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Polymer Chemistry 2018 Polymer Sciences
ISSN: 2471-9935 Page 26
March 26-28, 2018
Vienna, Austria
3rd Edition of International Conference and Exhibition on
Polymer Chemistry
One of the leading positions in the list of industrially
significant natural polymers, both in sense terms of
availability and in the breadth of possible fields of application,
for many years retains amino polysaccharide chitosan. Despite
the fact that the unique characteristics of native chitosan ensure
its relevance in various technological processes, chemical
modification allows obtaining new products for solving
specific problems. In this study, the synthesis of nano-chitosan
Bombyx mori was carried out by fractional precipitation in the
presence of a surface modifier. The optimal concentration of
the solution of chitosan, pH, the ratio of the chitosan solution to
stabilizer were determined experimentally. The resulting nano-
chitosan had a low molecular weight of 70 kDa, an intrinsic
viscosity of 1.5 dl/g, a nitrogen content of 8.22%, and a high
solubility- 99.2%. Nano-chitosan Bombyx mori was tested for
antibacterial activity on various strains of microorganisms:
St.saprofiticus, Str.pyogens, Ent.faecalis, Esch. Coli LP, Esch.
Coli LN, Prot.vulgaris, Klebsiella, Actinomyces. Investigations
of the immunomodulatory properties of nanochitosan have
been carried out and it has been revealed that the polymers have
the ability to increase the immune response to erythrocytes of
the mice, the antibody titer in the peripheral blood, stimulate
cell proliferation in the central (thymus, bone marrow) and
peripheral (spleen, lymph nodes) immunity organs, increase
the number of erythrocytes and leukocytes in the blood of
mice. When studying the effect of chitosan on the number
of cells in the central organ of immunity-bone marrow, it was
shown that chitosan, almost doubles the number of cells in the
bone marrow. Initial chitosan has an obstacle to biomedical
applications due to poor water solubility, a high positive charge
in acidic media (pH <6.5), which induces, in contact with blood,
problems such as hemolysis or thrombolysis. To overcome
these problems, chitosan is chemically modified by grafting
polyethylene glycol (PEG) to the chitosan chain. PEGylation of
chitosan is mainly achieved by grafting PEG onto amino groups
(N-modification), but this approach induces changes in the
chain of chitosan and the loss of physicochemical properties.
PEGylation to OH-groups (O-modification) is more interesting,
since the O-modification does not affect the free amino groups
in the chitosan chain. Grafting of PEG on chitosan Bombyx
mori was carried out in a sequence of several steps: activation
of PEG monomethyl ether using triphenyl phosphate to prevent
product hydrolysis, protecting the amino groups of chitosan
with phthalic anhydride, reaction of N-phthaloyl chitosan
and activated polyethylene glycol, removal of N-phthaloyl
groups by hydrazine monohydrate. The graft copolymers
of (PEG-O-ChsBm) with different content of amino groups
were synthesized and nanoparticles of copolymers were
obtained by self-organization in dilute aqueous solutions. The
supramolecular assemblies of PEG-O-ChsBm copolymers
were characterized by light scattering, a combination of TEM,
SEM, and cryo-TEM. Nanoparticles with an average diameter
in the range of 140 nm-210 nm, depending on the content of
amino groups was obtained. The toxicity of the nanoparticles
was evaluated in HeLa and THP-1 cell lines. It was show
the nontoxicity of both the chitosan Bombyx mori and its
nanoparticles, besides it was found that the content of amino
groups in the nanoparticles of the PEG-O-ChsBm copolymers
acts as a trigger for the delivery of molecules, including most
effective way.
Biography
Milusheva R Yu is a leading researcher in the Institute of Polymer Chemistry
and Physics Academy of Sciences of Uzbekistan. She awarded PhD from
Tashkent Polytechnic Institute. Her research interests lies in chemistry of
macromolecular compounds; chemistry and technology of chitin and its de-
rivatives, the creation of nanostructured polymers; physicochemical proper-
ties and structural morphology of nanopolysaccharide systems. In the field
of applied research - the development of preparations based on polysaccha-
rides and their use in the treatment of diseases of various etiologies.
Synthesis of nanochitosan Bombyx mori and its
derivatives for medicine
Milusheva R Yu and Rashidova S Sh
Institute of Polymer Chemistry and Physics Academy of Sciences of Uzbekistan, Uzbekistan
Milusheva R Yu et al., Polym Sci, Volume 4
DOI: 10.4172/2471-9935-C1-008