Micelles formed by pluronic triblock copolymers are known to be a promising class of drug delivery vehicles.

Bovine serum albumin (BSA) is an important transport protein of the blood and its aggregation/fibrillation would adversely affect its transport ability leading to metabolic disorder. Therefore, understanding the mechanism of fibrillation/aggregation of BSA and design of suitable inhibitor molecules for stabilizing its native conformation, are of utmost importance. The qualitative and quantitative aspects of the effect of osmolytes (proline, hydroxyproline, glycine betaine, sarcosine and sorbitol) on heat induced aggregation/fibrillation of BSA at physiological pH (pH 7.4) have been studied employing a combination of fluorescence spectroscopy, Rayleigh scattering, isothermal titration calorimetry (ITC), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Formation of fibrils by BSA under the given conditions was confirmed from increase in fluorescence emission intensities of Thioflavin T over a time period of 600 minutes and TEM images. Absence of change in fluorescence emission intensities of 8-Anilinonaphthalene-1-sulfonic acid (ANS) in presence of native and aggregated BSA signify the absence of any amorphous aggregates. ITC results have provided important insights on the energetics of interaction of these osmolytes with different stages of the fibrillar aggregates of BSA, thereby suggesting the possible modes/mechanism of inhibition of BSA fibrillation by these osmolytes. The heats of interaction of the osmolytes with different stages of fibrillation of BSA do not follow a trend, suggesting that the interactions of stages of BSA aggregates are osmolyte specific. Among the osmolytes used here, we found glycine betaine to be supporting and promoting the aggregation process while hydroxyproline to be maximally efficient in suppressing the fibrillation process of BSA, followed by sorbitol, sarcosine and proline in the following order of their decreasing potency: Hydroxyproline> Sorbitol> Sarcosine> Proline> Glycine betaine.

Serum albumins being the most abundant proteins in the blood and cerebrospinal fluid are significant carriers of essential transition metal ions in the human body. Studies of copper (II) complexes have gained attention because of their potential applications in synthetic, biological, and industrial processes. Study of binding interactions of such bioinorganic complexes with serum albumins improves our understanding of biomolecular recognition process essential for rational drug design. In the present investigation, we have applied quantitative approach to explore interactions of novel synthesized copper (II) complexes viz. [Cu(L¹)(L²)ClO₄] (complex I), [Cu(L²)(L³)]ClO₄] (complex II) and [Cu(L⁴)₂(H₂O)₂] (complex III) with bovine serum albumin (BSA) to evaluate their binding characteristics, site and mode of interaction. The fluorescence quenching of BSA initiated by complexation has been observed to be static in nature. The binding interactions are endothermic driven by entropic factors as confirmed by high sensitivity isothermal titration calorimetry. Changes in secondary and tertiary structure of protein have been studied by circular dichroism and significant reduction in α-helical content of BSA was observed upon binding. Site marking experiments with warfarin and ibuprofen indicated that copper complexes bind at site II of the protein.