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12. TOF-SIMS and principal component analysis characterization of the multilayer surface grafting of small molecules: antibacterial furanones

Author

Bataineh, Sameer A. Al-, Jasieniak, Marek, Britcher, Leanne G., and Griesser, Hans J.

Subjects
Antibacterial agents -- Properties, Time-of-flight mass spectrometry -- Methods, Secondary ion mass spectrometry -- Methods, Principal components analysis -- Methods, Chemistry
Abstract

Furanone compounds (fimbrolides) have attracted interest as antibacterial compounds for use in human health care, for instance, as an antibacterial coating for medical devices to combat device-centered infections. To ensure effectiveness for extended periods of time, they must be immobilized covalently onto a device surface; in this study, this was done via azide/nitrene chemistry and photochemical coupling. However, the detection and quantification of surface-immobilized small molecules such as fitranones presents a considerable analytical challenge, yet is necessary for optimization of coatings and reliable interpretation of biological responses. We have utilized the surface sensitivity and chemical specificity of time-of-flight secondary ion mass spectrometry (TOF-SIMS) to characterize each step of the grafting sequence. On account of the complexity of the data, principal component analysis (PCA) was used to interpret and compare spectra. The results demonstrate the utility of TOF-SIMS with PCA for the detection of the surface-grafted small molecules azidoaniline and a brominated furanone; imaging of the bromine ion peaks also enabled assessment of grafting uniformity. Thus, successful multilayer coating and furanone grafting was observed, and substantial and uniform coverage of furanone molecules on the surface. Even multiple grafting steps involving, in the present case, two low molecular weight compounds can readily be disentangled by PCA. The utility of TOF-SIMS analysis with PCA is particularly well illustrated in the present case by the grafting of the furanone molecules, which did not yield a singular unique peak in the positive ion mass spectra, whereas the collective spectral changes elucidated by PCA provided unambiguous verification of successful grafting of this low molecular weight compound.

Published
2008

21. Outside Front Cover: Plasma Process. Polym. 7/2023.

Author

Chakraborty, Argha, Jasieniak, Marek, Coad, Bryan R., and Griesser, Hans J.

Subjects
*PLASMA materials processing, *PLASMA waves, *PLASMA polymerization
Abstract

Even without an additional layer of pulsed wave glycidol plasma polymer. B Outside Front Cover b : Continuous wave plasma polymerization of glycidol can directly immobilize amine containing anti-fungal biomolecules on substrates such as biomedical devices. This is facilitated by the abundance of epoxide groups on such plasma polymers to undergo ring-opening reaction. [Extracted from the article]

Published
2023
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23. Comparison of plasma polymerization under collisional and collision-less pressure regimes

Author

Saboohi, Solmaz, Jasieniak, Marek, Coad, Bryan R., Griesser, Hans J., Short, Robert D., Michelmore, Andrew, Saboohi, Solmaz, Jasieniak, Marek, Coad, Bryan R., Griesser, Hans J., Short, Robert D., and Michelmore, Andrew

Abstract

While plasma polymerization is used extensively to fabricate functionalized surfaces, the processes leading to plasma polymer growth are not yet completely understood. Thus, reproducing processes in different reactors has remained problematic, which hinders industrial uptake and research progress. Here we examine the crucial role pressure plays in the physical and chemical processes in the plasma phase, in interactions at surfaces in contact with the plasma phase, and how this affects the chemistry of the resulting plasma polymer films using ethanol as the gas precursor. Visual inspection of the plasma reveals a change from intense homogeneous plasma at low pressure to lower intensity bulk plasma at high pressure, but with increased intensity near the walls of the chamber. It is demonstrated that this occurs at the transition from a collision-less to a collisional plasma sheath, which in turn increases ion and energy flux to surfaces at constant RF power. Surface analysis of the resulting plasma polymer films show that increasing the pressure results in increased incorporation of oxygen and lower cross-linking, parameters which are critical to film performance. These results and insights help to explain the considerable differences in plasma polymer properties observed by different research groups using nominally similar processes.

Published
2015

30. Grafting of poly(ethylene glycol) on click chemistry modified Si(100) surfaces

Author

Flavel, Benjamin S, Jasieniak, Marek, Velleman, Leonora, Ciampi, Simone, Luais, Erwann, Peterson, J R, Griesser, Hans J, Shapter, J G, Gooding, J Justin, Flavel, Benjamin S, Jasieniak, Marek, Velleman, Leonora, Ciampi, Simone, Luais, Erwann, Peterson, J R, Griesser, Hans J, Shapter, J G, and Gooding, J Justin

Abstract

Poly(ethylene glycol) (PEG) is one of the most extensively studied antifouling coatings due to its ability to reduce protein adsorption and improve biocompatibility. Although the use of PEG for antifouling coatings is well established, the stability and density of PEG layers are often inadequate to provide optimum antifouling properties. To improve on these shortcomings, we employed the stepwise construction of PEG layers onto a silicon surface. Acetylene-terminated alkyl monolayers were attached to nonoxidized crystalline silicon surfaces via a one-step hydrosilylation procedure with 1,8-nonadiyne. The acetylene-terminated surfaces were functionalized via a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of the surface-bound alkynes with an azide to produce an amine terminated layer. The amine terminated layer was then further conjugated with PEG to produce an antifouling surface. The antifouling surface properties were investigated by testing adsorption of human serum albumin (HSA) and lysozyme (Lys) onto PEG layers from phosphate buffer solutions. Detailed characterization of protein fouling was carried out with X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) combined with principal component analysis (PCA). The results revealed no fouling of albumin onto PEG coatings whereas the smaller protein lysozyme adsorbed to a very low extent. 2013 American Chemical Society.

Published
2013

48. Serrulatane Diterpenoid from Eremophila neglectaExhibits Bacterial Biofilm Dispersion and Inhibits Release of Pro-inflammatory Cytokines from Activated Macrophages

Author

Mon, Htwe H., Christo, Susan N., Ndi, Chi P., Jasieniak, Marek, Rickard, Heather, Hayball, John D., Griesser, Hans J., and Semple, Susan J.

Abstract

The purpose of this study was to assess the biofilm-removing efficacy and inflammatory activity of a serrulatane diterpenoid, 8-hydroxyserrulat-14-en-19-oic acid (1), isolated from the Australian medicinal plant Eremophila neglecta.Biofilm breakup activity of compound 1on established Staphylococcus epidermidisand Staphylococcus aureusbiofilms was compared to the antiseptic chlorhexidine and antibiotic levofloxacin. In a time-course study, 1was deposited onto polypropylene mesh to mimic a wound dressing and tested for biofilm removal. The ex-vivocytotoxicity and effect on lipopolysaccharide-induced pro-inflammatory cytokine release were studied in mouse primary bone-marrow-derived macrophage (BMDM) cells. Compound 1was effective in dispersing 12 h pre-established biofilms with a 7 log10reduction of viable bacterial cell counts, but was less active against 24 h biofilms (approximately 2 log10reduction). Compound-loaded mesh showed dosage-dependent biofilm-removing capability. In addition, compound 1displayed a significant inhibitory effect on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) secretion from BMDM cells, but interleukin-1 beta (IL-1β) secretion was not significant. The compound was not cytotoxic to BMDM cells at concentrations effective in removing biofilm and lowering cytokine release. These findings highlight the potential of this serrulatane diterpenoid to be further developed for applications in wound management.

Published
2015
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50. Grafting of Poly(ethylene glycol) on Click ChemistryModified Si(100) Surfaces.

Author

Flavel, Benjamin S., Jasieniak, Marek, Velleman, Leonora, Ciampi, Simone, Luais, Erwann, Peterson, Joshua R., Griesser, Hans J., Shapter, Joe G., and Gooding, J. Justin

Subjects
*POLYETHYLENE glycol, *GRAFT copolymers, *CLICK chemistry, *SILICON, *SURFACE chemistry, *PROTEINS, *ADSORPTION (Chemistry)
Abstract

Poly(ethylene glycol)(PEG) is one of the most extensively studiedantifouling coatings due to its ability to reduce protein adsorptionand improve biocompatibility. Although the use of PEG for antifoulingcoatings is well established, the stability and density of PEG layersare often inadequate to provide optimum antifouling properties. Toimprove on these shortcomings, we employed the stepwise constructionof PEG layers onto a silicon surface. Acetylene-terminated alkyl monolayerswere attached to nonoxidized crystalline silicon surfaces via a one-stephydrosilylation procedure with 1,8-nonadiyne. The acetylene-terminatedsurfaces were functionalized via a copper-catalyzed azide–alkynecycloaddition (CuAAC) reaction of the surface-bound alkynes with anazide to produce an amine terminated layer. The amine terminated layerwas then further conjugated with PEG to produce an antifouling surface.The antifouling surface properties were investigated by testing adsorptionof human serum albumin (HSA) and lysozyme (Lys) onto PEG layers fromphosphate buffer solutions. Detailed characterization of protein foulingwas carried out with X-ray photoelectron spectroscopy (XPS) and time-of-flightsecondary ion mass spectrometry (ToF-SIMS) combined with principalcomponent analysis (PCA). The results revealed no fouling of albuminonto PEG coatings whereas the smaller protein lysozyme adsorbed toa very low extent. [ABSTRACT FROM AUTHOR]

Published
2013
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