Heparinized collagen-based hydrogels for tissue engineering: physical, mechanical and biological properties.

As the main protein forming the vascular extracellular matrix, collagen has a weak antigenicity, making it an attractive candidate for coatings of vascular grafts. In order to bring antithrombotic properties to collagen for obtaining suitable blood compatibility of surfaces and further bioactive molecule carrying capacity, heparinization appears as a method of choice. Thus, in this article, pH-driven self-assembly was used to form collagen-based hydrogels with physical incorporation of heparins, especially low molecular weight heparin or unfractionated heparin at 1 IU/mL and 6 IU/mL.

Preparation and optimization of agarose or polyacrylamide/amino acid-based double network hydrogels for photocontrolled drug release.

The high water content and biocompatibility of amino-acid-based supramolecular hydrogels have generated growing interest in drug delivery research. Nevertheless, the existing dominant approach of constructing such hydrogels, the exploitation of a single amino acid type, typically comes with several drawbacks such as weak mechanical properties and long gelation times, hindering their applications. Here, we design a near-infrared (NIR) light-responsive double network (DN) structure, containing amino acids and different synthetic or natural polymers, i.

Gelatin Methacryloyl (GelMA) Hydrogel Scaffolds: Predicting Physical Properties Using an Experimental Design Approach.

There is a growing interest for complex in vitro environments that closely mimic the extracellular matrix and allow cells to grow in microenvironments that are closer to the one in vivo. Protein-based matrices and especially hydrogels can answer this need, thanks to their similarity with the cell microenvironment and their ease of customization. In this study, an experimental design was conducted to study the influence of synthesis parameters on the physical properties of gelatin methacryloyl (GelMA).

Metal-chelating activity of soy and pea protein hydrolysates obtained after different enzymatic treatments from protein isolates.

Soy and pea proteins are two rich sources of essential amino acids. The hydrolysis of these proteins reveals functional and bioactive properties of the produced small peptide mixtures. In our study, we employed the hydrolysis of soy and pea protein isolates with the endopeptidases Alcalase® and Protamex®, used alone or followed by the exopeptidase Flavourzyme®.

On the Observation of N Quadrupole Resonance Transitions in Water Proton NMR Relaxometry Dispersion Curves: The Case of a Labile NH Grouping in a Semirigid Molecular Moiety.

The electric field gradient tensor (considered here at the level of a nitrogen nucleus) can be described by two parameters: the largest element in the (,,) principal axis system, denoted by (leading to the nuclear quadrupole coupling), and the asymmetry parameter η = (|| - ||)/|| with || > || > ||. The frequencies of the three nitrogen-14 nuclear quadrupole resonance (NQR) transitions depend on both parameters but, for sensitivity reasons, their determination may be especially difficult and time consuming. For a partly rigid NH grouping with a labile proton, water nuclear magnetic resonance (NMR) relaxometry curves may exhibit these three transitions (dubbed quadrupolar dips or quadrupole relaxation enhancement (QRE)), provided that the NH grouping belongs to a moiety possessing a sufficient degree of ordering.

Emerging low-molecular weight nucleopeptide-based hydrogels: state of the art, applications, challenges and perspectives.

Over the last twenty years, low-molecular weight gelators and, in particular, peptide-based hydrogels, have drawn great attention from scientists thanks to both their inherent advantages in terms of properties and their high modularity (, number and nature of the amino acids). These supramolecular hydrogels originate from specific peptide self-assembly processes that can be driven, modulated and optimized specific chemical modifications brought to the peptide sequence. Among them, the incorporation of nucleobases, another class of biomolecules well-known for their abilities to self-assemble, has recently appeared as a new promising and burgeoning approach to finely design supramolecular hydrogels.

Bio-Inspired Casein-Derived Antioxidant Peptides Exhibiting a Dual Direct/Indirect Mode of Action.

Antioxidant compounds are chemicals of primary importance, especially for their applications in nutrition and healthcare, thanks to their abilities to prevent oxidation processes and to limit and/or rebalance the oxidative stress, well-known for its impact on a wide variety of diseases. While several biomolecules are well-known for their antioxidant properties (, ascorbic acid, carotenoids, phenolic derivatives), bio-sourced antioxidants have drawn considerable attention in the last decades, especially bioactive peptides, mainly obtained by the hydrolysis process. Antioxidant peptide sequences are mainly identified a posteriori, thanks to fastidious and time-consuming approaches and techniques, limiting the discovery of new efficient peptides.

Electrically Switchable Nanolever Technology for the Screening of Metal-Chelating Peptides in Hydrolysates.

Metal-chelating peptides (MCP) are considered as indirect antioxidants due to their capacity to inhibit radical chain reaction and oxidation. Here, we propose a new proof of concept for the screening of MCPs present in protein hydrolysates for valorizing their antioxidant properties by using the emerging time-resolved molecular dynamics technology, switchSENSE. This method unveils possible interactions between MCPs and immobilized nickel ions using fluorescence and electro-switchable DNA chips.

Co-assembly and multicomponent hydrogel formation upon mixing nucleobase-containing peptides.

Peptide-based hydrogels are physical gels formed through specific supramolecular self-assembling processes, leading to ordered nanostructures which constitute the water entrapping scaffold of the soft material. Thanks to the inherent properties of peptides, these hydrogels are highly considered in the biomedical domain and open new horizons in terms of application in advanced therapies and biotechnologies. The use of one, and only one, native peptide to formulate a gel is by far the most reported approach to design such materials, but suffers from several limitations, including in terms of mechanical properties.

Improving and fine-tuning the properties of peptide-based hydrogels via incorporation of peptide nucleic acids.

Peptide self-assemblies have attracted intense research interest over the last few decades thanks to their implications in key biological processes (e.g., amyloid formation) and their use in biotechnological and (bio)material fields.

Both metal-chelating and free radical-scavenging synthetic pentapeptides as efficient inhibitors of reactive oxygen species generation.

Reactive oxygen species (ROS) are major sources of oxidative stress playing prominent roles in the development of several pathologies including cardiovascular and neurodegenerative diseases or cancers. The presence of transition biometal ions, specifically copper and iron, induces ROS formation by catalyzing the reduction of molecular oxygen to superoxide anion (O2˙-), hydrogen peroxide (H2O2) and hydroxyl (HO˙) radical. To limit ROS production and their detrimental effects, we report on the synthesis, physicochemical studies and antioxidant assays of an innovative series of synthetic pentapeptides exhibiting a dual direct/indirect mode of action, both as iron(iii)-chelators and as radical scavengers.

Synthetic G-Quartets as Versatile Nanotools for the Luminescent Detection of G-Quadruplexes.

Recent years have witnessed a tremendous increase in the biotechnological applications of nucleic acid-based nanotools. Beyond their biological relevance, nucleobases have indeed found new scopes of applications in bionanotechnology, which are expanding nowadays at an accelerated pace. Among the four canonical nucleobases (adenine, guanine, cytosine and thymine), guanine is certainly the most useful and used base, thanks to its versatile H-bond donating/accepting properties that make it suitable for being involved in various assemblies ranging from base-pairs to base-quartets.

Supramolecular amplification of amyloid self-assembly by iodination.

Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together.

A twice-as-smart synthetic G-quartet: PyroTASQ is both a smart quadruplex ligand and a smart fluorescent probe.

Recent and unambiguous evidences of the formation of DNA and RNA G-quadruplexes in cells has provided solid support for these structures to be considered as valuable targets in oncology. Beyond this, they have lent further credence to the anticancer strategies relying on small molecules that selectively target these higher-order DNA/RNA architectures, referred to as G-quadruplex ligands. They have also shed bright light on the necessity of designing multitasking ligands, displaying not only enticing quadruplex interacting properties (affinity, structural selectivity) but also additional features that make them usable for detecting quadruplexes in living cells, notably for determining whether, when, and where these structures fold and unfold during the cell cycle and also for better assessing the consequences of their stabilization by external agents.

Porphyrin-based design of bioinspired multitarget quadruplex ligands.

Secondary nucleic acid structures, such as DNA and RNA quadruplexes, are potential targets for cancer therapies. Ligands that interact with these targets could thus find application as anticancer agents. Synthetic G-quartets have recently found numerous applications, including use as bioinspired G-quadruplex ligands.

Caffeine-based gold(I) N-heterocyclic carbenes as possible anticancer agents: synthesis and biological properties.

A new series of gold(I) N-heterocyclic carbene (NHC) complexes based on xanthine ligands have been synthesized and characterized by mass spectrometry, NMR, and X-ray diffraction. The compounds have been tested for their antiproliferative properties in human cancer cells and nontumorigenic cells in vitro, as well as for their toxicity in healthy tissues ex vivo. The bis-carbene complex [Au(caffein-2-ylidene)2][BF4] (complex 4) appeared to be selective for human ovarian cancer cell lines and poorly toxic in healthy organs.

Surface-immobilized DNAzyme-type biocatalysis.

The structure of the double helix of deoxyribonucleic acid (DNA, also called duplex-DNA) was elucidated sixty years ago by Watson, Crick, Wilkins and Franklin. Since then, DNA has continued to hold a fascination for researchers in diverse fields including medicine and nanobiotechnology. Nature has indeed excelled in diversifying the use of DNA: beyond its canonical role of repository of genetic information, DNA could also act as a nanofactory able to perform some complex catalytic tasks in an enzyme-mimicking manner.

Multitasking water-soluble synthetic G-quartets: from preferential RNA-quadruplex interaction to biocatalytic activity.

Natural G-quartets, a cyclic and coplanar array of four guanine residues held together through a Watson-Crick/Hoogsteen hydrogen-bond network, have received recently much attention due to their involvement in G-quadruplex DNA, an alternative higher-order DNA structure strongly suspected to play important roles in key cellular events. Besides this, synthetic G-quartets (SQ), which artificially mimic native G-quartets, have also been widely studied for their involvement in nanotechnological applications (i.e.

Closer to nature: an ATP-driven bioinspired catalytic oxidation process.

The capability of DNA to acquire enzyme-like properties has led to the emergence of the so-called DNAzyme field; herein, we take a further leap along this nature-inspired road, demonstrating that a template assembled synthetic G-quartet (TASQ) can act as a pre-catalyst for catalytic peroxidase-mimicking oxidation reactions, whatever its nature (guanine or guanosine-based G-quartets), in an ATP-dependent manner, thereby bringing this bioinspired TASQzyme process even closer to nature.

A model of smart G-quadruplex ligand.

An unprecedented strategy to control the quadruplex- vs duplex-DNA selectivity of a ligand is reported. We designed a compound whose structure can rearrange when it interacts with a G-quadruplex, thereby controlling its affinity. Thus, the first "smart G-quadruplex ligand" is reported, since this ligand experiences a structural change in the presence of quadruplexes but not in the presence of duplexes, ensuring a high level of quadruplex selectivity.

Assessing the differential affinity of small molecules for noncanonical DNA structures.

The targeting of higher-order DNA structures has been thoroughly developed with G-quadruplex DNA but not with other structures like branched DNA (also known as DNA junctions). Because these alternative higher-order DNA architectures might be of high biological relevance, we implemented a high-throughput version of the FRET melting assay that enabled us to map the interactions of a candidate with four different DNA structures (duplex- and quadruplex DNA, three- and four-way junctions) in a rapid and reliable manner. We also introduce a novel index, the BONDS (branched and other noncanonical DNA selectivity) index, to conveniently quantify this differential affinity.

Insights into how nucleotide supplements enhance the peroxidase-mimicking DNAzyme activity of the G-quadruplex/hemin system.

Since the initial discovery of the catalytic capability of short DNA fragments, this peculiar enzyme-like property (termed DNAzyme) has continued to garner much interest in the scientific community because of the virtually unlimited applications in developing new molecular devices. Alongside the exponential rise in the number of DNAzyme applications in the last past years, the search for convenient ways to improve its overall efficiency has only started to emerge. Credence has been lent to this strategy by the recent demonstration that the quadruplex-based DNAzyme proficiency can be enhanced by ATP supplements.