Eliciting macroporosity in polyacrylamide and agarose gels with polyethylene glycol

Preparation of highly porous polyacrylamide has recently been described (Righetti et al., Electrophoresis, 1992, 13, 587-595). In this report we add new observations on the conditions of promoting macroporosity in polyacrylamide gels and extend the possibility of eliciting this phenomenon to agarose matrices by the combined use of polyethylene glycol and glycerol. The process of cluster formation in hot agarose solutions was studied and gel structures were examined by scanning electron microscopy. A definition of macroporosity in gel, related to controlled microsyneresis during gelation, is tentatively proposed. The unexpected influence of acrylamide and agarose concentrations upon the size of macroporous structures in the corresponding gels is revealed.