Fluorescent PCDTBT Nanoparticles with Tunable Size for Versatile Bioimaging
Srujan Cheruku,
Lien D’Olieslaeger,
Nick Smisdom,
Joeri Smits,
Dirk Vanderzande,
Wouter Maes,
Marcel Ameloot,
Anitha Ethirajan
Affiliations
Srujan Cheruku
Nanobiophysics and Soft Matter Interfaces group (NSI), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Lien D’Olieslaeger
Nanobiophysics and Soft Matter Interfaces group (NSI), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Nick Smisdom
Biomedical Research Institute (BIOMED), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Joeri Smits
Nanobiophysics and Soft Matter Interfaces group (NSI), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Dirk Vanderzande
Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Wouter Maes
Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Marcel Ameloot
Biomedical Research Institute (BIOMED), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Anitha Ethirajan
Nanobiophysics and Soft Matter Interfaces group (NSI), Institute for Materials Research (IMO-IMOMEC), UHasselt—Hasselt University, 3590 Diepenbeek, Belgium
Conjugated polymer nanoparticles exhibit very interesting properties for use as bio-imaging agents. In this paper, we report the synthesis of PCDTBT (poly([9-(1’-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophene-diyl)) nanoparticles of varying sizes using the mini-emulsion and emulsion/solvent evaporation approach. The effect of the size of the particles on the optical properties is investigated using UV-Vis absorption and fluorescence emission spectroscopy. It is shown that PCDTBT nanoparticles have a fluorescence emission maximum around 710 nm, within the biological near-infrared “optical window”. The photoluminescence quantum yield shows a characteristic trend as a function of size. The particles are not cytotoxic and are taken up successfully by human lung cancer carcinoma A549 cells. Irrespective of the size, all particles show excellent fluorescent brightness for bioimaging. The fidelity of the particles as fluorescent probes to study particle dynamics in situ is shown as a proof of concept by performing raster image correlation spectroscopy. Combined, these results show that PCDTBT is an excellent candidate to serve as a fluorescent probe for near-infrared bio-imaging.
