Dual red-NIR luminescent Eu-Yb heterolanthanide nanoparticles as promising basis for cellular imaging and sensing

The present work introduces ternary Ln(III) (Ln = Eu, Yb, Lu) complexes with thenoyltriflouro1,3-diketonate (TTA) and phosphine oxide derivative (PhO) as building blocks for core-shell nanoparticles with both Eu(III)- or Yb(III)-centered luminescence and the dual Eu(III)-Yb(III)-centered luminescence. Solvent-mediated self-assembly of the complexes is presented herein as the procedure for formation of Eu-Lu, Eu-Yb and Yb-Lu heterometallic or homometallic cores coated by hydrophilic polystyrenesulfonate-based shells. Steady state and time resolved Eu-centered luminescence in homolanthanide and heterolanthanide Eu-Lu and Eu-Yb cores is affected by Eu -> Eu and Eu -> Yb energy transfer due to a close proximity of the lanthanide blocks within the core of nanoparticles. The Eu -> Yb energy transfer is highlighted to be the reason for the enhancement of the NIR Yb-centered luminescence. Efficient cellular uptake, low cytotoxicity towards normal and cancer cells, and sensing ability of Eu-Yb nanoparticles on lomefloxacin additives via both red and NIR channels make them promising as cellular imaging agents and sensors.