Search

A DNA-sensing platform is developed by exploiting the easy surface functionalization of metal-organic framework (MOF) particles and their highly parallelized fluorescence detection by flow cytometry. Two strategies were employed to functionalize the surface of MIL-88A, using either covalent or non-covalent interactions, resulting in alkyne-modified and biotin-modified MIL-88A, respectively. Covalent surface coupling of an azide-dye and the alkyne-MIL-88A was achieved by means of a click reaction. Non-covalent streptavidin-biotin interactions were employed to link biotin-PNA to biotin-MIL-88A particles mediated by streptavidin. Characterization by confocal imaging and flow cytometry demonstrated that DNA can be bound selectively to the MOF surface. Flow cytometry provided quantitative data of the interaction with DNA. Making use of the large numbers of particles that can be simultaneously processed by flow cytometry, this MOF platform was able to discriminate between fully complementary, single-base mismatched, and randomized DNA targets. [ABSTRACT FROM AUTHOR]

The direct delivery of specific proteins to live cells promises a tremendous impact for biological and medical applications, from therapeutics to genetic engineering. However, the process mostly involves tedious techniques and often requires extensive alteration of the protein itself. Herein we report a straightforward approach to encapsulate native proteins by using breakable organosilica matrices that disintegrate upon exposure to a chemical stimulus. The biomolecule-containing capsules were tested for the intracellular delivery of highly cytotoxic proteins into C6 glioma cells. We demonstrate that the shell is broken, the release of the active proteins occurs, and therefore our hybrid architecture is a promising strategy to deliver fragile biomacromolecules into living organisms. [ABSTRACT FROM AUTHOR]

Parallel PNA:PNA duplexes were synthesized and conjugated with meso-tris(pyridyl)phenylporphyrin carboxylic acid at the N-terminus. The introduction of one porphyrin unit was shown to affect slightly the stability of the PNA:PNA parallel duplex, whereas the presence of two porphyrin units at the same end resulted in a dramatic increase of the melting temperature, accompanied by hysteresis between melting and cooling curves. The circular dichroism (CD) profile of the Soret band and fluorescence quenching strongly support the occurrence of a face-to-face interaction between the two porphyrin units. Introduction of a L-lysine residue at the C-terminal of one strand of the parallel duplex induced a left-handed helical structure in the PNA:PNA duplex if the latter contains only one or no porphyrin moiety. The left-handed helicity was revealed by nucleobase CD profile at 240-280 nm and by the induced-CD observed in the presence of the DiSC2(5) cyanine dye at ~500-550 nm. Surprisingly, the presence of two porphyrin units led to the disappearance of the nucleobase CD signal and the absence of CD exciton coupling within the Soret band region. In addition, a dramatic decrease of induced CD of DiSC2(5) was observed. These results are in agreement with a model where the porphyrin-porphyrin interactions cause partial loss of chirality of the PNA:PNA parallel duplex, forcing it to adopt a ladder-like conformation. Chirality 27:864-874, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The design and synthesis of multifunctional nanomaterials could lead to applications relevant for biomedicine. Manufacturing porous particles to make them able to carry bioactive molecules into living cells represents a substantial goal towards the development of powerful tools for nanomedicine. This work describes a first example of using zeolite-L crystals as multifunctional nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. Multifunctional zeolite-L was prepared by filling the pore system with guest molecules, whilst DNA was adsorbed electrostatically on their surface. The release kinetics of DNA and of the guest molecules into living cells was studied to prove the multiple-drug-delivery ability of the system. The localization of all the components in different cellular compartments was followed. The presented system may be a prototype for the development of novel nanoparticles for drug delivery and gene therapy. [ABSTRACT FROM AUTHOR]

A 10-mer duplex formed between a PNA containing a 'chiral box' of three adjacent D-Lys-based monomers and its complementary DNA strand has been crystallized for the first time. Crystals have been obtained using PEG 8000 as precipitant and cacodylate at pH 6.3 as buffer. The crystals belong to the space group P31 or to its enantiomorph P32, with unit-cell parameters a = b = 35.00, c = 35.91 Å. A complete data set has been collected at the synchrotron source Elettra in Trieste to 1.85 Å resolution, using a single frozen crystal. [ABSTRACT FROM AUTHOR]

A breakable shell for the encapsulation of proteins allows their delivery into cells and subsequent release. In their Communication on page 3323 ff., L. De Cola, E. A. Prasetyanto et al. describe the construction of a breakable shell comprising silica units that are held together by disulfide bridges. Once the encapsulated proteins are internalized in cells, reduction of the disulfide groups results in disintegration of the shells and release of the proteins, which retain their activity throughout the process. [ABSTRACT FROM AUTHOR]

In einer zerbrechlichen Schale eingeschlossene Proteine können in Zellen transportiert und anschließend freigesetzt werden. L. De Cola, E. A. Prasetyanto et al. beschreiben in ihrer Zuschrift auf S. 3384 ff. eine solche Schale, die aus disulfidverbrückten Siliciumdioxideinheiten aufgebaut ist. Nach Überführung der eingeschlossenen Proteine in die Zelle werden die Disulfidgruppen durch Reduktion gespalten, die Schalen reißen auf und die aktiven Proteine werden freigesetzt. [ABSTRACT FROM AUTHOR]

Manufacturing porous particles to enable them to carry bioactive molecules into living cells is a target for the development of personalized nanomedicine. In their Communication on page 10900 ff., L. De Cola et al. describe using zeolite ‐ L crystals as multifunctional nanocontainers to simultaneously deliver DNA oligonucleotides and organic molecules into living cells. Multifunctional zeolite ‐ L was prepared by filling the pore system with guest molecules, whilst DNA was adsorbed electrostatically on their surface. [ABSTRACT FROM AUTHOR]