The present invention relates to a bi-functional compound containing a linking material, and a particle comprising a linking material, and a linking material comprising a polyethylene glycol macromonomer backbone with a radical polymerizable group at one end of the macromonomer backbone and a different reactive chemical functionality at the other end of the macromonomer backbone, according to Formula I: wherein X is CH3, CN or H; Y is O, NR1, or S; L is a linking group or spacer; FG is a functional group; n is greater than 4 and less than 1000; and wherein R1 and R2 are independently selected from substituted or unsubstituted alkyl, aryl, or heteroyl.