Vesicle buster: Versatile functionalized nanocontainers, based on the stable incorporation of 22 mer DNA‐b‐PPO block copolymers (DBCs) into lipid vesicles, are presented (see picture). The study shows effective and sequence‐specific cargo release from the DBC–lipid vesicles. Hybridization of these vesicles with an oligonucleotide photosensitizer allows for singlet oxygen generation upon irradiation, which induces cargo release.

No abstract

We present a new class of polymeric dyes bearing the difluoroboraindacene (BODIPY) chromophore within the main chain. Starting from a diiodinated BODIPY monomer, homo-and copolymers with a fully conjugated backbone were efficiently synthesized by transition-metal-catalyzed polycondensation reactions. The photophysical properties of the resulting polymeric materials were investigated in bulk and at the single molecule level. It was found that the BODIPY homopolymer resembles the absorption and emission properties of the individual BODIPY chromophore. In contrast, the copolymer products of 1,4-diethynylbenzene and benzene exhibit absorption and emission spectra that are shifted hypsochromically and bathochromically in regard to the homopolymer, respectively, allowing for easy color tuning by the choice of comonomers. The fluorescence quantum yield of the BODIPY homopolymer is remarkably high (57%). The exceptional brightness of the materials was confirmed in the single molecule investigations; the BODIPY homopolymer emitted several times more photons than the well-established fluorescent probe Rhodamine 6G with a quantum yield close to unity.

Platforms for targeted drug-delivery must simultaneously exhibit serum stability, efficient directed cell internalization, and triggered drug release. Here, using lipid-mediated self-assembly of aptamers, we combine multiple structural motifs into a single nanoconstruct that targets hepatocyte growth factor receptor (cMet). The nanocarrier consists of lipidated versions of a cMet-binding aptamer and a separate lipidated GC-rich DNA hairpin motif loaded with intercalated doxorubicin. Multiple 2′,6′-dimethylazobenzene moieties are incorporated into the doxorubicin-binding motif to trigger the release of the chemotherapeutics by photoisomerization. The lipidated DNA scaffolds self-assemble into spherical hybrid-nanoconstructs that specifically bind cMet. The combined features of the nanocarriers increase serum nuclease resistance, favor their import into cells presumably mediated by endocytosis, and allow selective photo-release of the chemotherapeutic into the targeted cells. cMet-expressing H1838 tumor cells specifically internalize drug-loaded nanoconstructs, and subsequent UV exposure enhances cell mortality. This modular approach thus paves the way for novel classes of powerful aptamer-based therapeutics.

Photoregulation is among the most promising tools for development of dynamic DNA nanosystems, due to its high spatiotemporal precision, biocompatibility, and ease of use. So far, azobenzene and its derivatives have shown high potential in photocontrolling DNA duplex hybridization by light-dependent photoisomerization. Despite many recent advances, obtaining sufficiently high photoswitching efficiency under conditions more suitable for work with DNA nanostructures are challenging. Here we introduce a pair of arylazopyrazoles as new photoswitches for efficient and reversible control of DNA hybridization achieved even at room temperature with a low number of required modifications. Their photophysical properties in the native state and in DNA strands result in near-quantitative isomerization rates by irradiation with UV and orange light. To demonstrate the applicability of these photoswitches, we have successfully applied one of them to open and close a DNA hairpin by light at room temperature.