Fluorescent PLA-CY5 from PolySciTech used as tracer in development of cell-mediated drug delivery

 

A fundamental problem with nanoparticles is that they are small. Although this is the mode of their action it also presents the problem that they are difficult to image and track during their application. Recently, researchers at EPFL (Switzerland) used PLA-Cyanine 5 (AV032) from PolySciTech (www.polyscitech.com) to create fluorescently-labelled particles which could be easily visualized during their uptake. This research holds promise to improve drug-delivery methods. Read more: Thomsen, Tanja, Ahmed B. Ayoub, Demetri Psaltis, and Harm-Anton Klok. "Fluorescence-based and Fluorescent label-free Characterization of Polymer Nanoparticle Decorated T cells." Biomacromolecules (2020). https://pubs.acs.org/doi/abs/10.1021/acs.biomac.0c00969

“Abstract: Cells are attractive carriers for the transport and delivery of nanoparticulate cargo. The use of cell-based carriers allows to enhance control over the biodistribution of drug-loaded polymers and polymer nanoparticles. One key element in the development of cell-based delivery systems is the loading of the cell-based carrier with the nanoparticle cargo, which can be achieved either by internalization of the payload or by immobilization on the cell surface. The surface modification of cells with nanoparticles or the internalization of nanoparticles by cells is usually monitored with fluorescence-based techniques, such as flow cytometry and confocal microscopy. In spite of the widespread use of these techniques, the use of fluorescent labels also poses some risks and has several drawbacks. Fluorescent dyes may bleach, or leach from the nanoparticles or alter the physicochemical properties of nanoparticles and their interactions and uptake by cells. Using poly(D,L-lactic acid) nanoparticles that are loaded with Coumarin 6, BODIPY 493/503 or DiO dyes as a model system, this manuscript demonstrates that the use of physically entrapped fluorescent labels can lead to false negative or erroneous results. The use of nanoparticles that contain covalently tethered fluorescent dyes instead was found to provide a robust approach to monitor cell surface conjugation reactions and to quantitatively analyze nanoparticle-decorated cells. Finally, it is shown that optical diffraction tomography is an attractive, alternative technique for the characterization of nanoparticle-decorated cells, which obviates the need for fluorescent labels.”