3.4 Cisplatin delivery to the embedded spheroids
To evaluate the exploitation of these 3D systems as a drug-screening
platform, the MCF-7 spheroids embedded either in the 0.25%-0.02% or
0.125%-0.02% A-C hydrogels were treated with 100 µM cisplatin. After
24 h incubation, the Live/Dead assay was performed and the samples were
analysed under the fluorescence microscope. The images of Figure 8 show
that the dead cells were detected in the hydrogels administered with
cisplatin, while control samples were brightly green fluorescent. The
analysis of the distribution of the fluorescent pixels performed on 25
spheroids for each type of sample evidenced that the difference between
the number of dead cells of the control and those of the drug-treated
samples is statistically significant (p <0.01) (Figure 8,
lower panel). Furthermore, it looked that the penetration of the drug
depended on the agarose percentage amount, as indeed, the number of dead
cells was higher in the hydrogels containing 0.125% agarose.
Interestingly, when the samples, after 24 h incubation with the drug,
were kept in fresh medium for additional 5 days and then observed under
the microscope, the structure of the spheroids was dramatically altered.
A huge number of dead cells peeled off from the spheroids and many
cellular debris were spread into the matrix while small residues of the
3D structures were still visible (Figure 9S). This effect was observed
in both types of matrices at 5 days post drug treatment.