framework-8 nanoparticles, which has been adhered to a
sterile gauze and it may have the capability to be used as
wound dressing.
A hydrogel composed of guar gum-graftedpolyacrylamidoglycolic embedding with Ag nanoparticles
has been suggested by Palem et al. (2019) as a potential
wound dressing. NaBH 4 was used as both reducing agent for
the in situ fabrication of Ag nanoparticles from its precursor
and plays the role of crosslinker for fast fabrication of
hydrogel. However, presence of Ag nanoparticles reduced
the cell viability of the prepared hydrogel nanocomposite
and it endows bacterial inactivity to the hydrogel, which is
known as one of the requirements of wound healing materials. As an advantage, the nanocomposite hydrogel was
processable to different shapes. Thanks to crosslinking via
borate ions, the hydrogel was injectable and stretchable.
Chitosan/dextran nanocomposite loaded with curcumin
was designed as an advanced wound dressing (Xu et al.
2019). Apart from inhibitory effects for Streptococcus
mutans and Escherichia coli growth, the prepared
curcumin-loaded nanocomposite had the potential to be used
for tissue regeneration and deposition of collagen on the
abdominal wound tissue.
Pan et al. (2019) pointed out an important issue that
restricts antibacterial materials, i.e., leaching the antibacterial
agent which causes deactivation of the material and damages
to the environment. They propose covalent bonding of
guanidine-based polymer onto baggase cellulose using
epichlorohydrin as a coupling agent. Satisfactory antibacterial activity without any leaching, high degree of swelling,
proper cell viability, and improved mechanical strength
confirmed that it could be proper to be used for wound
dressing applications.
Mehrabani et al. (2018) suggested the advantage of using
chitin in the preparation of chitin/silk fibroin-based bionanocomposites containing different percentages of TiO 2
nanoparticles to be used as a wound dressing. It was
observed that participation of chitin within the bionanocomposite helped to improve mechanical features as
well as biodegradability. Also, blood clothing was improved
in the presence of chitin, which could be due to its cationic
characteristic. Meanwhile, presence of TiO 2 nanoparticles
endows significant antibacterial and antifungal properties to
the bionanocomposites.
5.4 Catalyst Supports
Some excellent features of the polysaccharides prompted
scientists to use them as the catalyst supports. Apart from
their renewability, they contain a lot of functional groups
which enable them to bind with metals. Also, they are not
soluble in a wide range of organic solvents (Rincon et al.
2019), which remove obstacles for catalyst recovery
(Nguyen 2019; Rincon et al. 2019).
A bionanocomposite based on modified chitosan has been
proposed as a catalyst for a series of Hantzsch condensation
reactions (Asgharnasl et al. 2020). For this aim, chitosan was
first modified with creatine-terephthaloyl chloride ligand and
then Fe 3 O 4 nanoparticles were prepared in situ in the presence of as-modified chitosan. Figure 15 shows uniform
distribution of the Fe 3 O 4 nanoparticles with the average
particle size of 25–30 nm. Then, the catalytic performance
of the prepared bionanocomposite in the synthesis of a series
of 1, 8-dioxo-decahydroacridine derivatives was evaluated
and high-yield percentages of the products along with green
reaction conditions were observed.
Nguyen et al. (2019) used a hybrid of polysaccharides
including 2-hydroxypropyl-b-cyclodextrin and sodium alginate as a support for palladium nanoclusters. The resulted
bionanocomposite was used as the catalyst in degradation of
4-nitrophenol, methyl orange, and rhodamine B and their
complete degradation occurred within 24 min, 20 min, and
16 min, respectively. Also, the catalyst efficiency in Sonogashira coupling reaction of phenylacetylene with a series of
aryl halides as model precursors was studied and showed
satisfactory yields for those aryl halides having
electron-neutral and electron-donating groups. The catalyst
was capable to reuse several times and they acclaimed the
problem of palladium catalysts recyclability has been solved
to high extents in this study.
A nanocomposite based on cellulose was designed by
Maleki et al. (2019) to be used as a catalyst for the synthesis
of dihydropyridine and polyhydroquinoline derivatives.
A bimetallic system composed of Cu and magnetic c-Fe 2 O 3
nanoparticles was used to immobilize on the cellulose surface. The plausible mechanism which illustrates the role of
c-Fe 2 O 3 /Cu@cellulose in the activation of the reactants as
well as some of the intermediates of the reaction is
demonstrated in Fig. 16. As the synergism, presence of both
Cu and c-Fe 2 O 3 nanoparticles on the cellulose endows to the
resulted nanocomposite some important features such as
easy separation and reusability. In the presence of the suggested catalyst, the mentioned reactions can be carried out
without any need for harsh reaction conditions such as using
toxic solvents, reflux, complex workup procedures, and low
yields, which are commonly being criticized by green
chemistry.
One of the limitations in the usage of NaBH 4 is the low
rate of hydrolysis at room temperature. In a study, Liao and
Huang (2020) used magnetic chitin/Cu hydrogel nanocomposites to overcome this problem. It was observed that the
concentration of Cu
2+ precursor and NaBH 4 , catalyst
amount, and temperature were effective factors on the catalytic performance of the prepared nanocomposites. Owing
to the magnetic response, the catalyst had the capability to be
208
S. Mallakpour and M. Naghdi
sterile gauze and it may have the capability to be used as
wound dressing.
A hydrogel composed of guar gum-graftedpolyacrylamidoglycolic embedding with Ag nanoparticles
has been suggested by Palem et al. (2019) as a potential
wound dressing. NaBH 4 was used as both reducing agent for
the in situ fabrication of Ag nanoparticles from its precursor
and plays the role of crosslinker for fast fabrication of
hydrogel. However, presence of Ag nanoparticles reduced
the cell viability of the prepared hydrogel nanocomposite
and it endows bacterial inactivity to the hydrogel, which is
known as one of the requirements of wound healing materials. As an advantage, the nanocomposite hydrogel was
processable to different shapes. Thanks to crosslinking via
borate ions, the hydrogel was injectable and stretchable.
Chitosan/dextran nanocomposite loaded with curcumin
was designed as an advanced wound dressing (Xu et al.
2019). Apart from inhibitory effects for Streptococcus
mutans and Escherichia coli growth, the prepared
curcumin-loaded nanocomposite had the potential to be used
for tissue regeneration and deposition of collagen on the
abdominal wound tissue.
Pan et al. (2019) pointed out an important issue that
restricts antibacterial materials, i.e., leaching the antibacterial
agent which causes deactivation of the material and damages
to the environment. They propose covalent bonding of
guanidine-based polymer onto baggase cellulose using
epichlorohydrin as a coupling agent. Satisfactory antibacterial activity without any leaching, high degree of swelling,
proper cell viability, and improved mechanical strength
confirmed that it could be proper to be used for wound
dressing applications.
Mehrabani et al. (2018) suggested the advantage of using
chitin in the preparation of chitin/silk fibroin-based bionanocomposites containing different percentages of TiO 2
nanoparticles to be used as a wound dressing. It was
observed that participation of chitin within the bionanocomposite helped to improve mechanical features as
well as biodegradability. Also, blood clothing was improved
in the presence of chitin, which could be due to its cationic
characteristic. Meanwhile, presence of TiO 2 nanoparticles
endows significant antibacterial and antifungal properties to
the bionanocomposites.
5.4 Catalyst Supports
Some excellent features of the polysaccharides prompted
scientists to use them as the catalyst supports. Apart from
their renewability, they contain a lot of functional groups
which enable them to bind with metals. Also, they are not
soluble in a wide range of organic solvents (Rincon et al.
2019), which remove obstacles for catalyst recovery
(Nguyen 2019; Rincon et al. 2019).
A bionanocomposite based on modified chitosan has been
proposed as a catalyst for a series of Hantzsch condensation
reactions (Asgharnasl et al. 2020). For this aim, chitosan was
first modified with creatine-terephthaloyl chloride ligand and
then Fe 3 O 4 nanoparticles were prepared in situ in the presence of as-modified chitosan. Figure 15 shows uniform
distribution of the Fe 3 O 4 nanoparticles with the average
particle size of 25–30 nm. Then, the catalytic performance
of the prepared bionanocomposite in the synthesis of a series
of 1, 8-dioxo-decahydroacridine derivatives was evaluated
and high-yield percentages of the products along with green
reaction conditions were observed.
Nguyen et al. (2019) used a hybrid of polysaccharides
including 2-hydroxypropyl-b-cyclodextrin and sodium alginate as a support for palladium nanoclusters. The resulted
bionanocomposite was used as the catalyst in degradation of
4-nitrophenol, methyl orange, and rhodamine B and their
complete degradation occurred within 24 min, 20 min, and
16 min, respectively. Also, the catalyst efficiency in Sonogashira coupling reaction of phenylacetylene with a series of
aryl halides as model precursors was studied and showed
satisfactory yields for those aryl halides having
electron-neutral and electron-donating groups. The catalyst
was capable to reuse several times and they acclaimed the
problem of palladium catalysts recyclability has been solved
to high extents in this study.
A nanocomposite based on cellulose was designed by
Maleki et al. (2019) to be used as a catalyst for the synthesis
of dihydropyridine and polyhydroquinoline derivatives.
A bimetallic system composed of Cu and magnetic c-Fe 2 O 3
nanoparticles was used to immobilize on the cellulose surface. The plausible mechanism which illustrates the role of
c-Fe 2 O 3 /Cu@cellulose in the activation of the reactants as
well as some of the intermediates of the reaction is
demonstrated in Fig. 16. As the synergism, presence of both
Cu and c-Fe 2 O 3 nanoparticles on the cellulose endows to the
resulted nanocomposite some important features such as
easy separation and reusability. In the presence of the suggested catalyst, the mentioned reactions can be carried out
without any need for harsh reaction conditions such as using
toxic solvents, reflux, complex workup procedures, and low
yields, which are commonly being criticized by green
chemistry.
One of the limitations in the usage of NaBH 4 is the low
rate of hydrolysis at room temperature. In a study, Liao and
Huang (2020) used magnetic chitin/Cu hydrogel nanocomposites to overcome this problem. It was observed that the
concentration of Cu
2+ precursor and NaBH 4 , catalyst
amount, and temperature were effective factors on the catalytic performance of the prepared nanocomposites. Owing
to the magnetic response, the catalyst had the capability to be
208
S. Mallakpour and M. Naghdi