Optimisation of Polymer Particles Propulsion on Caesium Ion-exchanged Channel Waveguide for Stem Cells Sorting Applications

Optical trapping of particles has become a powerful non-mechanical and non-destructive technique for precise particle positioning. The manipulation of particles in the evanescent field of a channel waveguide potentially allows for sorting and trapping of several particles and cells simultaneously. This paper describes the studies carried out, both theoretically and experimentally, to optimise the propulsion of polymer particles on caesium ion-exchanged channel waveguides, to ultimately allow for the trapping and separation of stem cells according to their size and refractive index. The propulsion of polymer particles was observed to increase with the supplied input power and with laser polarisation at transverse magnetic (TM) mode. The propulsion of particles was demostrated to peak on a 4μm channel width of an 8 hours ion-exchanged waveguide. The work carried out provides the optimal optical and waveguide parameters to be exploited for trapping and sorting stem cells on caesium ion-exchanged waveguides.