Table 3. Soft- and hard-corona proteins, which are dissociated from the positive-, neutral and negative-charge SPIONs after washing with various washing solutions, as identified by LC-MS/MS (the yellow-brownish underlined fields in the “protein identity” column denote that these proteins are detected at all 3 different charged PVA-coated SPIONs; the grey underlined fields in the “charge” column denote that these proteins are common with the dextran-coated SPIONs).

Gel band Mw (Da)	Protein identity	Charge	NSpC
PBS	0.2 KCl	0.5 KCl	1 KCl	2 KCl	NPs
Soft corona				Hard corona				Tightly bound
621279	Hemicentin-1	positive				1.3
188377	Complement C3	neutral	0.3
188377	Complement C3	positive	1.4	0.5
164325	Alpha-2-macroglobulin	neutral	0.1
164325	Alpha-2-macroglobulin	positive			0.4
144053	Complement factor H	positive	0.1
139681	Collagen alpha-1	neutral	0.3
139681	Collagen alpha-1(I) chain	positive	0.3	0.3
106738	Inter-alpha-trypsin inhibitor heavy chain	neutral	0.6
93364	Plasminogen	negative	2.0
93364	Plasminogen	neutral	0.2
86462	Complement factor B	negative	1.4
86462	Complement factor B	neutral	0.8
80521	Fibulin-1	negative	1.2
79571	Testis-specific Y-encoded-like protein 2	negative	0.4	1.5
79450	Serotransferrin	negative	13.3	8.9
79450	Serotransferrin	neutral	9.6
79450	Serotransferrin	positive	5.0	2.7	10.8	4.3
71610	Prothrombin	negative	1.7	0.8
71610	Prothrombin	neutral	0.3	8.7
71610	Prothrombin	positive				9.6
71570	Mutated melanoma-associated antigen 1	negative	0.9	2.5
70858	Serum albumin	negative	39.1	46.4	61.5	100.0	71.2
70858	Serum albumin	neutral	26.5	29.8	44.8	100.0	100.0
70858	Serum albumin	positive	49.8	53.3	48.5	51.9	100.0
70015	Alpha-fetoprotein	negative	9.3	9.2	25.6		28.8
70015	Alpha-fetoprotein	neutral	8.1	19.5	38.9
70015	Alpha-fetoprotein	positive	1.3	1.2	12.3	19.7
69720	Kininogen-1	negative	3.6	2.5	12.9
69720	Kininogen-1	neutral	1.3	14.2	16.3
69720	Kininogen-1	positive	3.8	4.9	5.1	8.2
67385	Fibrinogen alpha chain	negative		3.5
67385	Fibrinogen alpha chain	neutral	1.8	5.5
67385	Fibrinogen alpha chain	positive	3.4	4.4	4.2
55791	Cytochrome P450 2C5	negative						12.2
55791	Cytochrome P450 2C5	neutral	0.2
55791	Cytochrome P450 2C5	positive			1.3
54915	Vitronectin	negative	2.3	2.1
54906	Alpha-2-antiplasmin	negative	2.8	4.3				24.9
54906	Alpha-2-antiplasmin	neutral	0.9
54906	Alpha-2-antiplasmin	positive			3.9
54595	Vitamin D-binding protein	negative	8.0	11.8				37.5
54595	Vitamin D-binding protein	neutral	5.0
54595	Vitamin D-binding protein	positive	7.3	9.3	2.6
53980	Alpha-1B-glycoprotein	negative	1.7	5.4				25.3
53980	Alpha-1B-glycoprotein	neutral	0.9
53980	Alpha-1B-glycoprotein	positive			1.3
53182	Vitronectin	negative	1.8	1.1
52728	Antithrombin-III	negative	1.2
52728	Antithrombin-III	neutral	0.6
51875	Factor XIIa inhibitor	negative	1.2
51875	Factor XIIa inhibitor	neutral	0.2
51410	Angiotensinogen	negative	1.8
51410	Angiotensinogen	neutral	0.2
50458	Serine protease inhibitor A3F	negative	0.6
46351	Alpha-1-antiproteinase	neutral	2.6
46351	Alpha-1-antiproteinase	positive	4.1	2.7	3.1	5.0
46300	Endopin-1	neutral	0.9
46300	Endopin-1	positive	2.0	1.8	3.1
46292	Pigment epithelium-derived factor	neutral	0.7
46292	Pigment epithelium-derived factor	negative			3.3
43280	Fetuin-B	neutral	0.5
43280	Fetuin-B	positive	3.5	2.9
39945	AMBP protein	neutral	3.1
39945	AMBP protein	positive	2.8	2.1
39284	Beta-2-glycoprotein 1	neutral	1.0
39038	Alpha-2-HS-glycoprotein	negative	4.8
39038	Alpha-2-HS-glycoprotein	neutral	9.1	22.3
39038	Alpha-2-HS-glycoprotein	positive	5.3	3.3
39008	Lumican	neutral	0.3
36130	Ecto-ADP-ribosyltransferase 4	negative	0.9
36130	Ecto-ADP-ribosyltransferase 4	neutral	0.3
30258	Apolipoprotein A-I	neutral	3.7
30258	Apolipoprotein A-I	positive	1.9	4.2
23398	Alpha-1-acid glycoprotein	plain	19.5
23398	Alpha-1-acid glycoprotein	positive	8.1	2.8
22498	Tetranectin	plain	0.5