Crosslinking with diacrylylpiperazine (PIP) reduces activation of complement by polyacrylamide microcapsules.

Activation of the complement system in vitro by a series of microcapsules based on polylysine, alginate or polyacrylamide was determined. Least activation was observed with microcapsules whose outer layer was composed of polyacrylamide. Activation was further reduced using diacrylylpiperazine instead of bisacrylamide as crosslinker.