Jiwen Luo
South China Normal University
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Featured researches published by Jiwen Luo.
Carbohydrate Polymers | 2015
Lixuan Zeng; Yufei Chen; Qiuyun Zhang; Xingmei Guo; Yanni Peng; Huijuan Xiao; Xiaocheng Chen; Jiwen Luo
Chitosan/rectorie (CTS/REC) nano-hybrid composite microsphere was prepared by changing the proportion of CTS/REC with 2:1, 3:1 and 4:1. Compared with the pure cross-linking chitosan microsphere, the nano-hybrid composite microsphere was proved to have better sorption capacity of Cd(II), Cu(II) and Ni(II), especially 2:1(CTS/REC-1). The adsorption behavior of the microsphere of Cd(II), Cu(II) and Ni(II) was investigated in single and binary metal systems. In single system, the equilibrium studies showed that the adsorption of Cd(II), Cu(II) and Ni(II) followed the Langmuir model and the pseudo-second-order kinetic model. The negative values of (ΔG) suggested that the adsorption process was spontaneous. In binary system, the combined action of the metals was found to be antagonistic and the metal sorption followed the order of Cu(II)>Cd(II)>Ni(II). The regeneration studies indicated that EDTA desorbed Cd(II), Cu(II) and Ni(II) from cross-linking microspheres better than HCl. The FT-IR and XPS spectra showed that coordination bonds were formed between Cd(II), Cu(II) and Ni(II) and the nitrogen atoms of cross-linking CTS/REC nano-hybrid composite microspheres.
Journal of Biomaterials Science-polymer Edition | 2013
Bo Liu; Jiwen Luo; Xiaoying Wang; Junxiang Lu; Hongbing Deng; Runcang Sun
Drug-delivery systems, using natural drug carriers, have become increasingly important because of their nontoxicity and biodegradability. In this study, firstly, quaternized carboxymethyl chitosan (QCMC) was intercalated into the interlayer of organic montmorillonite (OMMT) to obtain the QCMC/OMMT nanocomposites, their structure, morphology, and thermal stability were investigated. Next, crosslinked alginate/QCMC/OMMT (AQCOM) microsphere was obtained by crosslinking with CaCl2, and the drug-controlled release behavior was evaluated with bovine serum albumin (BSA) as model drug. The results suggested that, carboxyl groups in alginate and QCMC crosslinked with Ca2+, quaternary ammonium groups in QCMC or OMMT electrostatically interacted with carboxyl groups in alginate, and there was stable three-dimensional network in AQCOM microsphere. The swelling ratio of AQCOM microspheres decreased with the increase of OMMT content, the lowest one was only about 45% compared to the microsphere without OMMT of 197%. Besides, the in vitro release results for BSA indicated that the AQCOM microsphere displayed more excellent encapsulation and controlled release capacities than the microsphere without OMMT. The in vitro active cutaneous anaphylaxis test was carried out on Guinea pigs, which revealed that AQCOM microsphere did not cause anaphylaxis. Therefore, QCMC/OMMT nanocomposites from natural materials are considerably suitable to apply as drug-controlled release carriers.
Carbohydrate Polymers | 2013
Bo Liu; Xiaoying Wang; Chunsheng Pang; Jiwen Luo; Yuqiong Luo; Run-Cang Sun
Microwave irradiation was used to intercalate quaternized carboxymethyl chitosan oligosaccharide (QCMCO) into the layer of rectorite (REC) to prepare QCMCO/REC (QCOR) nanocomposites in 70 min, which was much faster than conventional heating method of 48 h. The structures and morphology of QCOR nanocomposites were characterized by XRD, TEM, FT-IR and zeta potential analysis, the thermal behavior and antimicrobial activity of QCOR nanocomposites were also discussed. The results revealed that the interlayer distance of QCOR nanocomposites enlarged with the increase of QCMCO content, hydrogen bonding and electrostatic interaction between QCMCO and REC took place. As compared to QCMCO, the crystallinity of QCOR nanocomposites reduced, the thermal stability of QCOR nanocomposites improved, and the inhibitory activity of QCOR nanocomposites against microorganisms was stronger, the lowest minimum inhibition concentration was only 0.025% (w/v), the antimicrobial mechanism was discussed via TEM and SEM micrographs.
RSC Advances | 2013
Bo Liu; Suqin Shen; Jiwen Luo; Xiaoying Wang; Runcang Sun
A rapid and green method is reported to synthesize silver nanoparticles (Ag NPs) and simultaneously achieve exfoliated chitosan/clay nanocomposite under microwave irradiation, in which quaternized chitosan (QCS), montmorillonite (MMT) and Gemini surfactant were used as reducing and stabilizing agents, other chemical reductants were not involved. XRD, FT-IR, NMR, TEM and AAS were performed to characterize Ag NP-loaded QCS/clay nanocomposites. The results indicated that the formation of spherical Ag NPs (about 26 nm) were mainly associated with reduction effect of QCS, surfactant and clay hardly participate in the synthesis of Ag NP, but benefited its formation. During the formation of Ag NPs, the layers of clay were peeled, the exfoliated Ag NP-loaded QCS/clay nanocomposites were obtained. Moreover, Ag NP-loaded QCS/clay nanocomposites showed excellent antimicrobial activity. The lowest minimum inhibition concentration against microorganisms was 0.00001 wt%. At last, the antimicrobial mechanism was evaluated by TEM and SEM micrographs.
Journal of Materials Chemistry B | 2017
Zuguang Shen; Guocheng Han; Xiaoying Wang; Jiwen Luo; Run-Cang Sun
This study reported the direct utilization of bagasse as an ultra-light aerogel with AgNPs for the first time. Firstly, AgNPs were synthesized in situ using a green route with bagasse, a by-product of the refined sugar industry. During the reaction, the crystalline region of cellulose in bagasse was destroyed, and some groups of bagasse were partly oxidized into C[double bond, length as m-dash]O of ketone, which confirms the reducing capacity of bagasse. Then, the obtained bagasse-AgNP composite was dissolved in EmimAc to prepare an aerogel with AgNPs. The aerogel piled up in slices, and its weight after swelling in water was about 19 times the dry weight, and the aerogel did not crush a flower branch because its density was only 0.035 g cm-3, although the mole and mass ratios of the Ag atom were 5.26% and 29.94% in the aerogel, respectively. Furthermore, the obtained aerogel showed a strong antibacterial effect, especially against E. coli and P. aeruginosa. This study not only provides an interesting way for bagasse to be applied directly, but also develops an antibacterial biomass-based ultra-light aerogel without AgNP dissociation.
Desalination and Water Treatment | 2014
Lixuan Zeng; Yufei Chen; Qiuyun Zhang; Yuan Kang; Jiwen Luo
AbstractIn this study, cross-linked chitosan resins were prepared through inverse suspension and were used to adsorb congo red (CR). FT-IR spectra and SEM technique characterized the chitosan resins. The influences of contact time, temperature, adsorbent dose, initial concentration of CR, and pH of CR solution on the adsorption behavior were investigated. The results showed that the chitosan beads made from 5% chitosan in 2% aqueous acetic acid had smooth surface and strong mechanical strength. When the contact time was 60 min, temperature was 50°C, adsorbent dose was 0.02 g, initial concentration of CR was 80 mg/L, and pH of CR solution was 7, the best adsorption capacity was obtained. The adsorption behavior can be fitted well by the Langmuir isotherm and also obeyed the pseudo-second-order kinetic expression. The intra-particle diffusion studies indicate that the diffusion step was not the only rate-limiting step. Thermodynamic studies illustrated that the adsorption reactions are exothermic and sponta...
Journal of Macromolecular Science, Part A | 2013
Yunzhi Ling; Yuqiong Luo; Jiwen Luo; Xiaoying Wang; Run-Cang Sun
The optimal conditions for synthesizing quaternized chitosan (QCS) via microwave irradiation were explored. The microwave temperature, time, power, mole ratio between chitosan and 2,3-epoxypropyltrimethyl ammonium chloride (ETA), volume ratio between isopropanol and water, and pH value of the reaction system were studied to evaluate the effect on the degree of substitution (DS). The structure of QCS was characterized by means of FT-IR, NMR, XPS and XRD. TGA and DTG were used to measure its thermal stability. At last, QCS acted as a reducing and stabilizing agent to greenly synthesize gold nanoparticles without adding any other chemical reagent.
Ecotoxicology and Environmental Safety | 2016
Yuan Kang; Weijian Pan; Siyun Liang; Lixuan Zeng; Qiuyun Zhang; Jiwen Luo; Xinmei Guo
The bioaccessibility of polybrominated diphenyl ethers (PBDEs) in indoor dust was estimated by a series of in vitro digestion methods. However, the absorption of PBDEs by intestinal cells after in vitro digestion was seldom studied. In the present study, the bioaccessibility of BDE-28, 47, 99 and 153 in indoor dust was firstly investigated by using the in vitro digestion method. Bioaccessibility in intestinal phase (BDE-28: 24.5-30.1%; BDE-47: 6.99-13.0; BDE-99: 1.61-14.2%; and BDE-153 5.97-24.4%.) was higher than that in gastric phase (BDE-28: 38.3-58.0; BDE-47: 9.62-30.9%; BDE-99: 9.71-24.3%; and BDE-153: 13.8-57.4%). The organic matter contents in indoor dust showed variable influence on the bioaccessibility of PBDEs. For the Caco-2 uptake assay, the BDE-28 showed greatest transport rate from medium to cell (Kmc: 0.525h-1), followed by -47, -99 and -153. The Kmc of PBDEs was significantly negative correlated with its corresponding KOW value. Similar pattern was found for the maximum uptake flux (Ju, max) and the transport rate from cell to medium (Kcm). The combination of bioacessibility and the absorption factor by Caco-2 cells could be used to estimate human intake of PBDEs via indoor dust would avoid overestimate the health risk.
Current Nanoscience | 2012
Jiwen Luo; Bo Liu; Xiaoying Wang; Yuanfeng Pan; Runcang Sun
The nanocomposites of chitosan and its derivatives with layered silicate have gained increasing attention since they showed many attracting properties. For the first time, the present study was carried out to investigate the intercalation of chitosan monomer (D- glucosamine hydrochloride, DGH) into organic rectorite (OREC). XRD, TEM, FTIR, 13 C NMR, SEM and TGA were performed to char- acterize the microstructure, morphology and properties of DGH/OREC nanocomposites. The results showed that DGH monosaccharide could insert into the interlayer of OREC, and intercalation result was similar to that of chitosan/OREC nanocomposites. The interlayer distance of DGH/OREC nanocomposites was not proportional to the mass ratio of DGH to OREC, it increased firstly to reach a peak value before it decreased with the increase of the DGH amount. The largest spacing of 6.13 nm was obtained when the mass ratio of DGH to OREC was at 12:1. The direct observation by TEM and SEM also confirmed the intercalated but not exfoliated DGH/OREC nanocomposites. Noteworthily, most strong crystals of DGH in DGH/OREC nanocomposites were destroyed greatly, but its two weak crystals were stronger. TGA result indicated that the thermal stability of DGH/OREC nanocomposites were higher than that of pristine DGH.
Science of The Total Environment | 2018
Yuan Kang; Diya Zeng; Yu Bon Man; Jing Liu; Yang Yang; Shuwei Li; Kaiqiao Situ; Wei Xiong; Lixuan Zeng; Qiuyun Zhang; Jiwen Luo; Weijian Pan; Feng Jiang; Ming Hung Wong
Sorptive sinks are extensively used in the bioaccessibility of organic contaminants, but their suitability for simulating the intestinal cell is seldom reported. In the present study, the sorption efficiency of PAHs by sorptive sinks including silica, poly(ethylene-co-vinyl acetate) (polyE), tenax, and C18 were compared with that by caco-2 cells. The elimination rate constants of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene by caco-2 cell were 0.0417 ± 0.006 min-1, 0.0411 ± 0.0074 min-1, 0.0362 ± 0.006 min-1, and 0.0526 ± 0.0037 min-1, respectively, which were more closely to that of silica and polyE compared to other materials. This indicated that these materials might be the preferable sorptive sinks to simulate absorption of PAHs by intestinal cells. The bioaccessibility of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene in indoor dust ranged from 15.5-43.5%, 9.10-38.8%, 10.0-37.9%, and 6.00-21.9%, respectively, based on physiologically based extraction test (PBET) and the sorptive sinks added in the intestinal solution led to 1.17 to 8.47-fold enhancement of bioaccessibility. The correlation of in vivo PAHs relative bioavailability (RBA) and in vitro digestion bioaccessibility with or without the sorptive sinks of indoor dust were measured, and the results indicated that silica and polyE were more likely to predict PAHs RBA of indoor dust, which was consistent with the results of sorption kinetics assay. The present results indicate that silica and polyE have the potential to simulate caco-2 cell and the inclusion of these materials in the PBET is likely to predict PAHs RBA in indoor dust. Capsule: Silica and polyE were more likely to simulate absorption of PAHs by intestinal cells, and to predict PAHs RBA of indoor dust.