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The capability of some natural molecular building blocksto self-organizeinto defined supramolecular architectures is a versatile tool fornanotechnological applications. Their site-selective integration intoa technical context, however, still poses a major challenge. RNA-directedself-assembly of tobacco mosaic virus-derived coat protein on immobilizedRNA scaffolds presents a possibility to grow nucleoprotein nanotubesin place. Two new methods for their site-selective, bottom-up assemblyare introduced. For this purpose, isothiocyanate alkoxysilane wasused to activate oxidic surfaces for the covalent immobilization ofDNA oligomers, which served as linkers for assembly-directing RNA.Patterned silanization of surfaces was achieved (1) on oxidic surfacesvia dip-pen nanolithography and (2) on polymer surfaces (poly(dimethylsiloxane))via selective oxidization by UV-light irradiation in air. Atomic forcemicroscopy and X-ray photoelectron spectroscopy were used to characterizethe surfaces. It is shown for the first time that the combinationof the mentioned structuring methods and the isothiocyanate-basedchemistry is appropriate (1) for the site-selective immobilizationof nucleic acids and, thus, (2) for the formation of viral nanoparticlesby bottom-up self-assembly after adding the corresponding coat proteins. [ABSTRACT FROM AUTHOR]

Oriented circular dichroism (OCD) is explored and successfully applied to investigate chiral surface-anchored metal-organic frameworks (SURMOFs) based on camphoric acid (D- and Lcam) with the composition [Cu2(Dcam)(2x)(Lcam)(2-2x)(dabco)]n (dabco = 1,4-diazabicyclo-[2.2.2]-octane). The three-dimensional chiral SURMOFs with high-quality orientation were grown on quartz glass plates by using a layer-by-layer liquid-phase epitaxy method. The growth orientation, as determined by X-ray diffraction (XRD), could be switched between the [001] and [110] direction by using either OH- or COOH-terminated substrates. These SURMOFs were characterized by using OCD, which confirmed the ratio as well as the orientation of the enantiomeric linker molecules. Theoretical computations demonstrate that the OCD band intensities of the enantiopure [Cu2(Dcam)2(dabco)]n grown in different orientations are a direct result of the anisotropic nature of the chiral SURMOFs. Finally, the enantiopure [Cu2(Dcam)2(dabco)]n and [Cu2(Lcam)2(dabco)]n SURMOFs were loaded with the two chiral forms of ethyl lactate [(+)-ethyl-D-lactate and (-)-ethyl-L-lactate)]. An enantioselective enrichment of >60 % was observed by OCD when the chiral host scaffold was loaded from the racemic mixture., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Surface-anchored, crystalline and oriented metal organic frameworks (SURMOFs) have huge potential for biological applications due to their well-defined and highly-porous structure. In this work we describe a MOF-based, fully autonomous system, which combines sensing, a specific response, and the release of an antimicrobial agent. The Cu-containing SURMOF, Cu-SURMOF 2, is stable in artificial seawater and shows stimulus-responsive anti-fouling properties against marine bacteria. When Cobetia marina adheres on the SURMOF, the framework's response is lethal to the adhering microorganism. A thorough analysis reveals that this response is induced by agents secreted from the microbes after adhesion to the substrate, and includes a release of Cu ions resulting from a degradation of the SURMOF. The stimulus-responsive antifouling effect of Cu-SURMOF 2 demonstrates the first application of Cu-SURMOF 2 as autonomous system with great potential for further microbiological and cell culture applications.