Significance of Plastic Recycling with the Focus on Polyesters – Creating a Circular Economy

Plastics materials are essential in every part of our lives, resulting in their increasing production and consumption. Consequently, recycling of plastics has been of great importance in the last decades. Among all types of plastics, polyesters have become very appealing for numerous kinds of applications, making their recycling crucial. Several techniques have been developed for the recycling of plastics with the aim of eliminating the waste accumulated, as well as to create a circular economy

Multivalent Pattern Recognition Through Engineering of Spatial Tolerance in DNA-Based Nanomaterials

Strength in numbers, combining many weak interactions into an overall strong connection, is the fundamental principle of multivaleny. This concept has been exploiting for the engineering of super-selective cell-targeting materials, which generally display high number of flexible ligands to enhance the systems' avidity. Many biological processes, however, function through a temporal spatial organization of receptors in patterns, matching with a controlled number of ligands to create a specific interaction. In this low-valency regime, the mechanics e.g. rigidity of the ligand-presenting architecture plays a critical role in the selectivity of the multivalent complex. Exploiting the precision in spatial design inherent to DNA nanotechnology, we engineered a library of scaffolds to explore how valency, affinity, and rigidity control the balance of super-selective multivalent binding. Depending on the affinity between the ligand and receptor, a pattern-dependent binding behavior was achieved when spatial tolerance of ligands matches the spatial organization of the target. We label this new form of mechanics-controlled multivalent binding "multivalent pattern recognition" (MPR). The main parameter controlling MPR is the rigidity of the ligand, which controls the over spatial tolerance of binding. Our findings contribute to the rational design of selective targeting with nanomaterials

Multivalent Pattern Recognition through Control of Nano-Spacing in Low-Valency Super-Selective Materials

Super-selective multivalent ligand–receptor interactions display a signature step-like onset in binding when meeting a characteristic density of target receptors. Materials engineered for super-selective binding generally display a high number of flexible ligands to enhance the systems’ avidity. In many biological processes, however, ligands are present in moderate copy numbers and arranged in spatio-temporal patterns. In this low-valency regime, the rigidity of the ligand-presenting architecture plays a critical role in the selectivity of the multivalent complex through decrease of the entropic penalty of binding. Exploiting the precision in spatial design inherent to the DNA nanotechnology, we engineered a library of rigid architectures to explore how valency, affinity, and nano-spacing control the presence of super-selectivity in multivalent binding. A micromolar monovalent affinity was required for super-selective binding to be observed within low-valency systems, and the transition point for stable interactions was measured at hexavalent ligand presentation, setting the limits of the low-valency regime. Super-selective binding was observed for all hexavalent architectures, and, more strikingly, the ligand pattern determined the selectivity onset. Hereby, we demonstrate for the first time that nano-control of geometric patterns can be used to discriminate between receptor densities in a super-selective manner. Materials that were indistinguishable in their molecular composition and ligand valency bound with various efficacies on surfaces with constant receptor densities. We define this new phenomenon in super-selective binding as multivalent pattern recognition