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3D Flower-Like FeWO4/CeO2 Hierarchical Architectures on rGO for Durable and High-Performance Microalgae Biophotovoltaic Fuel Cells

Karthikeyan C, Jenita Rani G, Ng FL, Periasamy V, Pappathi M, Jothi Rajan M, et al.

Appl Biochem Biotechnol, 2020 Nov;192(3):751-769.
PMID: 32557232 DOI: 10.1007/s12010-020-03352-4

A facile chemical reduction approach is adopted for the synthesis of iron tungstate (FeWO4)/ceria (CeO2)-decorated reduced graphene oxide (rGO) nanocomposite. Surface morphological studies of rGO/FeWO4/CeO2 composite reveal the formation of hierarchical FeWO4 flower-like microstructures on rGO sheets, in which the CeO2 nanoparticles are decorated over the FeWO4 microstructures. The distinct anodic peaks observed for the cyclic voltammograms of studied electrodes under light/dark regimes validate the electroactive proteins present in the microalgae. With the cumulative endeavors of three-dimensional FeWO4 microstructures, phase effect between rGO sheet and FeWO4/CeO2, highly exposed surface area, and light harvesting property of CeO2 nanoparticles, the relevant rGO/FeWO4/CeO2 nanocomposite demonstrates high power and stable biophotovoltaic energy generation compared with those of previous reports. Thus, these findings construct a distinct horizon to tailor a ternary nanocomposite with high electrochemical activity for the construction of cost-efficient and environmentally benign fuel cells.

Matched MeSH terms: Nanocomposites/chemistry
Fabrication of biopolymer polyhydroxyalkanoate/chitosan and 2D molybdenum disulfide-doped scaffolds for antibacterial and biomedical applications

Mukheem A, Shahabuddin S, Akbar N, Anwar A, Sarih NM, Sudesh K, et al.

Appl Microbiol Biotechnol, 2020 Apr;104(7):3121-3131.
PMID: 32060693 DOI: 10.1007/s00253-020-10416-2

Antibiotic resistance in pathogenic bacteria is a major health challenge, as Infectious Diseases Society of America (IDSA) has recognized that the past simply drugs susceptible pathogens are now the most dangerous pathogens due to their nonstop growing resistance towards conventional antibiotics. Therefore, due to the emergence of multi-drug resistance, the bacterial infections have become a serious global problem. Acute infections feasibly develop into chronic infections because of many factors; one of them is the failure of effectiveness of antibiotics against superbugs. Modern research of two-dimensional nanoparticles and biopolymers are of great interest to attain the intricate bactericidal activity. In this study, we fabricated an antibacterial nanocomposite consisting of representative two-dimensional molybdenum disulfide (2D MoS2) nanoparticles. Polyhydroxyalkanoate (PHA) and chitosan (Ch) are used to encapsulate MoS2 nanoparticles into their matrix. This study reports the in vitro antibacterial activity and host cytotoxicity of novel PHA-Ch/MoS2 nanocomposites. PHA-Ch/MoS2 nanocomposites were subjected to time-dependent antibacterial assays at various doses to examine their antibacterial activity against multi-drug-resistant Escherichia coli K1 (Malaysian Type Culture Collection 710859) and methicillin-resistant Staphylococcus aureus (MRSA) (Malaysian Type Culture Collection 381123). Furthermore, the cytotoxicity of nanocomposites was examined against spontaneously immortalized human keratinocyte (HaCaT) cell lines. The results indicated significant antibacterial activity (p value

Matched MeSH terms: Nanocomposites
Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite

Masri A, Abdelnasir S, Anwar A, Iqbal J, Numan A, Jagadish P, et al.

Appl Microbiol Biotechnol, 2021 Apr;105(8):3315-3325.
PMID: 33797573 DOI: 10.1007/s00253-021-11221-1

BACKGROUND: Conducting polymer based nanocomposites are known to be effective against pathogens. Herein, we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii).
RESULTS: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells.
CONCLUSION: These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications.
KEY POINTS: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.

Matched MeSH terms: Nanocomposites*
Fulltext Genotoxicity assessment of locally produced dental nanocomposite using Comet assay

Siti Robayah Mohd Zakri, Kannan, Thirumulu Ponnuraj, Nora Aziz, Siti Fadilah Abdullah, Dasmawati Mohamad, Ismail Ab Rahman, et al.

Archives of Orofacial Sciences, 2011;6(1):15-20.
MyJurnal

The aim of this study was to determine the genotoxicity of a locally produced nanocomposite by Universiti Sains Malaysia, Malaysia using Comet assay. Stem cells from human exfoliated deciduous teeth (SHED) were treated with the nanocomposite at five different concentrations (0.006, 0.0125, 0.025, 0.05, and 0.1 mg/ml) along with concurrent negative (medium alone) and positive control (zinc sulfate heptahydrate) and incubated at 37°C for 24 hours in an incubator at 5% CO2. The tail moment was used to assess the extent of DNA damage. The tail moment for the group of SHED treated with nanocomposite (for all the five different concentrations) was not statistically significant as compared to the negative control, suggesting that the locally produced dental nanocomposite did not induce any DNA damage. Hence, it can be concluded that the locally produced nanocomposite is non-genotoxic on stem cells from human exfoliated deciduous teeth.

Matched MeSH terms: Nanocomposites
Development of graphene based nanocomposites towards medical and biological applications

Mousavi SM, Low FW, Hashemi SA, Lai CW, Ghasemi Y, Soroshnia S, et al.

Artif Cells Nanomed Biotechnol, 2020 Dec;48(1):1189-1205.
PMID: 32930615 DOI: 10.1080/21691401.2020.1817052

Graphene and its derivative materials present high potential towards medical and biological applications, including drug delivery and bioimaging, due to their exceptional properties such as thermal conductivity and high specific surface area. The main focus of this work is to review the current development of graphene materials and the derivatives for biocompatible, bioimaging and drug delivery applications. Also, the synthesis methods with variation of graphene nanocomposites and the functionalisation will be further explained. For the graphene approaches, chemical vapour deposition (CVD) is the best-known technique to make high-quality graphene sheet by growth route with mass production. By considering the organic graphene nanocomposites, the biocompatibility and cytotoxic effects against graphene nanocomposites were evaluated for biomedical employments such as high quality bioimaging and effective drug delivery for cancer treatments. For example, graphene oxide incorporated with PEG and loaded with SN 38 for camptothecin analolgue as anticancer drug and revealed high cytotoxicity has an effect of 1000 times better effect than CPT in HCT-116 cells. Their drug delivery ability for both in-vivo and in-vitro applications compared to the controlled drugs such as doxorubicin (DOX) will be discussed accordingly. The graphene and its deriavatives possess some intriguing properties, which will lead to drug delivery due to strong biocompatibility and cyctotoxic effect towards biomedicine applications.

Matched MeSH terms: Nanocomposites/chemistry*
Fulltext Antimicrobial and controlled release studies of a novel nystatin conjugated iron oxide nanocomposite

Hussein-Al-Ali SH, El Zowalaty ME, Kura AU, Geilich B, Fakurazi S, Webster TJ, et al.

Biomed Res Int, 2014;2014:651831.
PMID: 24900976 DOI: 10.1155/2014/651831

Nystatin is a tetraene diene polyene antibiotic showing a broad spectrum of antifungal activity. In the present study, we prepared a nystatin nanocomposite (Nyst-CS-MNP) by loading nystatin (Nyst) on chitosan (CS) coated magnetic nanoparticles (MNPs). The magnetic nanocomposites were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), vibrating sample magnetometer (VSM), and scanning electron microscopy (SEM). The XRD results showed that the MNPs and nanocomposite are pure magnetite. The FTIR analysis confirmed the binding of CS on the surface of the MNPs and also the loading of Nyst in the nanocomposite. The Nyst drug loading was estimated using UV-Vis instrumentation and showing a 14.9% loading in the nanocomposite. The TEM size image of the MNPs, CS-MNP, and Nyst-CS-MNP was 13, 11, and 8 nm, respectively. The release profile of the Nyst drug from the nanocomposite followed a pseudo-second-order kinetic model. The antimicrobial activity of the as-synthesized Nyst and Nyst-CS-MNP nanocomposite was evaluated using an agar diffusion method and showed enhanced antifungal activity against Candida albicans. In this manner, this study introduces a novel nanocomposite that can decrease fungus activity on-demand for numerous medical applications.

Matched MeSH terms: Nanocomposites/chemistry*
Fulltext Polyurethane Elastomer Layered Nanocomposite Material for Sports Grounds and the Preparation Method Thereof

Ren C, Su Z, Su Y, Wang L

Biomed Res Int, 2022;2022:5152911.
PMID: 36093408 DOI: 10.1155/2022/5152911

Polyurethane, as a rubber material, can relieve the load on the ground and provide seismic design for the venue, which is of great significance for sports venues. In order to improve the seismic resistance and abrasion resistance of materials for sports fields and reduce accidents in sports, this article has carried out research on the polyurethane elastomer layered nanocomposites for sports fields and their preparation. Today's world is a challenging era of science and technology. The fields of biotechnology, information, medicine, energy, environment, and national defense and security are closely related to the development of high tech, and the requirements for materials are becoming increasingly diversified. Polymer nanocomposite coating has the dual characteristics of organic and inorganic components. It not only retains the advantages of a polymer but also endows it with versatility. It meets the current application needs. It is a hot spot in today's research. Among them, there are two major problems in the composite process of nanomaterials and polymers: dispersion and compatibility. How to improve the dispersion of nanoparticles and enhance the compatibility between nanoparticles and polymers is an urgent problem to be solved. In the method part, this article introduces a small amount of polyurethane and polyurethane elastomers formed after polyurethane modification and introduces layered compounds and nanocomposites and introduces several models involved in nanomaterials in terms of algorithms. In the analysis part, this paper conducts a comprehensive analysis of the hard segment mass fraction, mechanical properties, thermal decomposition behavior, degradation mechanism, and dynamic mechanical properties. With the increase of GO content, the tensile strength increases significantly and the elongation at break becomes smaller and smaller. When the GO content increases from 0% to 2%, the tensile properties of the WPU film increase from 2.6 MPa to 7.9 MPa and the fracture of the elongation decreased from 201.7% to 62.8%. This shows that the increase in GO content will make the composite material harder and brittle. It can be seen from the experimental results that the preparation of the polyurethane elastomer layered nanocomposite material designed in this paper has a good application effect on sports venues.

Matched MeSH terms: Nanocomposites*
A reduced graphene oxide-titanium dioxide nanocomposite based electrochemical aptasensor for rapid and sensitive detection of Salmonella enterica

Muniandy S, Teh SJ, Appaturi JN, Thong KL, Lai CW, Ibrahim F, et al.

Bioelectrochemistry, 2019 Jun;127:136-144.
PMID: 30825657 DOI: 10.1016/j.bioelechem.2019.02.005

Recent foodborne outbreaks in multiple locations necessitate the continuous development of highly sensitive and specific biosensors that offer rapid detection of foodborne biological hazards. This work focuses on the development of a reduced graphene oxide‑titanium dioxide (rGO-TiO2) nanocomposite based aptasensor to detect Salmonella enterica serovar Typhimurium. A label-free aptamer was immobilized on a rGO-TiO2 nanocomposite matrix through electrostatic interactions. The changes in electrical conductivity on the electrode surface were evaluated using electroanalytical methods. DNA aptamer adsorbed on the rGO-TiO2 surface bound to the bacterial cells at the electrode interface causing a physical barrier inhibiting the electron transfer. This interaction decreased the DPV signal of the electrode proportional to decreasing concentrations of the bacterial cells. The optimized aptasensor exhibited high sensitivity with a wide detection range (108 to 101 cfu mL-1), a low detection limit of 101 cfu mL-1 and good selectivity for Salmonella bacteria. This rGO-TiO2 aptasensor is an excellent biosensing platform that offers a reliable, rapid and sensitive alternative for foodborne pathogen detection.

Matched MeSH terms: Nanocomposites/ultrastructure; Nanocomposites/chemistry*
Fulltext Enhanced flexibility of polylactic acid/epoxidized palm oil/pineapple fiber composites

Nur Lisa Farhana Mohamad, Fathilah Binti Ali, Azlin Suhaida Azmi, Barre, Mohamed Soleiman, Hazleen Anuar

Biological and Natural Resources Engineering Journal, 2020;3(1):1-7.
MyJurnal

The concern about our dependency on non-renewable resources and overwhelming environmental issues such as pollution caused by non-degradable packaging materials has prompted researchers to come up with alternatives to solve this problem. Thermoplastic polylactic acid (PLA) has been gaining interest due to its versatility and easy processability, thus this study was carried out to find out the properties of PLA reinforced with pineapple fibers. However, surface of the natural fibers need to be treated for better properties enhancement in the polymer matrices. Considering this, fibers were treated with 10% (w/v) concentration of potassium hydroxide (KOH) and then continued for mixing with PLA at a fixed ratio of plasticizer by using internal mixer, and then the composites were prepared into sheet via hot press. Characterization for the mechanical and morphological was conducted by using tensile testing and scanning electron microscopy, respectively. After the analysis, it is found that the surface treated pineapple fiber composite showed better elongation at break compared to untreated fiber composite. The enhance properties of PLA nanocomposites has potential to be used in various packaging materials.

Matched MeSH terms: Nanocomposites
Sonochemical and sustainable synthesis of graphene-gold (G-Au) nanocomposites for enzymeless and selective electrochemical detection of nitric oxide

Geetha Bai R, Muthoosamy K, Zhou M, Ashokkumar M, Huang NM, Manickam S

Biosens Bioelectron, 2017 Jan 15;87:622-629.
PMID: 27616288 DOI: 10.1016/j.bios.2016.09.003

In this study, a sonochemical approach was utilised for the development of graphene-gold (G-Au) nanocomposite. Through the sonochemical method, simultaneous exfoliation of graphite and the reduction of gold chloride occurs to produce highly crystalline G-Au nanocomposite. The in situ growth of gold nanoparticles (AuNPs) took place on the surface of exfoliated few-layer graphene sheets. The G-Au nanocomposite was characterised by UV-vis, XRD, FTIR, TEM, XPS and Raman spectroscopy techniques. This G-Au nanocomposite was used to modify glassy carbon electrode (GCE) to fabricate an electrochemical sensor for the selective detection of nitric oxide (NO), a critical cancer biomarker. G-Au modified GCE exhibited an enhanced electrocatalytic response towards the oxidation of NO as compared to other control electrodes. The electrochemical detection of NO was investigated by linear sweep voltammetry analysis, utilising the G-Au modified GCE in a linear range of 10-5000μM which exhibited a limit of detection of 0.04μM (S/N=3). Furthermore, this enzyme-free G-Au/GCE exhibited an excellent selectivity towards NO in the presence of interferences. The synergistic effect of graphene and AuNPs, which facilitated exceptional electron-transfer processes between the electrolyte and the GCE thereby improving the sensing performance of the fabricated G-Au modified electrode with stable and reproducible responses. This G-Au nanocomposite introduces a new electrode material in the sensitive and selective detection of NO, a prominent biomarker of cancer.

Matched MeSH terms: Nanocomposites/ultrastructure; Nanocomposites/chemistry*
Sensitivity enhancement of graphene/zinc oxide nanocomposite-based electrochemical impedance genosensor for single stranded RNA detection

Low SS, Loh HS, Boey JS, Khiew PS, Chiu WS, Tan MTT

Biosens Bioelectron, 2017 Aug 15;94:365-373.
PMID: 28319904 DOI: 10.1016/j.bios.2017.02.038

An efficient electrochemical impedance genosensing platform has been constructed based on graphene/zinc oxide nanocomposite produced via a facile and green approach. Highly pristine graphene was synthesised from graphite through liquid phase sonication and then mixed with zinc acetate hexahydrate for the synthesis of graphene/zinc oxide nanocomposite by solvothermal growth. The as-synthesised graphene/zinc oxide nanocomposite was characterised with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffractometry (XRD) to evaluate its morphology, crystallinity, composition and purity. An amino-modified single stranded DNA oligonucleotide probe synthesised based on complementary Coconut Cadang-Cadang Viroid (CCCVd) RNA sequence, was covalently bonded onto the surface of graphene/zinc oxide nanocomposite by the bio-linker 1-pyrenebutyric acid N-hydroxysuccinimide ester. The hybridisation events were monitored by electrochemical impedance spectroscopy (EIS). Under optimised sensing conditions, the single stranded CCCVd RNA oligonucleotide target could be quantified in a wide range of 1.0×10-11M to 1.0×10-6 with good linearity (R =0.9927), high sensitivity with low detection limit of 4.3×10-12M. Differential pulse voltammetry (DPV) was also performed for the estimation of nucleic acid density on the graphene/zinc oxide nanocomposite-modified sensing platform. The current work demonstrates an important advancement towards the development of a sensitive detection assay for various diseases involving RNA agents such as CCCVd in the future.

Matched MeSH terms: Nanocomposites/chemistry
Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine) as a probe for simultaneous sensitive electrochemical determination of anticancer drugs, Ifosfamide and Etoposide

Hatamluyi B, Lorestani F, Es'haghi Z

Biosens Bioelectron, 2018 Nov 30;120:22-29.
PMID: 30144642 DOI: 10.1016/j.bios.2018.08.008

The simultaneous measurement of the concentration of anticancer drugs with a fast, sensitive and accurate method in biological samples is a challenge for better monitoring of drug therapy and better determine the pharmacokinetics. An electrochemical sensor was developed for the simultaneous determination of anticancer drugs, Ifosfamide (IFO) and Etoposide (ETO) based on pencil graphite electrode modified with Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to study the properties of the modified electrode. The electrochemical behavior of IFO and ETO on the Au/Pd@rGO@p(L-Cys) modified electrode was investigated by cyclic voltammetry and differential pulse voltammetry (DPV) techniques and the obtained results confirmed its efficiency for the individual and simultaneous sensing of IFO and ETO. After optimization of electrochemical parameters, the fabricated sensor presented excellent performance in simultaneous determination of IFO and ETO with a wide linear range from 0.10 to 90.0 μM and 0.01 to 40.0 μM and low detection limits (3 Sb/m) of 9.210 nM and 0.718 nM, respectively. In addition, this study proved that the constructed sensor could be useful to simultaneous analysis of IFO and ETO in biological samples and pharmaceutical compounds.

Matched MeSH terms: Nanocomposites/chemistry*
Graphene-based electrochemical biosensors for monitoring noncommunicable disease biomarkers

Taniselass S, Arshad MKM, Gopinath SCB

Biosens Bioelectron, 2019 Apr 01;130:276-292.
PMID: 30771717 DOI: 10.1016/j.bios.2019.01.047

Graphene is a 2-dimensional nanomaterial with an atomic thickness has attracted a strong scientific interest owing to their remarkable optical, electronic, thermal, mechanical and electrochemical properties. Graphene-based materials particularly graphene oxide and reduced graphene oxide are widely utilized in various applications ranging from food industry, environmental monitoring and biomedical fields as well as in the development of various types of biosensing devices. The richness in oxygen functional groups in the materials serves as a catalysis for the development of biosensors/electrochemical biosensors which promotes for an attachment of biological recognition elements, surface functionalization and compatible with micro- and nano- bio-environment. In this review, the graphene-based materials application in electrochemical biosensors based on recent advancement (e.g; the surface modification and analytical performances) and the utilization of such biosensors to monitor the noncommunicable diseases are presented. The detection performances of the graphene-based electrochemical biosensors are in the range of ng/mL and have reached up to fg/mL in detecting the targets of NCDs with higher selectivity, sensitivity and stability with good reproducibility attributes. We have discussed the advances while addressing the very specific biomarkers for the NCDs detection. Challenges and possible future research directions for the NCDs detection based on graphene nanocomposite with other 2D nanomaterials are outlined.

Matched MeSH terms: Nanocomposites/chemistry
Composite of medium-chain-length polyhydroxyalkanoates-co-methyl acrylate and carbon nanotubes as innovative electrodes modifier in microbial fuel cell

Sirajudeen AAO, Annuar MSM, Subramaniam R

Biotechnol Appl Biochem, 2021 Apr;68(2):307-318.
PMID: 32314420 DOI: 10.1002/bab.1928

A microbial fuel cell is a sustainable and environmental-friendly device that combines electricity generation and wastewater treatment through metabolic activities of microorganisms. However, low power output from inadequate electron transfer to the anode electrode hampers its practical implementation. Nanocomposites of oxidized carbon nanotubes and medium-chain-length polyhydroxyalkanoates (mcl-PHA) grafted with methyl acrylate monomers enhance the electrochemical function of electrodes in microbial fuel cell. Extensive polymerization of methyl acrylate monomers within mcl-PHA matrix, and homogenous dispersion of carbon nanotubes within the graft matrix are responsible for the enhancement. Modified electrodes exhibit high conductivities, better redox peak and reduction of cell internal resistance up to 76%. A stable voltage output at almost 700 mV running for 225 H generates maximum power and current density of 351 mW/m2 and 765 mA/m2 , respectively. Superior biofilm growth on modified surface is responsible for improved electron transfer to the anode hence stable and elevated power output generation.

Matched MeSH terms: Nanocomposites/chemistry*
Synthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/chitosan/silver nanocomposite material with enhanced antimicrobial activity

Rennukka M, Sipaut CS, Amirul AA

Biotechnol Prog, 2014 Nov-Dec;30(6):1469-79.
PMID: 25181613 DOI: 10.1002/btpr.1986

This work aims to shed light in the fabrication of poly(3-hydroxybutyrate-co-44%-4-hydroxybutyrate)[P(3HB-co-44%4HB)]/chitosan-based silver nanocomposite material using different contents of silver nanoparticle (SNP); 1-9 wt%. Two approaches were applied in the fabrication; namely solvent casting and chemical crosslinking via glutaraldehyde (GA). A detailed characterization was conducted in order to yield information regarding the nanocomposite material. X-ray diffraction analysis exhibited the nature of the three components that exist in the nanocomposite films: P(3HB-co-4HB), chitosan, and SNP. In term of mechanical properties, tensile strength, and elongation at break were significantly improved up to 125% and 22%, respectively with the impregnation of the SNP. The melting temperature of the nanocomposite materials was increased whereas their thermal stability was slightly changed. Scanning electron microscopy images revealed that incorporation of 9 wt% of SNP caused agglomeration but the surface roughness of the material was significantly improved with the loading. Staphylococcus aureus and Escherichia coli were completely inhibited by the nanocomposite films with 7 and 9 wt% of SNP, respectively. On the other hand, degradation of the nanocomposite materials outweighed the degradation of the pure copolymer. These bioactive and biodegradable materials stand a good chance to serve the vast need of biomedical applications namely management and care of wound as wound dressing.

Matched MeSH terms: Nanocomposites/chemistry*
Processing and analysis of chitosan nanocomposites reinforced with chitin whiskers and tannic acid as a crosslinker

Rubentheren V, Ward TA, Chee CY, Tang CK

Carbohydr Polym, 2015 Jan 22;115:379-87.
PMID: 25439908 DOI: 10.1016/j.carbpol.2014.09.007

Chitosan film reinforced with nano-sized chitin whiskers and crosslinked using tannic acid was synthesized by the casting-vaporation method. The mechanical and physicochemical properties of several film samples (consisting of different ratio of chitin and tannic acid) were compared with neat chitosan. Tensile tests show that the addition of chitin improves the nanocomposite films mechanical properties up to 137% compared to neat chitosan, but this is slightly degraded when tannic acid is introduced. However, tannic acid and chitin whisker content greatly reduced moisture content by 294% and water solubility by 13%. Transmission electron microscopy (TEM) and Fourier-transform-infrared spectroscopy (FTIR) were used to investigate the morphology and molecular interaction of film. X-ray diffraction results indicated that the samples with chitin whiskers had a more rigid structure. The addition of tannic acid changed the structure into an anhydrous crystalline conformation when compared to neat chitosan film.

Matched MeSH terms: Nanocomposites/chemistry*
Bionanocomposites of regenerated cellulose/zeolite prepared using environmentally benign ionic liquid solvent

Soheilmoghaddam M, Wahit MU, Tuck Whye W, Ibrahim Akos N, Heidar Pour R, Ali Yussuf A

Carbohydr Polym, 2014 Jun 15;106:326-34.
PMID: 24721086 DOI: 10.1016/j.carbpol.2014.02.085

Bionanocomposite films based on regenerated cellulose (RC) and incorporated with zeolite at different concentrations were fabricated by dissolving cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid using a simple green method. The interactions between the zeolite and the cellulose matrix were confirmed by Fourier transform infrared spectra. Mechanical properties of the nanocomposite films significantly improved as compared with the pure regenerated cellulose film, without the loss of extensibility. Zeolite incorporation enhanced the thermal stability and char yield of the nanocomposites. The scanning electron microscopy and transmission electron microscopy showed that zeolite was uniformly dispersed in the regenerated cellulose matrix. In vitro cytotoxicity test demonstrated that both RC and RC/zeolite nanocomposite films are cytocompatible. These results indicate that the prepared nanocomposites have potential applications in biodegradable packaging, membranes and biomedical areas.

Matched MeSH terms: Nanocomposites/chemistry*
Production and modification of nanofibrillated cellulose using various mechanical processes: a review

Abdul Khalil HP, Davoudpour Y, Islam MN, Mustapha A, Sudesh K, Dungani R, et al.

Carbohydr Polym, 2014 Jan;99:649-65.
PMID: 24274556 DOI: 10.1016/j.carbpol.2013.08.069

Nanofibrillated cellulose from biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. Although they still suffer from two major drawbacks. The first challenge is the exploration of raw materials and its application in nanocomposites production. Second one is high energy consumption regarding the mechanical fibrillation. However, pretreatments before mechanical isolation can overcome this problem. Hydrophilic nature of nano-size cellulose fibers restricts good dispersion of these materials in hydrophobic polymers and therefore, leads to lower mechanical properties. Surface modification before or after mechanical defibrillation could be a solution for this problem. Additionally, drying affects the size of nanofibers and its properties which needs to study further. This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying.

Matched MeSH terms: Nanocomposites/chemistry*
Development of regenerated cellulose/halloysites nanocomposites via ionic liquids

Hanid NA, Wahit MU, Guo Q, Mahmoodian S, Soheilmoghaddam M

Carbohydr Polym, 2014 Jan;99:91-7.
PMID: 24274483 DOI: 10.1016/j.carbpol.2013.07.080

In this study, regenerated cellulose/halloysites (RC/HNT) nanocomposites with different nanofillers loading were fabricated by dissolving the cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid. The films were prepared via solution casting method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties were investigated by tensile testing. It clearly displayed a good enhancement of both tensile strength and Young's modulus with HNT loading up to 5 wt%. As the HNT loadings increased to 5 wt%, the thermal behaviour and water resistance rate was also increased. The TEM and SEM images also depicted even dispersion of the HNT and a good intertubular interaction between the HNT and the cellulose matrix.

Matched MeSH terms: Nanocomposites/ultrastructure; Nanocomposites/chemistry*
Isolation and characterization of cellulose nanowhiskers from oil palm biomass microcrystalline cellulose

Haafiz MK, Hassan A, Zakaria Z, Inuwa IM

Carbohydr Polym, 2014 Mar 15;103:119-25.
PMID: 24528708 DOI: 10.1016/j.carbpol.2013.11.055

The objective of this study is to compare the effect of two different isolation techniques on the physico-chemical and thermal properties of cellulose nanowhiskers (CNW) from oil palm biomass obtained microcrystalline cellulose (MCC). Fourier transform infrared analysis showed that there are no significant changes in the peak positions, suggesting that the treatments did not affect the chemical structure of the cellulose fragment. Scanning electron microscopy showed that the aggregated structure of MCC is broken down after treatment. Transmission electron microscopy revealed that the produced CNW displayed a nanoscale structure. X-ray diffraction analysis indicated that chemical swelling improves the crystallinity of MCC while maintaining the cellulose I structure. Acid hydrolysis however reduced the crystallinity of MCC and displayed the coexistence of cellulose I and II allomorphs. The produced CNW is shown to have a good thermal stability and hence is suitable for a range of applications such as green biodegradable nanocomposites reinforced with CNW.

Matched MeSH terms: Nanocomposites/chemistry*

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