Xeno-Free Biocompatible Peptide-Based Bioinks Reinforced with Cellulose Nanofibers for 3D Printing.

Tissue regeneration is a complex biological process with limited self-repair capacity, necessitating engineered solutions to restore both mechanical integrity and biological functionality. In tissue engineering and regenerative medicine, 3D printing has emerged as a promising tool for fabricating scaffolds that mimic the natural extracellular matrix (ECM). However, many bioinks are derived from animal sources, posing risks of pathogen contamination and immune responses.

Coupling Peptide-Based Encapsulation of Enzymes with Bacteria for Paraoxon Bioremediation.

The catalytic efficiency of enzymes can be harnessed as an environmentally friendly solution for decontaminating various xenobiotics and toxins. However, for some xenobiotics, several enzymatic steps are needed to obtain nontoxic products. Another challenge is the low durability and stability of many native enzymes in their purified form.

Architecture-Based Programming of Polymeric Micelles to Undergo Sequential Mesophase Transitions.

Di- and triblock amphiphiles can form different mesophases ranging from micelles to hydrogels depending on their chemical structures, hydrophilic to hydrophobic ratios, and their ratio in the mixture. In addition, their different architectures dictate their exchange rate between the assembled and unimer states and consequently affect their responsiveness toward enzymatic degradation. Here we report the utilization of the different reactivities of di- and triblock amphiphiles, having exactly the same hydrophilic to lipophilic balance, toward enzymatic degradation as a tool for programming formulations to undergo sequential enzymatically induced transitions from (i) micelles to (ii) hydrogel and finally to (iii) dissolved polymers.

Ataxia Telangiectasia Mutated Signaling Delays Skin Pigmentation upon UV Exposure by Mediating MITF Function toward DNA Repair Mode.

Skin pigmentation is paused after sun exposure; however, the mechanism behind this pausing is unknown. In this study, we found that the UVB-induced DNA repair system, led by the ataxia telangiectasia mutated (ATM) protein kinase, represses MITF transcriptional activity of pigmentation genes while placing MITF in DNA repair mode, thus directly inhibiting pigment production. Phosphoproteomics analysis revealed ATM to be the most significantly enriched pathway among all UVB-induced DNA repair systems.

Molecular Engineering of Rigid Hydrogels Co-assembled from Collagenous Helical Peptides Based on a Single Triplet Motif.

The potential of ultra-short peptides to self-assemble into well-ordered functional nanostructures makes them promising minimal components for mimicking the basic ingredient of nature and diverse biomaterials. However, selection and modular design of perfect sequences are extremely tricky due to their vast possible combinatorial space. Moreover, a single amino acid substitution can drastically alter the supramolecular packing structure of short peptide assemblies.

Exploiting Minimalistic Backbone Engineered γ-Phenylalanine for the Formation of Supramolecular Co-Polymer.

Ordered supramolecular hydrogels assembled by modified aromatic amino acids often exhibit low mechanical rigidity. Aiming to stabilize the hydrogel and understand the impact of conformational freedom and hydrophobicity on the self-assembly process, two building blocks based on 9-fluorenyl-methoxycarbonyl-phenylalanine (Fmoc-Phe) gelator which contain two extra methylene units in the backbone, generating Fmoc-γPhe and Fmoc-(3-hydroxy)-γPhe are designed. Fmoc-γPhe spontaneously assembled in aqueous media forming a hydrogel with exceptional mechanical and thermal stability.

Thixotropic Red Microalgae Sulfated Polysaccharide-Peptide Composite Hydrogels as Scaffolds for Tissue Engineering.

Sulfated polysaccharides of red marine microalgae have recently gained much attention for biomedical applications due to their anti-inflammatory and antioxidant properties. However, their low mechanical properties limit their use in tissue engineering. Herein, to enhance the mechanical properties of the sulfated polysaccharide produced by the red marine microalga, sp.

Stabilizing gelatin-based bioinks under physiological conditions by incorporation of ethylene-glycol-conjugated Fmoc-FF peptides.

Over the last decade, three-dimensional (3D) printing technologies have attracted the interest of researchers due to the possibility of fabricating tissue- and organ-like structures with similarities to the organ of interest. One of the most widely used materials for the fabrication of bioinks is gelatin (Gel) due to its excellent biocompatibility properties. However, in order to fabricate stable scaffolds under physiological conditions, the most common approach is to use gelatin methacrylate (GelMA) that allows the crosslinking and therefore the stabilization of the hydrogel through UV crosslinking.

Bi-functional peptide-based 3D hydrogel-scaffolds.

Over the last few years, hydrogels have been proposed for many biomedical applications, including drug delivery systems and scaffolds for tissue engineering. In particular, peptides have been envisioned as excellent candidates for the development of hydrogel materials, due to their intrinsic biocompatibility, ease of handling, and intrinsic biodegradability. Recently, we developed a novel hybrid polymer-peptide conjugate, PEG8-(FY)3, which is able to self-assemble into a self-supporting soft hydrogel over dry and wet surfaces as demonstrated by molecular dynamics simulation.

UV-Protection Timer Controls Linkage between Stress and Pigmentation Skin Protection Systems.

Skin sun exposure induces two protection programs: stress responses and pigmentation, the former within minutes and the latter only hours afterward. Although serving the same physiological purpose, it is not known whether and how these programs are coordinated. Here, we report that UVB exposure every other day induces significantly more skin pigmentation than the higher frequency of daily exposure, without an associated increase in stress responses.