Supervisors info:
Ερμόλαος Ιατρού, Καθηγητής (Επιβλέπων), Πιτσικάλης Μαρίνος Καθηγητής, Σακελλαρίου Γεώργιος Επίκ. Καθηγητής
Summary:
In this survey is presented the synthesis and characterization of novel
crosslinked micelles (nanogels), which are double responsive: pH and redox
responsive. These nanogels consisted of a disulfide crosslinked
poly(L-histidine) (PHIS) core and poly(ethylene oxide) (PEO) corona. The
polymerization was conducted in one step, through Ring Opening Polymerization
(ROP). Methoxy poly(ethylene glycol) amine was used as the macro-initiator for
the ring opening copolymerization of Trt-HIS N-carboxy anhydride (Trt-HIS NCA)
and Cystine N-carboxy anhydride (Cys NCA). Cystine N-carboxy anhydride (Cys
NCA) was also used as a crosslinker. Three polymers were synthesized, whith
different rations of cystine: 35%, 12%, 7%. High vacuum techniques were used
for the purifications of the reactants, solvents, and for the synthesis of NCA’
s and polymers, and it had as a result well-defined crosslinked micelles. This
was followed by characterization of the products. Their structures were
identified by IR, NMR, TEM microscopy. DLS revealed the dimensions of the
crosslinked micelles, and their behavior as the pH was changing from 7.4 to 6.5
and 5.0. With DLS was also revealed the responsiveness of the nanogels to the
presence of a reducing agent, such as glutathione (GSH). The structure of the
system were confirmed via circular dichroism. Finally, poly(Histidine) of the
nanogels, was used as a reducing agent of the (ΗAuCl4 3H2O) in order it to form
gold nanoparticles. These results enable the nanogel as a very promising
candidate for a new drug delivery system.
Keywords:
Nanogels, Crosslinked micelles, Disulfide Bonds, N-Carboxyanydrides, Dual responsive
