Yeast Cells Encapsulating Polymer Nanoparticles as Trojan Particles via in Situ Polymerization inside Cells

Yeast cell envelopes including the cell membranes and cell walls are intriguing single bag-shaped structures and can stimulate macrophages activity throughout the body. In this work, we report on the formation of hierarchical particles of yeast cells encapsulating polymer nanoparticles via in situ free radical polymerization of vinyl monomers inside cells. Proper degree of cell autolysis is important for achieving high yields of polymer nanoparticles inside cells. When styrene is used as the model monomer, the nature of polymerization initiating systems affects the morphologies of obtained particles. Pomegranate-like yeast cellular particles carrying PS nanoparticles are obtained by a BPO-initiated free radical polymerization of styrene inside yeast cells. The in vitro tests showed that the macrophage cells could selectively take up the yeast particles bearing PS nanoparticles. These yeast microparticles carrying polymer nanoparticles can act as Trojan particles to carry and release polymer nanoparticles in a certain circumstance. Because of the controlled permeability of yeast membrane, the methodology developed in this work can be extended to produce cells bearing water-soluble polymers with big molecular weights. The yeast Trojan particles may find a broad scope of applications, not only as the Trojan particles for drug delivery but also as arterial embolic agents of tumors, as bioadsorption and separation materials, etc.