Thermodynamic and kinetic stability of DSPE-PEG(2000) micelles in the presence of bovine serum albumin.
This work investigated the stability of DSPE-PEG(2000) micelles in the presence of bovine serum albumin (BSA). DSPE-PEG(2000) was found to exist in equilibrium among monomeric, micellar, and BSA-bound states, and this equilibrium shifted toward the BSA-bound state when the temperature increased from 20 to 37 °C. The micellar state is thermodynamically unstable at both temperatures when the concentration of BSA approaches that of DSPE-PEG(2000), and micelle breakup occurs with a first-order time constant of 130 ± 9 min at 20 °C and 7.8 ± 1.6 min at 37 °C. Thus, previous targeting experiments that demonstrate synergistic effects in multiply functionalized DSPE-PEG(2000) micelles are likely due to targeting that occurs on a timescale faster than that of micelle breakup. Micelle breakup was limited by diffusion at 20 °C whereas at 37 °C monomer desorption from the micelle was the rate-limiting step. These findings give clear guidance concerning the lifetimes of micelles that may be used as diagnostic and therapeutic nanoparticles.
Kastantin
Mark
M
Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
Missirlis
Dimitris
D
Black
Matthew
M
Ananthanarayanan
Badriprasad
B
Peters
David
D
Tirrell
Matthew
M
D000818:Animals; D002417:Cattle; D007700:Kinetics; D008823:Micelles; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D008823:Micelles; D010714:Phosphatidylethanolamines; C038089:1,2-distearoylphosphatidylethanolamine; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols