The solution PTE-EA (10 μM) before and after addition of Cu 2+ (10 μM) was prepared in HEPES:CH3CN (3:7, v/v, pH 7.3) by filtering through a 0.02-micron filter membrane to remove any interfering impurities and the particle size determination was performed by using DLS. The solution of PTE-EA showed particle size within the hydrodynamic diameter of 200 -500 nm and after complexation the solution of PTE-EAꓵCu 2+ showed increase in the size in the range 300 -650 nm. Thus, increase in the particle size the large particle size showed by the DLS data after addition of Cu 2+ confirmed the formation of complex (Figure ).