Displaying publications 121 - 140 of 654 in total

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  1. Fulltext Hexaferrocenium tri[hexa(isothiocyanato)iron(III)] trihydroxonium complex as a new DNA intercalator for electrochemical DNA biosensor
    Ariffin EY, Zakariah EI, Ruslin F, Kassim M, Yamin BM, Heng LY, et al.
    Sci Rep, 2021 Apr 12;11(1):7883.
    PMID: 33846405 DOI: 10.1038/s41598-021-86939-z
    Ferrocene or ferrocenium has been widely studied in the field of organometallic complexes because of its stable thermodynamic, kinetic and redox properties. Novel hexaferrocenium tri[hexa(isothiocyanato)iron(III)]trihydroxonium (HexaFc) complex was the product from the reaction of ferrocene, maleic acid and ammonium thiocyanate and was confirmed by elemental analysis CHNS, FTIR and single crystal X-ray crystallography. In this study, HexaFc was used for the first time as an electroactive indicator for porcine DNA biosensor. The UV-Vis DNA titrations with this compound showed hypochromism and redshift at 250 nm with increasing DNA concentrations. The binding constant (Kb) for HexaFc complex towards CT-DNA (calf-thymus DNA) was 3.1 × 104 M-1, indicated intercalator behaviour of the complex. To test the usefulness of this complex for DNA biosensor application, a porcine DNA biosensor was constructed. The recognition probes were covalently immobilised onto silica nanospheres (SiNSs) via glutaraldehyde linker on a screen-printed electrode (SPE). After intercalation with the HexaFc complex, the response of the biosensor to the complementary porcine DNA was measured using differential pulse voltammetry. The DNA biosensor demonstrated a linear response range to the complementary porcine DNA from 1 × 10-6 to 1 × 10-3 µM (R2 = 0.9642) with a limit detection of 4.83 × 10-8 µM and the response was stable up to 23 days of storage at 4 °C with 86% of its initial response. The results indicated that HexaFc complex is a feasible indicator for the DNA hybridisation without the use of a chemical label for the detection of porcine DNA.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  2. Uptake and clearance analysis of Technetium99m labelled iron oxide nanoparticles in a rabbit brain
    Nadeem M, Ahmad M, Saeed MA, Shaari A, Riaz S, Naseem S, et al.
    IET Nanobiotechnol, 2015 Jun;9(3):136-41.
    PMID: 26023157 DOI: 10.1049/iet-nbt.2014.0012
    Nanoparticles as solid colloidal particles are extensively studied and used as anticancer drug delivery agents because of their physical properties. This current research aims to prepare water base suspension of uncoated iron oxide nanoparticles and their biodistribution study to different organs, especially the brain, by using a single photon emission computed tomography gamma camera. The water-based suspension of iron oxide nanoparticles was synthesised by a reformed version of the co-precipitation method and labelled with Tc99m for intravenous injection. The nanoparticles were injected without surface modification. X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and transmission electron microscope (TEM) techniques were used for characterisation. Peaks of XRD and EDS indicate that the particles are magnetite and exist in aqueous suspension. The average diameter of iron oxide nanoparticles without any surface coating determined by TEM is 10 nm. These particles are capable of evading the reticuloendothelial system and can cross the blood-brain barrier in the rabbit. The labelling efficiency of iron oxide nanoparticles labelled with Tc99m is 85%, which is good for the biodistribution study. The sufficient amount of iron oxide nanoparticles concentration in the brain as compared with the surrounding soft tissues and their long blood retention time indicates that the water-based suspension of iron oxide nanoparticles may be an option for drug delivery into the brain.
    Matched MeSH terms: Magnetite Nanoparticles/chemistry*
  3. Fulltext Cerium oxide nanoparticles: green synthesis and biological applications
    Charbgoo F, Ahmad MB, Darroudi M
    Int J Nanomedicine, 2017;12:1401-1413.
    PMID: 28260887 DOI: 10.2147/IJN.S124855
    CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. The physicochemical properties of CeO2-NPs, such as size, agglomeration status in liquid, and surface charge, play important roles in the ultimate interactions of the NP with target cells. Recently, CeO2-NPs have been synthesized through several bio-directed methods applying natural and organic matrices as stabilizing agents in order to prepare biocompatible CeO2-NPs, thereby solving the challenges regarding safety, and providing the appropriate situation for their effective use in biomedicine. This review discusses the different green strategies for CeO2-NPs synthesis, their advantages and challenges that are to be overcome. In addition, this review focuses on recent progress in the potential application of CeO2-NPs in biological and medical fields. Exploiting biocompatible CeO2-NPs may improve outcomes profoundly with the promise of effective neurodegenerative therapy and multiple applications in nanobiotechnology.
    Matched MeSH terms: Nanoparticles/chemistry*
  4. Recent advancements in bamboo nanocellulose-based bioadsorbents and their potential in wastewater applications: A review
    Othman JAS, Ilyas RA, Nordin AH, Ngadi N, Alkbir MFM
    Int J Biol Macromol, 2024 Oct;277(Pt 3):134451.
    PMID: 39102907 DOI: 10.1016/j.ijbiomac.2024.134451
    The research interest in sustainable and eco-friendly materials based on natural sources has increased dramatically due to their recyclability, biodegradability, compatibility, and nontoxic behavior. Recently, nanocellulose-based green composites are under extensive exploration and have gained popularity among researchers owing to their lightweight, lost cost, low density, excellent mechanical and physical characteristics. This review provides a comprehensive overview of the recent advancements in the extraction, modification, and application of bamboo nanocellulose as a high-performance bioadsorbent. Bamboo, a rapidly renewable resource, offers an eco-friendly alternative to traditional materials due to its abundant availability and unique structural properties. Significantly, bamboo comprises a considerable amount of cellulose, approximately 40 % to 50%, rendering it a valuable source of cellulose fiber for the fabrication of cellulose nanocrystals. The review highlights different various modification techniques which enhance the adsorption capacities and selectivity of bamboo nanocellulose. Furthermore, the integration of bamboo nanocellulose into novel composite materials and its performance in removing contaminants such as heavy metals, dyes, and organic pollutants from wastewater are critically analyzed. Emphasis is placed on the mechanisms of adsorption, regeneration potential, and the economic and environmental benefits of using bamboo-based bioadsorbents. The findings underscore the potential of bamboo nanocellulose to play a pivotal role in developing sustainable wastewater treatment technologies, offering a promising pathway towards cleaner water and a greener future.
    Matched MeSH terms: Nanoparticles/chemistry
  5. Tailoring structural and optical properties of Cu(II)-induced MgAl2O4 nanoparticles and their response to toxic dyes under solar illumination
    Javed M, Akbar N, Khan AA, Masood A, Ahmed N, Khan MJ, et al.
    Environ Sci Pollut Res Int, 2024 Aug;31(40):53532-53551.
    PMID: 39192152 DOI: 10.1007/s11356-024-34753-1
    Worldwide environmental challenges pose critical problems with the growth of the global economy. Addressing these issues requires the development of an eco-friendly and sustainable catalyst for degrading organic dye pollutants. In this study, copper-doped magnesium aluminates (CuxMg1-xAl2O4) with x = 0.0-0.8 were synthesized using a citrate-based combustion route. The inclusion of Cu(II) significantly impacted the structural, microstructural, optical, and photocatalytic activity of the catalyst. Rietveld analysis of X-ray diffraction powder profiles revealed single-phase spinels crystallized in the face-centered cubic unit cell with Fd 3 ¯ m space group. Chemical states of the ions, surface morphology, and elemental investigation were analyzed by X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. UV-visible and diffuse reflectance spectroscopies confirmed the reduction of the band gap due to Cu(II) doping, validated by first-principle investigations using the WIEN2k code. The catalyst with x = 0.8 showed higher photocatalytic efficacy (90% and 93%) for removing two azo organic dye pollutants, rhodamine B and methyl orange, respectively, within 120 min. Degradation kinetics followed a pseudo-first-order mechanism. The doped (0.8) sample was structurally and morphologically stable and reusable under visible irradiation, retaining performance after three runs. Scavenger studies confirmed hydroxyl and superoxide radicals' involvement in the degradation. This work presents an effective approach to enhancing CuxMg1-xAl2O4 catalysts' photodegradation performance, with potential applications in pharmaceuticals and wastewater remediation.
    Matched MeSH terms: Nanoparticles/chemistry
  6. Fulltext Development and characterization of a self-nano emulsifying drug delivery system (SNEDDS) for Ornidazole to improve solubility and oral bioavailability of BCS class II drugs
    Mohite P, Sule S, Pawar A, Alharbi HM, Maitra S, Subramaniyan V, et al.
    Sci Rep, 2024 Nov 12;14(1):27724.
    PMID: 39532892 DOI: 10.1038/s41598-024-73760-7
    This study aimed to investigate the in vitro performance of self-nanoemulsifying drug delivery systems (SNEDDSs) of Ornidazole (ORD), a poorly water-soluble drug. Self-nanoemulsifying drug delivery systems of ORD were prepared using various oils, non-ionic surfactants, and/or water-soluble co-solvents and assessed visually/by droplet size measurement. Equilibrium solubility of ORD in the anhydrous and diluted SNEDDS was conducted to achieve the maximum drug loading. The in vitro dissolution of SNEDDS was studied to compare the solubility of the representative formulations with API. The results from the characterization and solubility studies showed that SNEDDS formulations were stable with lower droplet sizes and showed higher ORD solubility. From the dissolution studies, it was found that the developed A7-SNEDDS formulation provided a significantly higher rate of ORD release (98.94 ± 0.68 in 1.0 h) compared to API. ORD-loaded SNEDDS formulations could be a potential oral pharmaceutical product with high drug-loading capacity, improved drug dissolution, and enhanced oral bioavailability.
    Matched MeSH terms: Nanoparticles/chemistry
  7. Fulltext Nanobiocatalyst advancements and bioprocessing applications
    Misson M, Zhang H, Jin B
    J R Soc Interface, 2015 Jan 06;12(102):20140891.
    PMID: 25392397 DOI: 10.1098/rsif.2014.0891
    The nanobiocatalyst (NBC) is an emerging innovation that synergistically integrates advanced nanotechnology with biotechnology and promises exciting advantages for improving enzyme activity, stability, capability and engineering performances in bioprocessing applications. NBCs are fabricated by immobilizing enzymes with functional nanomaterials as enzyme carriers or containers. In this paper, we review the recent developments of novel nanocarriers/nanocontainers with advanced hierarchical porous structures for retaining enzymes, such as nanofibres (NFs), mesoporous nanocarriers and nanocages. Strategies for immobilizing enzymes onto nanocarriers made from polymers, silicas, carbons and metals by physical adsorption, covalent binding, cross-linking or specific ligand spacers are discussed. The resulting NBCs are critically evaluated in terms of their bioprocessing performances. Excellent performances are demonstrated through enhanced NBC catalytic activity and stability due to conformational changes upon immobilization and localized nanoenvironments, and NBC reutilization by assembling magnetic nanoparticles into NBCs to defray the high operational costs associated with enzyme production and nanocarrier synthesis. We also highlight several challenges associated with the NBC-driven bioprocess applications, including the maturation of large-scale nanocarrier synthesis, design and development of bioreactors to accommodate NBCs, and long-term operations of NBCs. We suggest these challenges are to be addressed through joint collaboration of chemists, engineers and material scientists. Finally, we have demonstrated the great potential of NBCs in manufacturing bioprocesses in the near future through successful laboratory trials of NBCs in carbohydrate hydrolysis, biofuel production and biotransformation.
    Matched MeSH terms: Nanoparticles/chemistry; Metal Nanoparticles/chemistry*
  8. The role of particle-to-cell interactions in dictating nanoparticle aided magnetophoretic separation of microalgal cells
    Toh PY, Ng BW, Ahmad AL, Chieh DC, Lim J
    Nanoscale, 2014 Nov 7;6(21):12838-48.
    PMID: 25227473 DOI: 10.1039/c4nr03121k
    Successful application of a magnetophoretic separation technique for harvesting biological cells often relies on the need to tag the cells with magnetic nanoparticles. This study investigates the underlying principle behind the attachment of iron oxide nanoparticles (IONPs) onto microalgal cells, Chlorella sp. and Nannochloropsis sp., in both freshwater and seawater, by taking into account the contributions of various colloidal forces involved. The complex interplay between van der Waals (vdW), electrostatic (ES) and Lewis acid-base interactions (AB) in dictating IONP attachment was studied under the framework of extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) analysis. Our results showed that ES interaction plays an important role in determining the net interaction between the Chlorella sp. cells and IONPs in freshwater, while the AB and vdW interactions play a more dominant role in dictating the net particle-to-cell interaction in high ionic strength media (≥100 mM NaCl), such as seawater. XDLVO predicted effective attachment between cells and surface functionalized IONPs (SF-IONPs) with an estimated secondary minimum of -3.12 kT in freshwater. This prediction is in accordance with the experimental observation in which 98.89% of cells can be magnetophoretically separated from freshwater with SF-IONPs. We have observed successful magnetophoretic separation of microalgal cells from freshwater and/or seawater for all the cases as long as XDLVO analysis predicts particle attachment. For both the conditions, no pH adjustment is required for particle-to-cell attachment.
    Matched MeSH terms: Nanoparticles/chemistry*; Metal Nanoparticles/chemistry
  9. Fulltext Surface-Engineered Super-Paramagnetic Iron Oxide Nanoparticles For Chromium Removal
    Samrot AV, Sahithya CS, Selvarani A J, Pachiyappan S, Kumar S S
    Int J Nanomedicine, 2019;14:8105-8119.
    PMID: 31632021 DOI: 10.2147/IJN.S214236
    Background: Super-paramagnetic iron oxide nanoparticles (SPIONs) are widely used metal nanoparticles for various applications for its magnetic property and biocompatibility. In recent years, pollution of our environment especially with heavy metals in waterbodies has become a major threat and has left us very minimal sources of freshwater to drink. SPIONs or surface modified SPIONs can be used to remove these heavy metals.

    Methods: SPIONs were synthesized by co-precipitation method and further coated with a biopolymer, chitosan. Chromium solution was treated with the synthesized SPIONs to study the efficiency of chromium removal by surface adsorption. Later, the adsorption was analysed by direct and indirect analysis methods using UV-VIS spectrophotometry and isotherm studies.

    Results: Stable chitosan-coated SPIONs were synthesized and they adsorbed chromium better than the uncoated SPIONs, where it was adsorbing up to 100 ppm. Adsorption was found to be increasing with decrease in pH.

    Conclusion: The surface-modified SPIONs expressed cumulative adsorption action. Even after the adsorption studies, chitosan-coated SPIONs were possessing magnetic property. Thus, the surface-modified SPIONs can become an ideal nanotechnology tool to remove the chromium from groundwater.

    Matched MeSH terms: Nanoparticles/chemistry; Magnetite Nanoparticles/chemistry*
  10. Molecular insights and novel approaches for targeting tumor metastasis
    Das SS, Alkahtani S, Bharadwaj P, Ansari MT, ALKahtani MDF, Pang Z, et al.
    Int J Pharm, 2020 Jul 30;585:119556.
    PMID: 32574684 DOI: 10.1016/j.ijpharm.2020.119556
    In recent years, due to the effective drug delivery and preciseness of tumor sites or microenvironment, the targeted drug delivery approaches have gained ample attention for tumor metastasis therapy. The conventional treatment approaches for metastasis therapy have reported with immense adverse effects because they exhibited maximum probability of killing the carcinogenic cells along with healthy cells. The tumor vasculature, comprising of vasculogenic impressions and angiogenesis, greatly depends upon the growth and metastasis in the tumors. Therefore, various nanocarriers-based delivery approaches for targeting to tumor vasculature have been attempted as efficient and potential approaches for the treatment of tumor metastasis and the associated lesions. Furthermore, the targeted drug delivery approaches have found to be most apt way to overcome from all the limitations and adverse effects associated with the conventional therapies. In this review, various approaches for efficient targeting of pharmacologically active chemotherapeutics against tumor metastasis with the cohesive objectives of prognosis, tracking and therapy are summarized.
    Matched MeSH terms: Nanoparticles/chemistry*; Metal Nanoparticles/chemistry
  11. A new mechanism of thermal sensitivity for rapid drug release and low systemic toxicity in hyperthermia and thermal ablation temperature ranges
    Dabbagh A, Abdullah BJ, Abu Kasim NH, Abdullah H, Hamdi M
    Int J Hyperthermia, 2015 Jun;31(4):375-85.
    PMID: 25716769 DOI: 10.3109/02656736.2015.1006268
    The aim of this paper was to introduce a new mechanism of thermal sensitivity in nanocarriers that results in a relatively low drug release at physiological temperature and rapid release of the encapsulated drug at hyperthermia and thermal ablation temperature range (40-60 °C).
    Matched MeSH terms: Nanoparticles/chemistry*
  12. Application of response surface methodology in optimization of electrospinning process to fabricate (ferrofluid/polyvinyl alcohol) magnetic nanofibers
    Ahmadipourroudposht M, Fallahiarezoudar E, Yusof NM, Idris A
    Mater Sci Eng C Mater Biol Appl, 2015 May;50:234-41.
    PMID: 25746266 DOI: 10.1016/j.msec.2015.02.008
    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.
    Matched MeSH terms: Nanoparticles/chemistry*
  13. Fulltext Microwave irradiation of nanohydroxyapatite from chicken eggshells and duck eggshells
    Sajahan NA, Wan Ibrahim WM
    ScientificWorldJournal, 2014;2014:275984.
    PMID: 25383364 DOI: 10.1155/2014/275984
    Due to similarity in composition to the mineral component of bones and human hard tissues, hydroxyapatite with chemical formula Ca10(PO4)6(OH)2 has been widely used in medical field. Both chicken and duck eggshells are mainly composed of calcium carbonate. An attempt has been made to fabricate nanohydroxyapatite (nHA) by chicken (CES) and duck eggshells (DES) as calcium carbonate source (CaCO3). CES and DES were reacted with diammonium hydrogen [(NH4)2HPO4] solution and subjected to microwave heating at 15 mins. Under the effect of microwave irradiation, nHA was produced directly in the solution and involved in crystallographic transformation. Sample characterization was done using by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM).
    Matched MeSH terms: Nanoparticles/chemistry
  14. Fulltext Numerical investigation of heat transfer enhancement in a rectangular heated pipe for turbulent nanofluid
    Yarmand H, Gharehkhani S, Kazi SN, Sadeghinezhad E, Safaei MR
    ScientificWorldJournal, 2014;2014:369593.
    PMID: 25254236 DOI: 10.1155/2014/369593
    Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2 at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations.
    Matched MeSH terms: Nanoparticles/chemistry*
  15. Catalyst free silica templated porous carbon nanoparticles from bio-waste materials
    Kumar A, Hegde G, Manaf SA, Ngaini Z, Sharma KV
    Chem Commun (Camb), 2014 Oct 28;50(84):12702-5.
    PMID: 25100105 DOI: 10.1039/c4cc04378b
    Porous Carbon Nanoparticles (PCNs) with well-developed microporosity were obtained from bio-waste oil palm leaves (OPL) using single step pyrolysis in nitrogen atmosphere at 500-600 °C in tube-furnace without any catalysis support. The key approach was using silica (SiO2) bodies of OPL as a template in the synthesis of microporous carbon nanoparticles with very small particle sizes of 35-85 nm and pore sizes between 1.9-2 nm.
    Matched MeSH terms: Nanoparticles/chemistry*
  16. Fulltext A selective ultrahigh responding high temperature ethanol sensor using TiO2 nanoparticles
    Arafat MM, Haseeb AS, Akbar SA
    Sensors (Basel), 2014;14(8):13613-27.
    PMID: 25072346 DOI: 10.3390/s140813613
    In this research work, the sensitivity of TiO2 nanoparticles towards C2H5OH, H2 and CH4 gases was investigated. The morphology and phase content of the particles was preserved during sensing tests by prior heat treatment of the samples at temperatures as high as 750 °C and 1000 °C. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were employed to characterize the size, morphology and phase content of the particles. For sensor fabrication, a film of TiO2 was printed on a Au interdigitated alumina substrate. The sensing temperature was varied from 450 °C to 650 °C with varying concentrations of target gases. Results show that the sensor has ultrahigh response towards ethanol (C2H5OH) compared to hydrogen (H2) and methane (CH4). The optimum sensing temperature was found to be 600 °C. The response and recovery times of the sensor are 3 min and 15 min, respectively, for 20 ppm C2H5OH at the optimum operating temperature of 600 °C. It is proposed that the catalytic action of TiO2 with C2H5OH is the reason for the ultrahigh response of the sensor.
    Matched MeSH terms: Nanoparticles/chemistry*
  17. Fulltext Biotemplated synthesis of anatase titanium dioxide nanoparticles via lignocellulosic waste material
    Ramimoghadam D, Bagheri S, Abd Hamid SB
    Biomed Res Int, 2014;2014:205636.
    PMID: 25126547 DOI: 10.1155/2014/205636
    Anatase titanium dioxide nanoparticles (TiO2-NPs) were synthesized by sol-gel method using rice straw as a soft biotemplate. Rice straw, as a lignocellulosic waste material, is a biomass feedstock which is globally produced in high rate and could be utilized in an innovative approach to manufacture a value-added product. Rice straw as a reliable biotemplate has been used in the sol-gel method to synthesize ultrasmall sizes of TiO2-NPs with high potential application in photocatalysis. The physicochemical properties of titanium dioxide nanoparticles were investigated by a number of techniques such as X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), ultraviolet visible spectra (UV-Vis), and surface area and pore size analysis. All results consensually confirmed that particle sizes of synthesized titanium dioxide were template-dependent, representing decrease in the nanoparticles sizes with increase of biotemplate concentration. Titanium dioxide nanoparticles as small as 13.0 ± 3.3 nm were obtained under our experimental conditions. Additionally, surface area and porosity of synthesized TiO2-NPs have been enhanced by increasing rice straw amount which results in surface modification of nanoparticles and potential application in photocatalysis.
    Matched MeSH terms: Metal Nanoparticles/chemistry*
  18. Fulltext Conversion of lignocellulosic biomass to nanocellulose: structure and chemical process
    Lee HV, Hamid SB, Zain SK
    ScientificWorldJournal, 2014;2014:631013.
    PMID: 25247208 DOI: 10.1155/2014/631013
    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.
    Matched MeSH terms: Nanoparticles/chemistry*
  19. Fulltext Synthesis, characterization, and antimicrobial activity of an ampicillin-conjugated magnetic nanoantibiotic for medical applications
    Hussein-Al-Ali SH, El Zowalaty ME, Hussein MZ, Geilich BM, Webster TJ
    Int J Nanomedicine, 2014;9:3801-14.
    PMID: 25143729 DOI: 10.2147/IJN.S61143
    Because of their magnetic properties, magnetic nanoparticles (MNPs) have numerous diverse biomedical applications. In addition, because of their ability to penetrate bacteria and biofilms, nanoantimicrobial agents have become increasingly popular for the control of infectious diseases. Here, MNPs were prepared through an iron salt coprecipitation method in an alkaline medium, followed by a chitosan coating step (CS-coated MNPs); finally, the MNPs were loaded with ampicillin (amp) to form an amp-CS-MNP nanocomposite. Both the MNPs and amp-CS-MNPs were subsequently characterized and evaluated for their antibacterial activity. X-ray diffraction results showed that the MNPs and nanocomposites were composed of pure magnetite. Fourier transform infrared spectra and thermogravimetric data for the MNPs, CS-coated MNPs, and amp-CS-MNP nanocomposite were compared, which confirmed the CS coating on the MNPs and the amp-loaded nanocomposite. Magnetization curves showed that both the MNPs and the amp-CS-MNP nanocomposites were superparamagnetic, with saturation magnetizations at 80.1 and 26.6 emu g(-1), respectively. Amp was loaded at 8.3%. Drug release was also studied, and the total release equilibrium for amp from the amp-CS-MNPs was 100% over 400 minutes. In addition, the antimicrobial activity of the amp-CS-MNP nanocomposite was determined using agar diffusion and growth inhibition assays against Gram-positive bacteria and Gram-negative bacteria, as well as Candida albicans. The minimum inhibitory concentration of the amp-CS-MNP nanocomposite was determined against bacteria including Mycobacterium tuberculosis. The synthesized nanocomposites exhibited antibacterial and antifungal properties, as well as antimycobacterial effects. Thus, this study introduces a novel β-lactam antibacterial-based nanocomposite that can decrease fungus activity on demand for numerous medical applications.
    Matched MeSH terms: Magnetite Nanoparticles/chemistry*
  20. Fulltext A large response range reflectometric urea biosensor made from silica-gel nanoparticles
    Alqasaimeh M, Heng LY, Ahmad M, Raj AS, Ling TL
    Sensors (Basel), 2014 Jul 22;14(7):13186-209.
    PMID: 25054632 DOI: 10.3390/s140713186
    A new silica-gel nanospheres (SiO2NPs) composition was formulated, followed by biochemical surface functionalization to examine its potential in urea biosensor development. The SiO2NPs were basically synthesized based on sol-gel chemistry using a modified Stober method. The SiO2NPs surfaces were modified with amine (-NH2) functional groups for urease immobilization in the presence of glutaric acid (GA) cross-linker. The chromoionophore pH-sensitive dye ETH 5294 was physically adsorbed on the functionalized SiO2NPs as pH transducer. The immobilized urease determined urea concentration reflectometrically based on the colour change of the immobilized chromoionophore as a result of the enzymatic hydrolysis of urea. The pH changes on the biosensor due to the catalytic enzyme reaction of immobilized urease were found to correlate with the urea concentrations over a linear response range of 50-500 mM (R2 = 0.96) with a detection limit of 10 mM urea. The biosensor response time was 9 min with reproducibility of less than 10% relative standard deviation (RSD). This optical urea biosensor did not show interferences by Na+, K+, Mg2+ and NH4+ ions. The biosensor performance has been validated using urine samples in comparison with a non-enzymatic method based on the use of p-dimethylaminobenzaldehyde (DMAB) reagent and demonstrated a good correlation between the two different methods (R2 = 0.996 and regression slope of 1.0307). The SiO2NPs-based reflectometric urea biosensor showed improved dynamic linear response range when compared to other nanoparticle-based optical urea biosensors.
    Matched MeSH terms: Nanoparticles/chemistry*
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