Self-assembled multicolor nanoparticles based on functionalized twistacene dendrimer for cell fluorescent imaging

Xuemin Zhang,Jinchong Xiao,Shengliang Li,Zhenying Liu,Shu Wang

doi:10.1038/am.2015.126

Abstract

A series of twistacene-functionalized dendrimers were successfully synthesized and characterized. The model molecule DBPy has a twisted configuration with a torsional angle of 27.69° between pyrene and naphthalene units. The resulting compounds TPPh, TTPy, OTPy and TOPhP can self-assemble into organic nanoparticles through re-precipitation method and emit strong blue, cyan, green and red fluorescence in water, respectively. Additionally, the obtained multicolor nanoparticles showed low cytotoxicity and good photostability that selectively flow into the membrane and cytoplasm of HeLa cells, indicating the feasibility and efficiency in fluorescence imaging. This study might be a new avenue for the design of three-dimensional branched conjugated molecule and specific location imaging in living cell. Chinese researchers have developed a three-dimensional probe with tunable fluorescence emissions for improved imaging of living cells. Dendrimers are emerging polymer materials that grow into globular spheres through a branching process. Jinchong Xiao from the Hebei University and Shu Wang from the Beijing National Laboratory for Molecular Sciences and co-workers conjectured that combining the soft material properties of dendrimers with ‘twistacenes’ — a series of fused benzene rings that controllably emit light — could generate versatile imaging probes with greater affinity for intracellular positions. By tweaking molecular structures and self-assembling the dendrimers into larger organic nanoparticles in water, the researchers synthesized different probes with strong blue, cyan, green and red fluorescence emissions. Cell-based experiments revealed that the team's conjecture was correct: multicoloured nanoparticles were imaged as selectively entering HeLa cell membranes and cytoplasms while displaying minimal cytotoxic side-effects. A series of twistacene-functionalized dendrimers were successfully synthesized and characterized. They can self-assemble into organic nanoparticles through re-precipitation method and emit blue, cyan, green and red fluorescence in water. These multicolor nanoparticles showed low cytotoxicity and good photostability, which could be used for fluorescence imaging of living cells.

Highlights

Supramolecular assembly of organic conjugated small and polymers has become one of the most active research topics during the past two decades, because the performance of organic soft devices mainly depends on the molecular design, intermolecular interaction, ordered packing and optoelectronic properties to a great extent.[1,2,3,4,5,6,7,8,9] In general, these molecules can self-assemble into different microstructures/ nanostructures such as spheres, bars, wires, tubes and vesicles, and these ordered aggregations were used as key active layers in material science
In order to intensively realize the nucleus modification and diagnostic, prognostic information, fluorescence cell imaging has matured into a novel platform in recent years.[16,17,18,19,20,21,22]
Misra and co-workers prepared some highly photoluminescent semiconductor quantum dots based on ZnO that could be immobilized of HeLa cells, which was beneficial for detecting the cancer cells in cell therapy.[23,24,25]

Summary

INTRODUCTION

Supramolecular assembly of organic conjugated small and polymers has become one of the most active research topics during the past two decades, because the performance of organic soft devices mainly depends on the molecular design, intermolecular interaction, ordered packing and optoelectronic properties to a great extent.[1,2,3,4,5,6,7,8,9] In general, these molecules can self-assemble into different microstructures/ nanostructures such as spheres, bars, wires, tubes and vesicles, and these ordered aggregations were used as key active layers in material science. This systematic study provides a new platform for the construction of nanostructures by controlling optoelectronic property and biological affinity

MATERIALS AND METHODS

14 NH2 Br

RESULTS AND DISCUSSION