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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.

A detailed study was conducted to understand the formation of porous microstructure immersed in water and other solvents in plasma polymers deposited from n-heptylamine onto silicon wafers. The porous plasma polymer coatings with surface groups are found to be suitable for interfacial chemical immobilization reaction and might be used for various membrane and biotechnology applications.

In comparison with other chemistries, little has been reported on sulfur-containing plasma polymers; reasons include low volatility or high toxicity of monomers. Here, we report on plasma polymerization of dimethyl sulfoxide, by itself and its co-polymerization with 1,7-octadiene to generate S-containing plasma polymers. Results show dominance of SS, SH, and SC with small percentages of SO and SO2. Upon storage in air there were no observable changes to the oxidation states of the S atoms in these plasma polymers, whereas the hydrocarbon component underwent oxidative changes. Methods were studied to oxidize the initial sulfur-containing surface groups, but approaches such as H2O2 treatment post-deposition and electrical biasing during deposition did not affect the oxidation states of the incorporated S. [ABSTRACT FROM AUTHOR]

Phosphate groups are part of biological molecules involved in bio-interfacial phenomena but monomers containing these groups are not volatile enough to be plasma polymerized (pp). Hence monomers with lower oxidation states of P are needed which then does not enable prediction of the oxidation state(s) of P in the pps, nor of possible aging effects. XPS and FTIR analyses of pps from triisopropyl phosphite (TIP) and diethyl phosphite (DEP) reveal the presence of phosphate and polyphosphate groups, while phosphonate and phosphate are found in pps of co-polymerized 1,7-octadiene and TIP. Post-plasma aging and electrical biasing have negligible effects on the oxidation state of P in TIP pps. [ABSTRACT FROM AUTHOR]

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 furanones 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. [ABSTRACT FROM AUTHOR]

Porous silicon has received considerable interest in recent years in a range of biomedical applications, with its performance determined by surface chemistry. In this work, we investigate the PEGylation of porous silicon wafers using click chemistry. The porous silicon wafer surface chemistry was monitored at each stage of the reaction via photoacoustic Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, whereas sessile drop contact angle and model protein adsorption measurements were used to characterize the final PEGylated surface. This work highlights the simplicity of click-chemistry-based functionalization in tailoring the porous silicon surface chemistry and controlling protein-porous silicon interactions.

Purpose: To examine the ability of contact lenses coated with fimbrolides, inhibitors of bacterial quorum sensing, to prevent microbial adhesion and their safety during short-term clinical assessment., Methods: A fimbrolide was covalently attached to commercially available high Dk contact lenses. Subsequently Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, or Acanthamoeba sp. were added to the lenses and control uncoated contact lenses. Lenses plus microbes were incubated for 24 h, then washed thoroughly to remove non-adherent microbes. Lenses were macerated and resulting slurry plated onto agar plates. After appropriate incubation, the numbers of colony forming units of bacteria (or numbers of Acanthamoeba trophozoites measured using a hemocytometer) from fimbrolide-coated and uncoated lenses were examined. A Guinea Pig model of lens wear was used to assess the safety of lenses worn on a continuous basis for 1 month. In a separate study, 10 subjects wore fimbrolide-coated lenses for 24 h. The responses of the Guinea Pigs and human volunteers to the lenses were assessed by slit lamp examination., Results: The fimbrolides-coated lenses reduced the adhesion of all bacterial strains tested, with reductions occurring of between 67 and 92%. For Acanthamoeba a reduction of 70% was seen. There were no significant differences in ocular responses to fimbrolide-coated lenses compared with controls in either the 1 month animal model or overnight human trial., Conclusions: Fimbrolide-coated lenses show promise as an antibacterial and anti-acanthamoebal coating on contact lenses and appear to be safe when worn on the eye in an animal model.

The IR spectra of mincrocystin-LR (mLR) were studied by Fourier transform infrared spectroscopy in the scanning range of 4,000-600 cm(-1). The characteristic IR spectra from main function groups such as monosubstituted benzene, guanidine residues and gamma-carboxylic groups etc have been identified.