Double “click”: Two different molecules can be sequentially immobilized on defined areas of the same surface by utilizing the different reactivity of activated and non‐activated alkynyl groups (see ...picture). The reactions were carried out at room temperature in water, with the first immobilization step being catalyst‐free and the second step requiring CuI as a catalyst.
Controlled presentation of biomolecules on synthetic substrates is an important aspect for biomaterials development. If the immobilization of multiple biomolecules is required, highly efficient ...orthogonal surface chemistries are needed to ensure the precision of the immobilization. In this communication, chemical vapor deposition (CVD) copolymerization is used to fabricate polymer coatings with controlled ratio of alkyne and pentafluorophenyl ester (Pfp‐ester) groups. Cyclic argine‐glycine‐aspartic acid (cRGD) adhesion peptide and epidermal growth factor (EGF) are immobilized through alkyne–azide cycloaddtion (“click” chemistry) and active ester–amine reaction, respectively. Cell studies with human umbilical vein endothelial cells (HUVEC) and A431 cell lines demonstrate the biological activity of the coimmobilized biomolecules.
Polymer coatings with bio‐orthogonal functional groups are developed for co‐immobilization of adhesion peptide and growth factor. The coatings are generated by chemical vapor deposition polymerization, with both alkyne and pentafluorophenyl ester which are used to covalently tether the biomolecules. The biological activity of the co‐immobilized biomolecules is demonstrated.
A multifunctional copolymer with both aldehyde and alkyne groups is synthesized by chemical vapor deposition (CVD) for orthogonal co‐immobilization of biomolecules. Surface analytical methods ...including FTIR and XPS are used to confirm the surface modification. Heparin‐binding growth factors basic fibroblast growth factor (bFGF) in this study can be immobilized through interaction with heparin, which was covalently attached to the CVD surface through an aldehyde‐hydrazide reaction. In parallel, an alkyne–azide reaction is used to orthogonally co‐immobilize an adhesion peptide as the second biomolecule.
A generic strategy for immobilizing heparin‐binding growth factors on multifunctional chemical vapor deposition copolymer has been developed. Heparin is covalently attached to the aldehyde‐functionalized surface through a carbohydrazide linker. The growth factor then binds directly to the heparin. The alkyne group can then be used to orthogonally immobilize other biomolecule, such as azido‐functionalized adhesion peptides.
Polyethersulfone (PES)–organophilic montmorillonite (OMMT) hybrid particles, with various proportions of OMMT, were prepared by using a liquid–liquid phase separation technique, and then were used ...for the removal of bisphenol A (BPA) from aqueous solution. The adsorbed BPA amounts increased significantly when the OMMT were embedded into the particles. The structure of the particle was characterized by using scanning electron microscopy (SEM); and these particles hardly release small molecules below 250
°C which was testified by using thermogravimetric analysis (TGA). The experimental data of BPA adsorption were adequately fitted with Langmuir equations. Three simplified kinetics model including the pseudo-first-order (Lagergren equation), the pseudo-second-order, and the intraparticle diffusion model were used to describe the adsorption process. Kinetic studies showed that the adsorbed BPA amount reached an equilibrium value after 300
min, and the experimental data could be expressed by the intraparticular mass transfer diffusion model. Furthermore, the adsorbed BPA could be effectively removed by ethanol, which indicated that the hybrid particles could be reused. These results showed that the PES–OMMT hybrid particles have the potential to be used in the environmental application.
Immobilization of biomolecules, such as proteins or sugars, is a key issue in biotechnology because it enables the understanding of cellular behavior in more biological relevant environment. Here, ...poly(4-ethynyl-p-xylylene-co-p-xylylene) coatings have been fabricated by chemical vapor deposition (CVD) polymerization in order to bind bioactive molecules onto the surface of the material. The control of the thickness of the CVD films has been achieved by tuning the amount of precursor used for deposition. Copper-catalyzed Huisgen cycloaddition has then been performed via microcontact printing to immobilize various biomolecules on the reactive coatings. The selectivity of this click chemistry reaction has been confirmed by spatially controlled conjugation of fluorescent sugar recognizing molecules (lectins) as well as cell adhesion onto the peptide pattern. In addition, a microstructured coating that may undergo multiple click chemistry reactions has been developed by two sequential CVD steps. Poly(4-ethynyl-p-xylylene-co-p-xylylene) and poly(4-formyl-p-xylylene-co-p-xylylene) have been patterned via vapor-assisted micropatterning in replica structures (VAMPIR). A combination of Huisgen cycloaddition and carbonyl-hydrazide coupling was used to spatially direct the immobilization of sugars on a patterned substrate. This work opens new perspectives in tailoring microstructured, multireactive interfaces that can be decorated via bio-orthogonal chemistry for use as mimicking the biological environment of cells.
Along with traditional attributes such as the size, shape, and chemical structure of polymeric micro‐objects, control over material distribution, or selective compartmentalization, appears to be ...increasingly important for maximizing the functionality and efficacy of biomaterials. The fabrication of tri‐ and tetracompartmental colloids made from biodegradable poly(lactide‐co‐glycolide) polymers via electrohydrodynamic co‐jetting is demonstrated. The presence of three compartments is confirmed via flow cytometry. Additional chemical functionality is introduced via the incorporation of acetylene‐functionalized polymers into individual compartments of the particles. Direct visualization of the spatioselective distribution of acetylene groups is demonstrated by confocal Raman microscopy as well as by reaction of the acetylene groups with azide‐biotin via ‘click chemistry’. Biotin–streptavidin binding is then utilized for the controlled assembly and orientation of bicompartmental particles onto functionalized, micropatterned substrates prepared via chemical vapor deposition polymerization.
The fabrication of anisotropic microparticles containing up to four distinct compartments from biodegradable polymers is demonstrated via electrohydrodynamic co‐jetting. The particles are selectively surface‐modified with biotin and assembled on streptavidin, presenting substrates with specific orientation. The particles and their assemblies have application in diagnostic assays and energy storage devices.
A polyethersulfone (PES) membrane was modified by blending with a co-polymer of acrylic acid (AA) and N-vinyl pyrrolidone (VP), followed by immobilization of bovine serum albumin (BSA) onto the ...surface. The scanning electron microscopy results showed that PES had good miscibility
with the co-polymer. X-ray photoelectron spectroscopy confirmed the existence of P(VP-AA) co-polymer on the surface of the blended membrane and the existence of BSA after the immobilization process. The amount of BSA immobilized on the surface of the membranes was determined. It was found
that the protein adsorption amounts from BSA, human plasma fibrinogen and diluted human plasma solutions decreased significantly after modification. According to the circular dichroism results, the proteins kept more α-helix conformation in the modified membranes than in the pure
PES membrane. The number of the adhered platelets was reduced, and the morphology change for the adherent platelets was also suppressed by the modification with BSA. The SEM morphological observation of the cells and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay
demonstrated that the BSA-modified PES membrane surface promoted endothelial cell adhesion and proliferation.
Abstract In vivo regenerative gene therapy is a promising approach for bone regeneration and can help to address cell-source limitations through surgical implantation of osteoinductive materials and ...subsequent recruitment of host-derived cells. Localized viral delivery may reduce the risk of virus dispersion, enhance transduction efficiency, and reduce administration/injection dosing, which subsequently increases patient safety. In this manuscript, we present a custom-tailored strategy to immobilize adenovirus expressing runt-related transcription factor 2 (AdRunx2) by using reactive polymer coatings to enhance in vitro osteoblast differentiation of bone marrow stromal cells (BMSCs). A thin polymer film of poly p -xylylene carboxylic acid pentafluorophenol ester- co - p -xylylene equipped with amine-reactive active ester groups was deposited on the surface of poly (ε-caprolactone) (PCL) using the chemical vapor deposition (CVD) polymerization technique and then anti-adenovirus antibody was conjugated on the material with an amide chemical bond. Following antibody conjugation, AdRunx2 was conjugated to the PCL surface through antibody-antigen interaction. Osteoblast differentiation of BMSCs was induced by incubation in osteogenic medium. Alkaline phosphatase (ALP) activity, calcium deposition, and matrix mineralization were confirmed as markers of osteoblast formation. Incubation of the BMSCs in the presence of AdRunx2 modified PCL resulted in a 6.5-fold increase in ALP activity and significant increases in matrix mineralization when compared to controls. These results demonstrate that adenovirus vectors driving the expression of transcription factors can be delivered directly from biomaterials to direct cell differentiation.
Biomolecular interactions between proteins and synthetic surfaces impact diverse biomedical fields. Simple, quantitative, label-free technologies for the analysis of protein adsorption and binding of ...biomolecules are thus needed. Here, we report the use of a novel type of substrate, poly-p-xylylene coatings prepared by chemical vapor deposition (CVD) polymerization, for surface plasmon resonance enhanced ellipsometry (SPREE) studies and assess the reactive coatings as spatially resolved biomolecular sensing arrays. Prior to use in binding studies, reactive coatings were fully characterized by Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and ellipsometry. As a result, the chemical structure, thickness, and homogeneous coverage of the substrate surface were confirmed for a series of CVD-coated samples. Subsequent SPREE imaging and fluorescence microscopy indicated that the synthetic substrates supported detectable binding of a cascade of biomolecules. Moreover, analysis revealed a useful thickness range for CVD films in the assessment of protein and/or antigen−antibody binding via SPREE imaging. With a variety of functionalized end groups available for biomolecule immobilization and ease of patterning, CVD thin films are useful substrates for spatially resolved, quantitative binding arrays.
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