54
3 Chitin
deacetylated part of the chitosan polymer chain where the amino (–NH 2 ) group which
has been freed of the acetyl group can react with the negatively charged surface of the
bacteria cell. Another mechanism proposed is that the chelating property of chitosan
actually results in its antimicrobial properties. It is thought that the chitosan binds
with the trace metals on the bacteria cell and results in the production of toxins which
leads to cell death. The antimicrobial activity of chitosan could be further improved
by nanosizing. Nanoparticles of chitosan result in higher surface area of the polymer
available to bind with the microbes, hence increased effectiveness (Divya et al. 2017).
The antimicrobial activity of chitosan is dependent on the molecular weight of the
chitosan. At a sufficiently low molecular weight, chitosan is able to penetrate into
the bacterial cell wall and disrupt DNA and RNA replication which results in their
inhibition (Varum et al. 2017).
Resistance of microorganism is of huge clinical and industrial significance as
microorganisms have shown resistance to almost every antimicrobial agent that
exists. Chitosan has recently been of particular interest as there is yet to be reported
bacterial resistance to it. Great potential therefore lies in the use of chitosan in various
antimicrobial products. Antimicrobial activity of chitosan extends to a broad range of
microneedles which includes bacteria, filamentous fungi, yeast and even virus: bacteria such as Escherichia coli (E. coli), salmonella and staphylococcus, fungi such as
Aspergillus niger, Fusarium solani and Candida albicans and viruses such as H1N1
Influenza A and the human cytomegalovirus (9HMCV) strain AD169 (Divya et al.
2017). Chitosan acts against both gram-positive and gram-negative bacteria.
For these antimicrobial properties, chitosan has found application in, for example, antimicrobial food packaging, anti-acne cosmetic formulations, water treatment
and antimicrobial film in wound healing. Because chitosan has such diverse characteristics, in a single application more than two or more of these properties can be
implemented; for example, in its use as antimicrobial film, the excellent film-forming
property is combined with its antimicrobial property.
3.7.4 Biomedical Application
Owing to its biocompatible, non-toxic, film-forming and hydrophilic nature, there
are numerous biomedical applications of chitosan currently at different stages of
development from basic research to clinical trials. Biomedical applications of chitin
and chitosan include tissue repair, wound healing, scaffold production and biomedical
implants.
One of the novel applications of chitosan in the photochemical sutureless tissue
bonding. Post-surgery, it is required to close the incisions which have been made
in tissues such as skin, cornea or peripheral nerves. Manual suturing requires good
dexterity and can be quite time consuming with side effects. To address this, photochemical tissue bonding has been introduced. These involve the joining of tissue
through activation of chemical cross-linking of collagen fibers using rose bengal as
3 Chitin
deacetylated part of the chitosan polymer chain where the amino (–NH 2 ) group which
has been freed of the acetyl group can react with the negatively charged surface of the
bacteria cell. Another mechanism proposed is that the chelating property of chitosan
actually results in its antimicrobial properties. It is thought that the chitosan binds
with the trace metals on the bacteria cell and results in the production of toxins which
leads to cell death. The antimicrobial activity of chitosan could be further improved
by nanosizing. Nanoparticles of chitosan result in higher surface area of the polymer
available to bind with the microbes, hence increased effectiveness (Divya et al. 2017).
The antimicrobial activity of chitosan is dependent on the molecular weight of the
chitosan. At a sufficiently low molecular weight, chitosan is able to penetrate into
the bacterial cell wall and disrupt DNA and RNA replication which results in their
inhibition (Varum et al. 2017).
Resistance of microorganism is of huge clinical and industrial significance as
microorganisms have shown resistance to almost every antimicrobial agent that
exists. Chitosan has recently been of particular interest as there is yet to be reported
bacterial resistance to it. Great potential therefore lies in the use of chitosan in various
antimicrobial products. Antimicrobial activity of chitosan extends to a broad range of
microneedles which includes bacteria, filamentous fungi, yeast and even virus: bacteria such as Escherichia coli (E. coli), salmonella and staphylococcus, fungi such as
Aspergillus niger, Fusarium solani and Candida albicans and viruses such as H1N1
Influenza A and the human cytomegalovirus (9HMCV) strain AD169 (Divya et al.
2017). Chitosan acts against both gram-positive and gram-negative bacteria.
For these antimicrobial properties, chitosan has found application in, for example, antimicrobial food packaging, anti-acne cosmetic formulations, water treatment
and antimicrobial film in wound healing. Because chitosan has such diverse characteristics, in a single application more than two or more of these properties can be
implemented; for example, in its use as antimicrobial film, the excellent film-forming
property is combined with its antimicrobial property.
3.7.4 Biomedical Application
Owing to its biocompatible, non-toxic, film-forming and hydrophilic nature, there
are numerous biomedical applications of chitosan currently at different stages of
development from basic research to clinical trials. Biomedical applications of chitin
and chitosan include tissue repair, wound healing, scaffold production and biomedical
implants.
One of the novel applications of chitosan in the photochemical sutureless tissue
bonding. Post-surgery, it is required to close the incisions which have been made
in tissues such as skin, cornea or peripheral nerves. Manual suturing requires good
dexterity and can be quite time consuming with side effects. To address this, photochemical tissue bonding has been introduced. These involve the joining of tissue
through activation of chemical cross-linking of collagen fibers using rose bengal as