4-4-difluoro-4-bora-3a-4a-diaza-s-indacene and fluorene

Multiplexed optical encoding is emerging as a powerful technique for high-throughput cellular analysis and molecular assays. Most of the developed optical barcodes, however, either suffer from large particle size or are incompatible with most commercial optical instruments. Here, a new type of nanoscale fluorescent barcode (Pdot barcodes) was prepared from semiconducting polymers. The Pdot barcodes possess the merits of small size (∼20 nm in diameter), narrow emission bands (full-width-at-half-maximum (fwhm) of 30-40 nm), three-color emissions (blue, green, and red) under single-wavelength excitation, a high brightness, good pH and thermal stability, and efficient cellular uptake. The Pdot barcodes were prepared using a three-color and six-intensity encoding strategy; for ratiometric readout of the barcodes, one of the colors might be used as an internal reference. We used the Pdot barcodes to label 20 sets of cancer cells and then distinguished and identified each set based on the Pdot barcodes using flow cytometry. We also monitored and tracked single cells labeled with different Pdot barcodes, even through rounds of cell division. These results suggest Pdot barcodes are strong candidates for discriminating different labeled cell and for long-term cell tracking.

Topics: Boron Compounds; Color; Fluorenes; Fluorescent Dyes; Humans; Hydrogen-Ion Concentration; MCF-7 Cells; Molecular Structure; Optical Phenomena; Particle Size; Polymers; Quantum Dots; Semiconductors; Single-Cell Analysis; Surface Properties; Temperature; Tumor Cells, Cultured

A new water-soluble conjugated polymer containing fluorene and boron-dipyrromethene repeat units in the backbones (PBF) that exhibits red emission was synthesized and characterized. Cationic PBF forms uniform nanoparticles with negatively charged disodium salt 3,3'-dithiodipropionic acid (SDPA) in aqueous solution through electrostatic interactions. The nanoparticles display absorption maximum at 550 nm and emission maximum at 590 nm. Upon photoexcitation with white light (400-800 nm) with 90 and 45 mW·cm(-2) for bacteria and cancer cells killing respectively, PBF nanoparticles can sensitize the oxygen molecule to readily produce reactive oxygen species (ROS) for rapidly killing neighboring bacteria and cancer cells. Furthermore, PBF nanoparticles concurrently provide optical imaging capability. PBF nanoparticles are therefore a promising multifunctional material for treating cancers and bacteria infections, while concurrently providing optical monitoring capabilities.

Topics: Anti-Bacterial Agents; Antineoplastic Agents; Boron Compounds; Escherichia coli; Fluorenes; Light; Molecular Imaging; Nanoparticles; Optical Phenomena; Oxygen; Photosensitizing Agents; Polymers; Propionates; Quaternary Ammonium Compounds; Reactive Oxygen Species; Solubility; Static Electricity; Water