Interaction and energy transfer studies between bovine serum albumin and CdTe quantum dots conjugates: CdTe QDs as energy acceptor probes.
In this paper, a systematic investigation of the interaction of bovine serum albumin (BSA) with water-soluble CdTe quantum dots (QDs) of two different sizes capped with carboxylic thiols is presented based on steady-state and time-resolved fluorescence measurements. Efficient Förster resonance energy transfer (FRET) was observed to occur from BSA donor to CdTe acceptor as noted from reduction in the fluorescence of BSA and enhanced fluorescence from CdTe QDs. FRET parameters such as Förster distance, spectral overlap integral, FRET rate constant and efficiency were determined. The quenching of BSA fluorescence in aqueous solution observed in the presence of CdTe QDs infers that fluorescence resonance energy transfer is primarily responsible for the quenching phenomenon. Bimolecular quenching constant (kq) determined at different temperatures and the time-resolved fluorescence data provide additional evidence for this. The binding stoichiometry and various thermodynamic parameters are evaluated by using the van 't Hoff equation. The analysis of the results suggests that the interaction between BSA and CdTe QDs is entropy driven and hydrophobic forces play a key role in the interaction. Binding of QDs significantly shortened the fluorescence lifetime of BSA which is one of the hallmarks of FRET. The effect of size of the QDs on the FRET parameters are discussed in the light of FRET parameters obtained.
Laser Spectroscopy Programme, Department of Physics and UGC-Centre with Potential for Excellence (CPEPA), Karnatak University, Dharwad, India.
M G
MG
Kotresh
Molecular Endocrinology and Development Laboratory, Department of Zoology, and UGC-CPEPA, Karnatak University, Dharwad, India.
L S
LS
Inamdar
Laser Spectroscopy Programme, Department of Physics and UGC-Centre with Potential for Excellence (CPEPA), Karnatak University, Dharwad, India.
M A
MA
Shivkumar
Laser Spectroscopy Programme, Department of Physics and UGC-Centre with Potential for Excellence (CPEPA), Karnatak University, Dharwad, India.
K S
KS
Adarsh
Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India.
B N
BN
Jagatap
BLDE University, Bijapur, India.
B G
BG
Mulimani
Department of Biochemistry, Davangere University, Davangere, India.
G M
GM
Advirao
Laser Spectroscopy Programme, Department of Physics and UGC-Centre with Potential for Excellence (CPEPA), Karnatak University, Dharwad, India.
S R
SR
Inamdar
D019187:Cadmium Compounds / Q000737:chemistry*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D045663:Quantum Dots / Q000737:chemistry* / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013691:Tellurium / Q000737:chemistry*; D013816:Thermodynamics
D019187:Cadmium Compounds; D012710:Serum Albumin, Bovine; D013691:Tellurium; C028337:cadmium telluride
CdTe QDs; FRET; Gibb's free energy; bovine serum albumin; enthalpy; entropy; spectral overlap