Publications by authors named "Liying Qian"

10 Publications

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Preparation of conductive cellulose fabrics with durable antibacterial properties and their application in wearable electrodes.

Int J Biol Macromol 2021 May 3;183:651-659. Epub 2021 May 3.

School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:

Electroless silver plating on fabrics can obtain conductive and antibacterial bifunctional materials which can be used as electrodes in wearable electronic products. However, these activities are deteriorated easily after washing because of the falling off of silver coating resulted from the weak adhesion. In order to improve the binding force between silver and cellulose fabrics, 3-mercaptopropytrimethoxysilane (MPTS) was applied to modify cellulose fabrics before silver electroless plating to develop the durable conductive fabrics with excellent antibacterial. The silver nanoparticles (Ag NPs) deposition process was observed via field emission scanning electron microscopy (FESEM), thermal properties were evaluated by thermogravimetric analysis (TGA). A dense and uniform silver layer was formed on the fabric. The initial electrical resistance of the conductive fabric was 0.04 Ω/sq and lowered than 2 Ω/sq after 200 washing cycles. The antibacterial efficiency of the fabric after 200 washing cycles remained 92.82%, compared to 100% with the fabric before washing. Moreover, the inhibition rate was determined by optical density of bacteria suspension at 260 nm and further substantiated by releasing of Ag from the fabric. The conductive fabrics were applied as wearable electrodes to capture electrocardiogram (ECG) signals of human in static states and running states.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.04.176DOI Listing
May 2021

Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites.

Int J Mol Sci 2019 Dec 9;20(24). Epub 2019 Dec 9.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China.

Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young's modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency-their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young's modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.
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http://dx.doi.org/10.3390/ijms20246198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6940738PMC
December 2019

Comparison of different extraction methods for polysaccharides from Crataegus pinnatifida Bunge.

Int J Biol Macromol 2020 May 9;150:1011-1019. Epub 2019 Nov 9.

Jiangsu Key Laboratory of Regional Resource Exploitation and Medicinal Research, Huaiyin Institute of Technology, Huai'an 223003, PR China. Electronic address:

In this study, different extraction methods of polysaccharides from Crataegus pinnatifida Bunge (CPP) were compared by studying the extraction yield, structural characteristics and antioxidant activities. Firstly, polysaccharides were obtained using hot water extraction (CPPh), ultrasound assisted extraction (CPPu), enzyme assisted extraction (CPPe) and enzyme-ultrasound assisted extraction (CPPc), respectively. Meanwhile, the optimum extraction conditions of enzyme-ultrasonic assisted extraction were determined by response surface method (RSM). The extraction yields, structural characteristics and antioxidant activities were investigated and compared by visual photos, gas chromatography, ultraviolet-visible and Fourier-transform infrared spectroscopy. The results clearly showed that enzyme-ultrasonic assisted extraction possessed the highest extraction yield (10.39 ± 0.04%). The molecular weight of CPPh was the highest while the other polysaccharides had no significant difference. Besides, the monosaccharide composition of CPPc, CPPh, CPPu and CPPe were similar but the molar percentages of monosaccharide were different. Finally, the results of antioxidant activities showed that CPPc exhibited the highest scavenging effect of superoxide radical and lipids inhibiting ability. In summary, enzyme-ultrasonic assisted extraction was a high-efficient and low-energy consumption method for CPP extraction.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.11.056DOI Listing
May 2020

Preparation of Novel Nano-Sized Hydrogel Microcapsules via Layer-By-Layer Assembly as Delivery Vehicles for Drugs onto Hygiene Paper.

Polymers (Basel) 2018 Mar 19;10(3). Epub 2018 Mar 19.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Hydrogel microcapsules are improved transplantation delivery vehicles for pharmaceuticals by effectively segregating the active ingredients from the surroundings and delivering them to a certain target site. Layer-by-layer (LbL) assembly is an attractive process to fabricate the nano-sized hydrogel microcapsules. In this study, nano-sized hydrogel microcapsules were prepared through LbL assembly using calcium carbonate nanoparticles (CaCO₃ NPs) as the sacrificial inorganic template, sodium alginate (SA) and polyethyleneimine (PEI) as the shell materials. Ciprofloxacin was used to study the encapsulation and release properties of the hydrogel microcapsules. The hydrogel microcapsules were further adsorbed onto the paper to render antimicrobial properties. The results showed that the mean size of the CaCO₃ template was reduced after dispersing into sodium -dodecyl sulfate (SDS) solution under sonication. Transmission electron microscope (TEM) and atomic force microscope (AFM) revealed that some hydrogel microcapsules had a diameter under 200 nm, typical creases and collapses were found on the surface. The nano-sized PEI/SA hydrogel microcapsules showed high loading capacity of ciprofloxacin and a sustained release. PEI/SA hydrogel microcapsules rendered good antimicrobial properties onto the paper by the adsorption of hydrogel microcapsules, however, the mechanical properties of the hygiene paper were decreased.
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http://dx.doi.org/10.3390/polym10030335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414901PMC
March 2018

Novel Wearable Electrodes Based on Conductive Chitosan Fabrics and Their Application in Smart Garments.

Materials (Basel) 2018 Mar 2;11(3). Epub 2018 Mar 2.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Smart garments, which can capture electrocardiogram signals at any time or location, can alert others to the risk of heart attacks and prevent sudden cardiac death when people are sleeping, walking, or running. Novel wearable electrodes for smart garments based on conductive chitosan fabrics were fabricated by electroless plating of silver nanoparticles onto the surfaces of the fibers. The electrical resistance, which is related to the silver content of the composite fabrics, can be as low as 0.0332 ± 0.0041 Ω/sq due to the strong reactivity between amine groups and silver ions. After washing these fabrics eight times, the electrical resistance remained below 1 Ω/sq. The conductive chitosan fabrics were applied to smart garments as wearable electrodes to capture electrocardiogram signals of the human body in static state, jogging state, and running state, which showed good data acquisition ability and sensitivity.
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http://dx.doi.org/10.3390/ma11030370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872949PMC
March 2018

Microwave Assisted Preparation of Antimicrobial Chitosan with Guanidine Oligomers and Its Application in Hygiene Paper Products.

Polymers (Basel) 2017 Nov 24;9(12). Epub 2017 Nov 24.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and ¹H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and time were investigated and the degree of substitution of GCS reached a maximum of 25.5% under optimized conditions in this work. The resulting GCS showed significantly enhanced antimicrobial activities. The results obtained from the dynamic UV absorption of () and atomic force microscopy (AFM) revealed that the deactivation of by GCS was due to the destructing of the cell membrane and the prompt release of cytoplasm from the bacterial cells. The adsorption of GCS onto cellulose fibers and the antimicrobial efficiency of the hygiene papers with GCS were also investigated. Microwave irradiation as a green assisted method was applied to promote this reaction. This facile approach allowed chitosan to be guanidinylated without tedious preparation procedures and thus broadened its application as a biocompatible antimicrobial agent.
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http://dx.doi.org/10.3390/polym9120633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418732PMC
November 2017

Enhanced water vapour barrier and grease resistance of paper bilayer-coated with chitosan and beeswax.

Carbohydr Polym 2014 Jan 5;101:401-6. Epub 2013 Oct 5.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China; Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

In order to overcome the deficiencies of single layer coating, bilayer coated papers were prepared by two separate coating procedures using various combinations of proteins or polysaccharides with beeswax. Among those combinations, chitosan-beeswax bilayer coated paper showed the best water vapour barrier property. It was observed that as the concentration of chitosan solution increased from 1.0 to 3.0 wt%, its water vapour transport rate (WVTR) decreased from 171.6 to 52.8 g/m(2)/d but using reduced beeswax coating weight (from 10.1 to 4.9 g/m(2)). It also displayed an enhanced performance of grease resistance. Scanning electron microscopy (SEM) showed that beeswax layer was fitted to chitosan layer so closely that these two layers are indistinguishable. Confocal laser scanning microscope (CLSM) further confirmed the existence of an integrated chitosan film between beeswax layer and paper base and a thin composite layer consisting of chitosan and beeswax.
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http://dx.doi.org/10.1016/j.carbpol.2013.09.097DOI Listing
January 2014

Synthesis of modified guanidine-based polymers and their antimicrobial activities revealed by AFM and CLSM.

ACS Appl Mater Interfaces 2011 Jun 25;3(6):1895-901. Epub 2011 May 25.

State Key Lab of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Modified guanidine-based polymers with chain extension were synthesized by condensation and cross-linking polymerizations in an attempt to increase molecular weight and charge density of the antimicrobial polymers. The antimicrobial activity and the corresponding mechanisms were investigated by several approaches. The results indicated that the antimicrobial activities of the modified guanidine-based polymer, based on the minimum inhibition concentration (MIC) against E.coli, varied with alkyl monomer ratios. UV absorption at 260 nm further quantified the amount of intracellular components leaked into bacteria suspension. The UV absorption measurements were also used to monitor inhibition processes dynamically. It was found that the modified guanidine-based polymer inhibited the growth of bacteria by causing membrane compromised and intracellular leaked. Dual fluorescent dyes were used to stain all bacteria including the dead ones, which enabled us to utilize CLSM to visualize the viability of bacteria in the presence of various modified guanidine-based polymers without causing any damage. The morphologies of bacteria untreated and treated with modified guanidine-based polymer were observed using an atomic force microscope (AFM), which further demonstrated the damage of E.coli membrane and the leakage of intracellular component induced by the modified guanidine-based polymers.
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http://dx.doi.org/10.1021/am200094uDOI Listing
June 2011

Antimicrobial/Antimold polymer-grafted starches for recycled cellulose fibers.

J Biomater Sci Polym Ed 2010 8;21(10):1359-70. Epub 2010 Jun 8.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, Canada.

In this work, an antimicrobial guanidine polymer (PHGH) was grafted onto starch as a carrier to form branched or grafted chains along the starch backbone. This grafting improved the antimicrobial properties and the adsorption of the starch on recycled cellulose fibers. Similar work was also conducted on bleached sulfite fibers for comparison. The results showed that the starch, grafted with 12 wt% PHGH, adsorbed more on recycled fibers than on sulfite fibers. By applying the antimicrobial-modified starch to recycled or sulfite pulps up to 20 mg/g, both antimicrobial and antimold performances of the papers were improved substantially. Additionally, the PHGH-modified starch increased the tensile index of papers, but decreased the tear index slightly. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to investigate the morphologic changes of Escherichia coli bacteria and Chaetomium globosum fungi upon exposure to the PHGH-modified starch, thus demonstrating that the antimicrobial mechanism is based on the damage of bacterial membrane.
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http://dx.doi.org/10.1163/092050609X12517190417795DOI Listing
November 2010

Synergistic effects of chitosan-guanidine complexes on enhancing antimicrobial activity and wet-strength of paper.

Bioresour Technol 2010 Jul 3;101(14):5693-700. Epub 2010 Mar 3.

State Key Laboratory of Pulp and Paper Eng., South China University of Technology, Guangzhou 510640, PR China.

Chitosan-guanidine complexes were prepared by reacting chitosan and polyhexamethylene guanidine hydrochloride or crosslinked polyhexamethylene guanidine hydrochloride in the presence of sodium tripolyphosphate as a crosslinking agent. The complexes, used as functional additives for paper, synergistically improved wet-strength and antimicrobial activities. In comparison with the control sample, the wet/dry strength ratio of hand-sheets treated with the complexes was increased from 2.65% up to 23.3%. The MIC values of the chitosan-PHGH and chitosan-PHGHE complexes against Escherichia coli were 15.6 and 31.2 microg mL(-1), respectively, thus demonstrating excellent antimicrobial activity. Hand-sheets treated with the complexes exhibited antibacterial activity against E. coli and Staphylococcus aureus. The release of the guanidine polymers included in the complexes was dynamically monitored using UV and the results showed the amount released exceeded 80%. Atomic force microscopy images indicated that the antimicrobial mechanism of the complexes was likely due to membrane damage.
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http://dx.doi.org/10.1016/j.biortech.2010.02.046DOI Listing
July 2010