No abstract

Metal–organic framework nanoparticles (MOF NPs) are of growing interest in diagnostic and therapeutic applications, and due to their hybrid nature, they display enhanced properties compared to more established nanomaterials. The effective application of MOF NPs, however, is often hampered by limited control of their surface chemistry and understanding of their interactions at the biointerface. Using a surface coating approach, we found that coordinative polymer binding to Zr-fum NPs is a convenient way for peripheral surface functionalization. Different polymers with biomedical relevance were assessed for the ability to bind to the MOF surface. Carboxylic acid and amine containing polymers turned out to be potent surface coatings and a modulator replacement reaction was identified as the underlying mechanism. The strong binding of polycarboxylates was then used to shield the MOF surface with a double amphiphilic polyglutamate–polysarcosine block copolymer, which resulted in an exceptional high colloidal stability of the nanoparticles. The effect of polymer coating on interactions at the biointerface was tested with regard to cellular association and protein binding, which has, to the best of our knowledge, never been discussed in literature for functionalized MOF NPs. We conclude that the applied approach enables a high degree of chemical surface confinement, which could be used as a universal strategy for MOF NP functionalization. In this way, the physicochemical properties of MOF NPs could be tuned, which allows for control over their behavior in biological systems.

Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre-mRNA splicing. Similar to other classes of nucleic acid-based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyltetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain-promoted azide-alkyne cycloaddition conjugation with splice-switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice-switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K-mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice-switching at very low nanomolar concentrations. The presented aminoethylene-lipopeptides are thus a promising platform for the generation of PMO-therapeutics with a favorable activity/toxicity profile.

The programmable endonuclease activity and simple usage of CRISPR/Cas9 have revolutionized the field of genome editing. The binding of single guide RNA (sgRNA) by the Cas9 protein results in the formation of negatively charged ribonucleoprotein (RNP) complexes. The presence of this functional complex inside cells is imperative for the intended specific genome modifications. The direct intracellular delivery of Cas9/sgRNA RNP complexes is of great advantage. In this work, a compound library of sequence-defined oligo­(ethylenamino) amides containing structural motifs for stable nanoparticle formation, cellular uptake, and endosomal release was used for the screening and development of suitable Cas9 RNP delivery vehicles. Lipid-containing oligoaminoamides (lipo-OAAs) were identified as the most efficient carriers for intracellular Cas9/sgRNA delivery and gene disruption. Fluorescence correlation spectroscopy measurements indicated that the lipo-OAAs only interact with sgRNA-loaded Cas9 protein, which suggests exclusive ionic interaction with the negatively charged RNPs. The type of contained fatty acid turned out to have a critical impact on the knock out efficiency: the presence of one hydroxy group in the fatty acid dramatically changes the properties and performance of the resulting Cas9/sgRNA lipo-OAA complexes. The lipo-OAA-containing hydroxy-stearic acid (OHSteA) was superior to the analogues with saturated or unsaturated fatty acids without hydroxylation; it formed smaller and more defined nanoparticles with Cas9/sgRNA and improved the cellular uptake and endosomal release, which altogether resulted in an increased nuclear association and the highest gene knock out levels. The efficient and adaptable delivery platform has high potential for the future development of therapeutics based on precise genome modifications.

The conjugation of small molecule drugs to ligand containing carrier systems facilitates receptor targeted delivery. The folate receptor (FR) constitutes an ideal target for tumor selective therapy, being overexpressed on several tumor types. It can be targeted using the vitamin folic acid (FolA) or the structurally related drug methotrexate (MTX). Several sequence‐defined oligoamides with mono‐ and multivalent FolA or MTX ligands and an additional thiol conjugation site are synthesized via solid‐phase assisted synthesis. Their structure activity relationships are assessed in respect to dihydrofolate reductase inhibition, receptor mediated endocytosis, and cytotoxicity. Then, the tubulin‐binding agent pretubulysin (PT), a highly potent drug exhibiting antitumoral, antiangiogenic, and antimetastatic properties, is conjugated via an activated mercaptane derivative to the set of FR‐targeting oligoamides. In a combined PT/MTX cytotoxicity study in FR‐overexpressing KB and L1210 cells, a 2‐arm MTX‐PT construct or the 4‐arm analog displays the highest potency in the respective cell lines.

RNA interference provides enormous potential for the treatment of several diseases, including cancer. Nevertheless, successful therapies based on siRNA require overcoming various challenges, such as poor pharmacokinetic characteristics of the small RNA molecule and inefficient cytosolic accumulation. In this respect, the development of functional siRNA carrier systems is a major task in biomedical research. To provide such a desired system, the synthesis of 3‐arm and 6‐arm PeptoStars is aimed for. The different branched polypept(o)idic architectures share a stealth‐like polysarcosine corona for efficient shielding and a multifunctional polylysine core, which can be independently varied in size and functionality for siRNA complexation‐, transport and intra cellular release. The special feature of star‐like polypept(o)ides is in their uniform small size (<20 nm) and a core–shell structure, which implies a high stability and stealth‐like properties and thus, they may combine long circulation times and a deep penetration of cancerous tissue. Initial toxicity and complement studies demonstrate well tolerated cationic PeptoStars with high complexation capability toward siRNA (N/P ratio up to 3:1), which can lead to potent RNAi for optimized systems. Here, the synthetic development of 3‐arm and 6‐arm polypept(o)idic star polymers, their modification with endosomolytic moieties, and first in vitro insights on RNA interference are reported on.

Viruses are infectious agents that hijack the host cell machinery in order to replicate and generate progeny. Viral infection is initiated by attachment to host cell receptors, and typical viral receptors are cell-surface-borne molecules such as proteins or glycan structures. Sialylated glycans (glycans bearing sialic acids) and glycosaminoglycans (GAGs) represent major classes of carbohydrate receptors and have been implicated in facilitating viral entry for many viruses. As interactions between viruses and sialic acids have been extensively reviewed in the past, this review provides an overview of the current state of structural knowledge about interactions between non-enveloped human viruses and GAGs. We focus here on adeno-associated viruses, human papilloma viruses (HPVs), and polyomaviruses, as at least some structural information about the interactions of these viruses with GAGs is available. We also discuss the multivalent potential for GAG binding, highlighting the importance of charged interactions and positively charged amino acids at the binding sites, and point out challenges that remain in the field.

Es wurde gefunden, dal3 bei den Farbreaktionen, die die tricyclischen Psychopharmaka mit konzentrierter Schwefels5ure geben, nur die Phenothiazin-und Acridanderivate unter Radikalbildung reagieren. Bei zahlreichen anderen Derivaten sind die auftretenden Farbungen auf die Bildung von Carboniumionen zuriickzufuhren. Dies wurde insbesondere durch NMR-Spektroskopie bei den Thioxanthenen, Dihydroanthracenen, Dibenzo-oxepinen und Dibenzo-cycloheptadienen bewie sen. Keine FLbungen gaben die untersuchten Dibenzoazepine. Colour Reactions of Tricyclic PsychopharmacaIt was found that in colour reactions which tricyclic psychopharmaca give with concentrated sulphuric acid, only the derivatives of phenothiazine and acridane react under formation of radicals. The colours of other derivatives are caused by carbonium ions. This was especially proved by NMR spectroscopy of the thioxanthenes, dihydroanthracenes, dibenzo-oxepines and dibenzo-cycloheptadienes. The examined dibenzoazepines gave no colour with sulphuric acid. Im Zuge der Synthese neuer Psychopharmaka ist das Ausgangsringsystem des Phenothiazins vielfach variiert worden, wobei insbesondere der Mittelring.verandert wurde. So entstanden Acridane, Dihydroanthracene, Thioxanthene, Dibenzo-oxepine, -cycloheptadiene, -cycloheptatriene, Diphenylmethane, Dibenzoazepine und a nliche Derivate. Demgegeniiber blieb die basische Seitenkette relativ unverandert ein Propylrest mit einem Methyl-oder Dimethylamin-Substituenten, oder es wurde eine Piperidyl-oder Piperazinyl-Gruppe eingefuhrt. N-,I I