T90 spectrophotometer

The load of the anticancer doxorubicin (Dox) on the nanoparticles surface was carried out by suspending the NpMag in an aqueous solution of Dox following an adaptation of the protocol used by S. Kayal et al. [19 (link)]. For this, 5 mg of nanoparticles were added to 5 mL of an aqueous solution of Dox 0.1 mg/mL, pH 7.4. This mixture was kept under stirring at 25 °C for 24 h. The loaded nanoparticles, NpMag+Dox, were decanted by centrifugation at 12,000× g rpm for 30 min and the supernatant was reserved. For the measure of the loading efficiency (LE) of Dox, a measurement of UV/Vis (480 nm) absorbance of the supernatant was performed on a T90 spectrophotometer from PG Instruments Ltd., Leicestershire, United Kingdom. The drug loading efficiency rate was calculated by the Equation (1): $$LE(\%)=\frac{AB{S}_{total}-AB{S}_{drug}}{AB{S}_{Total}}\times 100 \left[\text{RB1}\right]$$
The resulting nanoparticles, NpMag+Dox, were dispersed in water and reserved. A drop of this solution was spread on a microscope slide and visualized under a fluorescence microscope (Olympus BX51 fluorescence microscope, Tokyo, Japan) as a first indication of the Dox presence in the nanoparticles. The images were recorded with an Olympus UC30 camera, Tokyo, Japan.