F2 excimer laser (157nm) radiation modification and surface ablation of PHEMA hydrogels and the effects on bioactivity: Surface attachment and proliferation of human corneal epithelial cells

Zainuddin, Zainuddin -; Chirilă, Traian V.; Barnard, Zeke; Watson, Gregory S.; Toh, Chiong; Blakey, Idriss; Whittaker, Andrew K.; Hill, David J. T.

doi:10.1016/j.radphyschem.2010.07.036

Cited by 15 publications

(18 citation statements)

References 65 publications

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“…Because PHEMA is a non-toxic material, is used in many biomedical applications including soft contact lenses, implants, controlled drug release, lab on a chip sensor, taste sensors, etc. [ 51 , 52 , 60 ].…”

Section: Resultsmentioning

confidence: 99%

“…The photon modification of PHEMA hydrogel surfaces, chemistry and topography, including an effective adhering ability of different biocells to attach to the modified areas were previously investigated. Only the outer exposed surface layers of the hydrogel were affected by exposure to 157 nm laser photons, because of water photolysis, including a direct surface water depletion that turns the surface to a hydrophobic one [ 52 ].…”

Section: Resultsmentioning

confidence: 99%

“…The mean Z i values were set up at 3.80 and 0.82 nm for the irradiated and non-irradiated layers, respectively, showing diverging surface topologies after 157 nm laser irradiation, making possible quantification of surface porosity and allowing an estimation of surface modification [ 17 , 52 , 53 , 61 ]. Two parameters are used to describe the porosity of a surface.…”

Section: Resultsmentioning

confidence: 99%

“…The methodology, besides chemical sensing, relative strain analysis of materials with sub-nm resolution and thermodynamic energy density flow in the pJm −3 range, has the potency to monitor electric dipole and entropic competition in small volumes. Likewise, decrypting the adsorption and diffusive behavior of various molecular analytes on porous materials [ 45 , 46 , 47 ] either from trapping within tiny cavities, or via shape, surface or volume deformation, might well boost novel potential applications in molecular sensing [ 37 , 38 , 48 ], gas separation [ 29 , 30 , 49 ], storage and applications with particular emphasis on nanomedicine [ 50 ], bioengineering [ 51 , 52 ], and drug delivery systems [ 53 ].…”

Section: Introductionmentioning

confidence: 99%

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Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities

Gavriil

Chatzichristidi

Kollia

et al. 2018

Entropy

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Abstract:In thin polymeric layers, external molecular analytes may well be confined within tiny surface nano/microcavities, or they may be attached to ligand adhesion binding sites via electrical dipole forces. Even though molecular trapping is followed by a variation of the entropic potential, the experimental evidence of entropic energy variation from molecular confinement is scarce because tiny thermodynamic energy density diverseness can be tracked only by sub-nm surface strain. Here, it is shown that water confinement within photon-induced nanocavities in Poly (2-hydroxyethyl methacrylate), (PHEMA) layers could be trailed by an entropic potential variation that competes with a thermodynamic potential from electric dipole attachment of molecular adsorbates in polymeric ligands. The nano/microcavities and the ligands were fabricated on a PHEMA matrix by vacuum ultraviolet laser photons at 157 nm. The entropic energy variation during confinement of water analytes on the photon processed PHEMA layer was monitored via sub-nm surface strain by applying white light reflectance spectroscopy, nanoindentation, contact angle measurements, Atomic Force Microscopy (AFM) imaging, and surface and fractal analysis. The methodology has the potency to identify entropic energy density variations less than 1 pJm −3 and to monitor dipole and entropic fields on biosurfaces.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities

Gavriil

Chatzichristidi

Kollia

et al. 2018

Entropy

View full text Add to dashboard Cite

show abstract

“…Such a knowledge is important for the present systems considering that the immobilization of biomolecules, within the hydrogel network, is expected to occur through complexation with transition metal ions (suitably dissolved in the swelling water), which can concurrently coordinate to the imidazole groups of the VI's constituents. A great deal of information on the chemical and conformational changes, which ensue the development of laser-induced microfoams on hydrophilic polymers, can be attained through a number of spectroscopic techniques including laser-induced fluorescence (LIF) [6,9,18], time-correlated single photon counting (TCSPC) fluorescence spectroscopy [18], Raman spectroscopy [11], Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR) [11,19], and X-ray photoelectron spectroscopy (XPS) [19]. Such spectroscopic studies will be the subject of a forthcoming investigation.…”

Section: Discussionmentioning

confidence: 99%

Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

Primo

Igarzabal

Pino

et al. 2016

Applied Surface Science

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This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

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Click functionalization of methacrylate-based hydrogels and their cellular response

Santander-Borrego

Green

Chirilă

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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Methacrylate‐based hydrogels, such as homo‐ and copolymers of 2‐hydroxyethyl methacrylate (HEMA), have demonstrated significant potential for use in biomedical applications. However, many of these hydrogels tend to resist cell attachment and growth at their surfaces, which can be detrimental for certain applications. In this article, glycidyl methacrylate (GMA) was copolymerized with HEMA to generate gels functionalized with epoxide groups. The epoxides were then functionalized by two sequential click reactions, namely, nucleophilic ring opening of epoxides with sodium azide and then coupling of small molecules and peptides via Huisgen's copper catalyzed 1,3‐dipolar cycloaddition of azides with alkynes. Using this strategy it was possible to control the degree of functionalization by controlling the feed ratio of monomers during polymerization. In vitro cell culture of human retinal pigment epithelial cell line (ARPE‐19) with the hydrogels showed improved cell adhesion, growth and proliferation for hydrogels that were functionalized with a peptide containing the RGD sequence. In addition, the cell attachment progressively decreased with increasing densities of the RGD containing peptide. In summary, a facile methodology has been presented that gives rise to hydrogels with controlled degrees of functionality, such that the cell response is directly related to the levels and nature of that functionality. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1781–1789

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F2 excimer laser (157nm) radiation modification and surface ablation of PHEMA hydrogels and the effects on bioactivity: Surface attachment and proliferation of human corneal epithelial cells

Cited by 15 publications

References 65 publications

Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities

Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities

Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

Click functionalization of methacrylate-based hydrogels and their cellular response

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