Gadolinium complex, synthetic approach used to prepare nanoparticle hydrogels, mean diameter of nanogels, relaxivity value at a 1 mM concentration and references.

System	Gd(iii) complex	Synthetic approach	Mean diameter (nm)	r 1p (mM−1 s−1)	# ref.
HA-Gd-DTPA	Gd-DTPA	Self-assembly of the Gd-derivative	300	11.4a	87
PAA/1Gd(iii)	Gd-DTPA	Inverse emulsion using Gd-complex as crosslinker	50 < d < 85	9.7b	88
PAA/2Gd(iii)	Gd-DOTA			17.6
PAA/3Gd(iii)	Gd-DOTA			14.8
Gd-CHPOA	Gd-DOTA	Photoinitiation using Gd-complex as crosslinker	65	24.1b	89
POEMA/AEMA/EGDMA	Gd-DTPA	Free radical polymerization and post-functionalization with Gd-complex	10	20.8c	90
VCL/VOU	NH2-DOTA(Gd)-GA	Precipitation and post-functionalization with Gd-complex	180	6.85c	91
Dex-PGMA	Gd-DTPA	Graft polymerization and post-functionalization Gd-complex	185	44.4a	92

^aThe relaxivity value was recorded at 3.0 T.

^bThe relaxivity value was recorded at 1.41 T.

^cThe relaxivity value was recorded at 0.5 T.