查找使用阿拉丁产品的科研文献

Synthesis of Cross-Linked Chitosan-Based Nanohydrogels in Inverse Miniemulsion

Cui Qinmin,Dai Lijun,Yang Liu,Ziener Ulrich,Cao Zhihai

Cross-linked chitosan (CS) nanohydrogels were successfully prepared via cross-linking CS nanodroplets in inverse miniemulsions. The cross-linker was transferred to the CS nanodroplets via the evaporation from its aqueous solution and diffusion through the continuous phase. The formation of cross-linked CS nanohydrogels was confirmed by the morphological investigation during the reaction and the successful preparation of acidic aqueous dispersion of CS nanohydrogels. The size and size distribution of the CS nanodroplets and nanohydrogels were characterized by dynamic light scattering (DLS). The particle morphology of CS nanohydrogels was observed by transmission electron microscopy (TEM). The influence of the synthetic parameters on the particle properties and colloidal stability was investigated with respect to sonication time, surfactant type and amount, type of low polarity solvent, and concentration of CS solution. The cross-linked CS nanohydrogels could be easily re-dispersed in water, and showed a pH sensitivity.

Assessment of Exenatide loaded Biotinylated Trimethylated Chitosan/HP- 55 Nanoparticles

Guo Hejian,Yan Xuehui,Tang Hao,Zhang Xiaoyan

Background: Exenatide(EXE) is an anti-hyperglycemic agent approved for treating type 2 diabetes by the Food and Drug Administration(FDA). However, twice-daily injection of exenatide is inconvenient for most of the patients. Objective: In this study, biotinylated trimethylated chitosan(Bio-TMC) based nanoparticles were proposed to promote oral absorption of exenatide. Realizing the oral administration of exenatide is very important to alleviate patient suffering and improve patient compliance. Methods: Bio-TMC was synthesized, and the chemical structure was characterized by Fourier transform infrared (FT-IR) spectroscopy and 1H NMR spectroscopy. Nanoparticles were prepared through polyelectrolyte interaction in the presence of sodium Tripolyphosphate (TPP) and hydroxypropyl methylcellulose phthalate (HP-55). Formulations were physically and chemically characterized. In vitro release was investigated in different pH media. In vivo antidiabetic activities of biotin modified and non-biotin modified chitosan were evaluated in db/db mice. Results: EXE-loaded Bio-TMC/HP-55 nanoparticles were spherical in shape with a mean diameter of 156.2 nm and zeta potential of +11.3 mV. The drug loading efficiency and loading content were 52.38% and 2.08%, respectively. In vitro release revealed that EXE-loaded Bio-TMC/HP-55 nanoparticles were released faster in pH 1.2 than pH 6.8 (63.71% VS 50.12%), indicating that nanoparticles have enteric characteristics. Antidiabetic activity study revealed that after oral administration to diabetic mice, the relative pharmacological bioavailability (FPharm%) of the biotin modified nanoparticles was found to be 1.27-fold higher compared to the unmodified ones, and the hypoglycemic effect was also found to be better. Conclusion: Bio-TMC/HP-55 nanoparticles are feasible as oral drug carriers of exenatide and have the potential to be extended to other drugs that are not readily oral, such as monoclonal antibodies, vaccines, genes, etc. These would be beneficial to the pharmaceutical industry. Further research will focus on the biodistribution of Bio-TMC/HP-55 nanoparticles after oral administration.

Thermal sensitive Poloxamer/Chitosan hydrogel for drug delivery in vagina

Qian Wu,Liang Li

In this paper, the composite gels based on poloxamer and chitosan with different contents were prepared for thermal sensitive mucosal drug delivery. The sol-gel transition temperature and rheological viscosity of the obtained gels were detected to select the optimum candidate for vaginal drug delivery. Electrochemistry impedance spectroscopy (EIS) was utilized to probe the hole structure in optimum hydrogel immersing in the vaginal fluid stimulant (VFS) for different time. The drug releasing rate of ethinyloestradiol loaded by the optimum hydrogel was examined. The drug releasing results suggested that the releasing rate satisfied with the Higuchi model, while the EIS results confirmed more pores in the composite gels would be formed during the immersing process in the VFS. The results indicated that the gel with the optimum formula met the requirements of vaginal medication. This research suggested poloxamer/chitosan might be an effective type of thermal gel for drug delivery in vagina.

Novel carboxymethyl chitosan-graphene oxide hybrid particles for drug delivery

Shi Yunfeng,Xiong Zhipeng,Lu Xuefei,Yan Xin,Cai Xiang,Xue Wei

Abstract We describe an electrostatic droplet generation method to prepare a novel carboxymethyl chitosan−graphene oxide hybrid particles for delivery purpose. Under an adjustable electrostatic field, graphene oxide and carboxymethyl chitosan mixed solution was sprayed as uniform micro-droplets, which were solidified as particles in CaCl 2 solution. Such hybrid particles are wished to have excellent stability in saline solution, and better delivery properties than pristine carboxymethyl chitosan particles. The effects of micro-droplets generation conditions on particles formation were systematically investigated. At conditions of 40 mg/ml of carboxymethyl chitosan, 2 mg/ml of graphene oxide, 3 ml/h of feed speed, electrostatic field parameters was 9 kV and 20 cm, uniformly sized carboxymethyl chitosan–graphene oxide particles in the diameter range of 250–300 μm was successfully prepared. In NaCl saline, these particles could maintain stable for at least a week, while pristine carboxymethyl chitosan particles quickly collapsed within an hour. The results of loading experiments showed that carboxymethyl chitosan–graphene oxide particles could effectively adsorb gatifloxacin, ofloxacin, bovine serum albumin, lysozyme, doxorubicin hydrochloride. And gatifloxacin was chosen as a model drug to study the exact effect of graphene oxide content on the loading and release properties. In 40:2 group, the highest loading capacity of 0.45 ± 0.19 mg/mg was achieved, and also a good sustained release was available. Above all, we believed that carboxymethyl chitosan–graphene oxide particles as a versatile carrier, has great potential in Medicine and Pharmacy. Graphical Abstract

Galactosylated chitosan–polycaprolactone nanoparticles for hepatocyte-targeted delivery of curcumin

Nuo Zhou,Xiaoli Zan,Zheng Wang,Hua Wu,Dengke Yin,Chunyan Liao,Ying Wan

Galactosylated chitosan–polycaprolactone (Gal-CH–PCL) copolymers with a galactosylation degree of around 10% and varied PCL percentages less than 40   wt% were synthesized and used to produce nanoparticles for delivering curcumin. Some nanoparticles with encapsulation efficiency of 70% or higher and sizes changing from 100 to 250   nm were able to deliver curcumin in a controlled manner. PCL content in Gal-CH–PCLs was found to be a key factor for governing the release behavior of nanoparticles. Hepatocyte-targeted characteristic of nanoparticles was confirmed using human hepatocellular carcinoma (HepG2) cells. In comparison to free curcumin, curcumin-loaded Gal-CH–PCL nanoparticles well retained its anticancer activity. At an equivalent curcumin-dose of around 20   μg/mL that was found to be relatively safe to human normal liver cells, the results obtained from flow-cytometry revealed that some optimized Gal-CH–PCL nanoparticles showed more than 6-fold increasing abilities to induce the apoptosis and necrosis of HepG2 cells during 72   h treatment compared to free curcumin.

Celastrol-conjugated chitosan oligosaccharide for the treatment of pancreatic cancer

Xiaohu Zeng,Xin Zhu,Qikang Tian,Xiaoke Tan,Ning Sun,Min Yan,Junwei Zhao,Xiangxiang Wu,Ruiqin Li,Zhenqiang Zhang,Huahui Zeng

Synthesis, Characterization, and Properties of Sulfonated Chitosan for Protein Adsorption

Xiaomin Zhang,Jie Sun

Chitosan sulfate was prepared and characterized as a new chromatography media for protein separation. The degree of sulfonation of chitosan could be well controlled and impacted under conditions in the synthesis process. The prepared chitosan sulfate shows improved binding capacity with proteins. Sulfonated chitosan shows improved ion-exchange adsorption properties with proteins, which could have good potential in protein purification.

Template synthesis of PMAA@chitosan hollow nanorods for docetaxel delivery

Yajuan Sun,Weibing Dong,Huiyuan Wang,Yongzhuo Huang,Huike Gu,Victor C. Yang,Junbo Gong

Nanorods are capable of enhanced intracellular delivery and prolonged blood circulation over their spherical counterparts, and thus can be used as unmatched drug carriers for cancer chemotherapy. An innovative method was developed to synthesize size-tunable, PMAA@chitosan-based, hollow polymeric nanorods for intracellular delivery, by using mesoporous silica nanorod templates. The morphology of the polymeric hollow nanorods was examined by TEM and FT-IR spectra, which indicated a homogeneous three-dimensional structure. An uptake study using human lung carcinoma A-549 cell lines revealed highly efficient cell internalization of the FITC-labeled nanorods, suggesting the potential of utilizing these nanorods as carriers in achieving effective intracellular drug delivery. Cell viability studies of the docetaxel-loaded nanorods yielded consistent results, as the drug-loaded nanorods produced a significantly higher inhibition of the growth of A-549 tumor cells when compared with treatment by free docetaxel. Overall, this preliminary in vitro investigation sheds light on the use of prepared hollow polymeric nanorods for drug delivery applications.

Preparation, characterization, and antifungal activity of hymexazol-linked chitosan derivatives

Li Yan,Qin Yukun,Liu Song,Li Pengcheng,Xing Rong’e

In this study, three hymexazol-linked chitosan derivatives (HML-CS) were synthesized and their structures confirmed by Fourier transform infrared and elemental analysis. Linkage ratios were measured by high performance liquid chromatography. The derivatives’ antifungal activity against the plant pathogenic fungi Rhizoctonia solani CGMCC 3.28 and Gibberella zeae CGMCC 3.42 were investigated at concentrations of 100, 200, and 400 mg/L. These HML-CS derivatives exhibited stronger antifungal activity than CS alone. HML-CS-1 showed the best antifungal activity against G. zeae , whose antifungal index was 65.9% at 400 mg/L, and also showed the best antifungal activity against R. solani , whose antifungal index was 52.7% at 400 mg/L. This conjugation of CS and HML suggested the presence of synergistic effects between the moieties and indicated that these derivatives possessed great potential as novel fungicides and require further research for the development of applications in crop protection.

Insight into the interaction between chitosan and bovine serum albumin

Guo Li,Jianying Huang,Tao Chen,Xiangyang Wang,Haijiang Zhang,Qing Chen

Exploiting the uses of proteins and polysaccharides is of increasing interest because the combination of the attributes of these two types of biopolymers can produce small emulsion droplets with good physical stability. The objective of this study was to evaluate the effect of adding chitosan to a bovine serum albumin (BSA) solution at different pH values, and the consequent conformational changes were monitored using UV–vis absorption spectroscopy and fluorescence spectroscopy. Spectroscopic observations were further combined with rheological analysis results to illustrate the interaction mechanism. The results showed that the pH and BSA/chitosan ratio significantly affected the interaction between BSA and chitosan. Additionally, the microenvironment and the secondary structure of BSA were changed with the addition of chitosan, and chitosan was found to quench the intrinsic fluorescence of BSA. The experimental results provide theoretical guidance for the design of new ingredients for the food industry.

Laser-Induced Graphene Formation on Chitosan Derivatives toward Ecofriendly Electronics

Qian-Ming Huang,Huiru Yang,Shaogang Wang,Xu Liu,Chunjian Tan,Anxin Luo,Siyuan Xu,Guoqi Zhang,Huaiyu Ye

Laser-induced graphene (LIG) has aroused a wide range of research interests ranging from micro-nano energy devices to the Internet of Things (IoT). Nevertheless, the non-degradability of most-used synthetic polymer carbon sources poses a serious threat to the environment. In this work, ecofriendly chitosan-based derivatives, including carboxymethyl chitosan (CMCS), chitosan oligosaccharide, and chitosan hydrochloride, are successfully converted into LIGs for the first time via a convenient one-step CO2 laser engraving at ambient air. The obtained LIGs are characterized by a three-dimensional hierarchical porous structure and exhibit good sheet conductivity. The consecutive carbonization and graphitization mechanism of target precursors induced by laser heat accumulation is also deeply discussed. Besides, based on a mechanically reliable LIG/CMCS composite film and tribo-negative acrylic/polyimide anti-layers, two contact-separation mode triboelectric nanogenerators are built and their power densities range from 1.44 to 2.48 mW cm–2. These devices with long cycle life can be used for low-frequency mechanical energy harvesting and commercial capacitance charging, which could be potentially applied in the wireless sensor network nodes. Such a family of chitosan derivatives paves a new route for LIG synthesis and provides new ideas for ecofriendly LIG electronics.

Fluorocarbon Modified Chitosan to Enable Transdermal Immunotherapy for Melanoma Treatment

Qi Zhuang,Ting Chao,Yuanyuan Wu,Ting Wei,Jiacheng Ren,Zhiqing Cao,Rui Peng,Zhuang Liu

Despite the rapid development of the immune checkpoint blockade (ICB) in melanoma treatment, the immunosuppressive tumor microenvironment (TME) still hinders the efficacy of immunotherapy. Recently, using agonists to modulate the TME have presented promising clinical responses in combination with ICB therapies. However, local intratumoral injection as the commonly used administration route for immune agonists would lead to low patient compliance. Herein, it is demonstrated that fluorocarbon modified chitosan (FCS) can self-assemble with immune adjuvant polyriboinosinic:polyribocytidylic acid (poly(I:C)), forming nanoparticles that can penetrate through cutaneous barriers to enable transdermal delivery. FCS/poly(I:C) can efficiently activate various types of cells presented on the transdermal route (through the skin into the TME), leading to IRF3-mediated IFN-β induction in the activated cells for tumor repression. Furthermore, transdermal FCS/poly(I:C) treatment can significantly magnify the efficacy of the programmed cell death protein 1 (PD-1) blockade in melanoma treatment through activating the immunosuppressive TME. This study approach offered an attractive transdermal approach in combined with ICB therapy for combined immunotherapy, particularly suitable for melanoma treatment.