However, binding to HSA involved only one hydrogen bond. We have further planned to extend our docking studies to study the interaction of BSA and HSA with anticancer drugs and drug-conjugated FeS nanoparticles. The constructive outcomes of the above studies could be used to perform in vitro studies.