Interaction between living cells and polymeric particles: potential application of ionic liquid for evaluating the cellular uptake of biodegradable polymeric particles composed of poly(amino acid)

The cellular uptake of biodegradable particles as drug or vaccine carriers was observed by scanning electron microscopy employing an ionic liquid. The samples were observed by simply dipping them into the ionic liquid, and high-resolution images (sub-nanometer order) were achieved. The cellular uptake of polymeric nanoparticles (NPs) composed of biodegradable amphiphilic polymers was observed using an ionic liquid method for the first time. In particular, these NPs were observed when the quantum dots were immobilized on the NPs. In addition, when the cells were incubated with microparticles (MPs), the filopodia that covered the MPs were observed, and the cellular uptake of the MPs was evaluated in a time-dependent manner. This ionic liquid method is a promising technique for evaluating the cellular uptake behavior of drug or vaccine carriers. This method also provides a strategy for observing carriers that are sensitive to conventional pretreatment conditions by choosing a suitable ionic liquid.