Shedding light on surfaces—using photons to transform and pattern material surfaces

Park, Ellane J.; Carroll, Gregory T.; Turro, Nicholas J.; Koberstein, Jeffrey T.

doi:10.1039/b807472k

Cited by 38 publications

(37 citation statements)

References 93 publications

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“…Figure 1(a) shows a reaction scheme where the benzophenone moiety in Bz is excited by UV illumination to form a bi-radical that can abstract a proton from any carbon-hydrogen containing molecules on a surface or in solution. 35,36 Additionally, the benzophenone moiety can abstract a proton from the acrylate double bond at either or both ends of the PEGDA molecule to initiate radical polymerization of PEGDA. 11 The activation of both the surface and PEGDA enables covalent coating of the formed PEGDA network to the polymer surface.…”

Section: Resultsmentioning

confidence: 99%

Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

2014

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Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists of PEG diacrylate (PEGDA) covalently grafted to polymer surfaces via UV light activation of the water soluble photoinitiator benzoyl benzylamine, a benzophenone derivative. The PEGDA coating was shown to efficiently limit the adsorption of antibodies and other proteins to <5% of the adsorbed amount on uncoated polymer surfaces. The coating could also efficiently suppress the adhesion of mammalian cells as demonstrated using the HT-29 cancer cell line. In a subsequent equivalent process step, protein in aqueous solution could be anchored onto the PEGDA coating in spatially defined patterns with a resolution of <15 μm using an inverted microscope as a projection lithography system. Surface patterns of the cell binding protein fibronectin were photochemically defined inside a closed microfluidic device that was initially homogeneously coated by PEGDA. The resulting fibronectin patterns were shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest.

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Section: Resultsmentioning

confidence: 99%

Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

2014

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“…For example, surface patterning should benefit from the ability to grow polymers of defined composition at defined places and times, enabling the creation of gradient surfaces. [107] Furthermore, periodic switching based on lattice commensurability could provide a means to introduce patterning on the nanoscale using a photochromic surface array. [108] In the case of biological studies as well, the ability to cycle between two states and thus improve the signal-to-noise ratio in highly sensitive optical measurements is attractive to investigate various processes.…”

Section: Light-gated Catalystsmentioning

confidence: 99%

Artificial Light‐Gated Catalyst Systems

2010

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Having control over an entity or even an entire process is arguably the ultimate demonstration of its understanding and it will enable its potential to be fully exploited. With this in mind, chemists have not only been creating and optimizing a myriad of different catalysts for most (relevant) chemical reactions over the past decades, but have recently started to implement controlling elements into the catalyst design. These incorporated gates operate upon exposure to suitable control stimuli, and light represents perhaps the scientifically and technologically most attractive stimulus. In principle, irradiation can thereby induce activity and selectivity in a given catalyst system with high spatial and temporal control, leading to an overall localization and amplification of an optical signal and translation into chemical action. While nature has developed and utilized this concept, in particular in the processes of vision and photomovement, such artificial photocontrolled catalyst systems offer unique opportunities and have high potential for future applications. In this Review, we outline the general concept of light-gated catalysis based on photocaged and also photoswitchable systems, and discuss relevant examples of the past and recent literature.

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“…reported the UV‐reactive azidophenyl lactamine grafted onto PET surface via a nitrene radical inserted into C−H, N−H and O−H bonds. In 2009, Park et al . reviewed phototransformation reactions of organic C−H bonds on polymer surfaces, providing a good guideline of photosensitive reagents and photoactive polymer grafting.…”

Section: Introductionmentioning

confidence: 99%

Surface Engineering of Organic Polymers by Photo‐induced Free Radical Coupling with p‐Dimethylaminophenyl Group as A Synthesis Block

et al. 2020

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This contribution presents a versatile strategy to transfer unactivated surface C–H bonds of polymeric substrates to C–R–F groups (R stands for a spacer and F stands for functional group) by UV light‐assisted surface free radical coupling. With p‐dimethylaminophenyl radical as a building block, various reactive groups, such as –CHO, –SH, –B(O)OH, –CN and –SO3−, are successfully grafted onto typical commercial polymer substrates including biaxially oriented polypropylene, polyethylene phthalate, ethylene tetrafluoroethylene copolymer and dimethyl silicone rubber. Fluorencence microscope images, X‐ray photoelectron spectroscopy, UV‐vis and fluorescence spectra support that the above functional groups are covalently bonded to the polymer substrates. The concentration of the reactive groups immobilized on the different substrates is in the order of 10−8 to 10−7 mmol mm−2 determined by UV‐vis spectrometry. In addition, as a proof‐of‐concept, the introduced functional groups are demonstrated by their special reactions, for example, –CHO reacting with –NH2 to synthesize Schiff base, –SH to detect silver ions, and the complexes of –C=N and Zn2+ to degrade Rhodamine B. The results indicate that one can fabricate an integrated molecular library on the surface of polymeric substrates at the molecular level by selecting the building blocks.

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Shedding light on surfaces—using photons to transform and pattern material surfaces

Cited by 38 publications

References 93 publications

Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

Artificial Light‐Gated Catalyst Systems

Surface Engineering of Organic Polymers by Photo‐induced Free Radical Coupling with p‐Dimethylaminophenyl Group as A Synthesis Block

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