Abstract:
A novel fluorescent temperature/pH responsive particle was designed, synthesized, characterised and tested for
toxicity. Poly (N-iso-propylacrylamide-co-5%-lucifer yellow) (p(NIPAM-co-5% LY)) was prepared using a surfactant
free emulsion polymerisation technique. The particles were negatively charged and were approximately 250 nm at
15°C. When the particles de-swell following an increase in temperature, a particle size around 100 nm is obtained. The
toxicity of different concentrations of the new particles (p(NIPAM)-co-5% LY, as well as the 100% p(NIPAM) and the
main monomer NIPAM was tested on two cell lines (Hela and Vero). The toxicity was tested in comparison to a positive
control (dextran sugar) and a negative one (poly(ethylenimine)) (PEI). The results show that the two particles show cell
viability over 80% (for both cell lines Hela and Vero) up to a concentration of 3 mg/mL while NIPAM monomer showed
cell viability over 80% at a concentration equal to or less than 0.3 mg/mL. The fluorescence property of the novel
particles make them traceable. Combining this property (tracing) to the ability of the particles to release their content in
response to temperature and pH change can be a potential drug delivery system for cancer treatment.
