Magnetic core/shell Fe₃O₄/Au nanoparticles for studies of quinolones binding to protein by fluorescence spectroscopy

Abstract

Magnetic core/shell Fe3O4/Au nanoparticles were used in the determination of drug binding to bovine serum albumin (BSA) using a fluorescence spectroscopic method. The binding constants and number of binding sites for protein with drugs were calculated using the Scatchard equation. Because of their superparamagnetic and biocompatible characteristics, magnetic core/shell Fe3O4/Au nanoparticles served as carrier proteins for fixing proteins. After binding of the protein to a drug, the magnetic core/shell Fe3O4/Au nanoparticles-protein-drug complex was separated from the free drug using an applied magnetic field. The free drug concentration was obtained directly by fluorescence spectrometry and the proteins did not influence the drug determination. So, the achieved number of binding sites should be reliable. The binding constant and site number for ciprofloxacin (CPFX) binding to BSA were 2.055 × 10(5) L/mol and 31.7, and the corresponding values for norfloxacin (NOR) binding to BSA were 1.383 × 10(5) L/mol and 38.8. Based on the achieved results, a suitable method was proposed for the determination of binding constants and the site number for molecular interactions. The method was especially suitable for studies on the interactions of serum albumin with the active ingredients of Chinese medicine.

Surface Modification of Magnetic Iron Oxide Nanoparticles

“…Carboxylic acid groups adsorbed AuCl 4 under acidic condition, and then NaBH 4 was added to form zero-valent Au which attached to Fe 3 O 4 NPs through the chemistry of the carboxylate group, and gradually the gold shell was formed around Fe 3 O 4 NPs [ 124 ]. Hydroxylamine hydrochloride is another reducing agent used [ 125 ].…”

Construction of polylysine dendrimer nanocomposites carrying nattokinase and their application in thrombolysis

“…Currently, fluorescence spectroscopy is the most widely used method for studying the interaction between proteins and other molecules . In general, the fluorescence of proteins is mainly due to tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) residues, and its endogenous fluorescence is mainly derived from Trp residues.…”

Iron Oxide and Gold Based Magneto-Plasmonic Nanostructures for Medical Applications: A Review

“…It offers a protective layer from aggregation and/or oxidation to the embedded NPs. In addition, incorporation of molecular dyes and/or drugs inside the carriers provides advantages for a wide range of biomedical applications [ 23 , 24 , 25 , 26 , 27 ]. This kind of NSs is usually produced by the self-assembly (or sol-gel process) of polymer and silica wrap to preformed functional NPs, including iron oxide and gold particles.…”