Multispectroscopic and computational study of interaction of the bovine serum albumin with atropine and atropine-loaded chitosan nanoparticles (synthesized and characterized)

Two different systems of bovine serum albumin (BSA) were used for multiple spectroscopic and computational studies to determine interaction of BSA and atropine (Atrop), that is, BSA-Atrop system and Atrop-loaded chitosan nanoparticles (Atrop@CS NPs), that is, BSA-Atrop@CS NPs system. The study suggests that BSA-Atrop system and BSA-Atrop@CS NPs system involve non-fluorescent complexes of K-sv = 3.2 x 10(3) Lmol(-1) and 3.1 x 10(4) Lmol(-1), k(q) = 3.2 x 10(11) Lmol(-1) s(-1) and 3.1 x 10(12) Lmol(-1) s(-1), the binding constant K-b = 1.4 x 10(3) Lmol(-1), 2.0 x 10(2) Lmol(-1), respectively, and number of binding sites n similar to 1 for both the systems. The negligible conformational changes induced in BSA were also observed. Synchronous fluorescence spectroscopic study revealed that more quenching occurred in intrinsic fluorescence of tryptophan (Trp, W) than that in tyrosine residue (Tyr, Y). UV-vis spectroscopic study verified the presence of static quenching from the presence of BSA-Atrop and BSA-Atrop@CS NPs complexes. CD spectra confirmed the conformational changes induced in BSA upon increment of concentrations of Atrop and Atrop@CS NPs separately into the constant concentration of BSA. The coherent observations from various spectroscopic studies were in agreement with those of computational study, showing BSA-Atrop complex formation and other related details. The hydrogen bonds (H-bonds), van der Walls (vdW) interactions and p-type of interactions were mainly involved in stabilization of the formed BSA-Atrop complex.

Automated summary

Two different systems, BSA-Atrop system and BSA-Atrop@CS NPs system, were used to study the interaction of bovine serum albumin (BSA) with atropine (Atrop). The study showed the formation of non-fluorescent complexes with binding constants and rates in both systems. Negligible conformational changes were observed in BSA. The spectroscopic studies and computational study provided consistent results, revealing the formation of BSA-Atrop complex and the involvement of hydrogen bonds, van der Waals interactions, and p-type interactions in stabilizing the complex.