Morphological analysis has been performed with transmission electronic microscopy (TEM) by a TEM microscope JEOL JEM1400Plus (Peabody, MA, USA), hydrodynamic diameter, and ζ-potential measurements were performed through the instrument Nano ZS90 (Malvern Instruments, Malvern, UK), as previous described [62 (link)].
Determination of antioxidant activity has been performed by neutralization of DPPH-free radicals (DPPH reagent from Sigma Aldrich, Italy). Briefly, 0.5 ml of samples (3 mg/ml of PAE and certain amounts of nanocrystals containing 3 mg/ml of PAE) was added to 2.5 ml of 0.1 mM DPPH-methanolic solution and vigorously shaken in the dark at room temperature. The absorbance of samples at 515 nm was measured after 30 min. Ascorbic acid and methanol were used as positive (standard) and negative controls, respectively. The antioxidant capacity (AC) of PAE, nanoCaCO3@PAE, and nanoCaCO3@PAE@CH solutions has been calculated using the following equation: where control is the DPPH-methanolic solution.
Determination of antioxidant activity has been performed by neutralization of DPPH-free radicals (DPPH reagent from Sigma Aldrich, Italy). Briefly, 0.5 ml of samples (3 mg/ml of PAE and certain amounts of nanocrystals containing 3 mg/ml of PAE) was added to 2.5 ml of 0.1 mM DPPH-methanolic solution and vigorously shaken in the dark at room temperature. The absorbance of samples at 515 nm was measured after 30 min. Ascorbic acid and methanol were used as positive (standard) and negative controls, respectively. The antioxidant capacity (AC) of PAE, nanoCaCO3@PAE, and nanoCaCO3@PAE@CH solutions has been calculated using the following equation: where control is the DPPH-methanolic solution.
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