Interaction of Globular Plasma Proteins with Water‐Soluble CdSe Quantum Dots

Abstract

The interactions between water-soluble semiconductor quantum dots [hydrophilic 3-mercaptopropionic acid (MPA)-coated CdSe] and three globular plasma proteins, namely, bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and human serum albumin (HSA), are investigated. Acidic residues of protein molecules form electrostatic interactions with these quantum dots (QDs). To determine the stoichiometry of proteins bound to QDs, we used dynamic light scattering (DLS) and zeta potential techniques. Fluorescence resonance energy transfer (FRET) experiments revealed energy transfer from tryptophan residues in the proteins to the QD particles. Quenching of the intrinsic fluorescence of protein molecules was noticed during this binding process (hierarchy HSA<β-Lg <BSA, lower binding affinity for hydrophobic protein molecules). Upon binding with QD particles, the protein molecules underwent substantial conformational changes at the secondary-structure level (50 % helicity lost), due to loss in hydration.

Quantum dots in nanomedicine: recent trends, advances and unresolved issues

“…Some of these interactions where the macromolecular scaffolds can serve as templates for ultra-small nanoparticles deposition and resulting changes in protein folding (summarised by Shemetov et al [121]), are bound to have profound bilateral effects both of protein and QDs properties. Indeed, Pathak et al more recently studied the interactions between water-soluble MPA-coated semiconductor CdSe QDs and three globular plasma proteins, including bovine serum albumin, b-lactoglobulin and human serum albumin and found that acidic residues of these proteins engaged in electrostatic interactions with QDs and upon binding with QDs, protein molecules underwent substantial conformational changes at the secondary-structure level with up to 50% loss in helicity [122]. Maffre et al investigated the adsorption of human serum albumin onto FeePt nanoparticles, CdSe/ZnS QDs, Au and Ag nanoclusters of 6, 5 and 1e4 nm radii, respectively.…”

Nano-Bio Interaction between Blood Plasma Proteins and Water-Soluble Silicon Quantum Dots with Enabled Cellular Uptake and Minimal Cytotoxicity

“…As an alternative, researchers choose semiconductor quantum dots (QDs) because of their high quantum yield and low photobleaching characters. Previously studied QDs that exhibit a molecular interaction with proteins consist of toxic heavy metal ions, such as cadmium, lead, selenium, or mercury [ 9 , 10 , 11 ].…”

Release of Warfarin from Human Serum Albumin by Water‐soluble CdSe Nanotetrapods

“…[48] Fluorescence investigation of bioconjugates comprising quantum dots and bovine serum albumin (BSA) has indicated the formation of a protein layer on the quantum dots. [49,50] Dye-quantum dot conjugates have been used for ratiometric sensing of proteins. [51] Literature report on water soluble nanotetrapods is scarce.…”