274
prolonged- release kinetics. Moreover, BSA encapsulation in
PAA-NS protected and stabilized the protein during storage [107].
Carboxylic CDNSs were functionalized with an anti-IgG antibody and loaded with horseradish peroxidase, an enzyme commonly used as a label in biosensor assays. The possibility to use
these modified CDNSs as a signal enhancement tool in enzymelinked colorimetric and electrochemical assays was evaluated using
a sandwich format comprising immobilized gliadin as the capture
molecule, a target anti-gliadin antibody, and an anti-IgG antibody.
This type of assay has been recognized as a diagnostic and therapeutic tool in celiac disease since levels of anti-gliadin antibodies in
serum are used for monitoring celiac patients’ compliance with a
gluten-free diet. CDNSs offer the advantage of one-step multigram preparation and ease of bioconjugation under mild conditions and the signal amplification obtained in the presence of
loaded horseradish peroxidase indicates that these types of nanobioconjugates are promising candidates in the development of
ultrasensitive biosensors (Fig. 8) [108].
Catechol 1,2-dioxygenases are iron-containing enzymes, a
precursor of the industrially important compound adipic acid. In
order to construct a bioreactor able to produce muconic acid with
high efficiency and operational stability, the enzyme catechol
1,2-dioxygenase was selected as it does not require any external
cofactor for catalysis. A small-scale bioreactor was constructed and
immobilized on β-CD-NS cross-linked with carbonate groups.
This support was chosen for its low cost and its ability to offer different types of interactions with the enzyme. The activity profiles at
different pH and temperatures showed a shift of the optimal pH
from 8.5, for the free protein, to 9.5, for the immobilized protein
and, similarly, a shift in optimal temperature from 30 °C to
50 °C. The activity was retained by the immobilized enzyme (with
high efficiency for 70 days) and toward other substrates [109].
Surface-active carbonyl diimidazole cross-linked β-CD-NSs
with and without CaCO 3 and CMC were prepared and impregnated by lysozyme due to their ability to adsorb protein via electrostatic interactions. Upon lysozyme impregnation, zeta potentials of
nanosponges were sufficiently increased suggesting stable formulations by preventing aggregation. In vitro release studies showed
controlled release of lysozyme and calcium over a period of 24 h.
Lysozyme-impregnated nanosponge was a smart formulation to
deliver lysozyme in a conformationally stable structure and therapeutically active form for antimicrobial action and calcium in hypocalcemia condition at a controlled rate [110].
Penetratin, a cell-penetrating peptide, was site-specifically
modified with a bis-β-cyclodextrin group. Insulin-loaded nanocomplexes were prepared by self-assembly using penetratin or its
bis-β-cyclodextrin-modified derivative (P-bis-CD). Different cellular internalization mechanisms were observed for the two nanoMaria Tannous et al.
prolonged- release kinetics. Moreover, BSA encapsulation in
PAA-NS protected and stabilized the protein during storage [107].
Carboxylic CDNSs were functionalized with an anti-IgG antibody and loaded with horseradish peroxidase, an enzyme commonly used as a label in biosensor assays. The possibility to use
these modified CDNSs as a signal enhancement tool in enzymelinked colorimetric and electrochemical assays was evaluated using
a sandwich format comprising immobilized gliadin as the capture
molecule, a target anti-gliadin antibody, and an anti-IgG antibody.
This type of assay has been recognized as a diagnostic and therapeutic tool in celiac disease since levels of anti-gliadin antibodies in
serum are used for monitoring celiac patients’ compliance with a
gluten-free diet. CDNSs offer the advantage of one-step multigram preparation and ease of bioconjugation under mild conditions and the signal amplification obtained in the presence of
loaded horseradish peroxidase indicates that these types of nanobioconjugates are promising candidates in the development of
ultrasensitive biosensors (Fig. 8) [108].
Catechol 1,2-dioxygenases are iron-containing enzymes, a
precursor of the industrially important compound adipic acid. In
order to construct a bioreactor able to produce muconic acid with
high efficiency and operational stability, the enzyme catechol
1,2-dioxygenase was selected as it does not require any external
cofactor for catalysis. A small-scale bioreactor was constructed and
immobilized on β-CD-NS cross-linked with carbonate groups.
This support was chosen for its low cost and its ability to offer different types of interactions with the enzyme. The activity profiles at
different pH and temperatures showed a shift of the optimal pH
from 8.5, for the free protein, to 9.5, for the immobilized protein
and, similarly, a shift in optimal temperature from 30 °C to
50 °C. The activity was retained by the immobilized enzyme (with
high efficiency for 70 days) and toward other substrates [109].
Surface-active carbonyl diimidazole cross-linked β-CD-NSs
with and without CaCO 3 and CMC were prepared and impregnated by lysozyme due to their ability to adsorb protein via electrostatic interactions. Upon lysozyme impregnation, zeta potentials of
nanosponges were sufficiently increased suggesting stable formulations by preventing aggregation. In vitro release studies showed
controlled release of lysozyme and calcium over a period of 24 h.
Lysozyme-impregnated nanosponge was a smart formulation to
deliver lysozyme in a conformationally stable structure and therapeutically active form for antimicrobial action and calcium in hypocalcemia condition at a controlled rate [110].
Penetratin, a cell-penetrating peptide, was site-specifically
modified with a bis-β-cyclodextrin group. Insulin-loaded nanocomplexes were prepared by self-assembly using penetratin or its
bis-β-cyclodextrin-modified derivative (P-bis-CD). Different cellular internalization mechanisms were observed for the two nanoMaria Tannous et al.