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Displaying publications 61 - 64 of 64 in total

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Toxicity of Carbon Nanotubes: Molecular Mechanisms, Signaling Cascades, and Remedies in Biomedical Applications

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
Composite of medium-chain-length polyhydroxyalkanoates-co-methyl acrylate and carbon nanotubes as innovative electrodes modifier in microbial fuel cell

Sirajudeen AAO, Annuar MSM, Subramaniam R

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

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

Matched MeSH terms: Nanotubes, Carbon/chemistry*
Box-Behnken design optimisation of a green novel nanobio-based reagent for rapid visualisation of latent fingerprints on wet, non-porous substrates

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*
Fabrication and dialysis performance of functionalized multiwall carbon nanotubes integrated cellulose acetate/poly(vinylpyrrolidone) membranes

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*