and the public worldwide have already benefited from the unique application of
these nanomaterials.
Polymer-based functional nanomaterials are mostly used as nanosized drug
carriers. When the drug are dissolved or encapsulated in the nanoparticles some
interactions occur both physically and chemically. The polymeric nanoparticles
have some advantages for drug delivery. Nanoparticles can be made from polymers
(polymeric nanoparticles, micelles, or dendrimers), lipids (liposomes), viruses, and
even from organometallic compounds. The use of polymeric nanoparticles as drug
delivery systems has many advantages [11–14]. Two types of polymers are used as
drug conjugates, i.e., natural and synthetic polymers. Various types of polymers
such as albumin, chitosan, and heparin occur naturally and are used to deliver
oligonucleotides, DNA, proteins, and drugs.
Of all the natural polymers, chitosan has received increased attention in recent
years, especially for biomedical applications [15]. Chitosan is the second-most
abundant biopolymer in nature, just after cellulose. It is a linear polysaccharide
consisting of β-(1,4) linked D-glucosamine residues and N-acetyl-glucosamine
groups [16] and is obtained from chitin by deacetylation. Chitin is commonly
found in the shells of insects and crustaceans, as well as in the cell walls of some
fungi. Chitosan has some unique properties, including biocompatibility, biodegradability, hydrophilicity, nontoxicity and nonantigenicity, as well as bioadherence
and cell affinity [17]. It is the only positively charged naturally occurring polysaccharide and can interact strongly with negatively charged entities. Thus, chitosan
itself has several inherent characteristics and no doubt its use in functional
nanomaterials [18] will draw the attention of the scientific community. However,
the work reported on chitosan-based functional nanomaterials is limited and not
well documented. In this chapter, an effort has been made to develop an interest in
chitosan-based functional nanomaterials, looking at its versatility and end-use
applications for the benefit of the readers, researchers and workers involved in
this field of research.
2 Functionalized Nanomaterials
Although nanomaterials have a wide range of applications, these application are
limited. However, when these nanomaterials are functionalized with different
organic or inorganic ligands and various type of biomolecules then the number of
applications increases rapidly. Although some nanomaterials have excellent physical and chemical bulk properties, they do not posses surface properties suitable for
specific applications. Consequently, it may be necessary to modify or functionalize
the surface of such materials. There are the several advantages to the surface
modification or functionalization of nanomaterials, e.g. to stabilize nanomaterials
against agglomeration [19], to render them compatible with another phase, to use
modified inorganic nanofillers in organic polymers, and to enable their
self-organization. Functional organic groups on the particle surface may allow
deliberate interaction of the nanoparticles with molecules, other nanoparticle
surfaces or solids. The functionalized nanoparticles with combination of unique
Functionalized Nanoparticles and Chitosan-Based Functional Nanomaterials
3
these nanomaterials.
Polymer-based functional nanomaterials are mostly used as nanosized drug
carriers. When the drug are dissolved or encapsulated in the nanoparticles some
interactions occur both physically and chemically. The polymeric nanoparticles
have some advantages for drug delivery. Nanoparticles can be made from polymers
(polymeric nanoparticles, micelles, or dendrimers), lipids (liposomes), viruses, and
even from organometallic compounds. The use of polymeric nanoparticles as drug
delivery systems has many advantages [11–14]. Two types of polymers are used as
drug conjugates, i.e., natural and synthetic polymers. Various types of polymers
such as albumin, chitosan, and heparin occur naturally and are used to deliver
oligonucleotides, DNA, proteins, and drugs.
Of all the natural polymers, chitosan has received increased attention in recent
years, especially for biomedical applications [15]. Chitosan is the second-most
abundant biopolymer in nature, just after cellulose. It is a linear polysaccharide
consisting of β-(1,4) linked D-glucosamine residues and N-acetyl-glucosamine
groups [16] and is obtained from chitin by deacetylation. Chitin is commonly
found in the shells of insects and crustaceans, as well as in the cell walls of some
fungi. Chitosan has some unique properties, including biocompatibility, biodegradability, hydrophilicity, nontoxicity and nonantigenicity, as well as bioadherence
and cell affinity [17]. It is the only positively charged naturally occurring polysaccharide and can interact strongly with negatively charged entities. Thus, chitosan
itself has several inherent characteristics and no doubt its use in functional
nanomaterials [18] will draw the attention of the scientific community. However,
the work reported on chitosan-based functional nanomaterials is limited and not
well documented. In this chapter, an effort has been made to develop an interest in
chitosan-based functional nanomaterials, looking at its versatility and end-use
applications for the benefit of the readers, researchers and workers involved in
this field of research.
2 Functionalized Nanomaterials
Although nanomaterials have a wide range of applications, these application are
limited. However, when these nanomaterials are functionalized with different
organic or inorganic ligands and various type of biomolecules then the number of
applications increases rapidly. Although some nanomaterials have excellent physical and chemical bulk properties, they do not posses surface properties suitable for
specific applications. Consequently, it may be necessary to modify or functionalize
the surface of such materials. There are the several advantages to the surface
modification or functionalization of nanomaterials, e.g. to stabilize nanomaterials
against agglomeration [19], to render them compatible with another phase, to use
modified inorganic nanofillers in organic polymers, and to enable their
self-organization. Functional organic groups on the particle surface may allow
deliberate interaction of the nanoparticles with molecules, other nanoparticle
surfaces or solids. The functionalized nanoparticles with combination of unique
Functionalized Nanoparticles and Chitosan-Based Functional Nanomaterials
3