Publications by authors named "Ani Idris"

33 Publications

Review on Nanocrystalline Cellulose in Bone Tissue Engineering Applications.

Polymers (Basel) 2020 Nov 27;12(12). Epub 2020 Nov 27.

c/o Institute of Bioproduct Development, School of Chemical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Johor Bahru, Johor 81310, Malaysia.

Nanocrystalline cellulose is an abundant and inexhaustible organic material on Earth. It can be derived from many lignocellulosic plants and also from agricultural residues. They endowed exceptional physicochemical properties, which have promoted their intensive exploration in biomedical application, especially for tissue engineering scaffolds. Nanocrystalline cellulose has been acknowledged due to its low toxicity and low ecotoxicological risks towards living cells. To explore this field, this review provides an overview of nanocrystalline cellulose in designing materials of bone scaffolds. An introduction to nanocrystalline cellulose and its isolation method of acid hydrolysis are discussed following by the application of nanocrystalline cellulose in bone tissue engineering scaffolds. This review also provides comprehensive knowledge and highlights the contribution of nanocrystalline cellulose in terms of mechanical properties, biocompatibility and biodegradability of bone tissue engineering scaffolds. Lastly, the challenges for future scaffold development using nanocrystalline cellulose are also included.
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http://dx.doi.org/10.3390/polym12122818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761060PMC
November 2020

Papain grafted into the silica coated iron-based magnetic nanoparticles 'IONPs@SiO-PPN' as a new delivery vehicle to the HeLa cells.

Nanotechnology 2020 May 24;31(19):195603. Epub 2020 Jan 24.

Isfahan Clinical Toxicology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. Institute of Bioproduct Development, Department of Bioprocess Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, Skudai 81110, Johor Bahru, Johor, Malaysia.

The present study aims at engineering, fabrication, characterization, and qualifications of papain (PPN) conjugated SiO-coated iron oxide nanoparticles 'IONPs@SiO-PPN'. Initially fabricated iron oxide nanoparticles (IONPs) were coated with silica (SiO) using sol-gel method to hinder the aggregation and to enhance biocompatibility. Next, PPN was loaded as an anticancer agent into the silica coated IONPs (IONPs@SiO) for the delivery of papain to the HeLa cancer cells. This fabricated silica-coated based magnetic nanoparticle is introduced as a new physiologically-compatible and stable drug delivery vehicle for delivering of PPN to the HeLa cancer cell line. The IONPs@SiO-PPN were characterized using FT-IR, AAS, FESEM, XRD, DLS, and VSM equipment. Silica was amended on the surface of iron oxide nanoparticles (IONPs, γ-FeO) to modify its biocompatibility and stability. The solvent evaporation method was used to activate PPN vectorization. The following tests were performed to highlight the compatibility of our proposed delivery vehicle: in vitro toxicity assay, in vivo acute systemic toxicity test, and the histology examination. The results demonstrated that IONPs@SiO-PPN successfully reduced the IC values compared with the native PPN. Also, the structural alternations of HeLa cells exposed to IONPs@SiO-PPN exhibited higher typical hallmarks of apoptosis compared to the cells treated with the native PPN. The in vivo acute toxicity test indicated no clinical signs of distress/discomfort or weight loss in Balb/C mice a week after the intravenous injection of IONPs@SiO (10 mg kg). Besides, the tissues architectures were not affected and the pathological inflammatory alternations detection failed. In conclusion, IONPs@SiO-PPN can be chosen as a potent candidate for further medical applications in the future, for instance as a drug delivery vehicle or hyperthermia agent.
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http://dx.doi.org/10.1088/1361-6528/ab6fd4DOI Listing
May 2020

Hemodialysis performance and anticoagulant activities of PVP-k25 and carboxylic-multiwall nanotube composite blended Polyethersulfone membrane.

Mater Sci Eng C Mater Biol Appl 2019 Oct 18;103:109769. Epub 2019 May 18.

Institute of Bioproduct Development, Department of Bioprocess and Polymer Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address:

Non-covalent electrostatic interaction between amide nitrogen and carbonyl carbon of shorter chain length of polyvinylpyrrolidone (PVP-k25) was developed with in-house carboxylic oxidized multiwall carbon nanotubes (O-MWCNT) and then blended with Polyethersulfone (PES) polymer. FTIR analysis was utilized to confirm bonding nature of nano-composites (NCs) of O-MWCNT/PVP-k25 and casting membranes. Non-solvent induces phase separation process developed regular finger-like channels in composite membranes whereas pristine PES exhibited spongy entities as studied by cross sectional analysis report of FESEM. Further, FESEM instrument was also utilized to observe the dispersion of O-MWCNT/PVP based nanocomposite (NCs) with PES and membranes leaching phenomena analysis. Contact angle experiments described 24% improvement of hydrophilic behaviour, leaching ratio of additives was reduced to 1.89%, whereas water flux enhanced up to 6 times. Bovine serum albumin (BSA) and lysozyme based antifouling analysis shown up to 25% improvement, whereas 84% of water flux was regained after protein fouling than pristine PES. Anticoagulant activity was reported by estimating prothrombin, thrombin, plasma re-calcification times and production of fibrinogen cluster with platelets-adhesions photographs and hemolysis experiments. Composite membranes exhibited 3.4 and 3 times better dialysis clearance ratios of urea and creatinine solutes as compared to the raw PES membrane.
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http://dx.doi.org/10.1016/j.msec.2019.109769DOI Listing
October 2019

Novel Processing Technique to Produce Three Dimensional Polyvinyl Alcohol/Maghemite Nanofiber Scaffold Suitable for Hard Tissues.

Polymers (Basel) 2018 Mar 22;10(4). Epub 2018 Mar 22.

Department of Mechanical Engineering, Curtin University, 98009 Miri, Malaysia.

Fabrication of three dimensional (3D) tissue engineering scaffolds, particularly for hard tissues remains a challenge. Electrospinning has been used to fabricate scaffolds made from polymeric materials which are suitable for hard tissues. The electrospun scaffolds also have structural arrangement that mimics the natural extracellular matrix. However, electrospinning has a limitation in terms of scaffold layer thickness that it can fabricate. Combining electrospinning with other processes is the way forward, and in this proposed technique, the basic shape of the scaffold is obtained by a fused deposition modelling (FDM) three dimensional (3D) printing machine using the partially hydrolysed polyvinyl alcohol (PVA) as the filament material. The 3D printed PVA becomes a template to be placed inside a mould which is then filled with the fully hydrolysed PVA/maghemite (γ-Fe₂O₃) solution. After the content in the mould solidified, the mould is opened and the content is freeze dried and immersed in water to dissolve the template. The 3D structure made of PVA/maghemite is then layered by electrospun PVA/maghemite fibers, resulting in 3D tissue engineering scaffold made from PVA/maghemite. The morphology and mechanical properties (strength and stiffness) were analysed and in vitro tests by degradation test and cell penetration were also performed. It was revealed that internally, the 3D scaffold has milli- and microporous structures whilst externally; it has a nanoporous structure as a result of the electrospun layer. The 3D scaffold has a compressive strength of 78.7 ± 0.6 MPa and a Young's modulus of 1.43 ± 0.82 GPa, which are within the expected range for hard tissue engineering scaffolds. Initial biocompatibility tests on cell penetration revealed that the scaffold can support growth of human fibroblast cells. Overall, the proposed processing technique which combines 3D printing process, thermal inversion phase separation (TIPS) method and electrospinning process has the potential for producing hard tissue engineering 3D scaffolds.
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http://dx.doi.org/10.3390/polym10040353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414894PMC
March 2018

Fabrication and performance evaluation of blood compatible hemodialysis membrane using carboxylic multiwall carbon nanotubes and low molecular weight polyvinylpyrrolidone based nanocomposites.

J Biomed Mater Res A 2019 03 28;107(3):513-525. Epub 2018 Nov 28.

Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad (CUI), Lahore Campus, Defence Road, Off Raiwind Road, Lahore, Pakistan.

This study focused to optimize the performance of polyethersulfone (PES) hemodialysis (HD) membrane using carboxylic functionalized multiwall carbon nanotubes (c-MWCNT) and lower molecular weight grade of polyvinylpyrrolidone (PVP-k30). Initially, MWCNT were chemically functionalized by acid treatment and nanocomposites (NCs) of PVP-k30 and c-MWCNT were formed and subsequently blended with PES polymer. The spectra of FTIR of the HD membranes revealed that NCs has strong hydrogen bonding and their addition to PES polymer improved the capillary system of membranes as confirmed by Field Emission Scanning Electron Microscope (FESEM) and leaching of the additive decreased to 2% and hydrophilicity improved to 22%. The pore size and porosity of NCs were also enhanced and rejection rate was achieved in the establish dialysis range (<60 kDa). The antifouling studies had shown that NCs membrane exhibited 30% less adhesion of protein with 80% flux recovery ratio. The blood compatibility assessment disclosed that NCs based membranes showed prolonged thrombin and prothrombin clotting times, lessened production of fibrinogen cluster, and greatly suppressed adhesion of blood plasma than a pristine PES membrane. The results also unveiled that PVP-k30/NCs improved the surface properties of the membrane and the urea and creatinine removal increased to 72% and 75% than pure PES membranes. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 513-525, 2019.
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http://dx.doi.org/10.1002/jbm.a.36566DOI Listing
March 2019

Kinetics, thermodynamics, equilibrium isotherms, and reusability studies of cationic dye adsorption by magnetic alginate/oxidized multiwalled carbon nanotubes composites.

Int J Biol Macromol 2019 Feb 14;123:539-548. Epub 2018 Nov 14.

Institute of Bioproduct Development, Department of Bioprocess Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia.

Magnetic beads (AO-γ-FeO) of alginate (A) impregnated with citrate coated maghemite nanoparticles (γ-FeO) and oxidized multiwalled carbon nanotubes (OMWCNTs) were synthesized and used as adsorbent for the removal of methylene blue from water. The XRD analysis revealed that the diameter of γ-FeO is 10.24 nm. The mass saturation magnetization of AO-γ-FeO and γ-FeO were found to be 27.16 and 42.63 emu·g, respectively. The adsorption studies revealed that the data of MB isotherm were well fitted to the Freundlich model. The Langmuir isotherm model exhibited a maximum adsorption capacity of 905.5 mg·g. The adsorption was very dependent on initial concentration, adsorbent dose, and temperature. The beads exhibited high adsorption stability in large domain of pH (4-10). The thermodynamic parameters determined at 283, 293, 303, and 313 K revealed that the adsorption occurring was spontaneous and endothermic in nature. Adsorption kinetic data followed the intraparticle diffusion model. The AO-γ-FeO beads were used for six cycles without significant adsorptive performance loss. Therefore, the eco-friendly prepared AO-γ-FeO beads were considered as highly recyclable and efficient adsorbent for methylene blue as they can be easily separated from water after treatment.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.11.102DOI Listing
February 2019

3D Biofabrication of Thermoplastic Polyurethane (TPU)/Poly-l-lactic Acid (PLLA) Electrospun Nanofibers Containing Maghemite (γ-Fe₂O₃) for Tissue Engineering Aortic Heart Valve.

Polymers (Basel) 2017 Nov 6;9(11). Epub 2017 Nov 6.

Department of Materials, Manufacturing & Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.

Valvular dysfunction as the prominent reason of heart failure may causes morbidity and mortality around the world. The inability of human body to regenerate the defected heart valves necessitates the development of the artificial prosthesis to be replaced. Besides, the lack of capacity to grow, repair or remodel of an artificial valves and biological difficulty such as infection or inflammation make the development of tissue engineering heart valve (TEHV) concept. This research presented the use of compound of poly-l-lactic acid (PLLA), thermoplastic polyurethane (TPU) and maghemite nanoparticle (γ-Fe₂O₃) as the potential biomaterials to develop three-dimensional (3D) aortic heart valve scaffold. Electrospinning was used for fabricating the 3D scaffold. The steepest ascent followed by the response surface methodology was used to optimize the electrospinning parameters involved in terms of elastic modulus. The structural and porosity properties of fabricated scaffold were characterized using FE-SEM and liquid displacement technique, respectively. The 3D scaffold was then seeded with aortic smooth muscle cells (AOSMCs) and biological behavior in terms of cell attachment and proliferation during 34 days of incubation was characterized using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and confocal laser microscopy. Furthermore, the mechanical properties in terms of elastic modulus and stiffness were investigated after cell seeding through macro-indentation test. The analysis indicated the formation of ultrafine quality of nanofibers with diameter distribution of 178 ± 45 nm and 90.72% porosity. In terms of cell proliferation, the results exhibited desirable proliferation (109.32 ± 3.22% compared to the control) of cells over the 3D scaffold in 34 days of incubation. The elastic modulus and stiffness index after cell seeding were founded to be 22.78 ± 2.12 MPa and 1490.9 ± 12 Nmm², respectively. Overall, the fabricated 3D scaffold exhibits desirable structural, biological and mechanical properties and has the potential to be used in vivo.
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http://dx.doi.org/10.3390/polym9110584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418800PMC
November 2017

Trastuzumab-decorated nanoparticles for in vitro and in vivo tumor-targeting hyperthermia of HER2+ breast cancer.

J Mater Chem B 2017 Sep 24;5(35):7369-7383. Epub 2017 Aug 24.

Department of Bioprocess Engineering, Faculty of Chemical Engineering c/o Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai 81310, Johor Bahru, Johor, Malaysia.

In this study, a magnetic core-shell modified tumor-targeting nanocarrier (MNPs-PEG-TRA) was engineered and demonstrated for the efficient in vitro and in vivo hyperthermia treatment of breast cancer. Magnetic nanoparticles were used as the initial nanocarriers and modified via PEGylation followed by immobilization of Trastuzumab (TRA) with tumor-targeting function towards cancer cells. The hyperthermia performance of the developed targeting drug delivery system was explored using an in vitro study with SK-BR-3 cancer cells and an in vivo study using animal models (mouse) with DMBA-induced breast cancer. The average size of the engineered system was about 100 nm and its zeta potential was about +13 mV, whereby the stability of the system in biological media is enormously enhanced while the possibility of it being removed via the immune system is diminished. The investigation was pursued based on comparing the changes in growth inhibition rates of HSF 1184, MDA-MB-231, MDA-MB-468 and SK-BR-3 cell lines at different temperatures (37 °C, 40 °C, 42 °C, and 45 °C). Compared with bare MNPs and MNPs-PEG, a remarkably enhanced hyperthermia effect using MNPs-PEG-TRA was observed not only in cultured SK-BR-3 cells in vitro but also in an in vivo DMBA tumor bearing mice model. These results are attributed to an about 4 fold higher concentration of MNPs-PEG-TRA carriers in the tumor site compared to the other organs confirming the considerable potential of the magnetic tumor-targeting hyperthermia concept for breast cancer treatment.
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http://dx.doi.org/10.1039/c7tb01305aDOI Listing
September 2017

Optimization and development of Maghemite (γ-FeO) filled poly-l-lactic acid (PLLA)/thermoplastic polyurethane (TPU) electrospun nanofibers using Taguchi orthogonal array for tissue engineering heart valve.

Mater Sci Eng C Mater Biol Appl 2017 Jul 18;76:616-627. Epub 2017 Mar 18.

Department of Materials, Manufacturing & Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.

Tissue engineering (TE) is an advanced principle to develop a neotissue that can resemble the original tissue characteristics with the capacity to grow, to repair and to remodel in vivo. This research proposed the optimization and development of nanofiber based scaffold using the new mixture of maghemite (γ-FeO) filled poly-l-lactic acid (PLLA)/thermoplastic polyurethane (TPU) for tissue engineering heart valve (TEHV). The chemical, structural, biological and mechanical properties of nanofiber based scaffold were characterized in terms of morphology, porosity, biocompatibility and mechanical behaviour. Two-level Taguchi experimental design (L8) was performed to optimize the electrospun mats in terms of elastic modulus using uniaxial tensile test where the studied parameters were flow rate, voltage, percentage of maghemite nanoparticles in the content, solution concentration and collector rotating speed. Each run was extended with an outer array to consider the noise factors. The signal-to-noise ratio analysis indicated the contribution percent as follow; Solution concentration>voltage>maghemite %>rotating speed>flow rate. The optimum elastic modulus founded to be 28.13±0.37MPa in such a way that the tensile strain was 31.72% which provided desirability for TEHV. An empirical model was extracted and verified using confirmation test. Furthermore, an ultrafine quality of electrospun nanofibers with 80.32% porosity was fabricated. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and cell attachment using human aortic smooth muscle cells exhibited desirable migration and proliferation over the electrospun mats. The interaction between blood content and the electrospun mats indicated a mutual adaption in terms of clotting time and hemolysis percent. Overall, the fabricated scaffold has the potential to provide the required properties of aortic heart valve.
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http://dx.doi.org/10.1016/j.msec.2017.03.120DOI Listing
July 2017

A review of evolution of electrospun tissue engineering scaffold: From two dimensions to three dimensions.

Proc Inst Mech Eng H 2017 Jul 28;231(7):597-616. Epub 2017 Mar 28.

3 Department of Mechanical Engineering, Curtin University, Miri, Malaysia.

The potential of electrospinning process to fabricate ultrafine fibers as building blocks for tissue engineering scaffolds is well recognized. The scaffold construct produced by electrospinning process depends on the quality of the fibers. In electrospinning, material selection and parameter setting are among many factors that contribute to the quality of the ultrafine fibers, which eventually determine the performance of the tissue engineering scaffolds. The major challenge of conventional electrospun scaffolds is the nature of electrospinning process which can only produce two-dimensional electrospun mats, hence limiting their applications. Researchers have started to focus on overcoming this limitation by combining electrospinning with other techniques to fabricate three-dimensional scaffold constructs. This article reviews various polymeric materials and their composites/blends that have been successfully electrospun for tissue engineering scaffolds, their mechanical properties, and the various parameters settings that influence the fiber morphology. This review also highlights the secondary processes to electrospinning that have been used to develop three-dimensional tissue engineering scaffolds as well as the steps undertaken to overcome electrospinning limitations.
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http://dx.doi.org/10.1177/0954411917699021DOI Listing
July 2017

Development of highly porous biodegradable γ-FeO/polyvinyl alcohol nanofiber mats using electrospinning process for biomedical application.

Mater Sci Eng C Mater Biol Appl 2017 Jan 7;70(Pt 1):520-534. Epub 2016 Sep 7.

Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.

The use of electrospinning process in fabricating tissue engineering scaffolds has received great attention in recent years due to its simplicity. The nanofibers produced via electrospinning possessed morphological characteristics similar to extracellular matrix of most tissue components. Porosity plays a vital role in developing tissue engineering scaffolds because it influences the biocompatibility performance of the scaffolds. In this study, maghemite (γ-FeO) was mixed with polyvinyl alcohol (PVA) and subsequently electrospun to produce nanofibers. Five factors; nanoparticles content, voltage, flow rate, spinning distance, and rotating speed were varied to produce the electrospun nanofibrous mats with high porosity value. Empirical model was developed using response surface methodology to analyze the effect of these factors to the porosity. The results revealed that the optimum porosity (90.85%) was obtained using 5% w/v nanoparticle content, 35kV of voltage, 1.1ml/h volume flow rate of solution, 8cm spinning distance and 2455rpm of rotating speed. The empirical model was verified successfully by performing confirmation experiments. The properties of optimum PVA/γ-FeO nanofiber mats such as fiber diameter, mechanical properties, and contact angle were investigated. In addition, cytocompatibility test, in vitro degradation rate, and MTT assay were also performed. Results revealed that high porosity biodegradable γ-FeO/polyvinyl alcohol nanofiber mats have low mechanical properties but good degradation rates and cytocompatibility properties. Thus, they are suitable for low load bearing biomedical application or soft tissue engineering scaffold.
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http://dx.doi.org/10.1016/j.msec.2016.09.002DOI Listing
January 2017

In vitro evaluation of actively targetable superparamagnetic nanoparticles to the folate receptor positive cancer cells.

Mater Sci Eng C Mater Biol Appl 2016 Dec 1;69:1147-58. Epub 2016 Aug 1.

Faculty of Biomedical Engineering, Universiti Teknologi Malaysia, Skudai, 81310 Johor Bahru, Johor, Malaysia.

Engineering of a physiologically compatible, stable and targetable SPIONs-CA-FA formulation was reported. Initially fabricated superparamagnetic iron oxide nanoparticles (SPIONs) were coated with citric acid (CA) to hamper agglomeration as well as to ameliorate biocompatibility. Folic acid (FA) as a targeting agent was then conjugated to the citric acid coated SPIONs (SPIONs-CA) for targeting the specific receptors expressed on the FAR+ cancer cells. Physiochemical characterizations were then performed to assure required properties like stability, size, phase purity, surface morphology, chemical integrity and magnetic properties. In vitro evaluations (MTT assay) were performed on HeLa, HSF 1184, MDA-MB-468 and MDA-MB-231cell lines to ensure the biocompatibility of SPIONs-CA-FA. There were no morphological changes and lysis in contact with erythrocytes recorded for SPIONs-CA-FA and SPIONs-CA. High level of SPIONs-CA-FA binding to FAR+ cell lines was assured via qualitative and quantitative in vitro binding studies. Hence, SPIONs-CA-FA was introduced as a promising tool for biomedical applications like magnetic hyperthermia and drug delivery. The in vitro findings presented in this study need to be compared with those of in vivo studies.
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http://dx.doi.org/10.1016/j.msec.2016.07.076DOI Listing
December 2016

Mechanical properties and biocompatibility of co-axially electrospun polyvinyl alcohol/maghemite.

Proc Inst Mech Eng H 2016 Aug 18;230(8):739-49. Epub 2016 May 18.

Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Skudai, Malaysia Department of Mechanical, Robotics, and Energy Engineering, Dongguk University, Seoul, Korea

Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method.
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http://dx.doi.org/10.1177/0954411916649632DOI Listing
August 2016

Synthesis, characterization and in vitro evaluation of exquisite targeting SPIONs-PEG-HER in HER2+ human breast cancer cells.

Nanotechnology 2016 Mar 10;27(10):105601. Epub 2016 Feb 10.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai 81310, Johor Bahru, Johor, Malaysia.

A stable, biocompatible and exquisite SPIONs-PEG-HER targeting complex was developed. Initially synthesized superparamagnetic iron oxide nanoparticles (SPIONs) were silanized using 3-aminopropyltrimethoxysilane (APS) as the coupling agent in order to allow the covalent bonding of polyethylene glycol (PEG) to the SPIONs to improve the biocompatibility of the SPIONs. SPIONs-PEG were then conjugated with herceptin (HER) to permit the SPIONs-PEG-HER to target the specific receptors expressed over the surface of the HER2+ metastatic breast cancer cells. Each preparation step was physico-chemically analyzed and characterized by a number of analytical methods including AAS, FTIR spectroscopy, XRD, FESEM, TEM, DLS and VSM. The biocompatibility of SPIONs-PEG-HER was evaluated in vitro on HSF-1184 (human skin fibroblast cells), SK-BR-3 (human breast cancer cells, HER+), MDA-MB-231 (human breast cancer cells, HER-) and MDA-MB-468 (human breast cancer cells, HER-) cell lines by performing MTT and trypan blue assays. The hemolysis analysis results of the SPIONs-PEG-HER and SPIONs-PEG did not indicate any sign of lysis while in contact with erythrocytes. Additionally, there were no morphological changes seen in RBCs after incubation with SPIONs-PEG-HER and SPIONs-PEG under a light microscope. The qualitative and quantitative in vitro targeting studies confirmed the high level of SPION-PEG-HER binding to SK-BR-3 (HER2+ metastatic breast cancer cells). Thus, the results reflected that the SPIONs-PEG-HER can be chosen as a favorable biomaterial for biomedical applications, chiefly magnetic hyperthermia, in the future.
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http://dx.doi.org/10.1088/0957-4484/27/10/105601DOI Listing
March 2016

Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production.

Bioresour Technol 2016 Apr 30;206:150-154. Epub 2016 Jan 30.

Borneo Marine Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia.

The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production.
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http://dx.doi.org/10.1016/j.biortech.2016.01.084DOI Listing
April 2016

Efficiency of barium removal from radioactive waste water using the combination of maghemite and titania nanoparticles in PVA and alginate beads.

Appl Radiat Isot 2015 Nov 26;105:105-113. Epub 2015 Jun 26.

Construction Research Center (CRC), Institute for Smart Infrastructure and Innovation Construction (ISIIC), Faculty of Civil Engineering, UniversitiTeknologi Malaysia, UTM Skudai, 81310, Johor Bahru, Malaysia.

In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA-alginate beads fitted the pseudo first order and second order Langmuir-Hinshelwood (L-H) kinetic model.
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http://dx.doi.org/10.1016/j.apradiso.2015.06.028DOI Listing
November 2015

Overview of PES biocompatible/hemodialysis membranes: PES-blood interactions and modification techniques.

Mater Sci Eng C Mater Biol Appl 2015 Nov 19;56:574-92. Epub 2015 Jun 19.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development, Universiti Teknologi Malaysia, 81300 UTM Skudai, Johor, Malaysia. Electronic address:

Polyethersulfone (PES) based membranes are used for dialysis, but exposure to blood can result in numerous interactions between the blood elements and the membrane. Adsorption and transformation of plasma proteins, activation of blood cells, adherence of platelets and thrombosis reactions against PES membrane can invoke severe blood reactions causing the increase rate of mortality and morbidity of hemodialysis (HD) patients. In order to minimize blood immune response, different biomimetic, zwitterionic, non-ionic, anticoagulant molecules and hydrophilic brushes were immobilized or blended with PES polymers. These additives modified the nature of the membrane, enhanced their biocompatibility and also increased the uremic waste dialysis properties. In this review, current perspectives of the different additives which are used with PES are highlighted in relation with PES membrane-associated blood reactions. The additive's purpose, compatibility, preparation techniques, methods of addition to polymer and influence on the chemistry and performance of hemodialysis membranes are described.
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http://dx.doi.org/10.1016/j.msec.2015.06.035DOI Listing
November 2015

γ-Fe2O3 nanoparticles filled polyvinyl alcohol as potential biomaterial for tissue engineering scaffold.

J Mech Behav Biomed Mater 2015 Sep 9;49:90-104. Epub 2015 May 9.

Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai, Malaysia.

Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.
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http://dx.doi.org/10.1016/j.jmbbm.2015.04.029DOI Listing
September 2015

Application of response surface methodology in optimization of electrospinning process to fabricate (ferrofluid/polyvinyl alcohol) magnetic nanofibers.

Mater Sci Eng C Mater Biol Appl 2015 May 11;50:234-41. Epub 2015 Feb 11.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310, UTM, Johor Bahru, Johor, Malaysia.

Magnetic nanofibers are composed of good dispersion of magnetic nanoparticles along an organic material. Magnetic nanofibers are potentially useful for composite reinforcement, bio-medical and tissue engineering. Nanofibers with the thinner diameter have to result in higher rigidity and tensile strength due to better alignments of lamellae along the fiber axis. In this study, the performance of electrospinning process was explained using response surface methodology (RSM) during fabrication of magnetic nanofibers using polyvinyl alcohol (PVA) as a shelter for (γ-Fe2O3) nanoparticles where the parameters investigated were flow rate, applied voltage, distance between needle and collector and collector rotating speed. The response variable was diameter distribution. The two parameters flow rate and applied voltage in primary evaluation were distinguished as significant factors. Central composite design was applied to optimize the variable of diameter distribution. Quadratic estimated model developed for diameter distribution indicated the optimum conditions to be flow rate of 0.25 ml/h at voltage of 45 kV while the distance and rotating speed are at 8 cm and 1500 rps respectively. The obtained model was verified successfully by the confirmation experiments.
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http://dx.doi.org/10.1016/j.msec.2015.02.008DOI Listing
May 2015

A review of: application of synthetic scaffold in tissue engineering heart valves.

Mater Sci Eng C Mater Biol Appl 2015 Mar 9;48:556-65. Epub 2014 Dec 9.

Department of Materials, Manufacturing & Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.

The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems.
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http://dx.doi.org/10.1016/j.msec.2014.12.016DOI Listing
March 2015

Evaluation of direct transesterification of microalgae using microwave irradiation.

Bioresour Technol 2014 Dec 14;174:281-6. Epub 2014 Oct 14.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address:

Nannochloropsis sp. wet biomass was directly transesterified under microwave (MW) irradiation in the presence of methanol and various alkali and acid catalyst. Two different types of direct transesterification (DT) were used; one step and two step transesterification. The biodiesel yield obtained from the MWDT was compared with that obtained using conventional method (lipid extraction followed by transesterification) and water bath heating DT method. Findings revealed that MWDT efficiencies were higher compared to water bath heating DT by at least 14.34% and can achieve a maximum of 43.37% with proper selection of catalysts. The use of combined catalyst (NaOH and H2SO4) increased the yield obtained by 2.3-folds (water bath heating DT) and 2.87-folds (MWDT) compared with the one step single alkaline catalyst respectively. The property of biodiesel produced by MWDT has high lubricating property, good cetane number and short carbon chain FAME's compared with water bath heating DT.
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http://dx.doi.org/10.1016/j.biortech.2014.10.035DOI Listing
December 2014

Rapid alkali catalyzed transesterification of microalgae lipids to biodiesel using simultaneous cooling and microwave heating and its optimization.

Bioresour Technol 2014 Dec 18;174:311-5. Epub 2014 Oct 18.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address:

Biodiesel with improved yield was produced from microalgae biomass under simultaneous cooling and microwave heating (SCMH). Nannochloropsis sp. and Tetraselmis sp. which were known to contain higher lipid species were used. The yield obtained using this novel technique was compared with the conventional heating (CH) and microwave heating (MWH) as the control method. The results revealed that the yields obtained using the novel SCMH were higher; Nannochloropsis sp. (83.33%) and Tetraselmis sp. (77.14%) than the control methods. Maximum yields were obtained using SCMH when the microwave was set at 50°C, 800W, 16h of reaction with simultaneous cooling at 15°C; and water content and lipid to methanol ratio in reaction mixture was kept to 0 and 1:12 respectively. GC analysis depicted that the biodiesel produced from this technique has lower carbon components (<19 C) and has both reasonable CN and IV reflecting good ignition and lubricating properties.
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http://dx.doi.org/10.1016/j.biortech.2014.10.015DOI Listing
December 2014

Synergistic effect of optimizing light-emitting diode illumination quality and intensity to manipulate composition of fatty acid methyl esters from Nannochloropsis sp.

Bioresour Technol 2014 Dec 30;173:284-290. Epub 2014 Sep 30.

Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, c/o B.M. Nagano Industries Sdn. Bhd., Jalan Keluli 3, Kawasan Perindustrian Pasir Gudang, 81700 Johor, Malaysia.

In the study, the relationship between the quality and intensity of LED illumination with FAMEs produced were investigated. Nannochloropsis sp. was cultivated for 14 days under different intensities of 100, 150 and 200 μmol photons m(-2) s(-1) of red, blue and mixed red blue LED. The findings revealed that suitable combination of LED wavelengths and intensity; (red LED: 150, blue: 100 and mixed red blue: 200 μmol photons m(-2) s(-1)) produced maximum biomass growth and lipid content. It was observed that the quality and intensity of LED significantly influenced the composition of FAMEs. FAMEs produced under blue LED has high degree of unsaturation (DU) and low cetane number while those under red LED has low DU but higher CN. The combination of red blue LED has produced FAMEs with high ignition and lubricating property and also good oxidation stability indicated by the DU and CN values which lies midway between the red and blue.
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http://dx.doi.org/10.1016/j.biortech.2014.09.110DOI Listing
December 2014

Enhancing the various solvent extraction method via microwave irradiation for extraction of lipids from marine microalgae in biodiesel production.

Bioresour Technol 2014 Nov 12;171:477-81. Epub 2014 Aug 12.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address:

The types of microalgae strains and the method used in lipid extraction have become crucial factors which influence the productivity of crude oil. In this paper, Nannochloropsis sp. and Tetraselmis sp. were chosen as the strains and four different methods were used to extract the lipids: Hara and Radin, Folch, Chen and Bligh and Dyer. These methods were performed by using conventional heating and microwave irradiation methods. Results revealed that highest lipid yield from the different species was obtained using different extraction methods; both under microwave irradiation. The lipid yield for Tetraselmis sp. and Nannochloropsis sp. was highest when Hara and Radin (8.19%), and Folch (8.47%) methods were used respectively under microwave irradiation. The lipids extracted were then transesterified to biodiesel and the quality of the biodiesel was analyzed using the gas chromatography.
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http://dx.doi.org/10.1016/j.biortech.2014.08.024DOI Listing
November 2014

Enhancing growth and lipid production of marine microalgae for biodiesel production via the use of different LED wavelengths.

Bioresour Technol 2014 Jun 1;162:38-44. Epub 2014 Apr 1.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address:

Wavelength of light is a crucial factor which renders microalgae as the potential biodiesel. In this study, Tetraselmis sp. and Nannochloropsis sp. as famous targets were selected. The effect of different light wavelengths on growth rate and lipid production was studied. Microalgae were cultivated for 14 days as under blue, red, red-blue LED and white fluorescent light. The growth rate of microalgae was analyzed by spectrophotometer and cell counting while oil production under improved Nile red method. Optical density result showed the microalgae exhibited better growth curve under blue wavelength. Besides, Tetraselmis sp. and Nannochloropsis sp. under blue wavelength showed the higher growth rate (1.47 and 1.64 day(-1)) and oil production (102.954 and 702.366 a.u.). Gas chromatography analysis also showed that palmitic acid and stearic acid which were compulsory components for biodiesel contribute around 49-51% of total FAME from Nannochloropsis sp. and 81-83% of total FAME from Tetraselmis sp.
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http://dx.doi.org/10.1016/j.biortech.2014.03.113DOI Listing
June 2014

Recent advances in production of succinic acid from lignocellulosic biomass.

Appl Microbiol Biotechnol 2014 Feb 30;98(3):987-1000. Epub 2013 Nov 30.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia.

Production of succinic acid via separate enzymatic hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) are alternatives and are environmentally friendly processes. These processes have attained considerable positions in the industry with their own share of challenges and problems. The high-value succinic acid is extensively used in chemical, food, pharmaceutical, leather and textile industries and can be efficiently produced via several methods. Previously, succinic acid production via chemical synthesis from petrochemical or refined sugar has been the focus of interest of most reviewers. However, these expensive substrates have been recently replaced by alternative sustainable raw materials such as lignocellulosic biomass, which is cheap and abundantly available. Thus, this review focuses on succinic acid production utilizing lignocellulosic material as a potential substrate for SSF and SHF. SSF is an economical single-step process which can be a substitute for SHF - a two-step process where biomass is hydrolyzed in the first step and fermented in the second step. SSF of lignocellulosic biomass under optimum temperature and pH conditions results in the controlled release of sugar and simultaneous conversion into succinic acid by specific microorganisms, reducing reaction time and costs and increasing productivity. In addition, main process parameters which influence SHF and SSF processes such as batch and fed-batch fermentation conditions using different microbial strains are discussed in detail.
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http://dx.doi.org/10.1007/s00253-013-5319-6DOI Listing
February 2014

Intensity of blue LED light: a potential stimulus for biomass and lipid content in fresh water microalgae Chlorella vulgaris.

Bioresour Technol 2013 Nov 11;148:373-8. Epub 2013 Sep 11.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development, Universiti Teknologi Malaysia, 81310 UTM, Johor Bahru, Johor, Malaysia.

Light quality and the intensity are key factors which render microalgae as a potential source of biodiesel. In this study the effects of various intensities of blue light and its photoperiods on the growth and lipid content of Chlorella vulgaris were investigated by using LED (Light Emitting Diode) in batch culture. C. vulgaris was grown for 13 days at three different light intensities (100, 200 and 300 μmol m(-2)s(-1)). Effect of three different light and dark regimes (12:12, 16:08 and 24:00 h Light:Dark) were investigated for each light intensity at 25°C culture temperature. Maximum lipid content (23.5%) was obtained due to high efficiency and deep penetration of 200 μmol m(-2)s(-1) of blue light (12:12 L:D) with improved specific growth (1.26 d(-1)) within reduced cultivation time of 8 days. White light could produce 20.9% lipid content in 10 days at 16:08 h L:D.
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http://dx.doi.org/10.1016/j.biortech.2013.08.162DOI Listing
November 2013

The influence of light intensity and photoperiod on the growth and lipid content of microalgae Nannochloropsis sp.

Bioresour Technol 2013 Feb 16;129:7-11. Epub 2012 Nov 16.

Universiti Kuala Lumpur, Malaysian Institute of Chemical and Bioengineering Technology, 78000 Alor Gajah, Melaka, Malaysia.

Illumination factors such as length of photoperiod and intensity can affect growth of microalgae and lipid content. In order to optimize microalgal growth in mass culture system and lipid content, the effects of light intensity and photoperiod cycle on the growth of the marine microalgae, Nannochloropsis sp. were studied in batch culture. Nannochloropsis sp. was grown aseptically for 9 days at three different light intensities (50, 100 and 200 μmol m(-2) s(-1)) and three different photoperiod cycles (24:0, 18:06 and 12:12 h light:dark) at 23 °C cultivation temperature. Under the light intensity of 100 μmol m(-2) s(-1) and photoperiod of 18 h light: 6 h dark cycle, Nannochloropsis sp. was found to grow favorably with a maximum cell concentration of 6.5×10(7) cells mL(-1), which corresponds to the growth rate of 0.339 d(-1) after 8 day cultivation and the lipid content was found to be 31.3%.
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http://dx.doi.org/10.1016/j.biortech.2012.11.032DOI Listing
February 2013

Modified PVA-alginate encapsulated photocatalyst ferro photo gels for Cr(VI) reduction.

J Hazard Mater 2012 Aug 27;227-228:309-16. Epub 2012 May 27.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.

In this study magnetic separable photocatalyst beads containing maghemite nanoparticles (γ-Fe(2)O(3)) in polyvinyl alcohol (PVA) polymer were prepared and used in the reduction of Cr(VI) to Cr(III) in an aqueous solution under sunlight. The unique superparamagnetic property of the photocatalyst contributed by the γ-Fe(2)O(3) and robust property of PVA polymer allow the magnetic beads to be recovered easily and reused for at least 7 times without washing. The concentration of γ-Fe(2)O(3) was varied from 8% (v/v) to 27% (v/v) and the results revealed that the beads with 8% (v/v) γ-Fe(2)O(3) exhibited the best performance where Cr(VI) was reduced to Cr(III) in only 30 min under sunlight. The use of the PVA has improved the bead properties and life cycle of beads which is in line with sustainable practices.
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http://dx.doi.org/10.1016/j.jhazmat.2012.05.065DOI Listing
August 2012

Immobilized Candida antarctica lipase B: Hydration, stripping off and application in ring opening polyester synthesis.

Biotechnol Adv 2012 May-Jun;30(3):550-63. Epub 2011 Oct 24.

Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia.

This work reviews the stripping off, role of water molecules in activity, and flexibility of immobilized Candida antarctica lipase B (CALB). Employment of CALB in ring opening polyester synthesis emphasizing on a polylactide is discussed in detail. Execution of enzymes in place of inorganic catalysts is the most green alternative for sustainable and environment friendly synthesis of products on an industrial scale. Robust immobilization and consequently performance of enzyme is the essential objective of enzyme application in industry. Water bound to the surface of an enzyme (contact class of water molecules) is inevitable for enzyme performance; it controls enzyme dynamics via flexibility changes and has intensive influence on enzyme activity. The value of pH during immobilization of CALB plays a critical role in fixing the active conformation of an enzyme. Comprehensive selection of support and protocol can develop a robust immobilized enzyme thus enhancing its performance. Organic solvents with a log P value higher than four are more suitable for enzymatic catalysis as these solvents tend to strip away very little of the enzyme surface bound water molecules. Alternatively ionic liquid can work as a more promising reaction media. Covalent immobilization is an exclusively reliable technique to circumvent the leaching of enzymes and to enhance stability. Activated polystyrene nanoparticles can prove to be a practical and economical support for chemical immobilization of CALB. In order to reduce the E-factor for the synthesis of biodegradable polymers; enzymatic ring opening polyester synthesis (eROPS) of cyclic monomers is a more sensible route for polyester synthesis. Synergies obtained from ionic liquids and immobilized enzyme can be much effective eROPS.
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http://dx.doi.org/10.1016/j.biotechadv.2011.10.002DOI Listing
August 2012