Table 3.

Comparison of solid phase immunoadsorption, Combinatorial Peptide Ligand Libraries and hydrogel nanoparticles for separating urine proteins [22,23,25,105,107,129,166].

	Solid Phase immunoadsorption	Combinatorial Peptide Ligand Libraries	Hydrogel nanoparticles
Separation method	Subtraction	Equilibration enrichment	Enrichment/size exclusion
Protein interaction principles	Antigen-antibody interaction	Physicochemical interaction (including hydrophobic, van der Waals, hydrogen bonding) between complementary hexapeptides and proteins	Hydrophobic and electrostatic interactions between the dye bait and protein
Affinity molecule	Monoclonal or polyclonal antibody	Hexapeptides or hexapeptides+Alcian blue dye	Organic dyes Acrylic acid Vinylsulfonic acid
Size exclusion	No	No	Yes
Thermo-reversible	No	No	Yes
Low abundance protein enrichment	Possible	Yes	Yes
Affinity	Moderate (antibody dependent)	Weak-Strong	Strong
Specificity	High	Moderate	Moderate (dependent on the class of dye used as the affinity bait)