This serves as a proof of principle for surface-mediated drug delivery [226]. Silicabased nanomaterials are largely explored for biomedical applications. We have seen
that ZL-based composites emerged as potent biomedical tools for imaging applications and as a platform for cell growth and interactions, since they show defined
shape and size distributions and allow for both encapsulation of luminescent guests
and exohedral surface modification. It is remarkable that the targeting action and fast
cancer cell uptake of nanosized guest-ZL was observed for nanocrystals
functionalized with Ctxb antibodies. This suggests feasibility of designing novel
theranostic tools based on such composites [227]. Following this internalization,
studies on disc-shaped ZL composites with DXP as guest using human cells were
performed, because understanding the interaction between the ZL nanoparticles and
cells is imperative for improving their potentialities. The intracellular trafficking and
internalization kinetics of ZL into breast cancer cells and normal epithelial mammary
cells were analyzed using scanning electron microscopy, confocal luminescence
microscopy, and transmission electron microscopy. The uptake was observed to
depend on the cell type. It was faster and more efficient in breast cancer cells, with a
higher number of ZL particles being internalized by cancer cells over time, compared to that in the epithelial mammary cells. TEM results showed that the internalized nanoparticles were mainly localized in the cell vacuoles. SEM analysis revealed
that cell internalization of ZL was faster in breast cancer cells when compared to
normal breast cells, with some particles being already internalized after 5 min of
incubation. Internalization of ZL by the normal epithelial mammary cells was
slower, and, even after 60 min of incubation, only a small number of nanoparticles
were internalized. The same behavior was observed by confocal fluorescence
microscopy and TEM analyses. This evidenced that breast cancer cells internalize
a higher number of ZL nanoparticles than epithelial mammary cells, with the
particles being mainly localized in the vacuoles in both of the cell lines. The use
of endocytic pharmacological inhibitors suggests that ZL is internalized by the cells
by means of a caveolin-mediated process since dynasore significantly inhibited the
uptake [164]. These are important results. They demonstrate the enormous potential
of ZL-based composites for contributing to the elucidation of biological and biomedical processes.
11 Summary
The discoverers of zeolite L, Breck and Flaningen, would be surprised and delighted
to learn about the world of properties, composites, science, and applications that
have emerged from their invention and the fact that there is much more expected to
come. Zeolite L seems to be the only known thermally and mechanically stable
material with linear channels of about 1 nm diameter where the size of the particles
and, hence, the length of the channels, can be tuned in the range from about 30 nm up
to about 20
0 000 nm which can be synthesized as crystals of different morphology
such as discs, barrels, and elongated tubes.
62
G. Calzaferri
that ZL-based composites emerged as potent biomedical tools for imaging applications and as a platform for cell growth and interactions, since they show defined
shape and size distributions and allow for both encapsulation of luminescent guests
and exohedral surface modification. It is remarkable that the targeting action and fast
cancer cell uptake of nanosized guest-ZL was observed for nanocrystals
functionalized with Ctxb antibodies. This suggests feasibility of designing novel
theranostic tools based on such composites [227]. Following this internalization,
studies on disc-shaped ZL composites with DXP as guest using human cells were
performed, because understanding the interaction between the ZL nanoparticles and
cells is imperative for improving their potentialities. The intracellular trafficking and
internalization kinetics of ZL into breast cancer cells and normal epithelial mammary
cells were analyzed using scanning electron microscopy, confocal luminescence
microscopy, and transmission electron microscopy. The uptake was observed to
depend on the cell type. It was faster and more efficient in breast cancer cells, with a
higher number of ZL particles being internalized by cancer cells over time, compared to that in the epithelial mammary cells. TEM results showed that the internalized nanoparticles were mainly localized in the cell vacuoles. SEM analysis revealed
that cell internalization of ZL was faster in breast cancer cells when compared to
normal breast cells, with some particles being already internalized after 5 min of
incubation. Internalization of ZL by the normal epithelial mammary cells was
slower, and, even after 60 min of incubation, only a small number of nanoparticles
were internalized. The same behavior was observed by confocal fluorescence
microscopy and TEM analyses. This evidenced that breast cancer cells internalize
a higher number of ZL nanoparticles than epithelial mammary cells, with the
particles being mainly localized in the vacuoles in both of the cell lines. The use
of endocytic pharmacological inhibitors suggests that ZL is internalized by the cells
by means of a caveolin-mediated process since dynasore significantly inhibited the
uptake [164]. These are important results. They demonstrate the enormous potential
of ZL-based composites for contributing to the elucidation of biological and biomedical processes.
11 Summary
The discoverers of zeolite L, Breck and Flaningen, would be surprised and delighted
to learn about the world of properties, composites, science, and applications that
have emerged from their invention and the fact that there is much more expected to
come. Zeolite L seems to be the only known thermally and mechanically stable
material with linear channels of about 1 nm diameter where the size of the particles
and, hence, the length of the channels, can be tuned in the range from about 30 nm up
to about 20
0 000 nm which can be synthesized as crystals of different morphology
such as discs, barrels, and elongated tubes.
62
G. Calzaferri