Biology subjects

van de Weert, M.

Publications and source records attributed to van de Weert, M..

4 recordsLinked to original sources

bioRxiv2026

Layer-by-Layer Polymeric Films: A Novel Approach to Buccal GLP-1 Delivery

Buccal delivery offers a promising alternative to oral drug administration by enabling direct systemic absorption and avoiding first-pass metabolism. Multilayer polymeric films represent a promising strategy for the sequential delivery of drug and absorption enhancer in the oral cavity. Here, dual- and triple-layer films were fabricated via slot-die coating, incorporating a GLP-1 receptor agonist (GLP-1-RA) and the penetration enhancer sodium glycodeoxycholate (GDC). These were co-loaded in dual-layer films or compartmentalized in triple-layer films. Scanning electron microscopy and optical coherence tomography confirmed well-defined, distinct layers with thicknesses suitable for buccal administration (339 {+/-} 10.24 {micro}m and 487 {+/-} 36.5 {micro}m for dual- and triple-layer films, respectively). Both designs exhibited good mucoadhesion and mucosal compatibility, and preserved the secondary structure of GLP-1-RA. In vitro release studies showed rapid diffusion of GDC and GLP-1-RA from dual-layer films, whereas triple-layer films enabled sustained, sequential release of GDC and GLP-1-RA. Ex vivo porcine buccal mucosa studies showed higher GLP-1-RA and GDC flux from triple-layer films compared to dual-layer films. The films also did not compromise epithelial integrity, in contrast to the direct application of GLP-1-RA and GDC, which caused significant epithelial disruption. These results demonstrate that multilayer film architecture and spatial layering can be harnessed to control release kinetics, maximize peptide penetration, and minimize tissue stress, offering a versatile platform for safe and effective peptide delivery. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/700335v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@76858borg.highwire.dtl.DTLVardef@1397e74org.highwire.dtl.DTLVardef@19d1841org.highwire.dtl.DTLVardef@a369c5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

Amyloid Morphology is Encoded in H-bonds and Electrostatics Interactions Ruling Protein Phase Separation

Ion-protein interactions regulate biological processes and are the basis of key strategies of modulating protein phase diagrams and stability in drug development. Here, we report the mechanisms by which H-bonds and electrostatic interactions in ion-protein systems determine phase separation and amyloid formation. Using microscopy, small-angle X-ray scattering, circular dichroism and atomistic molecular dynamics (MD) simulations, we found that anions specifically interacting with insulin induced phase separation by neutralising the protein charge and forming H-bond bridges between insulin molecules. The same interaction was responsible for an enhanced insulin conformational stability and resistance to oligomerisation. Under aggregation conditions, the anion-protein interaction translated into the activation of a coalescence process, leading to amyloid-like microparticles. This reaction is alternative to conformationally-driven pathways, giving rise to elongated amyloid-like fibrils and occurs in the absence of preferential ion-protein binding. Our findings depict a unifying scenario in which common interactions dictated both phase separation at low temperatures and the occurrence of pronounced heterogeneity in the amyloid morphology at high temperatures, similar to what has previously been reported for protein crystal growth.

biophysics↗

bioRxiv2022

Heterogeneous and Surface-Catalyzed Amyloid Aggregation Monitored by Spatially Resolved Fluorescence and Single Molecule Microscopy

Amyloid aggregation is associated with many diseases and may also occur in therapeutic protein formulations. Addition of co-solutes is a key strategy to modulate the stability of proteins in pharmaceutical formulations and select inhibitors for drug design in the context of diseases. However, the heterogeneous nature of this multi-component system in terms of structures and mechanisms poses a number of challenges for the analysis of the chemical reaction. Combining a spatially resolved fluorescence approach with single molecule microscopy and machine learning approaches, we disentangle the different contributions from multiple species within a single aggregation experiment. Moreover, we link the presence of interfaces to the degree of heterogeneity of the aggregation kinetics and retrieve the rate constants and underlying mechanisms for single aggregation events, providing a general tool for a comprehensive analysis of self-assembly reactions. Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/510935v2_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@c678eaorg.highwire.dtl.DTLVardef@2c6decorg.highwire.dtl.DTLVardef@e4c2e4org.highwire.dtl.DTLVardef@b741aa_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2021

Polysorbate 80 Controls Morphology, Structure and Stability of Human Insulin Amyloid-Like Spherulites

Amyloid protein aggregates are not only associated with neurodegenerative diseases and may also occur as unwanted by-products in protein-based therapeutics. Surfactants are often employed to stabilize protein formulations and reduce the risk of aggregation. However, surfactants alter protein-protein interactions and may thus modulate the physicochemical characteristics of any aggregates formed. Human insulin aggregation was induced at low pH in the presence of varying concentrations of the surfactant polysorbate 80. Various spectroscopic and imaging methods were used to study the aggregation kinetics, as well as structure and morphology of the formed aggregates. Molecular dynamics simulations were employed to investigate the initial interaction between the surfactant and insulin. Addition of polysorbate 80 slowed down, but did not prevent, aggregation of insulin. Amyloid spherulites formed under all conditions, with a higher content of intermolecular beta-sheets in the presence of the surfactant above its critical micelle concentration. In addition, a denser packing was observed, leading to a more stable aggregate. Molecular dynamics simulations suggested a tendency for insulin to form dimers in the presence of the surfactant, indicating a change in protein-protein interactions. It is thus shown that surfactants not only alter aggregation kinetics, but also affect physicochemical properties of any aggregates formed.

biophysics↗