Conjugated polymers (CPs) are organic semiconductors with a backbone of alternating multiple and single bonds which exhibit efficient coupling between optoelectronic segments. They have been used in a number of applications due to their optical properties such as bright photoluminescence and photo-stability. However, they are inherently hydrophobic which means, and in order to generate nanoparticles, either the micro-emulsion or nanoprecipitation method is used. Conjugated polymer nanoparticles (CPNs_ have a number of advantages over quantum dots (QDs) such as ease of processing, large absorption coefficients, tuneable optical properties, controllable dimensions and biologically inert components circumventing the issue of heavy metal toxicity of QDs. By using the nanoprecipitation method, we are able to encapsulate the CPs inside different chemical compositions and have done so with hydrophobins, as well as phospholipids, silica shells and a biodegradable polymer. We present work with conjugated polymer encapsulated in the self-assembling polymer poly(styrene-co-maleic acid) (PSMA) containing iron oxide with an emission peak of 657 nm and a quantum yield of 21%. We also show comparsion of the conjugated polymer relating to size and optical properties dependent on the micelles used, These nanoparticles have an average size of 65 nm and a zeta potential of -30 mV. We show that the nanoparticles are uptaken by HeLa, HCE and T-cells through subsequent imaging with a confocal scanning laser microscope, as well as being inherently non-toxic to cell viability and proliferation.

Encapsulation of conjugated polymers for use as biological imaging agents

256th National Meeting (2018)

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