transfer between the living cell and the matrix. This was explored in experiments
with disc-shaped ZL, loaded with DXP as fluorescent label, and aminofunctionalized channel entrances by the method as reported in Fig. 7b. One part of
the amino-functionalized ZL crystals was further functionalized with
d-penicillamine, and the other portion was reacted with l-penicillamine (penicillamine is a bioactive chelating agent). The so-modified composites were organized as
monolayers on a glass substrate, similar as reported in Fig. 12b). This allowed
studying stereo-controlled interactions of the obtained enantiomorphous substrate
with different cell types. The authors made the remarkable observation that this
strategy can be employed for the separation of primary cells and cancerogenic cells
[136, 225]. We have already seen that ZL is a biocompatible crystalline aluminosilicate. The possibility for completely sealing the channel entrances as explained in
Figs. 9, 10, and 19 was used successfully to prepare encapsulated
111
In
3+ in nanoZL, the surface of which can be further decorated as explained in Fig. 6, for
scintigraphic imaging [97]. This was the first report of in vivo experiments with
ZL composites. It demonstrated the feasibility of a new strategy for the radiolabeling
using porous nanocontainers. Studer et al. reported in an article entitled “SiteSpecific Immobilization of Proteins at ZL Crystals by Nitroxide Exchange Reactions” that surface nitroxide exchange reactions are well suited for a site-selective
modification of ZL crystals. They have shown that the nitroxide exchange is a
reversible process that can be conducted under mild, physiological conditions at
the ZL surface. Proteins can be immobilized site-specifically to ZL crystals by
covalent bond formation or by using his-tag, streptavidin-tag, or concanavalin
A-mannose interactions [106]. We have already mentioned studies regarding
bioconjugated fluorescent ZL composites as labels in protein microarrays
[221]. Drug delivery into living cells was demonstrated using multifunctional
ZL. The host was filled with a model drug, 4
0 ,6-diamidino-2-phenylindole (DAPI),
and functionalized with DNA oligonucleotides. The release kinetics of DNA and of
the guest molecules into living cells was studied to prove the multiple-drug-delivery
ability of the system. The release kinetics of the two molecules and the localization
of the nanocontainers were monitored by imaging them by confocal microscopy.
The two emissions, the blue and the red, could be followed independently from each
other to give information about the fate of the components inside of living cells. This
was the first example in literature of using ZL crystals as multifunctional
nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. The system can be regarded as a prototype for the development of novel nanoparticles for drug delivery and gene therapy [163]. The
preparation of density gradients made of bifunctional disc-shaped ZL crystals,
loaded with guest molecules, on glass surfaces and the realization of “Janus” density
gradient surfaces reported by Kehr et al. appears as an important extension of this
[226]. The authors observed that more cells adhered on the density gradient of
biopolymer-coated ZL than on uncoated ones, and they found that cells gradually
internalized the guest-ZL from the underlying density gradient containing bifunctional ZL crystals. This means that ZL acted as nanocontainer by transporting the
guest molecules housed within its channels into the cells through cellular uptake.
Guests in Nanochannels of Zeolite L
61
with disc-shaped ZL, loaded with DXP as fluorescent label, and aminofunctionalized channel entrances by the method as reported in Fig. 7b. One part of
the amino-functionalized ZL crystals was further functionalized with
d-penicillamine, and the other portion was reacted with l-penicillamine (penicillamine is a bioactive chelating agent). The so-modified composites were organized as
monolayers on a glass substrate, similar as reported in Fig. 12b). This allowed
studying stereo-controlled interactions of the obtained enantiomorphous substrate
with different cell types. The authors made the remarkable observation that this
strategy can be employed for the separation of primary cells and cancerogenic cells
[136, 225]. We have already seen that ZL is a biocompatible crystalline aluminosilicate. The possibility for completely sealing the channel entrances as explained in
Figs. 9, 10, and 19 was used successfully to prepare encapsulated
111
In
3+ in nanoZL, the surface of which can be further decorated as explained in Fig. 6, for
scintigraphic imaging [97]. This was the first report of in vivo experiments with
ZL composites. It demonstrated the feasibility of a new strategy for the radiolabeling
using porous nanocontainers. Studer et al. reported in an article entitled “SiteSpecific Immobilization of Proteins at ZL Crystals by Nitroxide Exchange Reactions” that surface nitroxide exchange reactions are well suited for a site-selective
modification of ZL crystals. They have shown that the nitroxide exchange is a
reversible process that can be conducted under mild, physiological conditions at
the ZL surface. Proteins can be immobilized site-specifically to ZL crystals by
covalent bond formation or by using his-tag, streptavidin-tag, or concanavalin
A-mannose interactions [106]. We have already mentioned studies regarding
bioconjugated fluorescent ZL composites as labels in protein microarrays
[221]. Drug delivery into living cells was demonstrated using multifunctional
ZL. The host was filled with a model drug, 4
0 ,6-diamidino-2-phenylindole (DAPI),
and functionalized with DNA oligonucleotides. The release kinetics of DNA and of
the guest molecules into living cells was studied to prove the multiple-drug-delivery
ability of the system. The release kinetics of the two molecules and the localization
of the nanocontainers were monitored by imaging them by confocal microscopy.
The two emissions, the blue and the red, could be followed independently from each
other to give information about the fate of the components inside of living cells. This
was the first example in literature of using ZL crystals as multifunctional
nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. The system can be regarded as a prototype for the development of novel nanoparticles for drug delivery and gene therapy [163]. The
preparation of density gradients made of bifunctional disc-shaped ZL crystals,
loaded with guest molecules, on glass surfaces and the realization of “Janus” density
gradient surfaces reported by Kehr et al. appears as an important extension of this
[226]. The authors observed that more cells adhered on the density gradient of
biopolymer-coated ZL than on uncoated ones, and they found that cells gradually
internalized the guest-ZL from the underlying density gradient containing bifunctional ZL crystals. This means that ZL acted as nanocontainer by transporting the
guest molecules housed within its channels into the cells through cellular uptake.
Guests in Nanochannels of Zeolite L
61