“…They are also used as components of optoelectronic materials, upconversion materials and fluorescent agents in biological imaging [11][12][13][14][15]. A wide range of preparation techniques have been developed for lanthanum based nanoparticles including non-aqueous [16], sol-gel [17,18], solvothermal [19], hydrothermal [20], sonochemical [8,9], microwave-assisted [21,22], etc. A common feature of several of these synthesis techniques is the use of toxic stabilising agents that makes them unsuitable for biomedical use.…”