Publications by authors named "Huining Xiao"

97 Publications

Functionalized Masks: Powerful Materials against COVID-19 and Future Pandemics.

Small 2021 Jul 28:e2102453. Epub 2021 Jul 28.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada.

The outbreak of COVID-19 revealed the vulnerability of commercially available face masks. Without having antibacterial/antiviral activities, the current masks act only as filtering materials of the aerosols containing microorganisms. Meanwhile, in surgical masks, the viral and bacterial filtration highly depends on the electrostatic charges of masks. These electrostatic charges disappear after 8 h, which leads to a significant decline in filtration efficiency. Therefore, to enhance the masks' protection performance, fabrication of innovative masks with more advanced functions is in urgent demand. This review summarizes the various functionalizing agents which can endow four important functions in the masks including i) boosting the antimicrobial and self-disinfectant characteristics via incorporating metal nanoparticles or photosensitizers, ii) increasing the self-cleaning by inserting superhydrophobic materials such as graphenes and alkyl silanes, iii) creating photo/electrothermal properties by forming graphene and metal thin films within the masks, and iv) incorporating triboelectric nanogenerators among the friction layers of masks to stabilize the electrostatic charges and facilitating the recharging of masks. The strategies for creating these properties toward the functionalized masks are discussed in detail. The effectiveness and limitation of each method in generating the desired properties are well-explained along with addressing the prospects for the future development of masks.
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http://dx.doi.org/10.1002/smll.202102453DOI Listing
July 2021

Benzenesulfonic acid-based hydrotropic system for achieving lignocellulose separation and utilization under mild conditions.

Bioresour Technol 2021 Oct 4;337:125379. Epub 2021 Jun 4.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353. Electronic address:

Developing low-cost and sustainable fractionation technology is the key to achieve the maximal utilization of lignocellulosic biomass. This study reported benzenesulfonic acid (BA) as a green hydrotrope for efficient lignocellulose conversion into two fractions at atmospheric pressure: (1) a primarily cellulosic solid residue that can be utilized to produce high-value building blocks (lignocellulosic nanomaterials or sugars), and (2) the collected spent acid liquor that can be diluted with anti-solvent to easily obtain lignin nanoparticles. BA hydrotropic method exhibited greater reaction selectivity to solubilize lignin, where approximately 80% lignin were removed at only 80 °C in 20 min. The lower lignin content substrates resulted in relatively higher enzymatic hydrolysis efficiency of 80% and less entangled lignocellulosic nanofibrils (LCNF). Furthermore, the separated lignin particles size can be easily adjusted by the initial acid concentration. Overall, this work presented a promising and simple technology in achieving lignocellulose separation and utilization under mild conditions.
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http://dx.doi.org/10.1016/j.biortech.2021.125379DOI Listing
October 2021

Thiomers of Chitosan and Cellulose: Effective Biosorbents for Detection, Removal and Recovery of Metal Ions from Aqueous Medium.

Chem Rec 2021 Jul 7;21(7):1876-1896. Epub 2021 Jun 7.

Department of Chemical Engineering, University of New Brunswick, E3B 5A3, Fredericton, New Brunswick, Canada.

Removal of toxic metal ions using adsorbents is a well-known strategy for water treatment. While chitosan and cellulose can adsorb weakly some types of metals, incorporating thiols as metal chelating agents can improve their sorption behaviors significantly. Presented in this review are the various chemical modification strategies applicable for thiolation of chitosan and cellulose in the forms of mercaptans, xanthates and dithiocarbamates. Moreover, much attention has been paid to the specific strategies for controlling the thiolation degree and characterization approaches for establishing the structure-property relationship. Also, the kinetics and isotherm models that elucidate the adsorption processes and mechanisms induced by the thiomers have been explained. These thiomers have found great potentials in the applications associated with metal removal, metal recovery and metal detection.
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http://dx.doi.org/10.1002/tcr.202100068DOI Listing
July 2021

Naturally Occurring Exopolysaccharide Nanoparticles: Formation Process and Their Application in Glutathione Detection.

ACS Appl Mater Interfaces 2021 May 21;13(17):19756-19767. Epub 2021 Apr 21.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.

Naturally occurring nanoscale exopolysaccharide (EPS) has attracted much attention in recent years. In this research, we obtained a new kind of naturally occurring spherical EPS nanoparticles (EPS-R503) from R503. The secretion, self-assembly process, morphological structure, and surface characteristics of the as-prepared nanoparticles were comprehensively revealed with transmission electron microscopy (TEM) and atomic force microscope (AFM) for the first time. It was found that the EPS-R503 nanoparticles consist of negatively charged heteropolysaccharide composed of mannose, glucose, galactose, and glucuronide with several functional groups including -OH, -COOH, and -NH. When different solvents were used to treat the EPS-R503 nanoparticles, the morphological structure and surface properties could be changed or manipulated. The forming mechanism of EPS-R503 was elucidated based on the aggregation processes from a fundamental point of view. Furthermore, EPS-R503 can serve as reducing and stabilizing agents for the biosynthesis of manganese dioxide nanosheets (MnO NSs), leading to EPS-MnO nanocomposite. The as-prepared nanocomposites can absorb fluorescein (FL) to form EPS-MnO-FL, which can be used to detect glutathione (GSH) with a low limit of detection (0.16 μM) and a wide detection range from 0.05 to 4 mM. The excellent biocompatibility of EPS-MnO-FL endows the feasibility of in vivo detection of GSH as well. Overall, the findings from this work not only benefit the exploitation of naturally occurring EPS nanomaterials but also provide a novel strategy for the green synthesis of metal-containing nanosheets for GSH detection.
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http://dx.doi.org/10.1021/acsami.1c03489DOI Listing
May 2021

Highly stretchable and self-healing cellulose nanofiber-mediated conductive hydrogel towards strain sensing application.

J Colloid Interface Sci 2021 Sep 5;597:171-181. Epub 2021 Apr 5.

College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China. Electronic address:

Hypothesis: Hydrogel-based sensors have attracted considerable attention due to potential opportunities in human health monitoring when both mechanical flexibility and sensing ability are required. Therefore, the integration of excellent mechanical properties, electrical conductivity and self-healing properties into hydrogels may improve the application range and durability of hydrogel-based sensors.

Experiments: A novel composite hydrogel composed of polyaniline (PANI), polyacrylic acid (PAA) and 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNFs) was designed. The viscoelastic, mechanical, conductive, self-healing and sensing properties of hydrogels were studied.

Findings: The TOCNF/PANI/PAA hydrogel exhibits a fracture strain of 982%, tensile strength of 74.98 kPa and electrical conductivity of 3.95 S m, as well as good mechanical and electrical self-healing properties within 6 h at ambient temperature without applying any stimuli. Furthermore, owing to the high sensitivity of the TOCNF/PANI/PAA-0.6 hydrogel-based strain sensor (gauge factor, GF = 8.0), the sensor can accurately and rapidly detect large-scale motion and subtle localized activity. The proposed composite hydrogel is as a promising material for use as soft wearable sensors for health monitoring and smart robotics applications.
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http://dx.doi.org/10.1016/j.jcis.2021.04.001DOI Listing
September 2021

Laccase immobilization onto natural polysaccharides for biosensing and biodegradation.

Carbohydr Polym 2021 Jun 19;262:117963. Epub 2021 Mar 19.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 5 A3, Canada.

Over the last few years, the focus of researchers have been set on enzyme engineering and enzyme immobilization technology using natural polysaccharides as promising and green supporting materials to address the challenges of free enzymes for various applications. Polysaccharides have been extensively implemented as enzyme carriers because they can be easily modified chemically according to the nature of immobilization. This process improves the stability and lifetime of laccase in catalytic reactions. Additionally, the selectivity of the enzymes can be preserved for particular application after immobilization onto polysaccharides. This review paper reveals the significance and potential of natural polysaccharides (including cellulose, chitosan, and alginate) and their composites as support materials for the laccases immobilization to expand the modified biocatalysts for industrial applications. Moreover, the roles of immobilized laccases are discussed from a fundamental point of view to elucidate their catalytic mechanisms as biocatalysts in the detection and degradation of environmental contaminants.
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http://dx.doi.org/10.1016/j.carbpol.2021.117963DOI Listing
June 2021

Impacts of degree of substitution of quaternary cellulose on the strength improvement of fiber networks.

Int J Biol Macromol 2021 Jun 23;181:41-44. Epub 2021 Mar 23.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

The degree of substitution (DS) of cellulose derivative is significantly associated with its properties. In this paper, a series of quaternary cellulose (QC) samples with different DS (ranging from 0.16 to 0.51) were synthesized with assistance of microwave and their relationship with strength improvement of fiber networks was investigated systematically. QCs were characterized by elemental analysis, FT-IR, H NMR, and TGA, etc. The results showed that the cationic quaternary ammonium salt group was successfully grafted onto the backbones of cellulose chains and the thermal stability was associated inversely with the DS of QCs. However, the results of strength test for the fiber networks from secondary fiber of old corrugated containers showed that the tensile and burst strength was enhanced by addition of QCs, and their performance was positively correlated their DS. The best result achieved in this investigation was in the case of QC with DS of 0.51, with increments of tensile and burst strength 6.17% and 11.68%, respectively, at a dosage of 1.0 wt% based on oven-dry pulp. This investigation highlights the importance of DS of QC to its application in strength improvement for fiber networks.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.03.121DOI Listing
June 2021

Antimicrobial/Biocompatible Hydrogels Dual-Reinforced by Cellulose as Ultrastretchable and Rapid Self-Healing Wound Dressing.

Biomacromolecules 2021 04 3;22(4):1654-1663. Epub 2021 Mar 3.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.

Hydrogels as a wound dressing, integrated with ultrastretchability, rapid self-healing, and excellent antimicrobial activity, are in high demand, particularly for joint skin wound healing. Herein, a multifunctional and ductile composite hydrogel was developed using poly(vinyl alcohol) (PVA)-borax gel as a matrix that was synergized or dual-reinforced with dopamine-grafted oxidized carboxymethyl cellulose (OCMC-DA) and cellulose nanofibers (CNF). Moreover, neomycin (NEO), an aminoglycoside antibiotic with multifunctional groups, was incorporated into the hydrogel network as both an antibacterial agent and a cross-linker. The dynamic reversible borate ester linkages and hydrogen bonds between OCMC-DA, PVA, and CNF, along with dynamic cross-linking imine linkages between NEO and OCMC-DA, endowed the hydrogel with excellent self-healing ability and stretchability (3300%). The as-reinforced networks enhanced the mechanical properties of hydrogels significantly. More remarkably, the composite hydrogel with improved biodegradability and biocompatibility is pH-responsive and effective against a broad spectrum of bacteria, which is attributed to the controllable release of NEO for steady availability of the antibiotic on the wound location. Overall, the antimicrobial hydrogel with rapid self-healing and reliable mechanical properties holds significant promise as dressing material for wound healing.
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http://dx.doi.org/10.1021/acs.biomac.1c00086DOI Listing
April 2021

Magnetic FeO/attapulgite hybrids for Cd(II) adsorption: Performance, mechanism and recovery.

J Hazard Mater 2021 06 26;412:125237. Epub 2021 Jan 26.

School of Chemistry and Environmental Engineering & Hubei Engineering Technology Research Center for Chemical Industry Pollution Control, Wuhan Institute of Technology, Wuhan 430205, China. Electronic address:

Herein, a FeO decorated attapulgite adsorbent (FA) is fabricated for the removal of Cd(II) from wastewater, and subsequently a feasible strategy for converting the saturated waste adsorbent to CdS/FA photocatalyst is reported. Owing to the in situ growth of FeO on the attapulgite (ATP), the FA adsorbents exhibit enlarged surface area and increased adsorption sites. More importantly, the strong interaction between FeO and ATP leads to changes of coordination environment around the O‒Fe‒O bond with the ATP. Based on the results of density functional theory calculations, the electrons are more readily transferred from Fe to O, and the hanging O atoms with more electronegativity act as the efficient adsorption sites for Cd(II), efficiently improving the adsorption performance of the FeO phases. Furthermore, the waste FA adsorbent could be conveniently separated from the treated water by magnets and converted to CdS/FA photocatalyst, which exhibits satisfying degradation efficiency for tetracycline with low concentration. This work provides a potential strategy to optimize the ATP-based materials for heavy ions adsorption and reutilize the waste adsorbents.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125237DOI Listing
June 2021

Nanocellulose-based lightweight porous materials: A review.

Carbohydr Polym 2021 Mar 13;255:117489. Epub 2020 Dec 13.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Nanocellulose has been widely concerned and applied in recent years. Because of its high aspect ratio, large specific surface area, good modifiability, high mechanical strength, renewability and biodegradability, nanocellulose is particularly suitable as a base for constructing lightweight porous materials. This review summarizes the preparation methods and applications of nanocellulose-based lightweight porous materials including aerogels, cryogels, xerogels, foams and sponges. The preparation of nanocellulose-based lightweight porous materials usually involves gelation and drying processes. The characteristics and influencing factors of three main drying methods including freeze, supercritical and evaporation drying are reviewed. In addition, the mechanism of physical and chemical crosslinking during gelation and the effect on the structure and properties of the porous materials in different drying methods are especially focused on. This contribution also introduces the application of nanocellulose-based lightweight porous materials in the fields of adsorption, biomedicine, energy storage, thermal insulation and sound absorption, flame retardancy and catalysis.
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http://dx.doi.org/10.1016/j.carbpol.2020.117489DOI Listing
March 2021

Multilayer surface construction for enhancing barrier properties of cellulose-based packaging.

Carbohydr Polym 2021 Mar 24;255:117431. Epub 2020 Nov 24.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B5A3, Canada. Electronic address:

It has been a consistent challenge to develop eco-friendly packaging in its entire life cycle with multiple barriers. Herein, a lignocellulose-derived strategy was developed for enhancing barrier properties of cellulose-based packaging. Porosity and hydrophilicity of paper packaging were remedied by the sequential deposition of oxalic acid modified microfibrillated cellulose (OMFC) and infiltration of nanosized alkaili lignin (NAL). OMFC deposition and NAL infiltration could fill the void among fibers and create hydrophobic micro/nano-roughness on paper surface, which showed synergetic effect on enhancing barrier and mechanical properties by self-bonding and crosslinking between cellulose and lignin. Water vapor transmission rate was reduced by 93 % with initial water contact angle at 113°. Besides, more than four-fold increase in tensile strength along with persisted water and grease resistance were achieved. The result suggests the barrier-enhanced packaging by multilayer surface construction has great potential in bio-based applications considering the biodegradability, biocompatibility, and recyclability.
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http://dx.doi.org/10.1016/j.carbpol.2020.117431DOI Listing
March 2021

Dual-responsive carboxymethyl cellulose/dopamine/cystamine hydrogels driven by dynamic metal-ligand and redox linkages for controllable release of agrochemical.

Carbohydr Polym 2021 Feb 8;253:117188. Epub 2020 Oct 8.

Department of Chemical Engineering, University of New Brunswick, Fredericton, E3B 5A3, NB, Canada. Electronic address:

The utilization of agrochemicals in crop production is often inefficient due to lack of appropriate carriers, raising in the significant concerns of ecological environment and public health. To enhance the efficiency of agrochemical delivery, a novel cellulose-based hydrogel was constructed in this work by cross-linking dopamine (DA)-modified carboxymethyl cellulose (CMC) with cystamine (CYS) in the presence of Fe ions. The hydrogels displayed reversible sol-gel transitions upon exposure to stimulation of changes in pH and redox, leading to the controllable release of model agrochemical (6-benzyladenine). Compared with single-triggered condition, the hydrogel doubled the cumulative release when co-triggered by pH and redox. The dynamic metal/catechol complexation and disulfide bonding coexist in the hydrogel networks, enabling occurrence of dynamic reaction under a variety of environmental conditions. The finite element method (FEM) was employed to simulate the hydrogel to provide a theoretical insight into the tested drug delivery. Benefitting from the reversibly cross-linked networks and the excellent biodegradability of the hydrogels, we anticipate that this dual-responsive, polysaccharide-based hydrogel will offer diverse applications to reach the full potential in sustainable advancement of crop production.
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http://dx.doi.org/10.1016/j.carbpol.2020.117188DOI Listing
February 2021

Novel multi-responsive and sugarcane bagasse cellulose-based nanogels for controllable release of doxorubicin hydrochloride.

Mater Sci Eng C Mater Biol Appl 2021 Jan 11;118:111357. Epub 2020 Aug 11.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Nanogel based on polysaccharides has attracted the tremendous interest due to its unique performance as drug carrier for in vivo release. In this work, the multi-responsive nanogels were developed based on the tailor-modified sugarcane bagasse cellulose (SBC). In the presence of crosslinking agent cystamine bisacrylamide (CBA), the in-situ free radical copolymerization of methacrylated monocarboxylic sugarcane bagasse cellulose (MAMC-SBC) and N-isopropylacrylamide (NIPAM) in aqueous phase was conducted, thus leading to redox, pH and thermal-responsive nanogels. The results obtained from FT-IR, SEM and particle sizer showed that the nanogels were highly stable with the desired particle size ranging from 90 to 180 nm and contained targeted polymeric segments and linkage for multi-responsivity. Doxorubicin hydrochloride (DOX) as a model drug was effectively loaded into the nanogels, partly driven by strong electrostatic association; and the loading efficiency reached up to 82.7%. Moreover, the drug release could be readily manipulated by the addition of reducing agent, pH and temperature, which is attributed to the multi-responsive behavior of nanogels as carrier and synergetic effects. The performance of nanogels was also governed by the ratio of reactive MAMC-SBC and NIPAM during polymerization; and the ratio at 1:1(wt) led to the optimal structure of nanogels.
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http://dx.doi.org/10.1016/j.msec.2020.111357DOI Listing
January 2021

Binding affinity of family 4 carbohydrate binding module on cellulose films of nanocrystals and nanofibrils.

Carbohydr Polym 2021 Jan 3;251:116725. Epub 2020 Jul 3.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada.

The binding affinity and thermodynamics of family 4 carbohydrate-binding module (CBM4), belonging to type B CBM, on model surfaces of cellulose nanocrystals (CNC) and nanofibrils (CNF) were investigated by quartz crystal microbalance with dissipation monitoring (QCM-D) technology in real-time at different temperatures. The thermodynamic parameters associated with the interaction, such as Gibbs free energy, enthalpy change, entropy change and heat capacity were obtained using the van't Hoff analysis via a nonlinear parameter estimation. The results demonstrated CBM4 binds preferentially to both CNF and CNC, whereas the driving forces behind them were very different. The former was related to the hydrogen bonds formed in the CBM4 clefts, resulting in a favorable enthalpy but compensated by unfavorable entropy change; on the contrary, the latter was mainly driven by favorable entropy but compensated by unfavorable enthalpic change due to water rearrangement.
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http://dx.doi.org/10.1016/j.carbpol.2020.116725DOI Listing
January 2021

A stretchable, self-healing conductive hydrogels based on nanocellulose supported graphene towards wearable monitoring of human motion.

Carbohydr Polym 2020 Dec 13;250:116905. Epub 2020 Aug 13.

College of Materials Science and Engineering, Joint International Research Lab of Lignocellulosic Functional Materials, Nanjing Forestry University, Nanjing, 210037, China. Electronic address:

Stretchable, self-healing and conductive hydrogels have attracted much attention for wearable strain sensors, which are highly required in health monitoring, human-machine interaction and robotics. However, the integration of high stretchability, self-healing capacity and enhanced mechanical performance into one single conductive hydrogel is still challenging. In this work, a type of stretchable, self-healing and conductive composite hydrogels are fabricated by uniformly dispersing TEMPO-oxidized cellulose nanofibers (TOCNFs)-graphene (GN) nanocomposites into polyacrylic acid (PAA) hydrogel through an in-situ free radical polymerization. The resulting hydrogels demonstrate a stretchability (∼850 %), viscoelasticity (storage modulus of 32 kPa), mechanical strength (compression strength of 2.54 MPa, tensile strength of 0.32 MPa), electrical conductivity (∼ 2.5 S m) and healing efficiency of 96.7 % within 12 h. The hydrogel-based strain sensor shows a high sensitivity with a gauge factor of 5.8, showing great potential in the field of self-healing wearable electronics.
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http://dx.doi.org/10.1016/j.carbpol.2020.116905DOI Listing
December 2020

Dispersion Properties of Nanocellulose: A Review.

Carbohydr Polym 2020 Dec 13;250:116892. Epub 2020 Aug 13.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

The development of science and technology brings forward higher and higher requirements for the properties of materials. Nanocellulose, with many fascinating properties including large specific surface area, template structure, good modifiability, biodegradability, and etc., has wide application prospects. The surface properties and interfacial compatibility of nanocellulose are the keys to its application performance. This review mainly summarizes the colloid and surface chemistry of nanocellulose and their effects on the dispersity in various solvents and polymer matrices, and especially focuses on the impact of surface hydrophilicity/hydrophobicity, charge repulsion and steric hindrance on the dispersion properties. Various surface modification methods to improve the dispersion performance of nanocellulose, such as oxidation, etherification, esterification, amidation, graft polymerization, and etc., are summarized. In addition, the application of nanocellulose as the dispersant for Pickering emulsion, carbon nanomaterials, metal nanoparticles and etc. is also introduced. The development trend and potential application of nanocellulose are finally prospected.
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http://dx.doi.org/10.1016/j.carbpol.2020.116892DOI Listing
December 2020

Ethylene scavengers for the preservation of fruits and vegetables: A review.

Food Chem 2021 Feb 4;337:127750. Epub 2020 Aug 4.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada. Electronic address:

The phytohormone ethylene is the main cause of postharvest spoilage of fruit and vegetables (F&V). To address the global challenge of reducing postharvest losses of F&V, effective management of ethylene is of great importance. This review summarizes the various ethylene scavengers/inhibitors and emerging technologies recently developed for the effective removal of ethylene released, paying particular attention to the ethylene scavenger/inhibitors containing catalysts to promote the in-situ oxidation of ethylene without inducing further pollution. Packing ethylene scavengers, such as zeolite, titanium dioxide and transition metals, in a small sachet has been practically used and widely reported. However, incorporating ethylene scavenger into food packaging materials or films along with the in-situ oxidation of ethylene has been rarely reviewed. The current review fills up this gap, covering the latest research progress on ethylene scavengers/inhibitors and discussion on the mechanisms of ethylene elimination and oxidation associated with F&V packaging.
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http://dx.doi.org/10.1016/j.foodchem.2020.127750DOI Listing
February 2021

Functional-modified polyurethanes for rendering surfaces antimicrobial: An overview.

Adv Colloid Interface Sci 2020 Sep 11;283:102235. Epub 2020 Aug 11.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada. Electronic address:

Antimicrobial surfaces and coatings are rapidly emerging as primary components in functional modification of materials and play an important role in addressing the problems associated with biofouling and microbial infection. Polyurethane (PU) consisting of alternating soft and hard segments has been one of the most important coating materials that have been widely applied in many fields due to its versatile properties. This review attempts to provide insight into the recent advances in antimicrobial polyurethane coatings or surfaces. According to different classes of antimicrobial components along with their antimicrobial mechanism, the synthesis pathways are presented systematically herein to afford polyurethane with antimicrobial properties. Also, the challenges and opportunities of antimicrobial PU coatings and surfaces are also discussed. This review will be beneficial to the exploitation and the further studies of antimicrobial polyurethane materials for a variety of applications.
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http://dx.doi.org/10.1016/j.cis.2020.102235DOI Listing
September 2020

Natural Polymer-Based Antimicrobial Hydrogels without Synthetic Antibiotics as Wound Dressings.

Biomacromolecules 2020 08 30;21(8):2983-3006. Epub 2020 Jul 30.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources and Joint International Research Lab of Lignocellulosic Functional Materials, Nanjing Forestry University, Nanjing 210037, China.

Wound healing is usually accompanied by bacterial infection. The excessive use of synthetic antibiotics leads to drug resistance, posing a significant threat to human health. Hydrogel-based wound dressings aimed at mitigating bacterial infections have emerged as an effective wound treatment. The review presented herein particularly focuses on the hydrogels originating from natural polymers. To further enhance the performance of wound dressings, various strategies and approaches have been developed to endow the hydrogels with excellent broad-spectrum antibacterial activity. Those that are summarized in the current review are the hydrogels with intrinsic or stimuli-triggered bactericidal properties and others that serve as vehicles for loading antibacterial agents without synthetic antibiotics. Specific attention is paid to antimicrobial mechanisms and the antibacterial performance of hydrogels. Practical antibacterial applications to accelerate the wound healing employing these antibiotic-free hydrogels are also introduced along with the discussion on the current challenges and perspectives leading to new technologies.
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http://dx.doi.org/10.1021/acs.biomac.0c00760DOI Listing
August 2020

Functionalized porous magnetic cellulose/FeO beads prepared from ionic liquid for removal of dyes from aqueous solution.

Int J Biol Macromol 2020 Nov 3;163:309-316. Epub 2020 Jul 3.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada. Electronic address:

Porous magnetic cellulose/FeO beads (CFBs), consisting of cellulose as matrix and ferrosoferric oxide, were successfully fabricated from microcrystalline cellulose dissolved in an ionic liquid and further modified with glutaric anhydride. The porous structure of modified magnetic cellulose/FeO beads (MCFBs) was created by nano-sized calcium carbonate (CaCO). The resulting MCFBs were well characterized and employed as effective adsorbents for removal of dyes from aqueous solution. The adsorption behaviors indicated that the adsorption kinetics was preferably fitted to the pseudo-second-order kinetic model; whereas the adsorption isotherms were well described by Langmuir model with the maximum adsorption capacity of 1186.8 and 151.8 mg/g for methylene blue (MB) and Rhodamine B (RhB), respectively. Moreover, MCFBs are magnetically separable, thus leading to a range of green-based and promising adsorbents towards organic pollutants with easy recovery.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.06.280DOI Listing
November 2020

Polycyclodextrins: Synthesis, functionalization, and applications.

Carbohydr Polym 2020 Aug 27;242:116277. Epub 2020 Apr 27.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3 Canada. Electronic address:

Cyclodextrins (CDs) are cyclic oligosaccharides with unique conical structure enabling host-guest inclusion complexes. However, virgin CDs sufferfrom low solubility, lack of functional groups and its inability to strong complexation with the guests. One of the most efficient ways to improve the properties of cyclodextrins is the synthesis of polycyclodextrins. Generally, there are two types of polycyclodextrins: 1) polymers containing CD units as parts of the main backbone; and 2) polymers with CD units as side chains. These polycyclodextrins are produced (i) from direct copolymerization of virgin cyclodextrins or cyclodextrins derivatives with various monomers including isocyanates, epoxides, carboxylic acids, anhydrides, acrylates, acrylamides and fluorinated aromatic compounds, or (ii) by post-functionalization of other polymers with CDs or CD derivatives.. By selecting the proper derivatives of CDs and controlling the polymerization, polycyclodextrins with linear, hyperbranched, and crosslinked structures have been synthesized. Polycyclodextrins have found significant applications in numerous areas, as adsorbents for removal of organic pollutants, carriers in gene/drug delivery, and for preparation of supramolecular based hydrogels. The focus of this review paper is placed on the synthesis, characterization, and applications of CDs so as to highlight challenges as well as the promising features of the future ahead of material developments based on CDs.
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http://dx.doi.org/10.1016/j.carbpol.2020.116277DOI Listing
August 2020

Cellulose-based adsorbents loaded with zero-valent iron for removal of metal ions from contaminated water.

Environ Sci Pollut Res Int 2020 Sep 12;27(26):33234-33247. Epub 2020 Jun 12.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada.

Sawdust loaded with zero-valent iron (S-ZVI) was prepared using a liquid phase reduction method for removing heavy metal ions from contaminated water. Surface chemistry and morphology of adsorbents were characterized with Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), SEM-mapping, EDX, and X-ray photoelectron spectrum (XPS). The results demonstrated that the zero-valent iron was successfully loaded onto the sawdust. The impact of various factors such as pH, initial metal ion concentration, temperature, and contact time on the removal capability of the adsorbents was systematically investigated. The equilibrium adsorption data showed that the adsorption of arsenic ions and Cr(III) followed the Langmuir model well, and the maximum adsorption reached 111.37 and 268.7 mg/g in an aqueous solution system. In addition, the adsorption kinetics was more accurately described by the pseudo-second-order model, suggesting the domination of chemical adsorption. Meanwhile, the results on recyclability indicated that the high performance of S-ZVI on the removal of arsenic ions was well maintained after three regeneration cycles. The adsorption mechanism revealed in this work suggested that S-ZVI improved the dispersion of ZVI by minimizing the agglomeration, thus leading to highly effective adsorption via chelation, electrostatic interaction, and redox reaction.
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http://dx.doi.org/10.1007/s11356-020-09390-zDOI Listing
September 2020

Dual-Functional Redox-Responsive Nanocarriers for Loading Phytohormone and Complexation with Heavy Metal Ions.

J Agric Food Chem 2020 May 28;68(18):5076-5085. Epub 2020 Apr 28.

Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.

This work focused on designing a novel redox-responsive nanocarrier synthesized from carboxymethyl-β-cyclodextrin-modified nanosilica, which could load and release plant hormones, such as salicylic acid (SA), in plant cells. When the SA-loaded nanoparticles cross the plant cell wall, the disulfide bond can be broken to form sulfhydryl groups under the action of reduced glutathione (GSH), thus releasing SA. Meanwhile, the resulting thiol groups exhibited strong affinity toward several heavy metal ions, mercury ions in particular, thus playing a role similar to phytochelatins for detoxification. The results of SA release in vitro proved that the release proceeded much faster in GSH-rich than in GSH-free environments. The adsorption behaviors of the redox-responsive nanoparticles toward heavy metal ions, after phytohormones release, were systematically investigated. Moreover, the synergetic effects on sustained release and metal ion capture enable the redox-responsive cyclodextrin-modified silica to be an effective and dual-functional nanocarrier that has great potential for agricultural applications.
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http://dx.doi.org/10.1021/acs.jafc.0c01651DOI Listing
May 2020

Layer-by-Layer Assembly for Surface Tethering of Thin-Hydrogel Films: Design Strategies and Applications.

Chem Rec 2020 Aug 14;20(8):857-881. Epub 2020 Apr 14.

College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China.

Manipulation and engineering of the surfaces has a key role in improving the materials properties. Anchoring of thin hydrogels on the materials surface is one of the recently developed methods to achieve surfaces with high potential applications. Layer-by-layer (LBL) has been used widely as a strong strategy for immobilization of thin hydrogel films on the surface of various organic/inorganic substrates. Electrostatic LBL and covalent LBL are two main strategies used in this regard. In electrostatic LBL, negatively and positively hydrophilic polymers are sequentially assembled to create a multilayer hydrogel which subsequent covalent crosslinking of multilayers improved the stability of the inserted layers. On the other hand, covalent LBL requires hydrophilic polymers bearing reactive telechelic groups. These reactive polymers are prepared by various polymerization techniques or by post-functionalization of biopolymers. The principles of hydrogel anchoring have described along with representative examples. Besides, the potential applications of the modified surfaces in specific cases have been addressed and overviewed.
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http://dx.doi.org/10.1002/tcr.202000007DOI Listing
August 2020

Self-Healable Electro-Conductive Hydrogels Based on Core-Shell Structured Nanocellulose/Carbon Nanotubes Hybrids for Use as Flexible Supercapacitors.

Nanomaterials (Basel) 2020 Jan 6;10(1). Epub 2020 Jan 6.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Recently, with the development of personal wearable electronic devices, the demand for portable power is miniaturization and flexibility. Electro-conductive hydrogels (ECHs) are considered to have great application prospects in portable energy-storage devices. However, the synergistic properties of self-healability, viscoelasticity, and ideal electrochemistry are key problems. Herein, a novel ECH was synthesized by combining polyvinyl alcohol-borax (PVA) hydrogel matrix and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-cellulose nanofibers (TOCNFs), carbon nanotubes (CNTs), and polyaniline (PANI). Among them, CNTs provided excellent electrical conductivity; TOCNFs acted as a dispersant to help CNTs form a stable suspension; PANI enhanced electrochemical performance by forming a "core-shell" structural composite. The freeze-standing composite hydrogel with a hierarchical 3D-network structure possessed the compression stress (~152 kPa) and storage modulus (~18.2 kPa). The composite hydrogel also possessed low density (~1.2 g cm), high water-content (~95%), excellent flexibility, self-healing capability, electrical conductivity (15.3 S m), and specific capacitance of 226.8 F g at 0.4 A g. The fabricated solid-state all-in-one supercapacitor device remained capacitance retention (~90%) after 10 cutting/healing cycles and capacitance retention (~85%) after 1000 bending cycles. The novel ECH had potential applications in advanced personalized wearable electronic devices.
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http://dx.doi.org/10.3390/nano10010112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022439PMC
January 2020

Methods and applications of nanocellulose loaded with inorganic nanomaterials: A review.

Carbohydr Polym 2020 Feb 13;229:115454. Epub 2019 Oct 13.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Nanocellulose obtained from natural renewable resources has attracted enormous interests owing to its unique morphological characteristics, excellent mechanical strength, biocompatibility and biodegradability for a variety of applications in many fields. The template structure, high specific surface area, and active surface groups make it feasible to conduct surface modification and accommodate various nano-structured materials via physical or chemical deposition. The review presented herein focuses on the methodologies of loading different nano-structured materials on nanocellulose, including metals, nanocarbons, oxides, mineral salt, quantum dots and nonmetallic elements; and further describes the applications of nanocellulose composites in the fields of catalysis, optical electronic devices, biomedicine, sensors, composite reinforcement, photoswitching, flame retardancy, and oil/water separation.
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http://dx.doi.org/10.1016/j.carbpol.2019.115454DOI Listing
February 2020

A Skin-Inspired Stretchable, Self-Healing and Electro-Conductive Hydrogel with A Synergistic Triple Network for Wearable Strain Sensors Applied in Human-Motion Detection.

Nanomaterials (Basel) 2019 Dec 6;9(12). Epub 2019 Dec 6.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

nanocellulose; polyacrylic acid; polypyrrole; hydrogel; self-healing and conductive.
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http://dx.doi.org/10.3390/nano9121737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6956062PMC
December 2019

Lignin Redistribution for Enhancing Barrier Properties of Cellulose-Based Materials.

Polymers (Basel) 2019 Nov 22;11(12). Epub 2019 Nov 22.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B5A3, Canada.

Renewable cellulose-based materials have gained increasing interest in food packaging because of its favorable biodegradability and biocompatibility, whereas the barrier properties of hydrophilic and porous fibers are inadequate for most applications. Exploration of lignin redistribution for enhancing barrier properties of paper packaging material was carried out in this work. The redistribution of nanolized alkali lignin on paper surface showed excellent water, grease, and water vapor barrier. It provided persisted water (contact angle decrease rate at 0.05°/s) and grease (stained area undetectable at 72 h) resistance under long-term moisture or oil direct contact conditions, which also inhibited the bacterial growth to certain degree. Tough water vapor transmission rate can be lowered 82% from 528 to 97 g/m/d by lignin redistribution. The result suggests that alkali lignin, with multiple barrier properties, has great potential in bio-based application considering the biodegradability, biocompatibility, and recyclability.
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http://dx.doi.org/10.3390/polym11121929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960624PMC
November 2019

Revealing Adsorption Behaviors of Amphoteric Polyacrylamide on Cellulose Fibers and Impact on Dry Strength of Fiber Networks.

Polymers (Basel) 2019 Nov 15;11(11). Epub 2019 Nov 15.

Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

Amphoteric polyacrylamide (AmPAM) has been widely used in a variety of industrial areas and the adsorption behavior of AmPAM plays a crucial role in its applications. In this study, a series of AmPAMs with various molecular weights (MW) were synthesized; and their impact on dry strength of fiber networks or paper was assessed. The results showed that the optimal MW of AmPAM for strength enhancement ranged between 300 and 500 k. More importantly, the adsorption behaviors of three typical AmPAM samples on silica (model substrate) and cellulose surfaces were revealed using a quartz crystal microbalance with dissipation monitoring (QCM-D) in situ and in real time. The adsorption dynamics of AmPAM and the conformation of the adlayers were further derived. The results indicated that a relatively high adsorption amount was achieved under the conditions of a high polymer concentration, a medium pH close to its isoelectric point (IEP), a mild ionic strength, and a high charged surface; whereas the MW of AmPAM had little effect on the equilibrium adsorption mass of AmPAM, but significantly affected the conformation of adsorbed layer on substrates. Based on the adsorption behaviors of AmPAM, the explanation of the best dry strength achieved in a narrow range of MW of AmPAM is proposed. It was concluded that the appropriate balance between bridging and flocculation, penetration into fiber pores, and conformation were only achieved in the optimal MW range of AmPAM. The findings obtained from in this work enable us to better understand the adsorption behaviors of polyampholyte, and provide a guideline on molecular design of AmPAM and its applications from both fundamental and practical points of view.
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http://dx.doi.org/10.3390/polym11111886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918427PMC
November 2019

Suppressing Ammonia Re-Emission with the Aid of the [email protected] Catalyst in Ammonia-Based Desulfurization.

Environ Sci Technol 2019 Nov 7;53(22):13477-13485. Epub 2019 Nov 7.

College of Environment , Zhejiang University of Technology , Hangzhou 310014 , Zhejiang , China.

The re-emission of NH and SO caused by the decomposition of (NH)SO is a crucial concern in ammonia-based desulfurization. In this study, a novel [email protected] catalyst with a three-dimensional two-helix structure is proposed for converting (NH)SO into (NH)SO. The oxidation rate of (NH)SO with the catalyst was 7.5 times that without any catalyst, and this improvement was attributed to appropriately dispersed CoO nanoparticles with a size of 4-10 nm that interacted with the KIT-6 support. Therefore, the number of active sites with substitution and hole defects was substantially increased, which is advantageous for high catalytic activities. Consequently, the amount of NH and SO re-emission during (NH)SO oxidation was reduced by 43.9%, which considerably reduced potential environmental risks. The results of this study serve to advance ammonia desulfurization by improving the desulfurization efficiency, downsizing the oxidation tank, and generating considerable profit from efficient reclaiming of (NH)SO as a fertilizer.
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http://dx.doi.org/10.1021/acs.est.9b03060DOI Listing
November 2019
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