For the purpose of tracking the uptake of micelles by macrophages, QDs were incorporated into find more the micelle preparations because of its extreme brightness and photostability in real time imaging. Furthermore, QDs can be substituted by other inorganic nanoparticles such as gadolinium, iron oxide, gold, and tantalum for clinical translation. The PS micelles were further assembled with an amphiphilic polymeric surfactant, phospholipid conjugated to polyethylene glycol (PL-PEG) for the solubilization of hydrophobic nanoparticles (QD), improved dispersibility of micelles

in physiological buffers and prolonged circulation in vivo [14]. However, PEGylation can potentially interfere with the interactions between ligand and cell surface receptor and reduce cellular uptake [17, 18], a fine balance between stability and targeting for PEGylated nanoparticles were extensively studied. We hypothesize that the ratio of PL-PEG and PS shell coverage for 6- to 8-nm hydrophobic trioctylphosphine oxide (TOPO) quantum dot (QD) could be optimized for colloidal stability and targeting efficacy. Methods Materials L-α-phosphatidylserine MK-8669 in vitro (PS), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (ammonium salt) (DSPE-mPEG, 2kDa) were purchased from Avanti Polar Lipids, Inc. (Alabaster, AL, USA). All other chemicals were obtained from Sigma-Aldrich Corporation (St. Louis,

MO, USA). Dulbecco’s modified Eagle’s medium (DMEM), fetal bovine serum (FBS), phosphate-buffered saline (PBS), penicillin-streptomycin, Montelukast Sodium and hydrophobic

trioctylphosphine oxide (TOPO) QDs (QD 620nm) were purchased from Ocean Nanotech, Corp (Carlsbad, CA, USA). MTT assay kit was purchased from Roche Applied Science (Indianapolis, IN, USA). Lab-TekTM chamber slide system was purchased from Thermo Scientific/Nalgene Nunc International (Rochester, NY, USA). Vectashield mounting medium with DAPI was purchased from Vector Laboratories, Inc. (Burlingame, CA, USA). J774A.1 monocytic cell line was obtained from American Type Cell line Collection (ATCC) (ATCC® TIB67™). A 100-kD dialysis membrane was purchased from Spectrum Laboratories (Irvine, CA, USA). Preparation of PS-QD micelles Micelles were prepared by the addition of hydrophobic QDs in chloroform to phospholipids (PLs) at each mole ratio (PEG/PS 100:0, 60:40, 50:50, 40:60, and 0:100) in hot water under vigorous stirring, followed by high-speed homogenization to form a uniform milky micro-emulsion. Unless otherwise mentioned, only PS mole ratio is shown and the remaining assumed for PL-PEG mole ratio (for example, PS (0) means micelles made entirely from phospholipid methoxy PEG, PS (40) means PS/PL-PEG mole ratio is 60:40). Briefly, the PLs at various mole ratios as indicated in Table 1 were first dissolved in water at 50°C and QD 620 (0.2 nmol) dissolved in chloroform was added to PLs in water and briefly sonicated for a few minutes.