The HFFF2 cells (1×104) were seeded in each well containing 100 l of the RPMI medium supplemented with 10% FBS in a 96 well plate. After 24 h of adhesion, a serial of doubling dilution of the SP-NLC was added to four replicate wells. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay described below.