Displaying publications 1 - 20 of 198 in total

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  1. Bosu S, Rajamohan N, Sagadevan S, Raut N
    Chemosphere, 2023 Dec;345:140471.
    PMID: 37871875 DOI: 10.1016/j.chemosphere.2023.140471
    The rapid consumption of metals and unorganized disposal have led to unprecedented increases in heavy metal ion concentrations in the ecosystem, which disrupts environmental homeostasis and results in agricultural biodiversity loss. Mitigation and remediation plans for heavy metal pollution are largely dependent on the discovery of cost-effective, biocompatible, specific, and robust detectors because conventional methods involve sophisticated electronics and sample preparation procedures. Carbon dots (CDs) have gained significant importance in sensing applications related to environmental sustainability. Fluorescence sensor applications have been enhanced by their distinctive spectral properties and the potential for developing efficient photonic devices. With the recent development of biomass-functionalized carbon dots, a wide spectrum of multivalent and bivalent transition metal ions responsible for water quality degradation can be detected with high efficiency and minimal toxicity. This review explores the various methods of manufacturing carbon dots and the biochemical mechanisms involved in metal detection using green carbon dots for sensing applications involving Cu (II), Fe (III), Hg (II), and Cr (VI) ions in aqueous systems. A detailed discussion of practical challenges and future recommendations is presented to identify feasible design routes.
    Matched MeSH terms: Carbon/chemistry
  2. Taer E, Yanti N, Padang E, Apriwandi A, Zulkarnain Z, Haryanti NH, et al.
    J Sci Food Agric, 2023 Dec;103(15):7411-7423.
    PMID: 37431642 DOI: 10.1002/jsfa.12846
    BACKGROUND: Porous carbon electrode (PCE) is identified as a highly suitable electrode material for commercial application due to its production process, which is characterized by simplicity, cost-effectiveness and environmental friendliness. PCE was synthesized using torch ginger (Etlingera elatior (Jack) R.M. Smith) leaves as the base material. The leaves were treated with different concentrations of ZnCl2 , resulting in a supercapacitor cell electrode with unique honeycomb-like three-dimensional (3D) morphological pore structure. This PCE comprises nanofibers from lignin content and volatile compounds from aromatic biomass waste.

    RESULTS: From the characterization of physical properties, PCE-0.3 had an impressive amorphous porosity, wettability and 3D honeycomb-like structural morphology with a pore framework consisting of micropores and mesopores. According to the structural advantages of 3D hierarchical pores such as interconnected honeycombs, PCE-0.3 as supercapacitor electrode had a high specific capacitance of up to 285.89 F g-1 at 1 A. Furthermore, the supercapacitor exhibited high energy and power density of 21.54 Wh kg-1 and 161.13 W kg-1 , respectively, with a low internal resistance of 0.059 Ω.

    CONCLUSION: The results indicated that 3D porous carbon materials such as interconnected honeycombs derived from the aromatic biomass of torch ginger leaves have significant potential for the development of sustainable energy storage devices. © 2023 Society of Chemical Industry.

    Matched MeSH terms: Carbon/chemistry
  3. Yeo RYZ, Chin BH, Hil Me MF, Chia JF, Pham HT, Othman AR, et al.
    ACS Biomater Sci Eng, 2023 Nov 13;9(11):6034-6044.
    PMID: 37846081 DOI: 10.1021/acsbiomaterials.3c00453
    Electrogenic microorganisms serve as important biocatalysts for microbial electrochemical sensors (MESes). The electrical signal produced is based on the rate of electron transfer between the microbes and electrodes, which represents the biotoxicity of water. However, existing MESes require complex and sophisticated fabrication methods. Here, several low-cost and rapid surface modification strategies (carbon powder-coated, flame-oxidized, and acid-bleached) have been demonstrated and studied for biosensing purposes. Surface-modified MESe bioanodes were successfully applied to detect multiple model pollutants including sodium acetate, ethanol, thinner, and palm oil mill effluent under three different testing sequences, namely, pollutant incremental, pollutant dumping, and water dilution tests. The carbon powder-coated bioanode showed the most responsive signal profile for all the three tests, which is in line with the average roughness values (Ra) when tested with atomic force microscopy. The carbon powder-coated electrode possessed a Ra value of 0.844, while flame-oxidized, acid-bleached, and control samples recorded 0.323, 0.336, and 0.264, respectively. The higher roughness was caused by the carbon coating and provided adhesive sites for microbial attachment and growth. The accuracy of MESe was also verified by correlating with chemical oxygen demand (COD) results. Similar to the sensitivity test, the carbon powder-coated bioanode obtained the highest R2 value of 0.9754 when correlated with COD results, indicating a high potential of replacing conventional water quality analysis methods. The reported work is of great significance to showcase facile surface modification techniques for MESes, which are cost-effective and sustainable while retaining the biocompatibility toward the microbial community with carbon-based coatings.
    Matched MeSH terms: Carbon/chemistry
  4. Elancheziyan M, Prakasham K, Eswaran M, Duraisamy M, Ganesan S, Lee SL, et al.
    Environ Res, 2023 Apr 15;223:115403.
    PMID: 36754108 DOI: 10.1016/j.envres.2023.115403
    The design and development of eco-friendly fabrication of cost-effective electrochemical nonenzymatic biosensors with enhanced sensitivity and selectivity are one of the emerging area in nanomaterial and analytical chemistry. In this aspect, we developed a facile fabrication of tertiary nanocomposite material based on cobalt and polymelamine/nitrogen-doped graphitic porous carbon nanohybrid composite (Co-PM-NDGPC/SPE) for the application as a nonenzymatic electrochemical sensor to quantify glucose in human blood samples. Co-PM-NDGPC/SPE nanocomposite electrode fabrication was achieved using a single-step electrodeposition method under cyclic voltammetry (CV) technique under 1 M NH4Cl solution at 20 constitutive CV cycles (sweep rate 20 mV/s). Notably, the fabricated nonenzymatic electroactive nanocomposite material exhibited excellent electrocatalytic sensing towards the quantification of glucose in 0.1 M NaOH over a wide concentration range from 0.03 to 1.071 mM with a sensitive limit of detection 7.8 μM. Moreover, the Co-PM-NDGPC nanocomposite electrode with low charge transfer resistance (Rct∼81 Ω) and high ionic diffusion indicates excellent stability, reproducibility, and high sensitivity. The fabricated nanocomposite materials exhibit a commendable sensing response toward glucose molecules present in the blood serum samples recommends its usage in real-time applications.
    Matched MeSH terms: Carbon/chemistry
  5. Fahmi MZ, Aung YY, Ahmad MA, Kristanti AN, Sakti SCW, Arjasa OP, et al.
    Nanotheranostics, 2023;7(3):281-298.
    PMID: 37064612 DOI: 10.7150/ntno.80030
    The fluorescent imaging and drug delivery utilizing carbon dots nanomaterials (CDs) have attracted tremendously due to their unique optical ability and outstanding biocompatibility. Herein, we reported a new design of chalcone-loaded carbon dots (Chalcone-APBA-CDs) to serve chalcone transport onto cancer cells and enhance the CDs bioimaging and antitumor activity. The boronic acid was directly introduced to carbon dots (CDs) via pyrolysis process to drive CDs specifically to the cancer cell, and chalcone was mediated on CDs by ultrasonication to perform facile release of the drug delivery model. The successfully synthesized Chalcone-APBA-CDs were proved by their chemical structure, fluorescent activities, in vitro and in vivo analyses, and drug release systems using different pH. In addition, flow cytometry and confocal fluorescent imaging proved CDs' cellular uptake and imaging performance. In vitro analyses further proved that the Chalcone-APBA-CDs exhibited a higher toxicity value than bare CDs and efficiently inhibited the proliferation of the HeLa cells depending on their dose-response. Finally, the performance of Chalcone-APBA-CDs on cancer healing capability was examined in vivo with fibrosarcoma cancer-bearing mice, which showed a remarkable ability to reduce the tumor volume compared with saline (control). This result strongly suggested that the Chalcone-APBA-CDs appear promising simultaneously as cancer cell imaging and drug delivery.
    Matched MeSH terms: Carbon/chemistry
  6. Issa MA, Zentou H, Jabbar ZH, Abidin ZZ, Harun H, Halim NAA, et al.
    Environ Sci Pollut Res Int, 2022 Dec;29(57):86859-86872.
    PMID: 35802332 DOI: 10.1007/s11356-022-21844-0
    In this study, luminescent bio-adsorbent nitrogen-doped carbon dots (N-CDs) was produced and applied for the removal and detection of Hg (II) from aqueous media. N-CDs were synthesized from oil palm empty fruit bunch carboxymethylcellulose (CMC) and urea. According to several analytical techniques used, the obtained N-CDs display graphitic core with an average size of 4.2 nm, are enriched with active sites, stable over a wide range of pH and have great resistance to photobleaching. The N-CDs have bright blue emission with an improved quantum yield (QY) of up to 35.5%. The effect of the variables including pH, adsorbent mass, initial concentration and incubation time on the removal of Hg (II) was investigated using central composite design. The statistical results confirmed that the adsorption process could reach equilibrium within 30 min. The reduced cubic model (R2 = 0.9989) revealed a good correlation between the observed values and predicted data. The optimal variables were pH of 7, dose of 0.1 g, initial concentration of 100 mg/L and duration of 30 min. Under these conditions, adsorption efficiency of 84.6% was obtained. The adsorption kinetic data could be well expressed by pseudo-second-order kinetic and Langmuir isotherm models. The optimal adsorption capacity was 116.3 mg g-1. Furthermore, the adsorbent has a good selectivity towards Hg (II) with a detection limit of 0.01 μM due to the special interaction between Hg (II) and carboxyl/amino groups on the edge of N-CDs. This work provided an alternative direction for constructing low-cost adsorbents with effective sorption and sensing of Hg (II).
    Matched MeSH terms: Carbon/chemistry
  7. Ashraf MA, Islam A, Butt MA, Hussain T, Khan RU, Bashir S, et al.
    Int J Biol Macromol, 2021 Nov 30;191:872-880.
    PMID: 34571131 DOI: 10.1016/j.ijbiomac.2021.09.131
    Mixed matrix membranes (MMMs) of cellulose acetate/poly(vinylpyrrolidone) (CA/PVP) infused with acid functionalized multiwall carbon nanotubes (f-MWCNTs) were fabricated by an immersion phase separation technique for hemodialysis application. Membranes were characterized using FTIR, water uptake, contact angle, TGA, DMA and SEM analysis. The FTIR was used to confirm the bonding interaction between CA/PVP membrane matrix and f-MWCNTs. Upon addition of f-MWCNTs, TGA thermograms and glass transition temperature indicated improved thermal stability of MMMs. The surface morphological analysis demonstrated revealed uniform distribution of f-MWCNTs and asymmetric membrane structure. The water uptake and contact angle confirmed that hydrophilicity was increased after incorporation of f-MWCNTs. The membranes demonstrated enhancement in water permeate flux, bovine serum albumin (BSA) rejection with the infusion of f-MWCNTs; whereas BSA based anti-fouling analysis using flux recovery ratio test shown up to 8.4% improvement. The urea and creatinine clearance performance of MMMs were evaluated by dialysis experiment. It has been found that f-MWCNTs integrated membranes demonstrated the higher urea and creatinine clearance with increase of 12.6% and 10.5% in comparison to the neat CA/PVP membrane. Thus, the prepared CA/PVP membranes embedded with f-MWCNTs can be employed for wide range of dialysis applications.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  8. Rizal S, Mistar EM, Oyekanmi AA, H P S AK, Alfatah T, Olaiya NG, et al.
    Molecules, 2021 Jul 13;26(14).
    PMID: 34299524 DOI: 10.3390/molecules26144248
    The use of chemical modification of cellulosic fibre is applied in order to increase the hydrophobicity, hence improving the compatibility between the fibre and matrix bonding. In this study, the effect of propionic anhydride modification of kenaf fibre was investigated to determine the role of bionanocarbon from oil palm shell agricultural wastes in the improvement of the functional properties of bionanocomposites. The vinyl esters reinforced with unmodified and propionic anhydride modified kenaf fibres bio nanocomposites were prepared using 0, 1, 3, 5 wt% of bio-nanocarbon. Characterisation of the fabricated bionanocomposite was carried out using FESEM, TEM, FT-IR and TGA to investigate the morphological analysis, surface properties, functional and thermal analyses, respectively. Mechanical performance of bionanocomposites was evaluated according to standard methods. The chemical modification of cellulosic fibre with the incorporation of bionanocarbon in the matrix exhibited high enhancement of the tensile, flexural, and impact strengths, for approximately 63.91%, 49.61% and 54.82%, respectively. The morphological, structural and functional analyses revealed that better compatibility of the modified fibre-matrix interaction was achieved at 3% bionanocarbon loading, which indicated improved properties of the bionanocomposite. The nanocomposites exhibited high degradation temperature which signified good thermal stability properties. The improved properties of the bionanocomposite were attributed to the effect of the surface modification and bionanocarbon enhancement of the fibre-matrix networks.
    Matched MeSH terms: Carbon/chemistry
  9. Mohammed NJ, Othman NK, Taib MFM, Samat MH, Yahya S
    Molecules, 2021 Jun 09;26(12).
    PMID: 34207914 DOI: 10.3390/molecules26123535
    Extracts from plant materials have great potential as alternatives to inorganic corrosion inhibitors, which typically have harmful consequences. Experimental and theoretical methodologies studied the effectiveness of agricultural waste, namely, date palm seed extract as a green anti-corrosive agent in 0.5 M hydrochloric acid. Experimental results showed that immersion time and temperature are closely related to the effectivity of date palm seed as a corrosion inhibitor. The inhibition efficiency reduced from 95% to 91% at 1400 ppm when the immersion time was increased from 72 h to 168 h. The experimental results also indicated that the inhibition efficiency decreased as the temperature increased. The presence of a protective layer of organic matter was corroborated by scanning electron microscopy. The adsorption studies indicated that date palm seed obeyed Langmuir adsorption isotherm on the carbon steel surface, and Gibbs free energy values were in the range of -33.45 to -38.41 kJ·mol-1. These results suggested that the date palm seed molecules interacted with the carbon steel surface through mixture adsorption. Theoretical calculations using density functional theory showed that the capability to donate and accept electrons between the alloy surface and the date palm seed inhibitor molecules is critical for adsorption effectiveness. The HOMO and LUMO result indicated that the carboxyl (COOH) group and C=C bond were the most active sites for the electron donation-acceptance type of interaction and most auxiliary to the adsorption process over the Fe surface.
    Matched MeSH terms: Carbon/chemistry*
  10. 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: Nanotubes, Carbon/chemistry*
  11. Azman AR, Mahat NA, Wahab RA, Ahmad WA, Puspanadan JK, Huri MAM, et al.
    Biotechnol Lett, 2021 Apr;43(4):881-898.
    PMID: 33389272 DOI: 10.1007/s10529-020-03052-3
    OBJECTIVE: Optimisation of the green novel nanobio-based reagent (NBR) for rapid visualisation of groomed fingerprints on wet non-porous substrates using response surface methodology and assessment of its stability and sensitivity were attempted for forensic applications.

    RESULTS: Scanning electron microscopy images demonstrated successful attachments of NBR onto the constituents of fingerprints on the substrates. The highest average quality of visualised fingerprints was attained at the optimum condition (100 mg of CRL; 75 mg of acid-functionalised multi-walled carbon nanotubes; 5 h of immobilisation). The NBR produced comparable average quality of fingerprints with the commercially available small particle reagent, even after 4 weeks of storage (without any preservatives) in both chilled and sultry conditions. The NBR was sensitive enough to visualise the increasingly weaker fingerprints, particularly on glass slides.

    CONCLUSION: The optimised novel NBR could be the relatively greener option for visualising latent fingerprints on wet, non-porous substrates for forensic applications.

    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  12. Yaacob NS, Ahmad MF, Kawasaki N, Maniyam MN, Abdullah H, Hashim EF, et al.
    Molecules, 2021 Jan 27;26(3).
    PMID: 33513787 DOI: 10.3390/molecules26030653
    Soil extracts are useful nutrients to enhance the growth of microalgae. Therefore, the present study attempts for the use of virgin soils from Peninsular Malaysia as growth enhancer. Soils collected from Raja Musa Forest Reserve (RMFR) and Ayer Hitam Forest Reserve (AHFR) were treated using different extraction methods. The total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved organic carbon (DOC) concentrations in the autoclave methods were relatively higher than natural extraction with up to 132.0 mg N/L, 10.7 mg P/L, and 2629 mg C/L, respectively for RMFR. The results of TDN, TDP, and DOC suggested that the best extraction methods are autoclaved at 121 °C twice with increasing 87%, 84%, and 95%, respectively. Chlorella vulgaris TRG 4C dominated the growth at 121 °C twice extraction method in the RMRF and AHRF samples, with increasing 54.3% and 14%, respectively. The specific growth rate (µ) of both microalgae were relatively higher, 0.23 d-1 in the Ayer Hitam Soil. This extract served well as a microalgal growth promoter, reducing the cost and the needs for synthetic medium. Mass production of microalgae as aquatic feed will be attempted eventually. The high recovery rate of nutrients has a huge potential to serve as a growth promoter for microalgae.
    Matched MeSH terms: Carbon/chemistry
  13. Trakunjae C, Boondaeng A, Apiwatanapiwat W, Kosugi A, Arai T, Sudesh K, et al.
    Sci Rep, 2021 01 21;11(1):1896.
    PMID: 33479335 DOI: 10.1038/s41598-021-81386-2
    Poly-β-hydroxybutyrate (PHB) is a biodegradable polymer, synthesized as carbon and energy reserve by bacteria and archaea. To the best of our knowledge, this is the first report on PHB production by a rare actinomycete species, Rhodococcus pyridinivorans BSRT1-1. Response surface methodology (RSM) employing central composite design, was applied to enhance PHB production in a flask scale. A maximum yield of 3.6 ± 0.5 g/L in biomass and 43.1 ± 0.5 wt% of dry cell weight (DCW) of PHB were obtained when using RSM optimized medium, which was improved the production of biomass and PHB content by 2.5 and 2.3-fold, respectively. The optimized medium was applied to upscale PHB production in a 10 L stirred-tank bioreactor, maximum biomass of 5.2 ± 0.5 g/L, and PHB content of 46.8 ± 2 wt% DCW were achieved. Furthermore, the FTIR and 1H NMR results confirmed the polymer as PHB. DSC and TGA analysis results revealed the melting, glass transition, and thermal decomposition temperature of 171.8, 4.03, and 288 °C, respectively. In conclusion, RSM can be a promising technique to improve PHB production by a newly isolated strain of R. pyridinivorans BSRT1-1 and the properties of produced PHB possessed similar properties compared to commercial PHB.
    Matched MeSH terms: Carbon/chemistry
  14. Saleemi MA, Hosseini Fouladi M, Yong PVC, Chinna K, Palanisamy NK, Wong EH
    Chem Res Toxicol, 2021 01 18;34(1):24-46.
    PMID: 33319996 DOI: 10.1021/acs.chemrestox.0c00172
    Carbon nanotubes (CNTs) are the most studied allotropic form of carbon. They can be used in various biomedical applications due to their novel physicochemical properties. In particular, the small size of CNTs, with a large surface area per unit volume, has a considerable impact on their toxicity. Despite of the use of CNTs in various applications, toxicity is a big problem that requires more research. In this Review, we discuss the toxicity of CNTs and the associated mechanisms. Physicochemical factors, such as metal impurities, length, size, solubilizing agents, CNTs functionalization, and agglomeration, that may lead to oxidative stress, toxic signaling pathways, and potential ways to control these mechanisms are also discussed. Moreover, with the latest mechanistic evidence described in this Review, we expect to give new insights into CNTs' toxicological effects at the molecular level and provide new clues for the mitigation of harmful effects emerging from exposure to CNTs.
    Matched MeSH terms: Nanotubes, Carbon/chemistry
  15. Mohd Zain NF, Paramasivam M, Tan JS, Lim V, Lee CK
    Biotechnol Prog, 2021 01;37(1):e3077.
    PMID: 32894656 DOI: 10.1002/btpr.3077
    The feasibility of using waste glycerol from the biodiesel industry for biosynthesis of polyhydroxyalkanoate (PHA) by Burkholderia cepacia BPT1213 was evaluated. Culture conditions were optimized by growing B. cepacia BPT1213 in mineral salt medium supplemented with 2% waste glycerol in a 2.5 L bioreactor. Response surface methodology was used to determine the influence of aeration rate (0.6-1.8 vvm), agitation speed (100-300 rpm), and cultivation period (48-72 hr) on PHA production. The optimum conditions for the growth and PHA accumulation were 1.5 vvm, 300 rpm, and 72 hr, with predicted values of 5.08 g/L cell dry weight (CDW), 66.07% PHA content, and 3.35 g/L total PHA concentration. Using these conditions, the experimental system produced 5.63 g/L of CDW with 64.00% wt/wt PHA content, which is threefold higher PHA concentration (3.60 g/L) compared to the non-optimized conditions. The melting temperature (Tm ) of purified PHA was 173.45 ± 1.05°C. In conclusion, the statistical approach was significantly increased the PHA production using waste glycerol as the sole carbon source.
    Matched MeSH terms: Carbon/chemistry
  16. Ong CE, Ahmad R, Goh YK, Azizan KA, Baharum SN, Goh KJ
    PLoS One, 2021;16(12):e0262029.
    PMID: 34972183 DOI: 10.1371/journal.pone.0262029
    Various phenolic compounds have been screened against Ganoderma boninense, the fungal pathogen causing basal stem rot in oil palms. In this study, we focused on the effects of salicylic acid (SA) on the growth of three G. boninense isolates with different levels of aggressiveness. In addition, study on untargeted metabolite profiling was conducted to investigate the metabolomic responses of G. boninense towards salicylic acid. The inhibitory effects of salicylic acid were both concentration- (P < 0.001) and isolate-dependent (P < 0.001). Also, growth-promoting effect was observed in one of the isolates at low concentrations of salicylic acid where it could have been utilized by G. boninense as a source of carbon and energy. Besides, adaptation towards salicylic acid treatment was evident in this study for all isolates, particularly at high concentrations. In other words, inhibitory effect of salicylic acid treatment on the fungal growth declined over time. In terms of metabolomics response to salicylic acid treatment, G. boninense produced several metabolites such as coumarin and azatyrosine, which suggests that salicylic acid modulates the developmental switch in G. boninense towards the defense mode for its survival. Furthermore, the liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis showed that the growth of G. boninense on potato dextrose agar involved at least four metabolic pathways: amino acid metabolism, lipid pathway, tryptophan pathway and phenylalanine pathway. Overall, there were 17 metabolites that contributed to treatment separation, each with P<0.005. The release of several antimicrobial metabolites such as eudistomin I may enhance G. boninense's competitiveness against other microorganisms during colonisation. Our findings demonstrated the metabolic versatility of G. boninense towards changes in carbon sources and stress factors. G. boninense was shown to be capable of responding to salicylic acid treatment by switching its developmental stage.
    Matched MeSH terms: Carbon/chemistry
  17. Sadrolhosseini AR, Krishnan G, Shafie S, Abdul Rashid S, Wadi Harun S
    Molecules, 2020 Dec 09;25(24).
    PMID: 33316885 DOI: 10.3390/molecules25245798
    This study used the carbon dots solution for the laser ablation technique to fabricate silver nanoparticles. The ablation time range was from 5 min to 20 min. Analytical methods, including Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, transmission electron microscopy, and Raman spectroscopy were used to categorize the prepared samples. The UV-visible and z-scan techniques provided optical parameters such as linear and nonlinear refractive indices in the range of 1.56759 to 1.81288 and 7.3769 × 10-10 cm2 W-1 to 9.5269 × 10-10 cm2 W-1 and the nonlinear susceptibility was measured in the range of 5.46 × 10-8 to 6.97 × 10-8 esu. The thermal effusivity of prepared samples, which were measured using the photoacoustic technique, were in the range of 0.0941 W s1/2 cm-2 K-1 to 0.8491 W s1/2 cm-2 K-1. The interaction of the prepared sample with fluoride was investigated using a Raman spectrometer. Consequently, the intensity of the Raman signal decreased with the increasing concentration of fluoride, and the detection limit is about 0.1 ppm.
    Matched MeSH terms: Carbon/chemistry*
  18. Jenol MA, Ibrahim MF, Kamal Bahrin E, Abd-Aziz S
    Bioprocess Biosyst Eng, 2020 Nov;43(11):2027-2038.
    PMID: 32572569 DOI: 10.1007/s00449-020-02391-9
    Sago hampas is a starch-based biomass from sago processing industries consisted of 58% remaining starch. This study has demonstrated the bioconversion of sago hampas to volatile fatty acids (VFAs) by Clostridium beijerinckii SR1 via anaerobic digestion. Higher total VFAs were obtained from sago hampas (5.04 g/L and 0.287 g/g) as compared to commercial starch (5.94 g/L and 0.318 g/g). The physical factors have been investigated for the enhancement of VFAs production using one-factor-at-a-time (OFAT). The optimum condition; 3% substrate concentration, 3 g/L of yeast extract concentration and 2 g/L of ammonium nitrate enhanced the production of VFAs by 52.6%, resulted the total VFAs produced is 7.69 g/L with the VFAs yield of 0.451 g/g. VFAs hydrolysate produced successfully generated 273.4 mV of open voltage circuit and 61.5 mW/m2 of power density in microbial fuel cells. It was suggested that sago hampas provide as an alternative carbon feedstock for bioelectricity generation.
    Matched MeSH terms: Carbon/chemistry*
  19. Sinduja B, Gowthaman NSK, John SA
    J Mater Chem B, 2020 10 28;8(41):9502-9511.
    PMID: 32996975 DOI: 10.1039/d0tb01681k
    In purine metabolism, the xanthine oxidoreductase enzyme converts hypoxanthine (HXN) to xanthine (XN) and XN to uric acid (UA). This leads to the deposition of UA crystals in several parts of the body and the serum UA level might be associated with various multifunctional disorders. The dietary intake of caffeine (CF) and ascorbic acid (AA) decreases the UA level in the serum, which leads to cellular damage. Hence, it is highly needed to monitor the UA level in the presence of AA, XN, HXN, and CF and vice versa. Considering this sequence of complications, the present paper reports the fabrication of an electrochemical sensor using low-cost N-doped carbon dots (CDs) for the selective and simultaneous determination of UA in the presence of AA, XN, HXN, and CF at the physiological pH. The colloidal solution of CDs was prepared by the pyrolysis of asparagine and fabricated on a GC electrode by cycling the potential from -0.20 to +1.2 V in a solution containing CDs and 0.01 M H2SO4. Here, the surface -NH2 functionalities of CDs were used to make a thin film of CDs on the GC electrode. FT-IR spectroscopy confirmed the involvement of the -NH2 group in the formation of the CD film. HR-TEM analysis depicts that the formed CDs showed spherical particles with a size of 1.67 nm and SEM analysis exhibits the 89 nm CD film on the GC electrode surface. The fabricated CD film was successfully used for the sensitive and selective determination of UA. The determination of UA was achieved selectively in a mixture consisting of AA, XN, HXN, and CF with 50-fold high concentration. The CDs-film fabricated electrode has several benefits over the bare electrode: (i) well-resolved oxidation peaks for five analytes, (ii) boosted sensitivity, (iii) shifted oxidation as well as on-set potentials toward less positive potentials, and (iv) high stability. The practical utility of the present sensor was tested by simultaneously determining the multifactorial disorders-causing agents in human fluids. The electrocatalyst developed in the present study is sustainable and can be used for multiple analyses; besides, the electrochemical method used for the fabrication of the CD film is environmentally benign.
    Matched MeSH terms: Carbon/chemistry
  20. Tan JM, Bullo S, Fakurazi S, Hussein MZ
    Sci Rep, 2020 10 09;10(1):16941.
    PMID: 33037287 DOI: 10.1038/s41598-020-73963-8
    This research work represents the first major step towards constructing an effective therapeutic silibinin (SB) in cancer treatment using oxidised multi-walled carbon nanotubes (MWCNT-COOH) functionalised with biocompatible polymers as the potential drug carrier. In an attempt to increase the solubility and dispersibility of SB-loaded nanotubes (MWSB), four water-soluble polymers were adopted in the preparation process, namely polysorbate 20 (T20), polysorbate 80 (T80), polyethylene glycol (PEG) and chitosan (CHI). From the geometry point of view, the hydrophobic regions of the nanotubes were loaded with water-insoluble SB while the hydrophilic polymers functionalised on the outer surfaces of the nanotubes serve as a protective shell to the external environment. The chemical interaction between MWSB nanocomposites and polymer molecules was confirmed by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Besides, high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA) and UV-visible spectrophotometry were also employed to characterise the synthesised nanocomposites. The morphological study indicated that the polymers were deposited on the external surfaces of MWSB and the nanocomposites were seen to preserve their tubular structures even after the coating process was applied. The TGA results revealed that the incorporation of biopolymers practically improved the overall thermal stability of the coated MWSB nanocomposites. Evaluation of the in vitro effect on drug release rate by the nanocomposites was found to follow a biphasic release manner, showing a fast release at an initial stage and then a sustained-release over 2500 min. Besides, the drug release mechanisms of the nanocomposites demonstrated that the amount of SB released in the simulated environment was governed by pseudo-second order in which, the rate-limiting step mainly depends on diffusion of drug through chemisorption reaction. Finally, MTT assay showed that the coated MWSB nanocomposites on 3T3 cells were very much biocompatible at a concentration up to 100 g/mL, which is an evidence of MWSB reduced cytotoxicity.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
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