Development of poly (3-hydroxybutyrate) (P(3HB))/Bioactive glass composite system for biomedical applications

Imperial Users onl

Does the doping strategy of ferrite nanoparticles create a correlation between reactivity and toxicity?

Owing to their remarkable properties in terms of electrical resistivity, chemical stability, and saturation magnetisation, ferrite nanoparticles are being increasingly used for a wide range of applications. This study looks to investigate as to whether ferrite nanoparticles can be safely and viably doped with transition metal elements without adversely affecting the stability and toxicity of the nanoparticles. Monodispersed and phase pure variants of ferrites (MxFe3−xO4 where M = Co, Cu, Zn, Mn) were synthesised with a size range of 9-11 nm using a wet chemistry route. The doping % within the ferrites was within the range of 15-18% for all the dopants. Compared to ferrite nanoparticles, Co and Mn doping significantly enhanced the dissolution, whereas doping with Cu and Zn had an opposite effect to dissolution. DFT calculations performed on the ferrites to calculate the vacancy formation energy of Fe and dopant atoms substantiated the experimental dissolution data. A549 cells showed a dose dependent response (10-200 μg mL−1) and the reduction in cell viability followed the trend of MnxFe3−xO4 &gt; CoxFe3−xO4 &gt; ZnxFe3−xO4 &gt; CuxFe3−xO4 &gt; Fe3O4. A correlation study between dissolution, cell viability and uptake indicated cell viability and dissolution had a strong negative correlation for Fe3O4, and CoxFe3−xO4 whereas for CuxFe3−xO4 this correlation was very weak. We conclude by providing an overview of the impact of doping on the safety of other metal-oxide nanoparticles (CuO, ZnO, TiO2 and CeO2) in comparison to ferrite nanoparticles.</p

Characterisation of carbon nanotubes in the context of toxicity studies

Nanotechnology has the potential to revolutionise our futures, but has also prompted concerns about the possibility that nanomaterials may harm humans or the biosphere. The unique properties of nanoparticles, that give them novel size dependent functionalities, may also have the potential to cause harm. Discrepancies in existing human health and environmental studies have shown the importance of good quality, well-characterized reference nanomaterials for toxicological studies

Development of poly (3-hydroxybutyrate) (P(3HB))/bioactive glass composite system for biomedical applications

P(3HB) was produced from a novel gram-positive micro-organism (Bacillus cereus SPV) using biotechnology routes based on a 14 L fermentation strategy. 45S5 Bioglass (BG) particles of micrometer (2 wt%) caused MG-63 osteoblast cell death, whereas in low concentrations MWCNTs increased the cell proliferation. Overall, the novel composites developed in this project represent a very attractive group of materials for bone tissue engineering applications.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Spin-Spin nuclear relaxation time as a metric to assess reactivity of CuO nanoparticles

by Archini Paruthi and Superb K. Misr

Photodegradation and Adsorption study of multifunctional ZnO-Fe3O4 nanocomposites for removal of heavy metals (Pb2+ and Cu2+) and organic dye (Methylene Blue)

by Prateek Goyal and Superb K. Misr

Multifunctional Fe3O4-ZnO nanocomposites for environmental remediation applications

We developed a one-pot synthesis route for multifunctional (ZnO-Fe3O4) nanocomposites. The Fe3O4 nanoparticles were decorated on the surface of ZnO. The formation of ZnO- Fe3O4 (ZF) nanocomposite was confirmed using XRD, FE-SEM and ICP-OES. This work comprises of adsorption, photocatalysis and antibacterial studies. Photocatalytic property of ZF nanocomposite was tested using degradation of methylene blue (MB) dye under UV irradiation. It was observed that 50?ppm of ZF nanocomposite was able to remove 89.2%. Adsorption efficiency of ZF nanocomposite was studied using adsorption of Pb2+ and Cu2+ metal ions (at pH 5.5) on the surface of ZF nanocomposite due to its high surface area. Antibacterial activity of ZF nanocomposite against E. coli and S. aureus was also tested and the nanocomposites showed efficient antimicrobial efficacy. The obtained multifunctional ZF nanocomposite demonstrated promising application in simultaneous removal of heavy metal ions, organic dye and bacterial pathogens, which can also be separated by magnet and can be reused multiple times. The results with ZF composites pave way to tailor the composition of the nano ZF composite adsorbent to tackle site-specific contamination.by Prateek Goyala, Swaroop Chakrabortyb and Superb K. Misra

Labelling nanoparticles with non-radioactive isotopes

by Agnieszka Dybowska, Superb K. Misra, and Eugenia Valsami-Jone

Hydrolytic Enzyme-Facilitated Mass Spectrometric Investigation of Metals in Processed Food Matrices

Greater access to processed foods worldwide poses challenges for regulatory bodies while feeding debates about the effect of such foods on human health. In contrast to their raw material ingredients, processed food matrices possess vastly more complex biochemical profiles. In this work, we demonstrate the ability of hydrolytic enzymes to facilitate the enhanced release of metals from three different processed food matrices. Our approach relies on the ability of the hydrolytic enzymes to cut or loosen biopolymeric components present in the processed food items, followed by the mass spectrometric detection of released metals. A combination of cellulase, pectinase, xylanase, and amylase disrupted the surface and overall architecture of the processed food items as indicated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Hydrolytic enzyme treatment resulted in the measurement of significantly higher levels of Cu, Mn, Zn, Cr, and As and between 20 and 250% higher levels of Pb and Sn across all three food matrices. We used RSM and ANOVA to optimize the conditions underlying hydrolytic enzyme treatment, for example, for Pb as pH 7, incubation time of 30–48 h, and enzyme concentration of 50 mg/mL. We analyzed the food product packaging materials as a prospective source of lead and tin and observed commensurate levels in the packaging to those measured after hydrolytic enzyme treatment of the contained foods. Treatment of the processed foods with immobilized hydrolytic enzymes results in a similar profile of the elements as obtained with the use of soluble enzymes, thereby promising the adaptability of our method to a reusable format. The approach presented in this work lays the groundwork for an important sample treatment strategy for the superior chemical analysis of processed foods