Showing papers on "Surface modification published in 2006"
TL;DR: In this paper, the functionalization of C-H bonds in complex organic substrates catalyzed by transition metal catalysts is studied and the key concepts and approaches aimed at achieving selectivity in complex settings are discussed.
Abstract: Direct and selective replacement of carbon-hydrogen bonds with new bonds (such as C-C, C-O, and C-N) represents an important and long-standing goal in chemistry. These transformations have broad potential in synthesis because C-H bonds are ubiquitous in organic substances. At the same time, achieving selectivity among many different C-H bonds remains a challenge. Here, we focus on the functionalization of C-H bonds in complex organic substrates catalyzed by transition metal catalysts. We outline the key concepts and approaches aimed at achieving selectivity in complex settings and discuss the impact these reactions have on synthetic planning and strategy in organic synthesis.
1,812 citations
Book•
01 Jan 2006
TL;DR: In this article, the use of wood is discussed in the twenty-first century and a number of techniques for modifying the properties of wood are presented. But none of them are suitable for outdoor use.
Abstract: Foreword. Series Preface. Preface. List of Abbreviations. 1. The Use of Timber in the Twenty-first Century 1.1 Introduction. 1.2 Nonrenewables: a Finite and Exhaustible Resource. 1.3 Renewable Materials. 1.4 The Global Timber Resource. 1.5 Timber Production. 1.6 Wood Preservation. 1.7 Preservative-treated Wood and Legislation. 1.8 Competition from Nonrenewable Materials. 1.9 The Need for Wood Modification. 1.10 Conclusions. 2. Modifying the Properties of Wood. 2.1 Introduction. 2.2 Wood Properties and Wood Modification. 2.3 Wood Modification Methods. 2.4 The Cell Wall of Wood. 2.5 The Chemical Constituents of Wood. 2.6 The Wood-Water Relationship. 2.7 The Mechanical Properties of Modified Wood. 2.8 Modified Wood and Biological Degradation. 2.9 Wood and Weathering. 2.10 Proof of Bonding. 2.11 Conclusions. 3. Chemical Modification of Wood (I): Acetic Anhydride Modification. 3.1 Introduction. 3.2 Reaction Protocols. 3.3 Cell Wall Reactivity. 3.4 Analysis of Anhydride-modified Wood. 3.5 Dimensional Stability. 3.6 Mechanical Properties. 3.7 Microbiological Degradation. 3.8 Biological Degradation by Insects and Marine Organisms. 3.9 Moisture Relationships of Anhydride-modified Wood. 3.10 Composites Utilizing Acetic Anhydride Modified Wood. 3.11 Conclusions. 4. Chemical Modification of Wood (II): Reaction with Other Chemicals. 4.1 Introduction. 4.2 Reaction of Wood with Other Noncyclic Anhydrides. 4.3 Reaction of Wood with Cyclic Anhydrides. 4.4 Acetylation Using Ketene Gas. 4.5 Carboxylic Acid Modification. 4.6 Acid Chloride Modification. 4.7 Isocyanate Modification. 4.8 Epoxide Modification. 4.9 Alkyl Halide Modification. 4.10 Aldehyde Modification. 4.11 Cyanoethylation. 4.12 Beta-Propiolactone. 4.13 Quinone Methides. 4.14 Conclusions. 5. Thermal Modification of Wood. 5.1 Introduction. 5.2 Process Variables. 5.3 Chemical Changes in Wood due to Thermal Modification. 5.4 Physical Changes in Wood due to Thermal Modification. 5.5 Biological Properties of Thermally Modified Wood. 5.6 Compressed Wood. 5.7 Oil Heat-treatments. 5.8 Conclusions. 6. Surface Modification. 6.1 Introduction. 6.2 Surface Chemical Modification for UV Stability. 6.3 Modification to Render the Wood Surface Hydrophobic. 6.4 Surface Chemical Modification for Bonding. 6.5 Enzymatic Modification. 6.6 Corona or Plasma Discharge. 6.7 Conclusions. 7. Impregnation Modification. 7.1 Introduction. 7.2 Resin Treatments. 7.3 Impregnations using Silicon-containing Compounds. 7.4 Other Inorganic Cell Wall Precipitation Treatments. 7.5 Cell Wall Impregnation with Monomers. 7.6 Cell Wall Impregnation with Polymers. 7.7 Conclusions. 8. Commercialization of Wood Modification. 8.1 Introduction. 8.2 Thermal Modification. 8.3 Oil Heat Modification/Treatments. 8.4 Acetylation. 8.5 Impregnation Modification. 8.6 Conclusions. 9. Wood Modification: Environmental Considerations and Future Developments. 9.1 Introduction. 9.2 Principles of the Determination of Environmental Impact. 9.3 Methods of Determining Environmental Impacts. 9.4 The Environmental Impact of Wood Modification. 9.5 Industrial Ecology and Wood Modification. 9.6 The Future of Wood Modification. References. Index.
1,192 citations
TL;DR: This review surveys methods for the fabrication of polymeric surfaces and thin plasma polymer coatings that contain reactive chemical groups useful for the subsequent covalent immobilization, by solution chemical reactions or vapor phase grafting, of molecules or polymers that can exert bio-specific interfacial responses.
Abstract: This review surveys methods for the fabrication, by plasma surface treatments or plasma polymerization, of polymeric surfaces and thin plasma polymer coatings that contain reactive chemical groups useful for the subsequent covalent immobilization, by solution chemical reactions or vapor phase grafting, of molecules or polymers that can exert bio-specific interfacial responses. Surfaces containing amine, carboxy, hydroxy, and aldehyde groups are the subject of this review. Aminated surfaces have been fabricated using various plasma vapors or mixtures and have found wide use for bio-interface applications. However, in many cases the amine surfaces have a rather limited shelf life, with post-plasma oxidation reactions and surface adaptation leading to the disappearance of amine groups from the surface. Aging is a widespread phenomenon that often has not been recognized, particularly in some of the earlier studies on the use of plasma-fabricated surfaces for bio-interfacial applications, and can markedly alter the surface chemistry. Plasma-fabricated surfaces that contain carboxy groups have also been well documented. Fewer reports exist on hydroxy and aldehyde surfaces prepared by plasma methods. Hydroxy surfaces can be prepared by water plasma treatment or the plasma polymerization of alkyl alcohol vapors. Water plasma treatment on many polymer substrates suffers from aging, with surface adaptation leading to the movement of surface modification effects into the polymer. Both hydroxy and aldehyde surfaces have been used for the covalent immobilization of biologically active molecules. Aging effects are less well documented than for amine surfaces. This review also surveys studies using such surfaces for cell colonization assays. Generally, these surface chemistries show good ability to support cell colonization, though the effectiveness seems to depend on the process vapor and the plasma conditions. Carboxylate co-polymer surfaces have shown excellent ability to support the colonization of some human cell lines of clinical interest. Immobilization of proteins onto plasma-carboxylated surfaces is also well established.
920 citations
TL;DR: Using these surface-modification schemes, fluorescent dye-doped silica nanoparticles can be more readily conjugated with biomolecules and used as highly fluorescent, sensitive, and reproducible labels in bioanalytical applications.
Abstract: In this article, a systematic study of the design and development of surface-modification schemes for silica nanoparticles is presented. The nanoparticle surface design involves an optimum balance of the use of inert and active surface functional groups to achieve minimal nanoparticle aggregation and reduce nanoparticle nonspecific binding. Silica nanoparticles were prepared in a water-in-oil microemulsion and subsequently surface modified via cohydrolysis with tetraethyl orthosilicate (TEOS) and various organosilane reagents. Nanoparticles with different functional groups, including carboxylate, amine, amine/phosphonate, poly(ethylene glycol), octadecyl, and carboxylate/octadecyl groups, were produced. Aggregation studies using SEM, dynamic light scattering, and zeta potential analysis indicate that severe aggregation among amine-modified silica nanoparticles can be reduced by adding inert functional groups, such as methyl phosphonate, to the surface. To determine the effect of various surface-modificati...
792 citations
TL;DR: In this in vitro study, a novel surface modification was tested to improve the initial wettability and to retain SLA microstructure and shows increased surface free energy (SFE) and increased hydrophilicity with initial water contact angles of 0 degrees compared to 139.9 degrees for SLA.
Abstract: Roughness-induced hydrophobicity, well-known from natural plant surfaces and intensively studied toward superhydrophobic surfaces, has currently been identified on microstructured titanium implant surfaces. Studies indicate that microstructuring by sandblasting and acid etching (SLA) enhances the osteogenic properties of titanium. The undesired initial hydrophobicity, however, presumably decelerates primary interactions with the aqueous biosystem. To improve the initial wettability and to retain SLA microstructure, a novel surface modification was tested. This modification differs from SLA by its preparation after acid etching, which was done under protective gas conditions following liquid instead of dry storage. We hypothesized that this modification should have increased wettability due to the prevention of contaminations that occurs during air contact. The main outcome of dynamic wettability measurements was that the novel modification shows increased surface free energy (SFE) and increased hydrophilicity with initial water contact angles of 0° compared to 139.9° for SLA. This hydrophilization was kept even after any drying. Reduced hydrocarbon contaminations were identified to play a possible role in altered surface thermodynamics. Such surfaces aim to retain the hydrophilicity and natural high surface energy of the Ti dioxide surface until surgical implants' insertion and are compared in this in vitro study with structural surface variants of titanium to compare roughness and chemically induced wettability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
593 citations
TL;DR: In this article, the surface of cathode materials including LiCoO2, LiNiO2 and LiMn2O4 was coated with oxides such as MgO, Al2O3, SiO 2, TiO 2, ZnO, SnO 2 O 2, Li2O·2B2O 3-glass and other materials.
558 citations
TL;DR: In this paper, a new method was developed to chemically functionalize multi-walled carbon nanotubes (MWCNTs) based on silanization reaction for use as the reinforcement for polymer matrix composites.
531 citations
TL;DR: It is demonstrated that SiNWs can be utilized to quantitate the solution-phase concentration of biomolecules at low concentrations, and the importance of surface chemistry for optimizing biomolecular sensing with silicon nanowires is demonstrated.
Abstract: The quantitative, real-time detection of single-stranded oligonucleotides with silicon nanowires (SiNWs) in physiologically relevant electrolyte solution is demonstrated. Debye screening of the hybridization event is circumvented by utilizing electrostatically adsorbed primary DNA on an amine-terminated NW surface. Two surface functionalization chemistries are compared: an amine-terminated siloxane monolayer on the native SiO2 surface of the SiNW, and an amine-terminated alkyl monolayer grown directly on a hydrogen-terminated SiNW surface. The SiNWs without the native oxide exhibit improved solution-gated field-effect transistor characteristics and a significantly enhanced sensitivity to single-stranded DNA detection, with an accompanying 2 orders of magnitude improvement in the dynamic range of sensing. A model for the detection of analyte by SiNW sensors is developed and utilized to extract DNA-binding kinetic parameters. Those values are directly compared with values obtained by the standard method of surface plasmon resonance (SPR) and demonstrated to be similar. The nanowires, however, are characterized by higher detection sensitivity. The implication is that SiNWs can be utilized to quantitate the solution-phase concentration of biomolecules at low concentrations. This work also demonstrates the importance of surface chemistry for optimizing biomolecular sensing with silicon nanowires.
508 citations
TL;DR: In this article, carbon nanotubes (CNTs) were treated by an acidic solution to remove impurities and modified subsequently by amine treatment or plasma oxidation to improve interfacial bonding and dispersion of CNTs in the epoxy matrix.
490 citations
TL;DR: In this paper, the synthesis of ZnO nanoparticles by calcination of the precursor at 450 degrees C for 3 h and the calcination after the heterogeneous azeotropic distillation of the precursors, respectively, were characterized by FT-IR, XRD and TEM.
451 citations
TL;DR: In a preliminary study on the gas sensitivity of SnO2 hollow spheres, considerably reduced "recovery times" were noted, exemplifying the distinct properties imparted by the hollow structure.
Abstract: A general method for the synthesis of metal oxide hollow spheres has been developed by using carbonaceous polysaccharide microspheres prepared from saccharide solution as templates. Hollow spheres of a series of metal oxides (SnO2, Al2O3, Ga2O3, CoO, NiO, Mn3O4, Cr2O3, La2O3, Y2O3, Lu2O3, CeO2, TiO2, and ZrO2) have been prepared in this way. The method involves the initial absorption of metal ions from solution into the functional surface layer of carbonaceous saccharide microspheres; these are then densified and cross-linked in a subsequent calcination and oxidation procedure to form metal oxide hollow spheres. Metal salts are used as starting materials, which widens the accessible field of metal oxide hollow spheres. The carbonaceous colloids used as templates have integral and uniform surface functional layers, which makes surface modification unnecessary and ensures homogeneity of the shell. Macroporous films or cheese-like nanostructures of oxides can also be prepared by slightly modified procedures. XRD, TEM, HRTEM, and SAED have been used to characterize the structures. In a preliminary study on the gas sensitivity of SnO2 hollow spheres, considerably reduced “recovery times” were noted, exemplifying the distinct properties imparted by the hollow structure. These hollow or porous nanostructures have the potential for diverse applications, such as in gas sensitivity or catalysis, or as advanced ceramic materials.
TL;DR: These dual-functional coatings showed very high initial bacteria-killing efficiency due to the release of Ag ions and retained significant antibacterial activity after the depletion of embedded Ag because of the immobilized quaternary ammonium salts.
Abstract: Using a combination of an aqueous layer-by-layer deposition technique, nanoparticle surface modification chemistry, and nanoreactor chemistry, we constructed thin film coatings with two distinct layered functional regions: a reservoir for the loading and release of bactericidal chemicals and a nanoparticle surface cap with immobilized bactericides. This results in dual-functional bactericidal coatings bearing both chemical-releasing bacteria-killing capacity and contact bacteria-killing capacity. These dual-functional coatings showed very high initial bacteria-killing efficiency due to the release of Ag ions and retained significant antibacterial activity after the depletion of embedded Ag because of the immobilized quaternary ammonium salts.
TL;DR: In this paper, the state of the art of nanoparticles/polymer composites, including specific surface pretreatment techniques and their applications, are reviewed, and the role of treated nanoparticles and the mechanisms involved in the improvement of mechanical properties and wear resistance of the composites are highlighted.
Abstract: Direct incorporation of inorganic nanoscale building blocks into polymers represents a typical way for preparing polymeric nanocomposites. The most important aspect in preparation of nanocomposites through dispersive blending is surface modification of the nanofillers. It is able to increase hydrophobicity of the fillers, enhance interfacial adhesion via chain entanglement or chemical bonding and eliminate the loosen structure of filler agglomerates. The present paper reviews the state of the art of nanoparticles/polymer composites, including the specific surface pretreatment techniques and their applications. Especially, the role of treated nanoparticles and the mechanisms involved in the improvement of mechanical properties and wear resistance of the composites are highlighted.
TL;DR: In this article, a simple but effective fiber treatment (i.e., alkalization) was proposed to enable a better adhesion between flax fibres and epoxy matrix.
Abstract: Present-day industry takes an interest in environment friendly materials, due to economic and ecological reasons. The use of natural materials in composite parts fits well into this picture: plant fibres that reinforce polymer matrices can replace glass fibres in many cases, although applications are often limited to non-structural parts. The poor interface in a non-treated natural fibre reinforced composite prevents the parts to be used to their full capacity. Consequently, this study concentrates on a simple but effective fibre treatment (i.e. alkalisation) that will enable a better adhesion between flax fibres and epoxy matrix. Parameters such as time and concentration are being optimised, in order to develop a continuous process for the treatment and resin impregnation of unidirectional flax fibre epoxy composites. This paper shows a clear improvement of the mechanical properties of the resulting material: e.g. a mild treatment in a 4% NaOH solution for 45 s will increase the transverse composite strength up to 30%.
TL;DR: In this paper, the surface structures of the graphitic carbon anodes are improved, and these improvements include smoothing the active edge surfaces by removing some reactive sites and/or defects on the graphite surface, forming a dense oxide layer on the surface, and covering active edge structures on the Graphite surface.
TL;DR: In this article, the dispersive effects achieved by a wide range of surface active agents, as well as surface oxidation and functionalization, are investigated for uniform, multi-walled carbon nanotube (MWNT) distribution in water-soluble (poly(ethylene glycol)) and water-insoluble polymers.
Abstract: Microscale aggregate formation, resulting from high intrinsic filler attractions, is one of the major issues in nanocomposite preparation and processing. Herein, the dispersive effects achieved by a wide range of surface-active agents, as well as surface oxidation and functionalization, are investigated. The aim of our research is to form a uniform, multiwalled carbon nanotube (MWNT) distribution in water-soluble (poly(ethylene glycol)) and water-insoluble (polypropylene) polymers. In order to understand the surface-charge-related stability of the treated nanotubes solutions, zeta-potential measurements are applied. Quantification of the state of the MWNT dispersion is derived from particle-size analysis, while visual characterization is based on optical and electron microscopy. To estimate the nucleating ability of the surface-modified carbon nanotubes, the temperature of crystallization and the degree of crystallinity are calculated from differential scanning thermograms. Finally, we suggest general guidelines to produce uniform MWNT dispersions using a dispersive agent and/or surface treatment in water-soluble and water-insoluble polymers.
TL;DR: In this paper, a method for controlled and homogeneous silica coating of low-aspect-ratio CTAB-stabilized gold nanorods has been developed through the combination of the LBL technique and the Stober method.
Abstract: A method for controlled and homogeneous silica coating of low-aspect-ratio CTAB-stabilized gold nanorods has been developed through the combination of the LBL technique and the Stober method. Hydrophobation of the gold nanoparticles was achieved via surface functionalization with a hydrophobic silane coupling agent.
TL;DR: In this paper, the hydrophilic stability of Sylgard 184 poly(dimethyl siloxane) (PDMS) was studied with the objective to create more stable hydrophobic surfaces.
TL;DR: In this article, a bi-functional coupling agent, (3-methacryloxypropyl)trimethoxysilane (MPS), was successfully functionalized with a facile neutral solvent method.
Abstract: Alumina nanoparticles were successfully functionalized with a bi-functional coupling agent, (3-methacryloxypropyl)trimethoxysilane (MPS), through a facile neutral solvent method. MPS was found to be covalently bound with the nanoparticles. The linked MPS was polymerized with a vinyl-ester resin monomer through a free radical polymerization. Atomic force microscope phase images showed a uniform distribution of nanoparticles. Microtensile test results revealed the Young's modulus and strength increasing with particle loading. Microscopic examinations revealed the presence of large plastic deformations at the micron scale in the nanocomposites in agreement with the observed strengthening effect of functionalized nanoparticles. Thermo-gravimetric analysis (TGA) did not show any significant change in the thermal degradation of the nanocomposite as compared with the neat resin. The polymer matrix effectively protected the alumina nanoparticles from dissolution in basic and acidic solutions.
TL;DR: In this paper, an alternative and novel approach for fabricating microlens arrays that is based on the confinement of surface wrinkles was introduced. But the ability to control the size and arrangement of the microlenses through clever control of the geometric shape and material properties of the wrinkled regions was demonstrated.
Abstract: The ability to generate microlens arrays in a rapid and costeffective manner allows for the fabrication of a variety of inexpensive functional devices, such as optical refractive elements or smart surfaces that mimic the patterned surfaces in biological systems used to control solid and liquid adhesion. A variety of strategies have been adopted for fabricating microlens structures. In general, they can be broadly classified into three categories: 1) surface-tension-driven techniques consisting of melt-reflow and ink-jet printing; 2) imprinting methods; and 3) lithographic approaches such as grayscale photolithography or interference lithography. While these approaches demonstrate the ability to produce microlens arrays with uniform surface profiles, the techniques are either high-cost or require long fabrication times. In this paper, we introduce an alternative and novel approach for fabricating microlens arrays that is based on the confinement of surface wrinkles. We demonstrate the ability to control the size and the arrangement of the microlenses through clever control of the geometric shape and material properties of the wrinkled regions. Our approach offers several advantages over previous methodologies of microlens fabrication, including: 1) the ability to create microlens arrays rapidly; 2) ease of tuning the dimensions of the microlenses; and 3) versatility in the process that allows the formation of microlens arrays on nonplanar substrates. We demonstrate the flexibility of our approach in patterning nonplanar surfaces by patterning a hemispherical surface with an array of microlenses, thereby forming a compound lens (Fig. 1). To fabricate the microlens arrays, we modified our previously developed methodology for generating wrinkle-pattern surfaces (Fig. 2a). We began by selective ultraviolet/ ozone (UVO) oxidation of a crosslinked polydimethylsiloxane (PDMS) film to convert specific regions of the PDMS surface into a silicate thin film. The chemical modification created the necessary elastic-moduli differences on the PDMS surface to allow us to control and define the wrinkle formation. Following the silicate formation, the surface was coated with photopolymerizable n-butyl acrylate (nBA) and then covered with a glass superstrate. The acrylate monomer swelled the PDMS surface globally, but the surface wrinkles occurred only in regions where the moduli mismatch existed—that is, in the oxidized PDMS regions. This selective UVO allowed for the control of the spatial distribution of the wrinkle patterns (Fig. 2b and c). The wrinkle patterns disappeared upon evaporation of the acrylate swelling agent; however, we stabilized these wrinkle structures through photopolymerization of the nBA. Finally, we lifted away the glass superstrate, which caused cohesive fracture of the polymerized poly(n-butyl acrylate) (PnBA) film. Due to the extreme interfacial moduli mismatch between the PnBA and silicate layers, the fracture path proceeded along the contours of the wrinkle surface. Hence, the microlens arrays were revealed upon removal of the glass superstrate (Fig. 2b). C O M M U N IC A TI O N
TL;DR: The surface properties of PSf-g-PEG modified membranes render them desirable candidates for hemodialysis, and when used as an additive in PSf membranes prepared by immersion precipitation, the graft copolymer preferentially segregates to the membrane surface, delivering enhanced wettability, porosity and protein resistance.
TL;DR: The organic functionalisation method for small detonation diamond agglomerates is reported, which is potentially useful for the synthesis of surface-bound peptides and for the attachment of biologically active building blocks, which could be used in drug delivery and fluorescence marker applications.
Abstract: Detonation diamond is a promising material for biological applications due to its biocompatibility and fluorescence from lattice defects. Here we report on the organic functionalisation method for small detonation diamond agglomerates. After surface homogenisation by reduction and grafting of a silane linker, amino acids have been coupled to the diamond surface and the formation of a small peptide has been achieved. These novel functionalised diamond materials are potentially useful for the synthesis of surface-bound peptides and for the attachment of biologically active building blocks, which could be used in drug delivery and fluorescence marker applications.
TL;DR: In this article, a dual-stimuli-responsive surfacewith tunable wettability, reversible switching between super-hydrophilicity and superhydrophobicity, and responsivity toboth temperature is presented.
Abstract: To the best of our knowledge, a dual-re-sponsive surface that switches between hydrophilic andhydrophobic has never been reported, to say nothing of adual-responsive surface that switches between superhydro-philic and superhydrophobic.In this communication, a dual-stimuli-responsive surfacewith tunable wettability, reversible switching between super-hydrophilicity and superhydrophobicity, and responsivity toboth temperature (
TL;DR: In this paper, the preparation of a series of dispersible nano-SiO 2 by surface modification in situ was described, and the results showed that they can evidently increase anti-wear ability and reduce the friction coefficient of lubricant.
TL;DR: In this article, screen printed thick films of pure and RuO 2 -doped zinc oxide were prepared and surface modified with ruthenium chloride, and the results were discussed and interpreted.
Abstract: Screen printed thick films of pure and RuO 2 -doped zinc oxide were prepared. Pure zinc oxide films were also surface modified with ruthenium chloride. Gas sensing properties of the pure, doped and surface modified films were studied. The films were observed to be most sensitive to NH 3 gas. The results are discussed and interpreted.
TL;DR: It is shown that the two cell lines had different adhesion characteristics on the various surfaces at different time points, and incompatibilities between certain resazurin, lysosomal incorporation assays (neutral red) and porous silicon are revealed.
TL;DR: Alternating exposures of nitrogen dioxide gas and trimethylaluminum vapor are shown to functionalize the surfaces of single-walled carbon nanotubes with a self-limited monolayer, which allows for the creation of coaxial nanotube structures of multiple materials with precisely controlled diameters.
Abstract: Alternating exposures of nitrogen dioxide gas and trimethylaluminum vapor are shown to functionalize the surfaces of single-walled carbon nanotubes with a self-limited monolayer. Functionalized nanotube surfaces are susceptible to atomic layer deposition of continuous, radially isotropic material. This allows for the creation of coaxial nanotube structures of multiple materials with precisely controlled diameters. Functionalization involves only weak physical bonding, avoiding covalent modification, which should preserve the unique optical, electrical, and mechanical properties of the nanotubes.
TL;DR: Results indicate that IKVAV is a suitable peptide sequence for use in surface modification techniques aimed at improving the attachment of ASCs to a tissue-engineered scaffold.
TL;DR: An improved approach composed of an oxidation reaction in acidic H2O2 solution and a sequential silanization reaction using neat silane reagents for surface modification of poly(dimethylsiloxane) (PDMS) substrates was developed, indicating that the PEG-grafted PDMS surfaces exhibit improved short-term surface dynamics and robust long-term stability.
Abstract: An improved approach composed of an oxidation reaction in acidic H2O2 solution and a sequential silanization reaction using neat silane reagents for surface modification of poly(dimethylsiloxane) (PDMS) substrates was developed. This solution-phase approach is simple and convenient for some routine analytical applications in chemistry and biology laboratories and is designed for intact PDMS-based microfluidic devices, with no device postassembly required. Using this improved approach, two different functional groups, poly(ethylene glycol) (PEG) and amine (NH2), were introduced onto PDMS surfaces for passivation of nonspecific protein absorption and attachment of biomolecules, respectively. X-ray electron spectroscopy and temporal contact angle experiments were employed to monitor functional group transformation and dynamic characteristics of the PEG-grafted PDMS substrates; fluorescent protein solutions were introduced into the PEG-grafted PDMS microchannels to test their protein repelling characteristics. These analytical data indicate that the PEG-grafted PDMS surfaces exhibit improved short-term surface dynamics and robust long-term stability. The amino-grafted PDMS microchannels are also relatively stable and can be further activated for modifications with peptide, DNA, and protein on the surfaces of microfluidic channels. The resulting biomolecule-grafted PDMS microchannels can be utilized for cell immobilization and incubation, semiquantitative DNA hybridization, and immunoassay.