A poly(amidoamine)-based polymeric nanoparticle platform for efficient in vivo delivery of mRNA.

The successful use of mRNA vaccines enabled and accelerated the development of several new vaccine candidates and therapeutics based on the delivery of mRNA. In this study, we developed bioreducible poly(amidoamine)-based polymeric nanoparticles (PAA PNPs) for the delivery of mRNA with improved transfection efficiency. The polymers were functionalized with chloroquinoline (Q) moieties for improved endosomal escape and further stabilization of the mRNA-polymer construct.

Cell uptake and intracellular trafficking of bioreducible poly(amidoamine) nanoparticles for efficient mRNA translation in chondrocytes.

Disulfide-containing poly(amidoamine) (PAA) is a cationic and bioreducible polymer, with potential use as a nanocarrier for mRNA delivery in the treatment of several diseases including osteoarthritis (OA). Successful transfection of joint cells with PAA-based nanoparticles (NPs) was shown previously, but cell uptake, endosomal escape and nanoparticle biodegradation were not studied in detail. In this study, C28/I2 human chondrocytes were transfected with NPs co-formulated with a PEG-polymer coating and loaded with EGFP mRNA for confocal imaging of intracellular trafficking and evaluation of transfection efficiency.

Fluorescence background quenching as a means to increase Signal to Background ratio - a proof of concept during Nerve Imaging.

Adequate signal to background ratios are critical for the implementation of fluorescence-guided surgery technologies. While local tracer administrations help to reduce the chance of systemic side effects, reduced spatial migration and non-specific tracer diffusion can impair the discrimination between the tissue of interest and the background. To combat background signals associated with local tracer administration, we explored a pretargeting concept aimed at quenching non-specific fluorescence signals.

Bioorthogonally Applicable Fluorescence Deactivation Strategy for Receptor Kinetics Study and Theranostic Pretargeting Approaches.

The availability of a receptor for theranostic pretargeting approaches was assessed by use of a new click-chemistry-based deactivatable fluorescence-quenching concept. The efficacy was evaluated in a cell-based model system featuring both membranous (available) and internalized (unavailable) receptor fractions of the clinically relevant receptor chemokine receptor 4 (CXCR4). Proof of concept was achieved with a deactivatable tracer consisting of a CXCR4-specific peptide functionalized with a Cy5 dye bearing a chemoselective azide handle (N -Cy5-AcTZ14011).

Tracers for Fluorescence-Guided Surgery: How Elongation of the Polymethine Chain in Cyanine Dyes Alters the Pharmacokinetics of a Dual-Modality c[RGDyK] Tracer.

The potential of receptor-mediated fluorescence-based image-guided surgery tracers is generally linked to the near-infrared emission profile and good-manufacturing-production availability of fluorescent dyes. Surprisingly, little is known about the critical interaction between the structural composition of the dyes and the pharmacokinetics of the tracers. In this study, a dual-modality tracer design was used to systematically and quantitatively evaluate the influence of elongation of the polymethine chain in a fluorescent cyanine dye on the imaging potential of a targeted tracer.

Hybrid Imaging Labels: Providing the Link Between Mass Spectrometry-Based Molecular Pathology and Theranostics.

Background: Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for and evaluation; e.g. fluorescence or nuclear medicine.

Versatile convergent synthesis of a three peptide loop containing protein mimic of whooping cough pertactin by successive Cu(I)-catalyzed azide alkyne cycloaddition on an orthogonal alkyne functionalized TAC-scaffold.

Synthetic mimics of discontinuous epitopes may have a wide range of potential applications, including synthetic vaccines and inhibition of protein-protein interactions. However, synthetic access to these relatively complex peptide molecular constructs is limited. This paper describes a versatile convergent strategy for the construction of protein mimics presenting three different cyclic peptides.

Synthesis, antimicrobial activity, and membrane permeabilizing properties of C-terminally modified nisin conjugates accessed by CuAAC.

Functionalization of the lantibiotic nisin with fluorescent reporter molecules is highly important for the understanding of its mode of action as a potent antimicrobial peptide. In addition to this, multimerization of nisin to obtain multivalent peptide constructs and conjugation of nisin to bioactive molecules or grafting it on surfaces can be attractive methods for interference with bacterial growth. Here, we report a convenient method for the synthesis of such nisin conjugates and show that these nisin derivatives retain both their antimicrobial activity and their membrane permeabilizing properties.

Glucocorticoid-loaded core-cross-linked polymeric micelles with tailorable release kinetics for targeted therapy of rheumatoid arthritis.

Polymerizable and hydrolytically cleavable dexamethasone (DEX, red dot in picture) derivatives were covalently entrapped in core-cross-linked polymeric micelles that were prepared from a thermosensitive block copolymer (yellow and gray building block). By varying the oxidation degree of the thioether in the drug linker, the release rate of DEX could be controlled. The DEX-loaded micelles were used for efficient treatment of inflammatory arthritis in two animal models.

A polymeric colchicinoid prodrug with reduced toxicity and improved efficacy for vascular disruption in cancer therapy.

Colchicinoids are very potent tubulin-binding compounds, which interfere with microtubule formation, giving them strong cytotoxic properties, such as cell mitosis inhibition and induction of microcytoskeleton depolymerization. While this makes them promising vascular disrupting agents (VDAs) in cancer therapy, their dose-limiting toxicity has prevented any clinical application for this purpose. Therefore, colchicinoids are considered attractive lead molecules for the development of novel vascular disrupting nanomedicine.

Protein macromonomers containing reduction-sensitive linkers for covalent immobilization and glutathione triggered release from dextran hydrogels.

We report an efficient strategy to conjugate methacrylamide moieties to the lysine units of lysozyme for co-polymerization and subsequent triggered release from hydrogels. Two novel linker molecules, containing an ester bond and/or a disulfide bond for temporary immobilization, were synthesized and conjugated to lysozyme. Lysozyme was successfully modified with on average 2.

Liposomes as carriers for colchicine-derived prodrugs: vascular disrupting nanomedicines with tailorable drug release kinetics.

Newly formed tumor vasculature has proven to be an effective target for tumor therapy. A strategy to attack this angiogenic tumor vasculature is to initiate local blood vessel congestion and consequently induce massive tumor cell necrosis. Vascular disrupting agents (VDAs) typically bind to tubulin and consequently disrupt microtubule dynamics.

Conjugation of methacrylamide groups to a model protein via a reducible linker for immobilization and subsequent triggered release from hydrogels.

An efficient strategy is reported to introduce methacrylamide groups on the lysine residues of a model protein (lysozyme) for immobilization and triggered release from a hydrogel network. A novel spacer unit was designed, containing a disulfide bond, such that the release of the protein can be triggered by reduction. The modified proteins were characterized by MALDI-TOF MS, titration of free NH(2) residues and spectral analysis.

Tailorable thiolated trimethyl chitosans for covalently stabilized nanoparticles.

A novel four-step method is presented to synthesize partially thiolated trimethylated chitosan (TMC) with a tailorable degree of quaternization and thiolation. First, chitosan was partially N-carboxylated with glyoxylic acid and sodium borohydride. Next, the remaining amines were quantitatively dimethylated with formaldehyde and sodium borohydride and then quaternized with iodomethane in NMP.

Synthesis, characterization and in vitro biological properties of O-methyl free N,N,N-trimethylated chitosan.

N,N,N-Trimethylated chitosan (TMC) with varying degree of quaternization (DQ) is currently being investigated in mucosal drug, vaccine and in gene delivery. However, besides N-methylation, O-methylation and chain scission occur during the synthesis of this polymer. Since both side reactions may affect the polymer characteristics, there is a need for TMCs without O-methylation and disparities in chain lengths while varying the DQ.