POLYMER DEGRADATION AND STABILITY
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2020
·
IF 4.032
Xianzhen Dong,Qiao Cheng,Yanpiao Long,Chao Xu,Honglin Fang,Yuzhe Chen,Honglian Dai
Chitosan exhibiting excellent functional properties was found to be potential in a wide variety of industrial and biomedical applications. The lack of biological activities and the poor mechanical properties somewhat limit its applications. To address these limitations, chemical modification has been proved to be an efficient method. Here, we immobilized arginine-glycine-aspartic acid (RGD) on chitosan molecules and incorporated the chitosan with Poly(L-lactide-co-glycolide)-Poly(ethylene glycol) (PLGA-PEG) and β-tricalcium phosphate (β-TCP) nanoparticles to obtain a chitosan-based scaffold with enhanced mechanical and biocompatible performance. XPS and FT-IR confirmed the successful grafting of RGD peptides onto the chitosan chain. The mechanical properties, hydrophilicity and degradation behaviors of the membrane were characterized by stress-strain, water contact angle, and weight loss, respectively. Cytotoxicity, cellular adhesion, and cellular viability of the scaffolds were studied by MTT assay, cell adhesion, and cell survival experiments, respectively. The advantageous mechanical properties and the hydrophilic surface of the chitosan-based scaffold were achieved by blending with PLGA-PEG. The preliminary biocompatibility studies revealed that all the scaffolds were cell compatible, and the hydrophilic surface was more suitable for cell adhesion. The scaffolds grafted with RGD exhibited high cell adhesion rate than the pure chitosan. The results suggested that the surface hydrophilicity and biocompatibility of the chitosan-based scaffolds play an important role in enhancing cell adhesion and growth.
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Polymers
·
2020
·Vol. 12
·期 4
·916
·
IF 3.426
Mengjie Wang,Yonggang Shangguan,Qiang Zheng
In this work, the transformation of chitosan-grafted-polyacrylamide (GPAM) aggregates in aqueous solution upon heating was explored by cryo-electron microscope (cryo-TEM) and dynamic light scattering (DLS), and larger aggregates were formed in GPAM aqueous solution upon heating, which were responsible for the thermo-thickening behavior of GPAM aqueous solution during the heating process. The heating initiates a transformation from H-bonding aggregates to a large-sized cluster formed by self-assembled hydrophobic chitosan backbones. The acetic acid (HAc) concentration has a significant effect on the thermo-thickening behavior of GPAM aqueous solution; there is a critical value of the concentration (>0.005 M) for the thermo-thickening of 10 mg/mL GPAM solution. The concentration of HAc will affect the protonation degree of GPAM, and affect the strength of the electrostatic repulsion between GPAM molecular segments, which will have a significant effect on the state of the aggregates in solution. Other factors that have an influence on the thermo-thickening behavior of GPAM aqueous solution upon heating were investigated and discussed in detail, including the heating rate and shear rate.Keywords:chitosan-grafted-polyacrylamide;thermo-thickening;rheological;dynamic light scattering;cryo-electron microscope
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Theranostics
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2020
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IF 8.579
Yuping Hong,Yaguang Han,Jun Wu,Xinxin Zhao,Jin Cheng,Guo Gao,Qirong Qian,Xiuying Wang,Weidong Cai,Hala Zreiqat,Dagan Feng,Jianrong Xu,Daxiang Cui
Chondral and osteochondral defects caused by trauma or pathological changes, commonly progress into total joint degradation, even resulting in disability. The cartilage restoration is a great challenge because of its avascularity and limited proliferative ability. Additionally, precise diagnosis using non-invasive detection techniques is challenging, which increases problems associated with chondral disease treatment. Methods: To achieve a theranostic goal, we used an integrated strategy that relies on exploiting a multifunctional nanoprobe based on chitosan-modified Fe3O4 nanoparticles, which spontaneously self-assemble with the oppositely charged small molecule growth factor, kartogenin (KGN). This nanoprobe was used to obtain distinctively brighter T 2 -weighted magnetic resonance (MR) imaging, allowing its use as a positive contrast agent, and could be applied to obtain accurate diagnosis and osteochondral regeneration therapy. Results: This nanoprobe was first investigated using adipose tissue-derived stem cells (ADSCs), and was found to be a novel positive contrast agent that also plays a significant role in stimulating ADSCs differentiation into chondrocytes. This self-assembled probe was not only biocompatible both in vitro and in vivo , contributing to cellular internalization, but was also used to successfully make distinction of normal/damaged tissue in T 2 -weighted MR imaging. This novel combination was systematically shown to be biosafe via the decrement of apparent MR signals and elimination of ferroferric oxide over a 12-week regeneration period. Conclusion: Here, we established a novel method for osteochondral disease diagnosis and reconstruction. Using the Fe 3 O 4 -CS/KGN nanoprobe, it is easy to distinguish the defect position, and it could act as a tool for dynamic observation as well as a stem cell-based therapy for directionally chondral differentiation.
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SURFACE & COATINGS TECHNOLOGY
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2020
·
IF 3.784
Jiang Hu,Jundong Zhu,Shengzhuo Ge,Chongwen Jiang,Tianyu Guo,Tangping Peng,Tao Huang,Le Xie
Three-dimensional aerogels with hydrophobic and lipophilic properties have attracted wide attention in the effective cleaning of oil-spills. However, cost-effectiveness, biodegradability, and recycling are still challenging in the application of aerogels for oil-water separation. In this paper, we have prepared high biocompatibility, low cost, and hydrophobic composite aerogels (WCA = 148°) through directional freezing-drying technology by using chitosan (CS) as the skeleton substrate, reduced graphene oxide nanosheets (rGO) as enhancements and hydrophobic silicon particles/polydimethylsioxane (H-SiO 2 /PDMS) as the hydrophobic modifier. The composite aerogel prepared has good adsorption capacity (18–45 g/g), good chemical and thermal stability in a harsh environment. More importantly, the adsorbed organic solvents and oils adsorbed can be easily extruded from aerogels due to its excellent compressive properties. In addition, adsorption rate for pump oil and silicone oil is accelerated with the increase of temperature. The adsorption kinetics of aerogel on silicone oil and pump oil can be well fitted by pseudo-first order kinetic equation.
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MICROCHEMICAL JOURNAL
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2020
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IF 3.594
Jincan He,Yuyuan Su,Zijun Sun,Runkun Zhang,Fuhai Wu,Yan Bai
In this paper, a fluorometric method based on chitosan-mediated “turn-on” strategy was proposed for rapid detection of perfluorooctane sulfonate (PFOS). The method can be performed by two steps of simple physical mix. The whole procedure takes no more than 25 min. In pH 5.50 Britton-Robinson buffer solution, a green fluorescent dye (trisodium-8-hydroxypyrene-1,3,6-trisulfonate, HPTS) reacted with protonated chitosan to form complex by electrostatic attraction, leading in the strong quenching of HPTS. In the presence of PFOS, the fluorescence of HPTS recovered resulting from the electrostatic and hydrophobic interactions between PFOS and chitosan. The spectral characteristics, the reaction mechanisms of fluorescence quenching and fluorescence recovery, and the analytical conditions were investigated. Under the optimum conditions, a fluorometric method based on the chitosan-mediated “turn-on” strategy was developed for detection of PFOS. The value of fluorescence restoration (Δ F ) was proportional to the concentration of PFOS in range of 0.0050–2.0 μmol/L with correlation coefficient of 0.9949. The limit of detection (LOD) was calculated to be 1.0 nmol/L. The method was applied to the determination of PFOS in environment water with recoveries of 90.8–102% and RSD of 2.8–5.9%. The fluorometric method based on chitosan-mediated “turn-on” strategy is simple, rapid, sensitive and economical, showing potentiality for detection of PFOS in environmental water samples.
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CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Piao Cheng,Hongyi Gao,Xiao Chen,Yuanyuan Chen,Mengyi Han,Liwen Xing,Panpan Liu,Ge Wang
Currently, most reported composite phase change materials (PCMs) are powdery shape, which require secondary processing for practical applications. Although some monolithic composite PCMs have been developed, their flexibility usually undergoes a remarkable reduction or even complete disappearance when supporting material s are infiltrated with PCMs. To solve this problem, we fabricated a flexible supporting material with a folded layer-bridge network structure by dispersing carbon nanotubes (CNTs) in acetic acid solution of chitosan (CS) with poly(vinyl alcohol) (PVA) using a directional freezing method. Then CS/PVA/CNTs (CPC) scaffold was infiltrated with polyethylene glycol (PEG) to prepare PEG@CPC composite PCM. The resulting flexible composite PCM displays excellent mechanical properties, such as high tensile strength of 2.42 MPa and bending resistance of >100 cycles. Moreover, it displays outstanding thermal properties, such as high crystallinity of close to 100% and encapsulation ratio of 92.6 wt%. This work provides a simple method for preparation of flexible monolithic composite PCMs for many potential applications, such as wearable fitting-skin temperature-controlled materials.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2020
·Vol. 146
·期 4
·1629-1639
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IF 2.731
Song Qingyi,Wu Hongjuan,Liu Hao,Wang Tian,Meng Weihua,Qu Hongqiang
A series of chitosan-modified inorganic oxyacid salt flame retardants (IOS-CS) were synthesized and used as flame retardants to improve the fire resistance of poly(vinyl chloride) (PVC) composites while improving the mechanical properties of the materials. The thermal stability of the material was analyzed by TG test; the flame-retardant and smoke suppression properties were evaluated by limiting oxygen index (LOI) and cone calorimeter test, and the mechanical properties were analyzed by tensile test and impact test. The TG results showed that the addition of flame retardant can promote the early cross-linking decomposition of PVC composites, not only advance the decomposition temperature of the material but also promote the formation of char layer and increase the char residual content. LOI and cone calorimeter test results showed that stannate chitosan (Sn-CS) can improve flame retardant and smoke suppression more effectively than other samples. Compared with pure PVC, the addition of Sn-CS increased its LOI from 26.6 to 30.5% and reduced the total heat release value and total smoke release by 18.23% and 52.55%, respectively. At the same time, the addition of the flame retardants had no large deterioration effect on the mechanical properties of the material. The tensile properties of flame-retardant PVC were slightly reduced compared with pure PVC, and the impact resistance was even improved to some extent.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
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IF 5.162
Qian Mao,Min Li,Shengjie Zhang,Xiujuan Zhang,Gaohong He,Wenjun Zhang
Alginate or chitosan microparticles as drug loading system performed pH-responsiveness and biocompatibility, yet with the burst-release and limited encapsulation. In order to improve the performance, herein, Pickering emulsion of chitosan-hydrophobic alginate nanocomposite (HSA-CS NCs) as the bio-stabilizer, was proposed as the drug-loading vehicle. Integrating the merits of HSA-CS and Pickering emulsion, such drug carrier of emulsion performed pH-response and biocompatibility from HSA-CS, and high loading capacity and rigid layer from Pickering emulsion, so as for the manipulated release behavior. With thorough investigation, via the various pH-response of HSA-CS nanocomposite in the continuous simulated gastrointestinal fluid, Pickering emulsion gradually released the loading drug (ibuprofen) out, performing the pH-triggered controlled-release behavior. Ibuprofen-loaded Pickering emulsions (30 mg/mL) released nearly none in SGF for 3 h, whereas in SIF, performed constant release in initial 5 h and continuous-release of 88.37% ibuprofen in 24 h with no drug-burst and high loading capacity, promisingly as the pH-responsive vehicle for drug delivery in oral route.
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MOLECULES
·
2020
·Vol. 25
·期 17
·3812
·
IF 3.267
Jifeng Li,Ting Fang,Wenjing Yan,Fei Zhang,Yunhui Xu,Zhaofang Du
In this study, oxidized chitosan grafted cashmere fibers (OCGCFs) were obtained by crosslinking the oxidized chitosan onto cashmere fibers by amide covalent modification. A novel method was developed for the selective oxidation of the C6 primary hydroxyls into carboxyl groups for chitosan. The effect of oxidization reaction parameters of HNO3/H3PO4–NaNO2mediated oxidation system on the oxidation degree, structure, and properties of chitosan were investigated. The chemical structure of the oxidized chitosan was characterized by solid-state cross-polarization magic angle spinning carbon-13 Nuclear Magnetic Resonance (CP/MAS13C-NMR), Fourier transform infrared spectroscopy (FT-IR), and its morphology was investigated by scanning electron microscopy (SEM). Subsequently, the effect of the oxidized chitosan grafting on OCGCF was examined, and the physical properties, moisture regain, and antibacterial activity of OCGCFs were also evaluated. The results showed that oxidation of chitosan mostly occurred at the C6 primary hydroxyl groups. Moreover, an oxidized chitosan with 43.5–56.8% carboxyl content was realized by ranging the oxidation time from 30 to 180 min. The resulting OCGCF had a C–N amido bond, formed as a result of the reaction between the primary amines in the cashmere fibers and the carboxyl groups in the oxidized chitosan through the amide reaction. The OCGCF exhibited good moisture regain and remarkable bacteriostasis against bothStaphylococcus aureusandEscherichia colibacteria with its durability.Keywords:chitosan;cashmere fiber;oxidization;graft;antibacterial property
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CARBOHYDRATE POLYMERS
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2020
·
IF 7.182
Rui Chen,Zijin Luo,XueJun Yu,Hao Tang,Yuan Zhou,Hong Zhou
A novel flame retardant CCD was synthesized by the condensation between cinnamalde and chitosan, followed by the addition reaction with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO), and CCD was named from the initials of the three raw materials. The intermediate product CC and the target product CCD was then characterized by infrared spectrometry and elemental analysis. The flame retardancy of EP thermosets modified by CCD was dramatically improved. Epoxy resin (EP) with 10wt% CCD passed vertical burning (UL-94) V-0 rating and possessed limited oxygen index (LOI) value of 31.6 %. Cone calorimeter test exhibited the introduction of 3.5g CCD into 35g EP decreased the total heat release by 38.8 % and decreased the total smoke product by 72.0 %. XPS, FTIR, SEM and Raman tests were proceeded to determine the char residue for EP/10 % CCD thermoset, and the results showed that char residue for EP/10 % CCD thermoset possessed dense and compact structure which played a positive effect in blocking the exchange of heat and gas.
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Nanoscale Research Letters
·
2020
·Vol. 15
·期 1
·1-13
·
IF 3.578
Cai Defu,Han Cuiyan,Liu Chang,Ma Xiaoxing,Qian Jiayi,Zhou Jianwen,Li Yue,Sun Yiming,Zhang Changting,Zhu Wenquan
An enzyme-responsive colon-specific delivery system was developed based on hollow mesoporous silica spheres (HMSS) to which biodegradable chitosan (CS) was attached via cleavable azo bonds (HMSS–N=N–CS). Doxorubicin (DOX) was encapsulated in a noncrystalline state in the hollow cavity and mesopores of HMSS with the high loading amount of 35.2%. In vitro drug release proved that HMSS–N=N–CS/DOX performed enzyme-responsive drug release. The grafted CS could increase the biocompatibility and stability and reduce the protein adsorption on HMSS. Gastrointestinal mucosa irritation and cell cytotoxicity results indicated the good biocompatibility of HMSS and HMSS–N=N–CS. Cellular uptake results indicated that the uptake of DOX was obviously increased after HMSS–N=N–CS/DOX was preincubated with a colonic enzyme mixture. HMSS–N=N–CS/DOX incubated with colon enzymes showed increased cytotoxicity, and its IC 50 value was three times lower than that of HMSS–N=N–CS/DOX group without colon enzymes. The present work lays the foundation for subsequent research on mesoporous carriers for oral colon-specific drug delivery.
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CARBOHYDRATE POLYMERS
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2020
·
IF 7.182
Fengxia Wang,Xu Ding,Xiaobo Niu,Xianyi Liu,Wei Wang,Ji Zhang
Although core-shell structure is favored by many applications, preparing it with green way is rarely been reported. Herein, a core-shell structured Cu@Pd-CS nanocomposite is greenly fabricated utilizing a natural chitosan and applied to glucose detection. As-obtained Cu@Pd-CS nanoparticles were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). When applied to glucose detection, the Cu@Pd-CS exhibits good stability, sensitivity and anti-interference. Moreover, it has a good linear relationship in glucose concentrations range of 0.1−1 mM with the sensitivity of 1.53 μA mM −1 cm −2 and 1−10 mM with the sensitivity of 23.00 μA mM −1 cm −2 . This work proves the practicability of building metal-based core-shell structure nanoparticles with green resources and glucose detection application.
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