Gadolinium expressed lipid nanoparticles for magnetic resonance imaging

A nanoparticle, comprising:

• (a) a phospholipid selected from distearoyl-phosphocholine (DSPC) or dipalmitoyl sphingomyelin (DPSP);
• (b) |N-(carbonyl-methoxypolyethyleneglycol)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (mPEG-DSPE);
• and
• (c) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-diethylenetriaminepenta-acetyl (DSPE-DTPA) with a chelated Gd3+ ion, wherein the nanoparticle is not a liposome, and wherein the nanoparticle has a T1 relaxivity constant (r1) of at least about 133 sec−1 mM−1 as determined by a magnetic resonance (MR) scanner;
• wherein the mPEG-DSPE is present in the amount from about 5 to about 20 mole percent of the combined phospholipid, the mPEG-DSPE, and DSPE-DTPA, and
• wherein the phospholipid:mPEG-DSPE:DSPE-DTPA ratio is from 8:1:0.9 to 8:2:1.