Gold Nanoparticles Decorated with HPLC6-Derived Peptides as a Platform for Ice Recrystallization Inhibition.

In nature, organisms living in extreme environmental conditions produce antifreeze proteins (AFPs) that prevent the growth of ice crystals and depress the freezing point of body fluids. In this study, three different peptides derived from the N-terminal sequence of the helical type I AFP HPLC6, along with a stapled derivative produced via on-resin microwave-assisted copper(I)-catalyzed azide-alkyne cycloaddition, were conjugated to gold nanoparticles. The aim of decorating the surface of the nanoparticles with multiple copies of the peptides was to combine the ice-binding capability of the peptides with the size of a nanoparticle, thus, mimicking the protein bulkiness to enhance the peptide antifreeze activity.

Hydrophobic Domain Modulation of Chemical Responsiveness in a Bolaamphiphile-Based Supramolecular Monomer.

Self-immolative chemistries that respond in an irreversible manner to external stimuli are highly attractive to permanently degrade filamentous supramolecular biomaterials. Within the monomer, a balance needs to be struck between its capacity to be supramolecularly polymerized and degraded at an appropriate rate for a given application. Herein, we unravel the structure-property-function relationships of a library of squaramide-based bolaamphiphiles bearing a central disulfide-based self-immolative spacer to construct supramolecular polymers responsive to chemical stimuli in aqueous solutions.

Hypothermic and cryogenic preservation of cardiac tissue-engineered constructs.

Cardiac tissue engineering (cTE) has already advanced towards the first clinical trials, investigating safety and feasibility of cTE construct transplantation in failing hearts. However, the lack of well-established preservation methods poses a hindrance to further scalability, commercialization, and transportation, thereby reducing their clinical implementation. In this study, hypothermic preservation (4 °C) and two methods for cryopreservation (, a slow and fast cooling approach to -196 °C and -150 °C, respectively) were investigated as potential solutions to extend the cTE construct implantation window.

Dampened Transient Actuation of Hydrogels Autonomously Controlled by pH-Responsive Bicontinuous Nanospheres.

The fabrication of a soft actuator with a dampened actuation response is presented. This was achieved via the incorporation into an actuating hydrogel of urease-loaded pH-responsive bicontinuous nanospheres (BCNs), whose membrane was able to regulate the permeability and thus conversion of fuel urea into ammonia. The dampened response of these nanoreactors to the enzymatically induced pH change was translated to a pH-responsive soft actuator.

Freezing-mediated formation of supraproteins using depletion forces.

Hypothesis Long-acting formulations such as microparticles, injectable depots and implantable devices can realize spatiotemporally controlled delivery of protein drugs to extend their therapeutic in vivo half-lives. To efficiently encapsulate the protein drugs into such drug delivery systems, (sub)micron-sized protein particles are needed. The formation of micronized supraproteins can be induced through the synergistic combination of attractive depletion forces and freezing.

Liquid crystalline inverted lipid phases encapsulating siRNA enhance lipid nanoparticle mediated transfection.

Efficient cytosolic delivery of RNA molecules remains a formidable barrier for RNA therapeutic strategies. Lipid nanoparticles (LNPs) serve as state-of-the-art carriers that can deliver RNA molecules intracellularly, as exemplified by the recent implementation of several vaccines against SARS-CoV-2. Using a bottom-up rational design approach, we assemble LNPs that contain programmable lipid phases encapsulating small interfering RNA (siRNA).

Synthesis of Polymeric Mimics of Ice-Binding Proteins.

Cobalt-mediated radical polymerization (CMRP) enables the preparation of both short and long polymers from acrylic and vinyl ester monomers with low dispersity. Here we describe the synthesis, purification, and characterization of polymeric mimics of ice-binding proteins based on the water-soluble polymer poly(vinyl alcohol) by CMRP. Block copolymers of poly(vinyl alcohol) and poly(acrylic acid) were prepared from the precursor copolymers poly(vinyl acetate)-b-poly(acrylonitrile) upon hydrolysis.

A peptide-binding domain shared with an Antarctic bacterium facilitates human cell binding and intestinal colonization.

the causative agent of the disease cholera, is responsible for multiple pandemics. binds to and colonizes the gastrointestinal tract within the human host, as well as various surfaces in the marine environment (e.g.

De novo designed ice-binding proteins from twist-constrained helices.

Attaining molecular-level control over solidification processes is a crucial aspect of materials science. To control ice formation, organisms have evolved bewildering arrays of ice-binding proteins (IBPs), but these have poorly understood structure-activity relationships. We propose that reverse engineering using de novo computational protein design can shed light on structure-activity relationships of IBPs.

DNA storage in thermoresponsive microcapsules for repeated random multiplexed data access.

DNA has emerged as an attractive medium for archival data storage due to its durability and high information density. Scalable parallel random access to information is a desirable property of any storage system. For DNA-based storage systems, however, this still needs to be robustly established.

Controlling the Formation of Polyelectrolyte Complex Nanoparticles Using Programmable pH Reactions.

Enabling complexation of weak polyelectrolytes, in the presence of a programmable pH-modulation, offers a means to achieve temporal control over polyelectrolyte coassembly. Here, by mixing oppositely charged poly(allylamine hydrochloride) and poly(sodium methacrylate) in a (bi)sulfite buffer, nanoscopic complex coacervates are formed. Addition of formaldehyde initiates the formaldehyde-sulfite clock reaction, affecting the polyelectrolyte assembly in two ways.

Nanoscopy of single antifreeze proteins reveals that reversible ice binding is sufficient for ice recrystallization inhibition but not thermal hysteresis.

Antifreeze proteins (AFPs) bind ice to reduce freezing temperatures and arrest ice crystal ripening, making AFPs essential for the survival of many organisms in ice-laden environments and attractive as biocompatible antifreezes in many applications. While their activity was identified over 50 years ago, the physical mechanisms through which they function are still debated because experimental insights at the molecular scale remain elusive. Here, we introduce subzero nanoscopy by the design and incorporation of a freezing stage on a commercial super-resolution setup to resolve the interfacial dynamics of single AFPs with ice crystal surfaces.

Impact of poly(ethylene glycol) functionalized lipids on ordering and fluidity of colloid supported lipid bilayers.

Colloid supported lipid bilayers (CSLBs) are highly appealing building blocks for functional colloids. In this contribution, we critically evaluate the impact on lipid ordering and CSLB fluidity of inserted additives. We focus on poly(ethylene glycol) (PEG) bearing lipids, which are commonly introduced to promote colloidal stability.

En Route to Stabilized Compact Conformations of Single-Chain Polymeric Nanoparticles in Complex Media.

Precise control over the folding pathways of polypeptides using a combination of noncovalent and covalent interactions has evolved into a wide range of functional proteins with a perfectly defined 3D conformation. Inspired hereby, we develop a series of amphiphilic copolymers designed to form compact, stable, and structured single-chain polymeric nanoparticles (SCPNs) of defined size, even in competitive conditions. The SCPNs are formed through a combination of noncovalent interactions (hydrophobic and hydrogen-bonding interactions) and covalent intramolecular cross-linking using a light-induced [2 + 2] cycloaddition.

Switchable Electrostatically Templated Polymerization.

We report a switchable, templated polymerization system where the strength of the templating effect can be modulated by solution pH and/or ionic strength. The responsiveness to these cues is incorporated through a dendritic polyamidoamine-based template of which the charge density depends on pH. The dendrimers act as a template for the polymerization of an oppositely charged monomer, namely sodium styrene sulfonate.

Parameterless detection of liquid-liquid interfaces with sub-micron resolution in single-molecule localization microscopy.

Hypothesis: Knowing the exact location of soft interfaces, such as between water and oil, is essential to the study of nanoscale wetting phenomena. Recently, iPAINT was used to visualize soft interfaces in situ with minimal invasiveness, but computing the exact location of the interface remains challenging. We propose a new method to determine the interface with high accuracy.

Spatial and Temporal Modulation of Cell Instructive Cues in a Filamentous Supramolecular Biomaterial.

Supramolecular materials provide unique opportunities to mimic both the structure and mechanics of the biopolymer networks that compose the extracellular matrix. However, strategies to modify their filamentous structures in space and time in 3D cell culture to study cell behavior as encountered in development and disease are lacking. We herein disclose a multicomponent squaramide-based supramolecular material whose mechanics and bioactivity can be controlled by light through co-assembly of a 1,2-dithiolane (DT) monomer that forms disulfide cross-links.

Inhibition of Ice Recrystallization by Nanotube-Forming Cyclic Peptides.

While most native ice-binding proteins are rigid, artificial (macro)molecular ice-binders are usually flexible. Realizing a regular array with precisely positioned ice-binding motifs on synthetic proteins, (macro)molecular ice-binders are thus challenging. Here, we exploit the predictable assembly of cyclic peptides into nanotubes as a starting point to prepare large, rigid ice-binders bearing an ice-binding site that is found in hyperactive ice-binding proteins in insects.

Molecular basis for inhibition of adhesin-mediated bacterial-host interactions through a peptide-binding domain.

Infections typically begin with pathogens adhering to host cells. For bacteria, this adhesion can occur through specific ligand-binding domains. We identify a 20-kDa peptide-binding domain (PBD) in a 1.

Small Peptide-Protein Interaction Pair for Genetically Encoded, Fixation Compatible Peptide-PAINT.

Super-resolution microscopy via PAINT has been widely adopted in life sciences to interrogate the nanoscale architecture of many cellular structures. However, obtaining quantitative information in fixed cellular samples remains challenging because control of labeling stoichiometry is hampered in current approaches due to click-chemistry and additional targeting probes. To overcome these challenges, we have identified a small, PDZ-based, peptide-protein interaction pair that is genetically encodable and compatible with super-resolution imaging upon cellular fixation without additional labeling.

Complex supramolecular fiber formed by coordination-induced self-assembly of benzene-1,3,5-tricarboxamide (BTA).

Hypothesis: In the quest for large but well-controlled supramolecular structures, the discotic benzene-1,3,5-tricarboxamide (BTA) has received quite some attention, because it can form hydrogen-bonded stacks that can be regarded as supramolecular polymers of which the single BTA molecule is the monomer. In this report, we consider a more complex BTA-based supramolecular polymer, namely one that is built up from supramolecular 'monomers'.

Experiments: We design a tris-ligand L consisting of a BTA core carrying three dipicolinic acid (DPA) groups.

A Roadmap to Cardiac Tissue-Engineered Construct Preservation: Insights from Cells, Tissues, and Organs.

Worldwide, over 26 million patients suffer from heart failure (HF). One strategy aspiring to prevent or even to reverse HF is based on the transplantation of cardiac tissue-engineered (cTE) constructs. These patient-specific constructs aim to closely resemble the native myocardium and, upon implantation on the diseased tissue, support and restore cardiac function, thereby preventing the development of HF.

Co-assembly of precision polyurethane ionomers reveals role of and interplay between individual components.

Industrial and household products, such as paints, inks and cosmetics usually consist of mixtures of macromolecules that are disperse in composition, in size and in monomer sequence. Identifying structure-function relationships for these systems is complicated, as particular macromolecular components cannot be investigated individually. For this study, we have addressed this issue, and have synthesized a series of five sequence-defined polyurethanes (PUs): one neutral-hydrophobic, one single-charged hydrophilic, one single-charged hydrophobic and two double-charged amphiphilic PUs (one symmetric and one asymmetric).