To obtain a stable and highly sensitive bioimaging fluorescence probe, polymer nanoparticles with embedded quantum dots (QDs) were prepared and the surface was covered with phospholipid polymer. The QDs are promising alternative to organic dyes for bioimaging. However, their use has been strongly limited by difficulties in obtaining biocompatibility of QDs. QDs were embedding in the polylactic acid (PLA) nanoparticles and the surface was covered with biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer (PMBN). The octaglycine(G8) immobilized-PMBN/polylactic acid (PLA) nanoparticles embedding QDs showed resistance to cellular uptake from HeLa cells owing to the nature of the phosphorylcholine groups in the MPC units. On the other hand, when an octaarginine (R8), which was one of the cell penetrating peptide, was immobilized at the surface of the nanoparticles, they could penetrate the membrane of HeLa cells effectively. Cytotoxicty of the PMBN/PLA/QD nanoparticles was not observed even after immobilization of R8. We examined the role of R8 by changing the ratio of R8/G8, more than 0.80 of this ratio was necessary to internalization to cells. Fluorescence intensity of the nanoparticles was not bleached during 30 h observation continuously. During proliferation of cells having the R8-PMBN/PLA/QD nanoparticles, the nanoparticles distributed to daughter and grand daughter cells (Fig 1). Thus, we obtained stable fluorescent polymer nanoparticles for excellent bioimaging probe.

Cell penetration and dynamics of oligopeptide-modified phospholipid polymer nanoparticles embedding quantum dots

247th National Meeting (2014)

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