Study of Fluorinated Quantum Dots-Protein Interactions at the Oil/Water Interface by Interfacial Surface Tension Changes

Abstract

Understanding the interaction of nanoparticles with proteins and how this interaction modifies the nanoparticles’ surface is crucial before their use for biomedical applications. Since fluorinated materials are emerging as potential imaging probes and delivery vehicles, their interaction with proteins of biological interest must be studied in order to be able to predict their performance in real scenarios. It is known that fluorinated planar surfaces may repel the unspecific adsorption of proteins but little is known regarding the same process on fluorinated nanoparticles due to the scarce examples in the literature. In this context, the aim of this work is to propose a simple and fast methodology to study fluorinated nanoparticle-protein interactions based on interfacial surface tension (IFT) measurements. This technique is particularly interesting for fluorinated nanoparticles due to their increased hydrophobicity. Our study is based on the determination of IFT variations due to the interaction of quantum dots of ca. 5 nm inorganic core/shell diameter coated with fluorinated ligands (QD_F) with several proteins at the oil/water interface. Based on the results, we conclude that the presence of QD_F do not disrupt protein spontaneous film formation at the oil/water interface. Even if at very low concentrations of proteins the film formation in the presence of QD_F shows a slower rate, the final interfacial tension reached is similar to that obtained in the absence of QD_F. The differential behaviour of the studied proteins (bovine serum albumin, fibrinogen and apotransferrin) has been discussed on the basis of the adsorption affinity of each protein towards DCM/water interface and their different sizes. Additionally, it has been clearly demonstrated that the proposed methodology can serve as a complementary technique to other reported direct and indirect methods for the evaluation of nanoparticle-protein interactions at low protein concentrations.

Surface‐Active Fluorinated Quantum Dots for Enhanced Cellular Uptake

“…The non‐fluorinated QD_TOPO were used as a control because they are also hydrophobic but lack fluorine atoms. Interfacial tension measurements performed by using the pendant drop method revealed the hydrophobic character of both QDs and that QD_F are more hydrophobic than QD_TOPO (Figure S5, Supporting Information).…”

Recent Developments in the Design of Non-Biofouling Coatings for Nanoparticles and Surfaces

“…For instance, fluorinated quantum dots of a 5 nm core diameter have been used to trap enzymes through hydrophobic interactions [85], for which it could be expected that those fluorinated QDs may form a protein corona. In addition, interfacial tension studies using those same fluorinated QDs showed that they do not prevent protein film formation at the water/oil interface when exposed to bovine serum albumin, apotransferrin, or fibrinogen, although at low protein concentrations, the film formation was slower than in the absence of QDs [86].…”

Nanoscale Biocompatible Structures Generated from Fluorinated Tripodal Phenylenes on Gold Nanoprisms

“…For instance, fluorinated quantum dots (QDs) of a 5 nm core diameter have been used to trap enzymes through hydrophobic interactions, [44] for which it could be expected that those fluorinated QDs may form a protein corona. [45] …”

“…For instance, fluorinated quantum dots (QDs) of a 5 nm core diameter have been used to trap enzymes through hydrophobic interactions, [44] for which it could be expected that those fluorinated QDs may form a protein corona. [45] Fluorinated NPs with 3 kDa PEG linkers were used to study protein corona formation through 19 F-based diffusion nuclear magnetic resonance (NMR) spectroscopy. [46] Changes in the diffusion coefficients (and hence in the size) of several fluorinated gold NPs were monitored by exposing them to single proteins, such as human serum albumin, but also to more complex media, such as blood, plasma, or cells.…”

“…Not many NPs with fluorine atoms exposed on the surface have so far been reported in a biological context and their interactions with proteins have scarcely been studied. For instance, fluorinated quantum dots (QDs) of a 5 nm core diameter have been used to trap enzymes through hydrophobic interactions, [44] for which it could be expected that those fluorinated QDs may form a protein corona [45] …”