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Describes the combination of microcontact printing and surface-initiated ring-opening metathesis polymerization to generate patterned polymers on surfaces. Application of the patterns as reactive ion etching resists; Identification of reliable, flexible process that can be used to generate patterned polymer films on technologically important surfaces.

Back and forth: Enzymatic, reversible polymerization on gold surfaces was efficiently carried out from surface ‐ tethered self ‐ priming oligodeoxynucleotides in a sequence ‐ specific fashion by using two kinds of enzymes. Taq DNA polymerase, acting as a catalyst, facilitated DNA polymerization, and DNA restriction enzymes cut DNA polymers from the surface. [ABSTRACT FROM AUTHOR]

The possibility of lateral extension of conjugation withina covalentlygrafted molecular layer by a scanning probe-based method was tested.A molecular layer derived from ω-(N-pyrrolyl)propanolwas formed on n-type Si(111) surface. Application of large samplebiases greater than ±4 V during conductive atomic force microscope(AFM) scans under vacuum resulted in changes of mechanical and electricalcharacteristics of the molecular layer: the tip–sample conductancewas increased greatly, the friction was reduced significantly, andthe surface potential of the scanned area was increased. The reductionin friction could be attributed to molecular linking formed withinthe layer. The increased conductance suggested extended conjugationamong the pyrrolyl end groups. Therefore, it was inferred that thebiased AFM scan successfully induced local polymerization/oligomerizationwithin the covalently grafted molecular layer. [ABSTRACT FROM AUTHOR]

A cytocompatible method of surface-initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI-ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine-based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material-independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical-scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell-division studies. This work will provide a strategic approach to the generation of living cell-polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy. [ABSTRACT FROM AUTHOR]

A cytocompatible method of surface-initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI-ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine-based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material-independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical-scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell-division studies. This work will provide a strategic approach to the generation of living cell-polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy. [ABSTRACT FROM AUTHOR]

Reversible polymerization has a great potential for the generation of reusable nanomaterials and complete repair of cracks or breaks in self ‐ healing materials. In their Communication on page 908   ff., Young Hwan Jung et   al. report on a surface ‐ initiated, reversible polymerization of DNA that is processed by enzymatic reactions. Elongation of DNA, catalyzed by Taq DNA polymerase, is performed from a self ‐ priming oligodeoxynucleotide anchored onto gold, and reversible de ‐ polymerization and re ‐ polymerization are achieved in a sequence ‐ specific manner by using a restriction enzyme and Taq DNA polymerase. The cover picture was designed by Juno Lee. [ABSTRACT FROM AUTHOR]

Abstract: A well-dispersed multiwall carbon nanotube (MWCNT)/syndiotactic polystyrene (sPS) composite was prepared by simple in-situ polymerization of styrene using pentamethylcyclopentadienyltitanium(IV) trimethoxide (Cp*Ti(OMe)3) attached to the shortened and functionalized MWCNT (f-MWCNT). The attachment of Cp*Ti(OMe)3 to the f-MWCNT was confirmed by thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy, and energy dispersive X-ray spectroscopy. Cp*Ti(OMe)3 attached to pristine MWCNT in the presence of methylaluminoxane (MAO) did not produce PS, whereas Cp*Ti(OMe)3 attached to f-MWCNT showed a high catalytic activity for the syndiospecific polymerization of styrene under the same polymerization conditions. Obtained sPS showed a narrow molecular weight distribution (PDI ≈ 2), a high SI value (≥90%), and a high melting point (≈272 °C). Scanning electron microscopy and transmission electron microscopy images showed that MWCNT strands were well dispersed in the MWCNT/sPS composite. Such composites had greatly improved thermal stability compared to normal sPS polymers. [Copyright &y& Elsevier]

Abstract: In this work, we compared the long-term stability and integrity of cell patterns on newly reported, zwitterionic poly((3-(methacryloylamino)propyl)dimethyl(3-sulfopropyl)ammonium hydroxide) (poly(MPDSAH)) films with those on widely used, poly(poly(ethylene glycol) methyl ether methacrylate) (poly(PEGMEMA)) ones. The micropatterns of both polymers were formed on a silicon oxide surface by a combination of micropattern generation of a photoresist, vapor deposition of a silane-based polymerization initiator, and surface-initiated, atom transfer radical polymerization (SI-ATRP) of each monomer, MPDSAH or PEGMEMA. The successful formation of the silane initiator SAMs, and poly(MPDSAH) and poly(PEGMEMA) micropatterns was confirmed by X-ray photoelectron spectroscopy (XPS) and imaging ellipsometry. Onto each substrate patterned with poly(MPDSAH) or poly(PEGMEMA), NIH 3T3 fibroblast cells were seeded, and the cell micropatterns were generated by the selective adhesion of cells on the cell-adhesive region of the patterned surfaces. The cell pattern formed on the poly(MPDSAH)-patterned surface was observed to have a superior ability of finely maintaining its original, line-shaped structure up to for 20 days, when compared with the cell pattern formed on the poly(PEGMEMA)-patterned surface. In order to verify the relationship between the integrity of the cell micropatterns and the stability of the underlying non-biofouling polymer layers, we also investigated the long-term stability of the polymer films themselves, immersed in the cell culture media, for one month, in the aid of ellipsometry, contact goniometry, and XPS. [Copyright &y& Elsevier]

Abstract: This paper describes the formation of poly(N-isopropylacrylamide) (PNIPAAm) and poly[(N-isopropylacrylamide)-r-((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)] (P(NIPAAm-r-MPDSAH)) films on a glass surface via surface-initiated, atom transfer radical polymerization as a cell-culture platform. The films of PNIPAAm with various thicknesses and of P(NIPAAm-r-MPDSAH) with various ratios of NIPAAm and MPDSAH are formed to investigate the behaviors of cell adhesion and detachment. In the case of the PNIPAAm-grafted glass surfaces, the optimal film thickness, achieving the effective control of both cell adhesion and detachment, is estimated to be 11–13nm for NIH 3T3 fibroblast cells. The adhesion and detachment behaviors of NIH 3T3 fibroblast cells are further tuned by incorporating the hydrophilic and non-biofouling MPDSAH moiety into the PNIPAAm system. The cell adhesion and detachment are controlled best, when the ratio of NIPAAm and MPDSAH is 75:1 (NIPAAm:MPDSAH). [Copyright &y& Elsevier]

A label-free, activity-based assay of matrix metalloproteinase (MMP) and its inhibition was demonstrated on peptide-conjugated gold nanoparticles (AuNPs) with nonbiofouling poly(ollgo(ethylene glycol) methacrylate) (pOEGMA) films using time-of-flight secondary ion mass spectrometry (FOF-SIMS). Following surface-initiated atom-transfer radical polymerization of OEGMA on a Si/SiO2 substrate, the MMP activity was determined by analyzing the cleaved peptide fragments using TOF-SIMS on the peptide-conjugated AuNPs. The use of nonbiofouling pOEGMA films in conjunction with AuNPs synergistically enhanced the sensitivity of assays for MMP activity and its inhibition in human serum. The detection sensitivity of MMP-7 in serum was as low as 20 ng mL-1 (1 pmol mL-1), and the half-maximal inhibitory concentration (1C50) of minocycline, which is a MMP-7 inhibitor, was estimated to be 450 nM. It is anticipated that the developed system will be broadly useful for conducting activity-based assays of serum proteases, as well as for screening of their inhibitors, with high sensitivity in a high-throughput manner. [ABSTRACT FROM AUTHOR]

Binding behaviors of streptavidin were investigated with different lateral packing densities of biotin-functionalized, non-biofouling pOEGMA brushes, synthesized by surface-initiated polymerization from mixed SAMs with different mole fractions of the polymerization initiator on gold surfaces. [ABSTRACT FROM AUTHOR]