To obtain the AgNp release rate, the pure NRL
membranes and the NRL–AgNP delivery systems
were individually immersed in a flask containing
20 mL of Mili-QTM water. Then, 2 mL of each
solution were collected for UV–Vis spectroscopy
experiments. The spectra of solutions containing
immersed NRL–AgNP were acquired using the solution
containing immersed pure NRL membrane as
reference, to subtract any possible absorption bands
arising from molecules released by the NRL membrane,
and insure that only the plasmon absorption
band of the AgNP was accounted for. After the UV–
Vis spectrum was registered, the aliquot was returned
to the flask, to avoid alteration in the total volume of
water. This procedure was repeated several times,
along 48 h.
The zeta potential and the particle size distributions
(PSD) were measured on a Zeta-Sizer system (Malvern
Instruments). The zeta potential of the nanoparticles
was measured from their electrophoretic
mobility by employing a quartz capillary cell containing
a pair of palladium electrodes. This dispersion was
injected into the capillary of the Zeta-Sizer system and
the zeta potential was measured ten times. The mean
zeta potential values for three replicates were calculated.
For the PSD, the data were collected at a fixed