Abstract
The possibility to easily and rapidly assess the presence of Gd3+ ions in solution is of paramount importance in many domains like magnetic resonance imaging. In that context, the use of easy to implement colorimetric sensing probes based on gold nanoparticles (AuNPs) is of special interest. Herein, AuNPs functionalized with a commercial bis(p-sulfonatophenyl)phenyl phosphine ligand (BSPP) (AuNP@BSPP), bearing negatively charged sulfonate groups are used as a colorimetric sensing probe. The addition of Gd3+ ions onto these NPs was studied through UV-visible absorbance measurements, Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and transmission electron microscopy and compared with citrate covered AuNPs. We evidenced interactions between the Gd3+ ions and their water rich coordination sphere and sulfonate groups on the surface of AuNP@BSPP via electrostatic interactions and hydrogen bonding. These interactions induce the reversible aggregation of AuNP@BSPP in the presence of concentrations of Gd3+ ions at a μM level. We took advantage of this phenomenon to develop a simple and fast bench colorimetric assay for the detection of free Gd3+ ions, based on the determination of a flocculation parameter thanks to UV-visible measurements. Limits of detection and quantification were found equal to 0.74 μM and 4.76 μM of Gd3+ ions, respectively, with a high sensitivity that competes with conventional methods used for lanthanide detection.
Highlights
Lanthanide ions have seen their eld of application increased in recent years, for their catalytic, optical and magnetic properties
The possibility to and rapidly assess the presence of Gd3+ ions in solution is of paramount importance in many domains like magnetic resonance imaging
AuNPs functionalized with a commercial bis(p-sulfonatophenyl)phenyl phosphine ligand (BSPP) (AuNP@BSPP), bearing negatively charged sulfonate groups are used as a colorimetric sensing probe
Summary
Lanthanide ions have seen their eld of application increased in recent years, for their catalytic, optical and magnetic properties. A slight increase of the maximum absorbance of the surface plasmon resonance peak and a red shi from 522 to 523 nm is observed upon addition of the phosphine ligand due to changes of the dielectric environment around nanoparticles.[5,13] An average diameter of 17.2 Æ 4.0 nm was measured from TEM images (Fig. 2B) in good agreement with pristine AuNP@citrate.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
