An investigation of the effect of PVP-coated silver nanoparticles on the interaction between clonazepam and bovine serum albumin based on molecular dynamics simulations and molecular docking

Comparative interaction of silver nanoparticles with diverse classes of proteins: Selectivity toward silk sericin protein from Antheraea assama

Nanotechnology, which investigates matter at the 1-100 nm scale, has led to significant advancements, particularly in biomedical sciences. Among nanomaterials, silver nanoparticles (AgNPs) stand out due to their unique physicochemical properties and promising biological applications. However, the mechanisms underlying AgNPs' interactions with biological molecules-especially proteins-remain key questions. In this study, we examined AgNPs interactions with various protein classes, including bovine serum albumin, bovine hemoglobin, α-amylase, and sericin from Antheraea assama. AgNPs were synthesized and characterized using powder X-ray diffraction, high-resolution transmission electron microscopy, and Zeta Sizer, revealing a crystal size of 15 nm and a zeta potential of -24.4 mV. Techniques such as UV-visible, fluorescence, circular dichroism, time-resolved fluorescence spectroscopy, isothermal titration calorimetry, molecular docking, and enzyme kinetics were used to study AgNPs-protein interactions. Our results showed simultaneous adsorption, secondary structure changes, and enhanced enzyme activity upon AgNPs binding. Notably, sericin, a random coil protein, exhibited dynamic quenching at lower AgNPs concentrations and static quenching at higher concentrations, along with thermodynamically favorable binding and hard corona formation, surrounded by dynamic outer layers due to weak protein-protein interactions. These findings emphasize the need to understand diverse biomolecular interactions before employing AgNPs in biomedical applications.

Adsorption and photocatalytic-conjugated activity of a chitosan-functionalized titanate coating for the removal of the drug clonazepam from drinking water

This research evaluated H2TiO7 nanotubes (TiNTs) functionalized with 1 (1TiCN), 5 (2TiCN), and 10 (3TiCN) wt.% of chitosan for the removal of clonazepam by an adsorption/photocatalysis-conjugated method. The samples were immobilized on glass, and their mechanical stability was tested by washings. The functionalization of the samples was verified by the FTIR and DRS techniques. SEM images displayed nanotubes in the samples and thickness of 4.24 μm for the 2TiCN coating. The chemical composition of the 2TiCN coating was obtained by EDS. The XRD patterns evidenced chitosan and titanate phases in the functionalized samples. Furthermore, the 2TiCN coating was evaluated in the removal of clonazepam, reaching 80.79% (4.38 and 49.64% more than the TiNT and commercial TiO2 powders, respectively) after 240 min and being 6.88% more efficient after 4 reuses than the 2TiCN powders. OH- ions were the main oxidizing species found by scavenger tests. The surface area of 2TiCN (168.6 m2/g) was 2 times higher than that of TiNTs, and its bandgap (2.95 eV) was the lowest. Therefore, the 2TiCN coating is an excellent alternative to remove clonazepam.

Interaction mechanism of benzophenone-type UV filters on bovine serum albumin: Insights from structure-affinity relationship

Benzophenone (BP)-type UV filters can cause structural changes of carrier protein in plasma. The binding process of five BP-type UV filters with bovine serum albumin (BSA) was investigated by multiple characterization methods, along with their structure-affinity relationship involving the structure of the five BP-type UV filters and their binding affinity for BSA. The BP-type UV filters investigated bound to BSA spontaneously, and altered conformation of BSA. The binding constants and number of binding sites between BP-type UV filters and BSA were 10³-10⁶ M^-1 and 0.82-1.26, respectively. These BP-type UV filters and BSA interacted with the same binding forces and went through the similar binding process, suggesting that the benzophenone skeleton structure was primarily responsible for the BP-type UV filters and BSA binding, and changes in the structure of the BSA. The BP-type UV filters with hydroxyl substituent (BP-1 and BP-9) and non-polar molecules (BP-6) had a high affinity for binding BSA and had a greater impact on BSA conformation.