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An effective and universal method for delivering structurally diverse biomolecules in vivo would greatly benefit modern drug therapy, but has yet to be discovered. Self-assembled supramolecular complexes containing vesicles of amphiphilic cyclodextrin and linker molecules with an azobenzene guest unit and a charged functionality have been established as nanoscale carriers for proteins and DNA, making use of multivalent electrostatic attraction. However, light-induced cargo release is only feasible up to a maximum net charge of the biomacromolecules. Herein, it is shown that it is possible to fine-tune macromolecular complex stability and size by addition of a competitive guest molecule that acts as a stopper, partly blocking the vesicle surface. The superior performance of arylazopyrazoles in photoisomerization compared to azobenzenes, which enables a lower surface charge density of the vesicles in the photostationary state, is also demonstrated. Both strategies allow reversible supramolecular aggregation of high molecular weight DNA (2 and 4.8 kbp)., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Isothermal titration calorimetry was applied to determine the thermodynamic parameters for the specific binding of Ag(I) ions to a series of DNA duplexes comprising Im:Im or Tr:Tr mispairs to form metal-mediated Im-Ag(I)-Im or Tr-Ag(I)-Tr base pairs (Im=imidazole nucleoside; Tr=1.2,4-triazole nucleoside). A total of seven different duplexes are discussed, incorporating one to three artificial base pairs in neighboring or non-neighboring positions. The association constant related to the formation of Tr-Ag(I)-Tr base pairs is estimated to be <10(3)M(-1). In contrast, Im-Ag(I)-Im base pairs are much more stable. The intrinsic association constant for their formation is in the order of 10(6)M(-1) and is therefore larger than that for the formation of T-Hg(II)-T and C-Ag(I)-C base pairs consisting of natural nucleobases. Two neighboring Im-Ag(I)-Im base pairs form cooperatively, whereas two remotely located Im-Ag(I)-Im base pairs form non-cooperatively. In general, the specific binding of Ag(I) to Im:Im-containing duplexes is enthalpically driven, with a significant additional entropic contribution in most cases., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The development of an effective and general delivery method that can be applied to a large variety of structurally diverse biomolecules remains a bottleneck in modern drug therapy. Herein, we present a supramolecular system for the dynamic trapping and light-stimulated release of both DNA and proteins. Self-assembled ternary complexes act as nanoscale carriers, comprising vesicles of amphiphilic cyclodextrin, the target biomolecules and linker molecules with an azobenzene unit and a charged functionality. The non-covalent linker binds to the cyclodextrin by host-guest complexation with the azobenzene. Proteins or DNA are then bound to the functionalized vesicles through multivalent electrostatic attraction. The photoresponse of the host-guest complex allows a light-induced switch from the multivalent state that can bind the biomolecules to the low-affinity state of the free linker, thereby providing external control over the cargo release. The major advantage of this delivery approach is the wide variety of targets that can be addressed by multivalent electrostatic interaction, which we demonstrate on four types of DNA and six different proteins., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We describe a microarray format that can detect double-stranded DNA sequences with a high degree of sequence selectivity. Cyclooctyne-derivatized pyrrole-imidazole polyamides were immobilized on azide-modified glass substrates using microcontact printing and a strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. These polyamide-immobilized substrates selectively detected a seven-base-pair binding site incorporated within a double-stranded oligodeoxyribonucleotide sequence even in the presence of an excess of a sequence with a single-base-pair mismatch.

DNA double helices comprising two neighbouring artificial imidazole-Ag(I)-imidazole base pairs incorporate the Ag(I) ions in a cooperative fashion. Isothermal titration calorimetry data confirm the theoretically predicted binding stoichiometry and indicate that Ag(I) binds with association constants >10(6) M(-1) to the metal-free DNA duplex.

This paper describes a straightforward procedure to immobilize oligonucleotides on glass substrates in well-defined micropatterns by microcontact printing with a dendrimer-modified stamp. The oligonucleotides are efficiently immobilized by "click" chemistry induced by microcontact printing. Acetylene-modified oligonucleotides were treated with an azide-terminated glass slide under the confinement of the dendrimer-modified stamp, without the use of a Cu(I) catalyst. The immobilization is an irreversible, covalent, and one-step reaction that results in stable attachment of the oligonucleotides. Oligonucleotides with the acetylene-modification at the 5' terminus hybridize selectively with full-length, complementary targets. Strands with more than one acetylene linker do not hybridize with complementary strands.

This paper describes a new method to replicate DNA and RNA microarrays. The technique, which facilitates positioning of DNA and RNA with submicron edge resolution by microcontact printing (muCP), is based on the modification of poly(dimethylsiloxane) (PDMS) stamps with dendrimers ("dendri-stamps"). The modification of PDMS stamps with generation 5 poly(propylene imine) dendrimers (G5-PPI) gives a high density of positive charge on the stamp surface that can attract negatively charged oligonucleotides in a "layer-by-layer" arrangement. DNA as well as RNA is transfer printed from the stamp to a target surface. Imine chemistry is applied to immobilize amino-modified DNA and RNA molecules to an aldehyde-terminated substrate. The labile imine bond is reduced to a stable secondary amine bond, forming a robust connection between the polynucleotide strand and the solid support. Microcontact printed oligonucleotides are distributed homogeneously within the patterned area and available for hybridization. By using a robotic spotting system, an array of hundreds of oligonucleotide spots is deposited on the surface of a flat, dendrimer-modified stamp that is subsequently used for repeated replication of the entire microarray by microcontact printing. The printed microarrays are characterized by homogeneous probe density and regular spot morphology.