nanogels. In brief, PIC were formed by interacting chitosan with a block copolymer
poly(ethylene oxide)-block-poly[sodium 2-(acrylamido)-2-methyl propane sulfonate] (PEO-b-PAMPS) synthesized by single-electron transfer living radical polymerization (SET-LRP). Numerous studies have shown that the size and shape of
the formed PIC nanoparticles significantly depend on the polymerization degree of
PEO block, medium conditions, and molar ratio between the polyelectrolyte blocks.
By controlling these parameters, small and highly uniform in size PIC can be
obtained with a diameter of 20–50 nm and a coacervate core of 5–15 nm
[193–195]. In this study, PIC with a small size of about 50 nm and low polydispersity were obtained up to 5 mg/mL. After crosslinking of chitosan with genipin, the
nanoreactors were dissociated by increasing the ionic strength by adding NaCl in
order to obtain the free nanogels. The size of the smallest nanogels was about 50 nm
in the swollen state and 20 nm in the dry state. The amount of genipin used during
reticulation was an important parameter in modulating the size of the nanogels in
solution.
Shen et al. [196] reported the synthesis of chitosan-based luminescent/magnetic
(CLM) nanomaterials by direct gelation of chitosan, CdTe, and supermagnetic iron
oxide into hybrid nanogels for insulin delivery, cell imaging, and research into
antidiabetic dietary supplements. The influence of various process parameters was
studied to see their effect on the size of the hybrid nanogels. It was found that with
an increase in reaction temperature, the size of the resulting hybrid nanogels
decreased because of the increasing mobility, weakened entangling degree, and
decreasing friction force between the chitosan molecules. However, the rigidity of
the product synthesized at high temperature was not enough to maintain a stable
shape due to the weak entangling degree. In addition, the photoluminescence
intensity of the resulting hybrid nanogels decreased due to changes in the surface
trap sites of CdTe quantum dots at high temperature [197].
Oridonin (ORI), extracted from the plant Rabdosia rubescens, is a potent anticancer agent in Chinese traditional medicine. Experimentally and clinically, ORI has
proven that it is effective against a variety of tumors and cancer cell types, namely
liver, prostate, breast, and cervical cancer cells; non-small lung cancer cells; acute
promyelocytic leukemia, and glioblastoma multiforme [198–200]. However, its
clinical applications against cancers have been impeded by its low therapeutic
index induced by the poor solubility and nonspecific systematic distribution. Therefore, it is of great necessity to develop an alternative carrier of ORI. Duan et al. [201],
reported the development and characterization of pH-responsive and biocompatible
ORI-loaded chitosan-g-PNIPAAm-based nanogels for a tumor extracellular targeting
DDS using a self-assembly method. In brief, copolymers (500 mg) and ORI (50 mg)
were dispersed in 50 mL distilled water and the dispersion was sonicated using a
probe-type sonifier at 100 W in an ice bath for 2 min. The resultant ORI-loaded
nanogels were collected by centrifugation and lyophilized for storage and use. The
drug-encapsulation efficiency and drug-loading efficiency were 86.3% and 5.34%,
respectively. From the particle size analysis, it was found that the average
Engineering of Polysaccharides via Nanotechnology
117
poly(ethylene oxide)-block-poly[sodium 2-(acrylamido)-2-methyl propane sulfonate] (PEO-b-PAMPS) synthesized by single-electron transfer living radical polymerization (SET-LRP). Numerous studies have shown that the size and shape of
the formed PIC nanoparticles significantly depend on the polymerization degree of
PEO block, medium conditions, and molar ratio between the polyelectrolyte blocks.
By controlling these parameters, small and highly uniform in size PIC can be
obtained with a diameter of 20–50 nm and a coacervate core of 5–15 nm
[193–195]. In this study, PIC with a small size of about 50 nm and low polydispersity were obtained up to 5 mg/mL. After crosslinking of chitosan with genipin, the
nanoreactors were dissociated by increasing the ionic strength by adding NaCl in
order to obtain the free nanogels. The size of the smallest nanogels was about 50 nm
in the swollen state and 20 nm in the dry state. The amount of genipin used during
reticulation was an important parameter in modulating the size of the nanogels in
solution.
Shen et al. [196] reported the synthesis of chitosan-based luminescent/magnetic
(CLM) nanomaterials by direct gelation of chitosan, CdTe, and supermagnetic iron
oxide into hybrid nanogels for insulin delivery, cell imaging, and research into
antidiabetic dietary supplements. The influence of various process parameters was
studied to see their effect on the size of the hybrid nanogels. It was found that with
an increase in reaction temperature, the size of the resulting hybrid nanogels
decreased because of the increasing mobility, weakened entangling degree, and
decreasing friction force between the chitosan molecules. However, the rigidity of
the product synthesized at high temperature was not enough to maintain a stable
shape due to the weak entangling degree. In addition, the photoluminescence
intensity of the resulting hybrid nanogels decreased due to changes in the surface
trap sites of CdTe quantum dots at high temperature [197].
Oridonin (ORI), extracted from the plant Rabdosia rubescens, is a potent anticancer agent in Chinese traditional medicine. Experimentally and clinically, ORI has
proven that it is effective against a variety of tumors and cancer cell types, namely
liver, prostate, breast, and cervical cancer cells; non-small lung cancer cells; acute
promyelocytic leukemia, and glioblastoma multiforme [198–200]. However, its
clinical applications against cancers have been impeded by its low therapeutic
index induced by the poor solubility and nonspecific systematic distribution. Therefore, it is of great necessity to develop an alternative carrier of ORI. Duan et al. [201],
reported the development and characterization of pH-responsive and biocompatible
ORI-loaded chitosan-g-PNIPAAm-based nanogels for a tumor extracellular targeting
DDS using a self-assembly method. In brief, copolymers (500 mg) and ORI (50 mg)
were dispersed in 50 mL distilled water and the dispersion was sonicated using a
probe-type sonifier at 100 W in an ice bath for 2 min. The resultant ORI-loaded
nanogels were collected by centrifugation and lyophilized for storage and use. The
drug-encapsulation efficiency and drug-loading efficiency were 86.3% and 5.34%,
respectively. From the particle size analysis, it was found that the average
Engineering of Polysaccharides via Nanotechnology
117