Ultraviolet depolymerization of photoresist polymers

Bolon, Donald A.; Kunz, Clemens

doi:10.1002/pen.760120206

Cited by 62 publications

(20 citation statements)

References 4 publications

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“…We used a total of five silicon nitride probes (DNP, Veeco Instruments Inc., Santa Barbara, CA) with measured spring constants of 0.12 N/m Ϯ 10%, resonance frequencies of ϳ5 kHz in liquid, and average radii of 40 nm (previously measured by electron microscopy; data not shown). Probes were immersed in 100% ethanol for 12 h and then subjected to UV treatment (365 nm) to remove organic films (4,38). AFM experiments were performed with ultrapure water.…”

Section: Methodsmentioning

confidence: 99%

Relating the Physical Properties of Pseudomonas aeruginosa Lipopolysaccharides to Virulence by Atomic Force Microscopy

et al. 2011

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Lipopolysaccharides (LPS) are an important class of macromolecules that are components of the outer membrane of Gram-negative bacteria such as Pseudomonas aeruginosa. P. aeruginosa contains two different sugar chains, the homopolymer common antigen (A band) and the heteropolymer O antigen (B band), which impart serospecificity. The characteristics of LPS are generally assessed after isolation rather than in the context of whole bacteria. Here we used atomic force microscopy (AFM) to probe the physical properties of the LPS of P. aeruginosa strain PA103 (serogroup O11) in situ. This strain contains a mixture of long and very long polymers of O antigen, regulated by two different genes. For this analysis, we studied the wild-type strain and four mutants, ⌬Wzz1 (producing only very long LPS), ⌬Wzz2 (producing only long LPS), D⌬M (with both the wzz1 and wzz2 genes deleted), and Wzy::GM (producing an LPS core oligosaccharide plus one unit of O antigen). Forces of adhesion between the LPS on these strains and the silicon nitride AFM tip were measured, and the Alexander and de Gennes model of steric repulsion between a flat surface and a polymer brush was used to calculate the LPS layer thickness (which we refer to as length), compressibility, and spacing between the individual molecules. LPS chains were longest for the wild-type strain and ⌬Wzz1, at 170.6 and 212.4 nm, respectively, and these values were not statistically significantly different from one another. Wzy::GM and D⌬M have reduced LPS lengths, at 34.6 and 37.7 nm, respectively. Adhesion forces were not correlated with LPS length, but a relationship between adhesion force and bacterial pathogenicity was found in a mouse acute pneumonia model of infection. The adhesion forces with the AFM probe were lower for strains with LPS mutations, suggesting that the wild-type strain is optimized for maximal adhesion. Our research contributes to further understanding of the role of LPS in the adhesion and virulence of P. aeruginosa.Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that can cause several different types of infections in both community and health care settings and is especially problematic for immunocompromised and cystic fibrosis patients, as well as burn victims (23,32). Surface structures on the bacterium are related to virulence and the ability to cause infections. They make it possible for P. aeruginosa to attach to a wide range of surfaces, as well as to interact with components of the host (20). The lipopolysaccharide (LPS) is an important virulence factor for P. aeruginosa (25). The structure of LPS consists of lipid A, which anchors the LPS to the outer membrane, the core oligosaccharide, and the highly variable Oantigen side chain, which consists of repeating saccharide units and confers serotype specificity to the bacterium. The O antigen protrudes into the environment and allows the bacterium to interact with its surroundings. There are 20 serotypes of P. aeruginosa (27), and 14 of those groups also produce the Aband saccharide ...

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Section: Methodsmentioning

confidence: 99%

Relating the Physical Properties of Pseudomonas aeruginosa Lipopolysaccharides to Virulence by Atomic Force Microscopy

et al. 2011

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“…This method is derived from a UV/ ozone exposure technique originally developed for the removal of organic contaminants from semiconductors as an alternative to oxygen plasma ashing (Bolon and Kunz 1972;Sowell et al 1974;Vig and LeBus 1976;Vig 1985). Using a low-pressure mercury lamp to expose a substrate in an air-filled chamber at atmospheric pressure, light output at a wavelength of 184.9 nm is absorbed by oxygen in the air, resulting in the generation of ozone.…”

Section: Surface Treatment and Modificationmentioning

confidence: 99%

Bonding of thermoplastic polymer microfluidics

Tsao

DeVoe

2008

Microfluid Nanofluid

534

442

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Thermoplastics are highly attractive substrate materials for microfluidic systems, with important benefits in the development of low cost disposable devices for a host of bioanalytical applications. While significant research activity has been directed towards the formation of microfluidic components in a wide range of thermoplastics, sealing of these components is required for the formation of enclosed microchannels and other microfluidic elements, and thus bonding remains a critical step in any thermoplastic microfabrication process. Unlike silicon and glass, the diverse material properties of thermoplastics opens the door to an extensive array of substrate bonding options, together with a set of unique challenges which must be addressed to achieve optimal sealing results. In this paper we review the range of techniques developed for sealing thermoplastic microfluidics and discuss a number of practical issues surrounding these various bonding methods.

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“…Bolon and Kunz [13] reported that exposure to ultraviolet light (UV) in an oxygen atmosphere leads to the depolymerization of photoresist polymers. The UV treatment has been widely used as an effective method of decomposing hydrocarbons on substrates [14,15].…”

Section: Introductionmentioning

confidence: 99%

Reusable hydroxyapatite nanocrystal sensors for protein adsorption

Tagaya

Ikoma

Hanagata

et al. 2010

Science and Technology of Advanced Materials

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The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp) nanocrystal sensors was investigated by Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance with dissipation (QCM-D) monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i) ammonia/hydrogen peroxide mixture (APM), (ii) ultraviolet light (UV), (iii) UV/APM, (iv) APM/UV and (v) sodium dodecyl sulfate (SDS) treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

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Ultraviolet depolymerization of photoresist polymers

Cited by 62 publications

References 4 publications

Relating the Physical Properties of Pseudomonas aeruginosa Lipopolysaccharides to Virulence by Atomic Force Microscopy

Relating the Physical Properties of Pseudomonas aeruginosa Lipopolysaccharides to Virulence by Atomic Force Microscopy

Bonding of thermoplastic polymer microfluidics

Reusable hydroxyapatite nanocrystal sensors for protein adsorption

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