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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).

This paper reports microcontact printing (μCP) to immobilize an alkoxyamine initiator (regulator) on glass and silicon substrates and subsequent surface-initiated alternating nitroxide-mediated copolymerization (siNMP) of hexafluoroisopropyl acrylate (HFIPA) and 7-octenylvinyl ether (OVE). The resulting patterned polymer brushes are analyzed by using atomic force microscopy (AFM). In addition, site-specific post-functionalization of the alternating polymer brushes by applying two orthogonal surface reactions is achieved with thiols and amines through μCP. The versatility of this post-polymerization modification approach is demonstrated by site-selective immobilization of small organic molecules, fluorophores, and ligands providing a binary bioactive surface. The successful side-by-side orthogonal immobilization is verified by using X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy.