5 research outputs found
Supramolecular Assembly of AminoethyleneâLipopeptide PMO Conjugates into RNA SpliceâSwitching Nanomicelles
Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of preâmRNA splicing. Similar to other classes of nucleic acidâbased therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinylâtetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strainâpromoted azideâalkyne cycloaddition conjugation with spliceâswitching 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 spliceâswitching 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 H2Kâmdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant spliceâswitching at very low nanomolar concentrations. The presented aminoethyleneâlipopeptides are thus a promising platform for the generation of PMOâtherapeutics with a favorable activity/toxicity profile
Dodecaborate-Functionalized Anchor Dyes for Cyclodextrin-Based Indicator Displacement Applications
A new
type of water-soluble anchor dyes, that is, dyes which carry
an auxiliary unit for strong binding to macrocyclic host molecules,
has been synthesized. It consists of 7-nitrobenzofurazan (NBD) as
a dye and the dodecaborate cluster (B<sub>12</sub>H<sub>11</sub>R)
as a dianionic, globular, and purely inorganic anchoring group for
cyclodextrins (<i>K</i><sub>a</sub> > 10<sup>5</sup> M<sup>â1</sup>). The synthesized dodecaborate-substituted dyes show
marked changes in their photophysical properties (UVâvis and
fluorescence) upon complexation with cyclodextrins (ÎČ-CD and
γ-CD), such that the resulting host·dye complexes (1:1
stoichiometry) present sensitive reporter pairs for indicator displacement
applications
Coordinative Binding of Polymers to MetalâOrganic Framework Nanoparticles for Control of Interactions at the Biointerface
Metalâorganic 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 polyglutamateâpolysarcosine 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