Table 1.

Chemical Characterization of NDG^a

	NDG	NDA	Gd–C5–COOH
Gd(III) content (μmol mg−1)	1.5 ± 0.2	n.a.	n.a.
primary amines (μmol mg−1)	0.2 ± 0.1	1.6 ± 0.3	n.a.
r1 at 1.4 T (mM−1 s−1)	11.1 ± 0.9	n.a.	6.4 ± 0.8
r2 at 1.4 T (mM−1 s−1)	16.1 ± 0.9	n.a.	10.4 ± 0.8
r1/r2 at 1.4 T	0.69	n.a	0.61
r1 at 7 T (mM−1 s−1)	11.5 ± 0.8	n.a	4.8 ± 0.7
r2 at 7 T (mM−1 s−1)	15.5 ± 0.8	n.a.	8.1 ± 0.7
r1/r2 at 7 T	0.74	n.a.	0.59

^aGd(III) content of NDG is quantified by ICP-MS. Peptide coupling is verified by comparing primary amine content in NDA (pre-coupling) and NDG (post-coupling). Primary amine content is assessed using a modified Kaiser test⁴¹ (see Figure S4). The number of primary amines is lower in NDG compared to NDA as a majority of surface amines are modified to amides post-chelate coupling. r₁ for NDG is two-fold greater, and r₂ is 1.5-fold greater, than Gd–C5–COOH at 1.4 T. Unlike other nanoformulations bearing Gd(III) that suffer from less efficient relaxation kinetics at higher field strengths, the longitudinal relaxivity of NDG and r₁/r₂ ratio are maintained at 7 T. n.a. = not applicable.