Cancer is a leading cause of mortality in the world,
with osteosarcoma being one of the most common types
among children between 1 and 14 years old. Current treat-
ments including preoperative chemotherapy, surgery and post-
operative chemotherapy produce several side effects with lim-
ited effectiveness. The use of lipid nanoparticles as biodegrad-
able shells for controlled drug delivery shows promise as a
more effective and targeted tumor treatment. However, in vitro
validation of these vehicles is limited due to fluid stagnation in
current techniques, in which nanoparticles sediment onto the
bottom of the wells killing the cells by asphyxiation. In the
current series of experiments, results obtained with
methotrexate-lipid nanoparticles under dynamic assay condi-
tions are presented as a promising alternative to current free
drug based therapies. Effects on the viability of the U-2 OS
osteosarcoma cell line of recirculation of cell media, free

• Effectiveness of nanoencapsulated methotrexate against osteosarcoma cells: in vitro cytotoxicity under dynamic conditions