Grafted Chitosan Oligosaccharide Research Articles

Antibacterial, conductive nanocomposite hydrogel based on dextran, carboxymethyl chitosan and chitosan oligosaccharide for diabetic wound therapy and health monitoring

Diabetic severe wound healing is challenging and also carries a high risk of bacterial infection and may be accompanied by serious complications. Electrical stimulation (ES) can effectively promote wound healing, but its effectiveness is often limited by incomplete contact between the electrodes and the wound site. In order to improve the efficiency of electrical stimulation utilization and to avoid wound infection, a multi-dynamically crosslinked nanocomposite hydrogel was prepared from dextran modified with aldehyde groups and phenylboronic acid esters (Dex-FA-BA), carboxymethyl chitosan (CMCS), polyaniline grafted chitosan oligosaccharide (CP), and Epigallocatechin Gallate/Ca2+ modified melanin-like nanoparticles (CEMNPs), based on dynamic Schiff base bonds, phenylboronic acid/diol interactions, and hydrogen bonding. The CEMNPs have good photothermal conversion properties and antioxidant activity and can also enhance the mechanical properties of the hydrogel system. The CP endows the hydrogel with good electrical conductivity and sensing properties and can record the respiratory and heart rate of rats in real time. Based on the convolutional neural networks (CNN) algorithm constructed by ResNet9, the respiratory and heart rate signals can be distinguished with 93.9 % accuracy. This multifunctional nanocomposite hydrogel can provide a new strategy to promote chronic wound healing and achieve health monitoring effectively.

Bufalin-loaded vitamin E succinate-grafted chitosan oligosaccharide/RGD-conjugated TPGS mixed micelles inhibit intraperitoneal metastasis of ovarian cancer

BackgroundIntraperitoneal metastasis is one of the major causes of the high mortality rate of ovarian cancer. Bufalin (BU) is an effective component of the traditional Chinese medicine Chansu that exerts antitumor effects, including metastasis inhibition. In our previous studies, we found that BU inhibited the migration and invasion of ovarian cancer cells. However, the application of BU is limited due to its insolubility, toxicity and imprecise targeting. The aim of this study was to use vitamin E succinate (VES)-grafted chitosan oligosaccharide (CSO)/arginine-glycine-aspartic acid peptide (RGD)-conjugated d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) mixed micelles (VeC/T-RGD MMs) to deliver BU to ovarian cancer cells to inhibit intraperitoneal metastasis. Moreover, the toxicity of BU was reduced by coating it with the mixed micelles to increase its biocompatibility for practical applications.ResultsThe BU-loaded VeC/T-RGD MMs (BU@MMs) had an average diameter of 161 ± 1.4 nm, a zeta potential of 4.49 ± 1.54 mV and a loading efficiency of 2.54%. The results showed that these micelles inhibited cell proliferation, induced apoptosis, and reduced the migration and invasion of A2780 and SKOV3 cells. Further studies indicated that BU@MMs enhanced the levels of e-cadherin and decreased the expression levels of N-cadherin, vimentin and Snail in vitro. In addition, the mixed micelles effectively enhanced the anticancer effect and inhibited intraperitoneal metastasis in intraperitoneal metastatic models. The BU@MMs exhibited fewer toxic side effects than BU, indicating better biocompatibility and biosafety for in vivo applications.ConclusionsOur studies show that BU@MMs are a potential multifunctional nano-drug delivery system that can effectively inhibit the intraperitoneal metastasis of ovarian cancer.

Effects of citronellol grafted chitosan oligosaccharide derivatives on regulating anti-inflammatory activity

In order to improve the anti-inflammatory activity of chitosan oligosaccharide (COS), chitosan oligosaccharide graft citronellol derivatives (COS-g-Cit1-3) were successfully synthesized via grafting citronellol (Cit) onto COS backbone. The degrees of substitution (DS) of COS-g-Cit1-3 were 0.165, 0.199 and 0.182, respectively. The structure of COS-g-Cit1-3 was confirmed by UV–vis, FT-IR, 1H NMR and elemental analysis. The in vivo anti-inflammatory activity evaluation results displayed that COS-g-Cit1-3 drastically reduced the paw swelling, and the oedema inhibitions were 22.58 %, 29.03 % and 25.81 %, respectively. The results indicated that the anti-inflammatory effects of COS-g-Cit1-3 were significantly higher than COS and COS-g-Cit2 exhibited the highest anti-inflammatory ability. The results also presented that COS-g-Cit1-3 reduced the expression levels of TNF-α by promoting the secretion of IL-4 and IL-10. Moreover, western blot analysis data proved that COS-g-Cit1-3 inactivated the NF-κB signaling pathway via inhibiting the phosphorylation of p65, IKBα and IKKβ.

Effect of Podophyllotoxin Conjugated Stearic Acid Grafted Chitosan Oligosaccharide Micelle on Human Glioma Cells.

ObjectiveTo study the physiochemical characteristics of podophyllotoxin (PPT) conjugated stearic acid grafted chitosan oligosaccharide micelle (PPT-CSO-SA), and evaluate the ability of the potential antineoplastic effects against glioma cells. MethodsPPT-CSO-SA was prepared by a dialysis method. The quality of PPT-CSO-SA including micellar size, zeta potential, drug encapsulation efficiency and drug release profiles was evaluated. Glioma cells were cultured and treated with PPT and PPT-CSO-SA. The ability of glioma cells to uptake PPT-CSO-SA was observed. The proliferation of glioma cells was determined by 3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. The apoptosis and morphology of U251 cells were observed by 4’,6-Diamidino-2-phenylindole dihydrochloride (DAPI) dye staining. Cell cycle analysis was performed by flow cytometry. The migration ability of U251 cells was determined by wound healing test. ResultsPPT-CSO-SA had nano-level particle size and sustained release property. The encapsulation efficiency of drug reached a high level. The cellular uptake percentage of PPT in glioma cells was lower than that of PPT-CSO-SA (p<0.05). The inhibitory effect of PPT-CSO-SA on glioma cells proliferation was significantly stronger than that of PPT (p<0.05). The morphologic change of apoptosis cell such as shrinkage, karyorrhexis and karyopyknosis were observed. The percentage of U251 cells in G2/M phase increased significantly in the PPT-CSO-SA group compared with PPT group (p<0.05). Compared with the PPT group, the cell migration ability of the PPT-CSO-SA group was significantly inhibited after 12 and 24 hours (p<0.05). ConclusionPPT-CSO-SA can effectively enhance the glioma cellular uptake of drugs, inhibit glioma cells proliferation and migration, induce G2/M phase arrest of them, and promote their apoptosis. It may be a promising anti-glioma nano-drug.

Vitamin E succinate-grafted-chitosan/chitosan oligosaccharide mixed micelles loaded with C-DMSA for Hg2+ detection and detoxification in rat liver.

AimTo determine whether the use of a mixed polymeric micelle delivery system based on vitamin E succinate (VES)-grafted-chitosan oligosaccharide (CSO)/VES-grafted-chitosan (CS) mixed micelles (VES-g-CSO/VES-g-CS MM) enhances the delivery of C-DMSA, a theranostic fluorescent probe, for Hg2+ detection and detoxification in vitro and in vivo.MethodsMixed micelles self-assembled from two polymers, VES-g-CSO and VES-g-CS, were used to load C-DMSA and afforded C-DMSA@VES-g-CSO/VES-g-CS MM for cell and in vivo applications. Fluorescence microscopy was used to assess C-DMSA cellular uptake and Hg2+ detection in L929 cells. C-DMSA@VES-g-CSO/VES-g-CS MM was then administered intravenously. Hg2+ detection was assessed by fluorescence microscopy in terms of bio-distribution while detoxification efficacy in Hg2+-poisoned rat models was evaluated in terms of mercury contents in blood and in liver.ResultsThe C-DMSA loaded mixed micelles, C-DMSA@VES-g-CSO/VES-g-CS MM, significantly enhanced cellular uptake and detoxification efficacy of C-DMSA in Hg2+ pretreated human L929 cells. Evidence from the reduction of liver coefficient, mercury contents in liver and blood, alanine transaminase and aspartate transaminase activities in Hg2+ poisoned SD rats treated with the mixed micelles strongly supported that the micelles were effective for Hg2+ detoxification in vivo. Furthermore, ex vivo fluorescence imaging experiments also supported enhanced Hg2+ detection in rat liver.ConclusionThe mixed polymeric micelle delivery system could significantly enhance cell uptake and efficacy of a theranostic probe for Hg2+ detection and detoxification treatment in vitro and in vivo. Moreover, this nanoparticle drug delivery system could achieve targeted detection and detoxification in liver.

Bufalin-loaded vitamin E succinate-grafted-chitosan oligosaccharide/RGD conjugated TPGS mixed micelles demonstrated improved antitumor activity against drug-resistant colon cancer.

BackgroundMultidrug resistance (MDR) is the major reason for the failure of chemotherapy in colon cancer. Bufalin (BU) is one of the most effective antitumor active constituents in Chansu. Our previous study found that BU can effectively reverse P-glycoprotein (P-gp)-mediated MDR in colon cancer. However, the clinical application of BU is limited due to its low solubility in water and high toxicity. In the present study, a multifunctional delivery system based on vitamin-E- succinate grafted chitosan oligosaccharide (VES-CSO) and cyclic (arginine-glycine-aspartic acid peptide) (RGD)-modified d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) was prepared by emulsion solvent evaporation method for targeted delivery of BU to improve the efficacy of drug-resistant colon cancer therapy.MethodsThe cytotoxicity of BU-loaded micelles against drug-resistant colon cancer LoVo/ADR and HCT116/LOHP cells was measured by CCK-8 assay. The cellular uptake, Rho123 accumulation, and cell apoptosis were determined by flow cytometry. The expression of apoptosis-related protein and P-gp was measured by Western blot assay. The antitumor activity of BU-loaded micelles was evaluated in LoVo/ADR-bearing nude mice.ResultsBU-loaded VES-CSO/TPGS-RGD mixed micelles (BU@VeC/T-RGD MM) were 140.3 nm in diameter with zeta potential of 8.66 mV. The BU@VeC/T-RGD MM exhibited good stability, sustained-release pattern, higher intracellular uptake, and greater cytotoxicity in LoVo/ADR cells. Furthermore, the mechanisms of the BU@VeC/T-RGD MM to overcome MDR might be due to enhanced apoptosis rate and P-gp efflux inhibition. Subsequently, in vivo studies confirmed an enhanced therapeutic efficiency and reduced side effects associated with BU@VeC/T-RGD MM compared with free BU, owing to the enhanced permeation and retention effect, improved pharmacokinetic behavior, and tumor targeting, which lead to MDR-inhibiting effect in LoVo/ADR-bearing nude mice.ConclusionOur results demonstrated that VeC/T-RGD MM could be developed as a potential delivery system for BU to improve its antitumor activity against drug-resistant colon cancer.

Geraniol grafted chitosan oligosaccharide as a potential antibacterial agent

The novel derivatives of geraniol grafted chitosan oligosaccharide were synthesized via substitution and deprotection reaction, respectively. The products were identified by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), X-ray diffraction analysis (XRD), Thermogravimetric analysis (TGA) and UV–vis absorption spectroscopy. It is revealed that the derivatives exhibited a good solubility, thermal stability and antibacterial properties.

Removal of toxic heavy metal lead (II) using chitosan oligosaccharide-graft-maleic anhydride/polyvinyl alcohol/silk fibroin composite

The present work was aimed to investigate the efficiency of novel chitosan oligosaccharide-graft-maleic anhydride(COS-g-MAH)/Polyvinyl alcohol (PVA)/silk fibroin (SF) composite for removing the toxic heavy metal lead (II) ion from aqueous solution by batch adsorption studies. Initially the chitosan oligosaccharide-graft-maleic anhydride copolymer has been prepared by utilizing ceric ammonium nitrate as an initiator and the optimised graft copolymer was then used for synthesizing COS-g-MAH/PVA/SF composite. The prepared samples were analyzed through FTIR and XRD studies. The FTIR results indicate that the grafted chitosan oligosaccharide copolymer was mixed homogeneously with silk fibroin and polyvinyl alcohol through intermolecular hydrogen bonding. The XRD results elucidate the changes in the crystalline behaviour of the prepared COS-g-MAH/PVA/silk fibroin composite. Both FTIR and XRD results revealed a strong interaction among COS-g-MAH, PVA and silk fibroin components. To evaluate the adsorption potential of the synthesized composite, the parameters such as pH, adsorbent dosage, contact time and initial Pb(II)ion concentration was investigated. The adsorption isotherms of Pb(II) could be described very well by Langmuir model and the kinetic results revealed that pseudo second order kinetics shows a better fit. This work provides a practical and high-efficient method for water treatment at moderate concentration of toxic heavy metals.

Vitamin E Succinate-Grafted-Chitosan Oligosaccharide/RGD-Conjugated TPGS Mixed Micelles Loaded with Paclitaxel for U87MG Tumor Therapy.

The poor therapeutic efficacy of hydrophobic chemotherapeutic drugs is an intrinsic limitation to successful chemotherapy. In the present study, a multitask delivery system based on arginine-glycine-aspartic acid peptide (RGD) decorated vitamin E succinate (VES)-grafted-chitosan oligosaccharide (CSO)/RGD-conjugated d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS-RGD) mixed micelles (VeC/T-RGD MM) was first prepared for targeted delivery of a hydrophobic anticancer drug, paclitaxel (PTX), to improve the efficacy of U87MG tumor therapy. VES grafted CSO (VES-g-CSO) and TPGS-RGD were synthesized as nanocarriers, and PTX loaded VeC/T-RGD MM (PTX@VeC/T-RGD MM) was prepared via the organic solvent emulsification-evaporation method. The PTX@VeC/T-RGD MM was 150.2 nm in diameter with uniform size distribution, 5.92% drug loading coefficient, and no obvious particle size changes within 7 days. The PTX@VeC/T-RGD MM showed sustained-release properties in vitro and high cytotoxicity, and could be efficiently taken up by human glioma U87MG cells. The tumor inhibitory rate of PTX@VeC/T-RGD MM treatment in U87MG tumor spheroids and U87MG tumor bearing mice was 49.3% and 88.4%, respectively, which indicated a superior therapeutic effect. PTX@VeC/T-RGD MM did not damage normal tissues in safety evaluations. These findings suggested that PTX@VeC/T-RGD MM could be developed for the delivery of hydrophobic drugs to U87MG tumors.

Synthesis, Characterization, and Antimicrobial Activity of Kojic Acid Grafted Chitosan Oligosaccharide

A novel water-soluble chitosan oligosaccharide (COS) derivative, chitosan oligosaccharide/kojic acid grafts assigned as COS/KA, was prepared by using the selective partial alkylation of N-benzylidene COS and chlorokojic acid in the presence of dimethyl sulfoxide (DMSO) and pyridine (Py). The derivative was characterized by UV-vis spectroscopy, FTIR, (1)H NMR, TGA, SEM, and XRD techniques, which showed that the alkylation reaction took place at the C-6 and C-3 positions of COS. The results showed that the degree of substitution (DS) for COS/KA was from 0.38 to 1.21, and the product exhibited an excellent solubility in organic solvents and distilled water. The antibacterial results indicated that the antibacterial activity of COS/KA was strengthened relative to COS with the increase of DS for Staphylococcus aureus , Escherichia coli , Aspergillus niger and Saccharomyces cerevisiae . These findings provide important supports for developing new antibacterial agents and expand the scope of application of COS in the food industry.

Preparation and evaluation in vitro and in vivo of docetaxel loaded mixed micelles for oral administration

A mixed micelle that comprised of monomethylol poly(ethylene glycol)-poly(d,l-lactic acid) (MPP), d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and stearic acid grafted chitosan oligosaccharide(CSO-SA) copolymers was developed to enhance the oral absorption of docetaxel (DTX). DTX-loaded MPP/TPGS/CSO-SA mixed polymeric micelles (MPMs) were prepared with thin film hydration method and characterized in terms of morphology, size, zeta potential, encapsulation efficiency, critical micellization concentration, and in vitro stability in media modeling physiological conditions. The in vitro release of docetaxel from the mixed micelles was studied with dialysis method. The oral bioavailability studies were conducted in rats and the pharmacokinetic parameters were evaluated. The results showed that DTX-loaded MPP/TPGS/CSO-SA MPMs had a mean diameter of 34.96nm and exhibited spherical shape under transmission electron microscopy. The drug loading of DTX in the mixed micelles was 19.15%. The critical micellization concentration of MPP/TPGS/CSO-SA copolymer was 2.11×10−5M, and the size of mixed micelles in gastric fluid (pH 1.6) for 2h and simulated intestinal fluid (pH 6.5) for 6h showed no significant change. The in vitro release study showed that DTX-loaded MPP/TPGS/CSO-SA MPMs exhibited slower release characteristics compared to DTX solution. The oral bioavailability of the DTX-loaded MPP/TPGS/CSO-SA MPMs was increased by 2.52 times compared to that of DTX solution. The current results encourage further development of DTX mixed polymeric micelles as the oral drug delivery system.

Effect of Proteins with Different Isoelectric Points on the Gene Transfection Efficiency Mediated by Stearic Acid Grafted Chitosan Oligosaccharide Micelles

A stearic acid-grafted chitosan oligosaccharide (CS-SA) micelle has been demonstrated as an effective gene carrier in vitro and in vivo. Although being advantageous for DNA package, protection, and excellent cellular internalization, a CS-SA based delivery system may lead to difficulties in the dissociation of polymer/DNA complexes in intracells. In this research, bovine serum albumin (BSA) with a different isoelectric point value (4.7, 6.0 and 9.3) was synthesized and incorporated into a CS-SA based gene delivery system. CS-SA/DNA binary complexes and CS-SA/BSA/DNA ternary complexes were then prepared and characterized. The binding ability of the CS-SA vector with DNA was not affected by the incorporation of BSA. However, referring to the transfection activity, the BSA of different isoelectric point value (pI) had a distinct influence on the CS-SA/BSA/DNA complexes. CS-SA/BSA(4.7)/DNA and CS-SA/BSA(6.0)/DNA complexes had better transfection efficiency than binary complexes, especially CS-SA/BSA(4.7)/DNA complexes which showed the highest transfection efficiency. On the contrary, CS-SA/BSA(9.3)/DNA complexes had undesirable performances. Interestingly, the incorporation of BSA(4.7) in CS-SA/DNA complexes significantly enhanced the dissociation of polymer/DNA complexes and improved the release of DNA intracellular without influencing their cellular uptake. The aforementioned results indicated that the acid group in protein played an important role in enhancing the transfection efficiency of CS/BSA/DNA complexes, and the study provided guidelines in the design of an efficient vector for DNA transfection.

Genotoxicity evaluation of stearic acid grafted chitosan oligosaccharide nanomicelles

Stearic acid grafted chitosan oligosaccharide (CSO-SA) nanomicelles could be promptly internalized into cancer cells; therefore, it is regarded as a promising drug carrier for cancer therapy. However, the toxicity of CSO-SA is not clear. In the present study, the genotoxic effects of CSO-SA nanomicelles (with high substitution degree of SA, 42.6±3.8%) were evaluated with a battery of genotoxicity assays. Mutagenicity was not found in Ames Salmonella/microsome mutagenicity assay (Ames test), while mild but definite positive results were observed in mouse bone marrow micronucleus assay and single cell gel electrophoresis (SCGE or comet assay) in A549 cells. CSO-SA was also found to induce apoptosis and oxidative stress through the induction of reactive oxygen species (ROS) in a dose-dependent manner in A549 cells. Preincubation with the free radical scavenger N-acetyl-l-cysteine (NAC) decreased the intracellular ROS level and alleviated the DNA damage in A549 cells. Expression levels of cleaved poly ADP-ribose polymerase (PARP), caspase-9 and caspase-3, markers of apoptosis, were significantly higher in CSO-SA treated cells. In conclusion, these results suggested significant genotoxicity of high doses of CSO-SA nanomicelles in vivo and in vitro. Oxidative stress was, at least partially, the possible mechanism underlying the genotoxicity induced by CSO-SA.

Inhibition on hepatitis B virus e-gene expression of 10–23 DNAzyme delivered by novel chitosan oligosaccharide–stearic acid micelles

Abstract 10–23 DNAzyme (DrzBC) could block the expression of HBV e-gene with application limit of dependence on exogenous delivery. Stearic acid grafted chitosan oligosaccharide (CSSA) could self-aggregate to form micelles in aqueous medium and bind with DrzBC by electrostatic interaction. Compared with Lipofectamine™ 2000, the CSSA micelles showed much lower cytotoxicity (412.5 μg/mL) and advantaged target in subcellular organelles-cytoplasm. Both including DrzBC of 1 μmol/L, Lipofectamine™ 2000/DrzBC complex showed maximum inhibition rate (IR) on HBeAg expression of 46.53 ± 2.00% at 48 h, and then decreased rapidly, while CSSA/DrzBC complex showed maximum IR of 82.51 ± 1.28% at 72 h, and hold on IR above 70% until 96 h. Moreover, within a concentration range of 0.1–2.0 μmol/L, and equally incubating for 48 h, the IR of Lipofectamine™ 2000/DrzBC complex was from 23.20 ± 1.61% to 66.27 ± 1.96%, while the IR of CSSA/DrzBC complex increased from 40.23 ± 3.28% to 80.95 ± 1.69%. CSSA/DrzBC complex is a promising effective system for inhibiting HBeAg expression.

Linoleic acid-grafted chitosan oligosaccharide micelles for intracellular drug delivery and reverse drug resistance of tumor cells

Intracellular drug delivery is an important rout to reverse drug resistance of tumor cells. In this study, the linoleic acid (LA)-grafted chitosan oligosaccharide (CSO) was synthesized to construct a micellar delivery system for intracellular delivery. The synthesized linoleic acid-grafted chitosan oligosaccharide (CSO-LA) with 10.3% graft ratio of LA could form micelles in aqueous with 86.69 μg/ml critical micellar concentration (CMC). The CSO-LA micelle had 46.2 ± 3.6 nm number average diameter and 36.0 ± 3.3 mV zeta potential. Taking doxorubicin base (DOX) as a model drug, the drug-loaded CSO-LA micelles (CSO-LA/DOX) was then prepared. The drug encapsulation efficiencies of CSO-LA/DOX were as high as 80%, and the drug loading capacity could be improved by increasing the charged DOX. Using MCF-7, Doxorubicin·HCl resistant MCF-7 (MCF-7/ADR), K562 and Doxorubicin·HCl resistant K562 (K562/ADR) cells as model drug sensitive and drug resistant tumor cells, the experiments demonstrated the CSO-LA had excellent cellular uptake ability by either drug sensitive tumor cells or drug resistance tumor cells. The CSO-LA micelles could deliver DOX into tumor cells, and the DOX in cells was increased with incubation time. As a result, the cytotoxicities of DOX encapsulated in CSO-LA micelles against drug resistance tumor cells were improved significantly, comparing to that of Doxorubicin·HCl solution.

Quaternary complexes composed of plasmid DNA/protamine/fish sperm DNA/stearic acid grafted chitosan oligosaccharide micelles for gene delivery

Quaternary complexes with condensed core of plasmid DNA, protamine, fish sperm DNA and shell of stearic acid grafted chitosan oligosaccharide (CSO-SA), were prepared. The CSO-SA could self-assemble to form nano-sized micelles in aqueous solution and demonstrated excellent internalization ability of tumor cells. Dynamic light scattering (DLS) measurement and transmission electrostatic microscope (TEM) images showed that quaternary complexes had spherical shape with about 25 nm number average diameter, and the size of quaternary complexes was smaller than that of CSO-SA micelles and CSO-SA micelles/plasmid DNA binary complexes. The transfection efficiencies of quaternary complexes on HEK293 and MCF-7 cells increased with incubation time, and were significantly higher than that of CSO-SA micelles/plasmid DNA binary complexes. The optimal transfection efficiency of quaternary complexes on HEK293 and MCF-7 cells measured by flow cytometer after 96 h was 23.82% and 41.43%, respectively. Whereas, the transfection efficiency of Lipofectamine™ 2000 on HEK293 and MCF-7 cells after 96 h was 32.45% and 33.23%, respectively. The data of luciferease activity measurement showed that the optimal ratio of plasmid DNA:fish sperm DNA:protamine:CSO-SA was 1:1:5:5. The results indicated that the present quaternary complexes were potential non-viral gene delivery system.

Preparation and pharmacodynamics of stearic acid and poly (lactic-co-glycolic acid) grafted chitosan oligosaccharide micelles for 10-hydroxycamptothecin

Stearic acid (SA) and poly (lactic-co-glycolic acid) (PLGA) grafted chitosan oligosaccharide (SA-CSO-PLGA SCP) tripolymer was synthesized via the reaction between the carboxyl group of SA or PLGA with carboxylic side group, and the amine group of CSO in the presence of 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The degrees of amino-substitution for SA and PLGA were assayed through 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) test and 13C NMR spectrum, which were 8.15% and 5.82%, respectively; the critical micelle concentrations of SCP in PBS (pH 7.4) and deionized water (DI water) were about 34.9 and 14.5 μg/ml, respectively. Using 10-hydroxycamptothecin (HCPT) as a model drug, the drug-loaded micelles showed above 86% encapsulation efficiency, which not only enhanced the solubility of HCPT in aqueous medium markedly, but also protected the lactone ring of HCPT. Cellular uptakes of SCP micelles against A549, MCF-7 and HepG-2 tumor cells showed a faster cellular internalization. Comparing to the commercial HCPT injection, HCPT-loaded micelles showed higher cytotoxicities against A549, MCF-7 and HepG-2 cells. The increased folds were 22, 18 and 15, respectively. These results suggested the SCP could be applied as a carrier for hydrophobic drugs.

Stearic acid grafted chitosan oligosaccharide micelle as a promising vector for gene delivery system: Factors affecting the complexation

Stearic acid (SA) grafted chitosan oligosaccharide (CSO-SA) with different molecular weight of chitosan oligosaccharide (CSO) and graft ratio of stearic acid were synthesized by coupling reaction of SA and CSO. The cationic polymeric micelles of CSO-SA via self-assemble formed and used for gene delivery of fish sperm DNA. Factors affecting complexation and stability of the complexes of CSO-SA micelles and DNA were investigated. The results indicated that pKa of CSO-SA with 3 kDa of CSO decreased from 8.16 to 6.02 as the substitution degree of amino groups of CSO in CSO-SA increased from 9.79% to 63.41%, whereas the molecular weight ( M W) of CSO less affected the pKa. As for the stability of complexes, ethidium bromide assay data demonstrated that the complexes consisting of CSO-SA with lower amino substitution degree or smaller molecular weight of CSO were more stable than that with the higher amino substitution degree or molecular weight of CSO. The results also presented that the low pH and ionic strength environment were in favor for the stability of complexes.

Synthesis and antitumor activity of doxorubicin conjugated stearic acid- g-chitosan oligosaccharide polymeric micelles

Doxorubicin conjugated stearic acid- g-chitosan oligosaccharide polymeric micelles (DOX–CSO–SA) was synthesized via cis-aconityl bond between the anticancer drug doxorubicin (DOX) and stearic acid grafted chitosan oligosaccharide (CSO–SA) in this paper. The CSO–SA micelles had been demonstrated faster internalization ability into tumor cells. Here, the CSO–SA with 6.47% amino substituted degree (SD%) was used to synthesize DOX–CSO–SA. The critical micelle concentration (CMC) was about 0.14 mg mL −1. The micelles with 1 mg mL −1 CSO–SA concentration had 32.7 nm number average diameter with a narrow size distribution and 51.5 mV surface potential. After conjugating with doxorubicin, CMC of DOX–CSO–SA descended; the micellar size increased; and the zeta potential decreased. The DOX–CSO–SA micelles indicated pH-dependent DOX release behavior. The release rate of DOX from DOX–CSO–SA micelles increased significantly with the reductions of the pH for release medium from 7.2 to 5.0. In vitro antitumor activity tests of DOX–CSO–SA micelles against human breast carcinoma (MCF-7) cells and their multi-drug resistant (MCF-7/Adr) cells presented the reversal activity against DOX resistance MCF-7 cells (MCF-7/Adr). The in vivo antitumor activity results showed that DOX–CSO–SA micelles treatments effectively suppressed the tumor growth and reduced the toxicity against animal body than commercial doxorubicin hydrochloride injection.

Enhanced cellular uptake of chlorine e6 mediated by stearic acid–grafted chitosan oligosaccharide micelles

Chlorines are attractive compounds for photodynamic therapy because of their high absorption in the red wavelength region. The stearic acid–grafted chitosan oligosaccharide (CSO-SA) micelles have been presented as potential candidates for intracellular drug delivery carrier because of their special structure. In this study, CSO-SA micelles were prepared to encapsulate chlorine e6 (Ce6). The physicochemical properties of synthesized CSO-SA micelles were characterized. The critical micelle concentration (CMC) of CSO-SA with 4.96% amino substituted degree (SD %) was about 36.27 ± 1.51 μg/mL. The Ce6-loaded CSO-SA micelles were then prepared by a dialysis method, and the properties and drug release profiles of Ce6-loaded CSO-SA micelles (CSO-SA/Ce6) were investigated. The loading of Ce6 in the CSO-SA micelles could reach higher drug encapsulation efficiency (%), which was ~100%. The size of CSO-SA/Ce6 decreased after the loading of Ce6. The zeta potential of CSO-SA/Ce6 and the drug release rate decreased with the loading content of drug. After the Ce6 molecules were encapsulated into the micelles of CSO-SA, the cellular uptake percentage of Ce6 was much more than that of the free drug. And the cellular uptake percentage of CSO-SA/Ce6 micelles was increased with the incubation time in a short period.