Functionalization of Reactive Polymeric Coatings via Diels-Alder Reaction Using Microcontact Printing (original) (raw)
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ChemBioChem, 2013
Herein, a combination of microcontact printing of functionalized alkanethiols and site-specific modification of proteins is utilized to chemoselectively immobilize proteins onto gold surfaces either by oxime or copper catalyzed alkyne-azide click chemistry. Two molecules capable of click reactions, an aminooxy-functionalized alkanethiol and an azide-functionalized alkanethiol, were synthesized, and self-assembled monolayer (SAM) formation on gold was confirmed by IR spectroscopy. The alkanethiols were then individually patterned onto gold surfaces by microcontact printing. Site-specifically modified proteins, horse heart myoglobin (HHMb) containing an N-terminal α-oxoamide and a red-fluorescent protein (mCherry-CVIA) with a Cterminal alkyne, respectively were immobilized by incubation onto the stamped functionalized alkanethiol patterns. Pattern formation was confirmed by fluorescence microscopy.
European Polymer Journal, 2006
Three different, complementary soft lithographic approaches for the fabrication of chemical patterns on ultrathin polystyrene-block-poly(tert-butyl acrylate) (PS 690 -b-PtBA 1210 ) films are discussed. Central to the methodology is the previously introduced reactive PS 690 -b-PtBA 1210 platform that allows one to covalently graft (bio)molecules via robust amide linkages in high densities on flat, as well as on structured, surfaces. As shown in this paper, the combination of the polymer-based platform and reactive microcontact printing (lCP) patterning approaches allows one to obtain patterns of (bio)molecules with (sub)micrometer feature sizes. The lCP approaches comprise: (A) the direct transfer of functional (bio)molecules from an oxidized elastomeric stamp to hydrolyzed and N-hydroxysuccinimide (NHS) activated PS 690 -b-PtBA 1210 ; (B) the transfer of a passivating poly(ethylene glycol) layer to hydrolyzed and NHS-activated PS 690 -b-PtBA 1210 followed by wet chemical grafting of functional moieties; (C) the local hydrolysis of the PtBA skin layer with trifluoroacetic acid (TFA), followed by NHS activation and wet chemical derivatization. The applicability and the versatility of the combination of the polymer thin film-based platform and soft lithographic methodologies for patterning biologically relevant molecules is demonstrated for polyamidoamine (PAMAM) dendrimers, different proteins, as well as probe DNA. The successful hybridization of target DNA and the immobilization of fibronectin in micropatterns show that ultrahigh density patterns for micro-and nano-arrays, as well as for studies of cell-surface interactions, can be conveniently fabricated based on these approaches and platforms.
ACS Applied Materials & Interfaces, 2012
A novel surface modification method was investigated. The surface of siliceous materials was modified using polystyrene, poly(acrylic acid), poly(N-isopropylacrylamide), and poly(p-acrylamidophenyl-α-mannoside) synthesized by reversible addition−fragmentation chain transfer polymerization. Thiol-terminated polymers were obtained by reduction of the thiocarbonate group using sodium borohydride. The polymers were immobilized on the surface via the thiol−ene click reaction, known as the Michael addition reaction. Immobilization of the polymers on the maleimidated surface was confirmed by X-ray photoelectron spectroscopy, infrared spectroscopy, and contact angle measurements. The polymer-immobilized surfaces were observed by atomic force microscopy, and the thickness of the polymer layers was determined by ellipsometry. The thickness of the polymer immobilized by the maleimide−thiol reaction was less than that formed by spin coating, except for polystyrene. Moreover, the polymer-immobilized surfaces were relatively smooth with a roughness of less than 1 nm. The amounts of amine, maleimide, and polymer immobilized on the surface were determined by quartz crystal microbalance measurements. The area occupied by the amine-containing silane coupling reagent was significantly less than the theoretical value, suggesting that a multilayer of the silane coupling reagent was formed on the surface. The polymer with low molecular weight had the tendency to efficiently immobilize on the maleimidated surface. When poly(p-acrylamidophenyl-α-mannoside)-immobilized surfaces were used as a platform for protein microarrays, strong interactions were detected with the mannose-binding lectin concanavalin A. The specificity of poly(pacrylamidophenyl-α-mannoside)-immobilized surfaces for concanavalin A was compared with poly-L-lysine-coated surfaces. The poly-L-lysine-coated surfaces nonspecifically adsorbed both concanavalin A and bovine serum albumin, while the poly(pacrylamidophenyl-α-mannoside)-immobilized surface preferentially adsorbed concanavalin A. Moreover, the poly(pacrylamidophenyl-α-mannoside)-immobilized surface was applied to micropatterning with photolithography. When the micropattern was formed on the poly(p-acrylamidophenyl-α-mannoside)-spin-coated surface by irradiation with ultraviolet light, the pattern of the masking design was not observed on the surface adsorbed with fluorophore-labeled concanavalin A using a fluorescent microscope because of elution of poly(p-acrylamidophenyl-α-mannoside) from the surface. In contrast, fluorophorelabeled concanavalin A was only adsorbed on the shaded region of the poly(p-acrylamidophenyl-α-mannoside)-immobilized surface, resulting in a distinctive fluorescent pattern. The surface modification method using maleimidation and reversible addition−fragmentation chain transfer polymerization can be used for preparing platforms for microarrays and micropatterning of proteins.
Micropatterning of biomolecules on polymer substrates
Langmuir, 1998
UV-excimer laser photoablation was used, in combination with surface blocking techniques, to pattern proteins on the surfaces of polyimide and poly(ethylene terephthalate). This technique involves physical adsorption of avidin through laser-defined openings in low-temperature laminates or adsorbed protein blocking layers. Visualization of biomolecular patterns were monitored using avidin and fluoresceinlabeled biotin as a model receptor-ligand couple. Adsorbed proteins could be shown to bind to UV-lasertreated polymer surfaces up to three times higher than on commercially available polymers. UV-laser photoablation was also used for the generation of three-dimensional structure, which leads to the possibility of biomolecule patterning within polymer-based microanalytical systems. The simplicity and easy handling of the described technique facilitate its application in microdiagnostic devices. Langmuir 1998, 14, 5526-5531 S0743-7463(98)00359-X CCC: $15.00
Site-Selective Surface-Initiated Polymerization by Langmuir–Blodgett Lithography
Angewandte Chemie International Edition, 2007
The growth of polymers from surfaces has been conducted to tune surface properties such as wettability, bioadhesion, and surface activity. Polymer brushes can be prepared by covalent attachment of a polymerization initiator onto the surface with subsequent surface-initiated polymerization (SIP) by the "grafting-from" approach. Atom-transfer radical polymerization (ATRP), nitroxide-mediated radical polymerization (NMP), and reversible addition fragmentation transfer polymerization (RAFT) have been used in SIP. Site-specific surface polymerization affords spatially controlled polymer brushes. Nanometer-sized structures are of increasing importance in various fields of nanoscale science. Microcontact printing, photolithography, electron-beam lithography, and other techniques have been used for spatially controlled covalent surface binding of the initiator. These techniques belong to the top-down strategies.
Microstamping on an activated polymer surface (MAPS) is a methodology that enables biomolecules to be patterned on polymers with micrometer spatial resolution. MAPS combines homogeneous surface derivatization of a polymer to introduce a reactive functional group followed by reactive microcontact printing (µCP) of a biological ligand of interest, linked to an appropriate reactive group. We demonstrate here that polyethylene, polystyrene, poly(methyl methacrylate), and poly(ethylene terephthalate) films can be successfully modified to introduce COOH groups on their surfaces, which can be subsequently patterned by reactive µCP of amine-terminated biotin after derivatization of the COOH groups with pentafluorophenol. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) confirmed the chemistry of MAPS at each stage of the derivatization of the polymer surfaces and reactive µCP of biotin. Micropatterned biotin surfaces fabricated by MAPS were patterned with streptavidin by exploiting molecular recognition between biotin and streptavidin. The formation of streptavidin patterns was examined by fluorescence microscopy of Alexa488-labeled streptavidin and by TOF-SIMS imaging of 15 N-labeled recombinant streptavidin, bound to biotin patterns. The contrast in the streptavidin micropatterns was optimized by examining the effect of blocking agents and streptavidin incubation time. Maximum contrast was obtained for binding of 0.1µM streptavidin from a buffer containing 0.02% (v/v) Tween 20 detergent for an incubation time of 1 min.
Molecular Imaging of a Micropatterned Biological Ligand on an Activated Polymer Surface
We report here molecular characterization of a new method derived from reactive microcontact printings microstamping on an activated polymer surface (MAPS)swhich enables biological ligands and proteins to be patterned on a polymer surface with a spatial resolution of at least 5 µm and good reproducibility. MAPS is a multistep procedure: first, the surface of a polymer is modified, in one or more steps, to introduce a reactive group of interest. In a subsequent step, an elastomeric stamp, inked with a biological ligand containing a complementary terminal reactive group, is brought into contact with the activated surface of the polymer. This results in spatially resolved transfer and coupling of the biological ligand to the reactive surface of the polymer. We used MAPS to pattern biotin on carboxylic acid derivatized poly-(ethylene terephthalate) (PET), and subsequently with streptavidin, mediated by the high affinity streptavidin-biotin interaction. X-ray photoelectron spectroscopy of biotin-derivatized PET showed that approximately one in five PET repeat units in the top 50-100 Å were functionalized with biotin. Timeof-flight secondary ion mass spectrometry (TOF-SIMS) suggested an increased concentration of PET oligomers in the top 10 Å due to chain scission during modification and clearly identified the derivatization of PET with biotin. TOF-SIMS imaging mapped biotin and streptavidin to the stamped regions. TOF-SIMS also imaged the spatial distribution of residual reagents from the multistep derivatization in MAPS, such aspentafluorophenol,Tween20surfactant,aswellaspoly(dimethylsiloxane)(PDMS),whichwastransferred from the elastomeric PDMS stamp to the surface during MAPS.