Characterization and release modelling in ELR-based nanocomposite hydrogel loaded with polylactic acid for the implementation of a biomedical device.

Cardiac tissues are difficult to regenerate due to the low proliferative capacity of cardiomyocytes. A new therapeutic strategy for cardiac regenerative medicine could include a device capable of ensuring cell grafting, stimulating cardiac tissue regeneration, and serving as an appropriate scaffold for the controlled and sustained release of lactate over time as an inducer of cardiomyocyte proliferation. An effective source of lactate could consist of the lactic acid polymer (PLA) itself, which generates free lactic acid during its degradation.

Assessing the feasibility of CRISPRa approaches to enhance protein-based biomaterial expression in bacterial systems for more efficient production.

Recombinant protein production is crucial for biomedical and industrial applications; however, achieving high yields for complex protein-like biomaterials such as elastin-like recombinamers (ELRs) remains challenging. ELRs, protein-based polymers derived from tropoelastin, emulate the mechanical and bioactive properties of natural tissues, making them valuable for numerous uses. Despite their promise, implementing a sophisticated molecular system for ELR production in involves overcoming multiple hurdles, including metabolic bottlenecks and low yields.

Pediatric cutaneous mucormicosis.

A 9-year-old boy diagnosed with acute myeloblastic leukemia and undergoing chemotherapy, was admitted with febrile neutropenia. During his admission, several violaceous plaques appeared on the upper extremities and anterior left hemithorax, which worsened and acquired a necrotic center. We performed a biopsy and histology showed a cutaneous infarction at the dermoepidermal and subcutaneous level.

formation of elastin-like recombinamer hydrogels with tunable viscoelasticity through efficient one-pot process.

Despite the remarkable progress in the generation of recombinant elastin-like (ELR) hydrogels, further improvements are still required to enhance and control their viscoelasticity, as well as limit the use of expensive chemical reagents, time-consuming processes and several purification steps. To alleviate this issue, the reactivity of carboxylic groups from glutamic (E) acid distributed along the hydrophilic block of an amphiphilic ELR (coded as E50I60) with amine groups has been studied through a one-pot amidation reaction in aqueous solutions, for the first time. By means of this approach, immediate conjugation of E50I60 with molecules containing amine groups has been performed with a high yield, as demonstrated by the H NMR and MALDI-TOF spectroscopies.

Protease-Sensitive, VEGF-Mimetic Peptide, and IKVAV Laminin-Derived Peptide Sequences within Elastin-Like Recombinamer Scaffolds Provide Spatiotemporally Synchronized Guidance of Angiogenesis and Neurogenesis.

Spatiotemporal control of vascularization and innervation is a desired hallmark in advanced tissue regeneration. For this purpose, we design a 3D model scaffold, based on elastin-like recombinamer (ELR) hydrogels. This contains two interior and well-defined areas, small cylinders, with differentiated bioactivities with respect to the bulk.

Mesenchymal Stromal Cells Combined With Elastin-Like Recombinamers Increase Angiogenesis After Hindlimb Ischemia.

Hindlimb ischemia is an unmet medical need, especially for those patients unable to undergo vascular surgery. Cellular therapy, mainly through mesenchymal stromal cell (MSC) administration, may be a potentially attractive approach in this setting. In the current work, we aimed to assess the potential of the combination of MSCs with a proangiogenic elastin-like recombinamer (ELR)-based hydrogel in a hindlimb ischemia murine model.

Recombinant Proteins-Based Strategies in Bone Tissue Engineering.

The increase in fracture rates and/or problems associated with missing bones due to accidents or various pathologies generates socio-health problems with a very high impact. Tissue engineering aims to offer some kind of strategy to promote the repair of damaged tissue or its restoration as close as possible to the original tissue. Among the alternatives proposed by this specialty, the development of scaffolds obtained from recombinant proteins is of special importance.

Combining tunable proteolytic sequences and a VEGF-mimetic peptide for the spatiotemporal control of angiogenesis within Elastin-Like Recombinamer scaffolds.

One of the main challenges in regenerative medicine is the spatiotemporal control of angiogenesis, which is key for the successful repair of many tissues, and determines the proper integration of the implant through the generation of a functional vascular network. To this end, we have designed a three-dimensional (3D) model consisting of a coaxial binary elastin-like recombinamer (ELR) tubular construct. It displays fast and slow proteolytic hydrogels on its inner and outer part, respectively, both sensitive to the urokinase plasminogen activator protease.

Biocasting of an elastin-like recombinamer and collagen bi-layered model of the tunica adventitia and external elastic lamina of the vascular wall.

The development of techniques for fabricating vascular wall models will foster the development of preventive and therapeutic therapies for treating cardiovascular diseases. However, the physical and biological complexity of vascular tissue represents a major challenge, especially for the design and the production of off-the-shelf biomimetic vascular replicas. Herein, we report the development of a biocasting technique that can be used to replicate the tunica adventitia and the external elastic lamina of the vascular wall.

Complex Morphogenesis by a Model Intrinsically Disordered Protein.

The development of intricate and complex self-assembling structures in the micrometer range, such as biomorphs, is a major challenge in materials science. Although complex structures can be obtained from self-assembling materials as they segregate from solution, their size is usually in the nanometer range or requires accessory techniques. Previous studies with intrinsically disordered proteins (IDPs) have shown that the active interplay of different molecular interactions provides access to new and more complex nanostructures.

Controlled Production of Elastin-like Recombinamer Polymer-Based Membranes at a Liquid-Liquid Interface by Click Chemistry.

Diffusion of organic and inorganic molecules controls most industrial and biological processes that occur in a liquid phase. Although significant efforts have been devoted to the design and operation of large-scale purification systems, diffusion devices with adjustable biochemical characteristics have remained difficult to achieve. In this regard, micrometer-scale, bioinspired membranes with tunable diffusion properties have been engineered by covalent cross-linking of two elastin-like recombinamers (ELRs) at a liquid-liquid interface.

Dual Self-Assembled Nanostructures from Intrinsically Disordered Protein Polymers with LCST Behavior and Antimicrobial Peptides.

Antimicrobial peptides (AMPs) have attracted great interest as they constitute one of the most promising alternatives against drug-resistant infections. Their amphipathic nature not only provides them antimicrobial and immunomodulatory properties but also the ability to self-assemble into supramolecular nanostructures. Here, we propose their use as self-assembling domains to drive hierarchical organization of intrinsically disordered protein polymers (IDPPs).

Elastin-Based Materials: Promising Candidates for Cardiac Tissue Regeneration.

Stroke and cardiovascular episodes are still some of the most common diseases worldwide, causing millions of deaths and costing billions of Euros to healthcare systems. The use of new biomaterials with enhanced biological and physical properties has opened the door to new approaches in cardiovascular applications. Elastin-based materials are biomaterials with some of the most promising properties.

Influence of the Thermodynamic and Kinetic Control of Self-Assembly on the Microstructure Evolution of Silk-Elastin-Like Recombinamer Hydrogels.

Complex recombinant biomaterials that merge the self-assembling properties of different (poly)peptides provide a powerful tool for the achievement of specific structures, such as hydrogel networks, by tuning the thermodynamics and kinetics of the system through a tailored molecular design. In this work, elastin-like (EL) and silk-like (SL) polypeptides are combined to obtain a silk-elastin-like recombinamer (SELR) with dual self-assembly. First, EL domains force the molecule to undergo a phase transition above a precise temperature, which is driven by entropy and occurs very fast.

Elastin-like recombinamers in collagen-based tubular gels improve cell-mediated remodeling and viscoelastic properties.

Natural polymers are commonly used as scaffolds for vascular tissue engineering. The recognized biological properties of this class of materials are often counterbalanced by their low mechanical performance. In this work, recombinant elastin-like polypeptides (or elastin-like recombinamers, ELRs) were mixed with collagen gel and cells to produce cellularized tubular constructs in an attempt to recapitulate the mechanical behavior of the vascular extracellular matrix (ECM).

Elastin-Like Recombinamer Hydrogels for Improved Skeletal Muscle Healing Through Modulation of Macrophage Polarization.

Large skeletal muscle injuries, such as a volumetric muscle loss (VML), often result in an incomplete regeneration due to the formation of a non-contractile fibrotic scar tissue. This is, in part, due to the outbreak of an inflammatory response, which is not resolved over time, meaning that type-1 macrophages (M1, pro-inflammatory) involved in the initial stages of the process are not replaced by pro-regenerative type-2 macrophages (M2). Therefore, biomaterials that promote the shift from M1 to M2 are needed to achieve optimal regeneration in VML injuries.

Recombinant AMP/Polypeptide Self-Assembled Monolayers with Synergistic Antimicrobial Properties for Bacterial Strains of Medical Relevance.

Nosocomial infections are one of the most frequent causes of indwelling biomedical device failure. In this regard, the use of antibiofilm nanocoatings based on antimicrobial peptides (AMPs) is a promising alternative to prevent multiresistant biofilm infections. However, the limitations of chemical production impede the large-scale development of advanced antimicrobial materials that improve the properties of AMPs.

Hydrophobic Cholesteryl Moieties Trigger Substrate Cell-Membrane Interaction of Elastin-Mimetic Protein Coatings in Vitro.

A cellular coating based on hydrophobic interactions of an elastin-like recombinamer (ELR) with the cell membrane is presented. It is well-documented that biophysical properties such as net charge, hydrophobicity, and protein-driven cell-ligand (integrin binding) interactions influence the interaction of polymers, proteins or peptides with model membranes and biological cells. Most studies to enhance membrane-substrate interactions have focused on the introduction of positively charged groups to foster electrostatic interactions with the negatively charged membrane.

A novel lipase-catalyzed method for preparing ELR-based bioconjugates.

Herein we present a novel one-pot method for the chemical modification of elastin-like recombinamers (ELRs) in a mild and efficient manner involving enzymatic catalysis with Candida antarctica lipase B. The introduction of different functionalities into such ELRs could open up new possibilities for the development of advanced biomaterials for regenerative medicine and, specifically, for controlled drug delivery given their additional ability to respond to stimuli other than pH or temperature, such as glucose concentration or electromagnetic radiation. Candida antarctica lipase B immobilized on a macroporous acrylic resin (Novozym 435) was used to enzymatically couple different aminated substrates to a recombinamer containing carboxylic groups along its amino acid chain by way of an amidation reaction.

Tuning the Stiffness of Surfaces by Assembling Genetically Engineered Polypeptides with Tailored Amino Acid Sequence.

We introduce elastin-like recombinamers (ELRs) as polypeptides with precise amino acid positioning to generate polypeptide coatings with tunable rigidity. Two ELRs are used: V84-ELR, a hydrophobic monoblock, and EI-ELR, an amphiphilic diblock. Both were modified with the amine-reactive tetrakis (hydroxymethyl) phosphonium chloride compound.

Protein disorder-order interplay to guide the growth of hierarchical mineralized structures.

A major goal in materials science is to develop bioinspired functional materials based on the precise control of molecular building blocks across length scales. Here we report a protein-mediated mineralization process that takes advantage of disorder-order interplay using elastin-like recombinamers to program organic-inorganic interactions into hierarchically ordered mineralized structures. The materials comprise elongated apatite nanocrystals that are aligned and organized into microscopic prisms, which grow together into spherulite-like structures hundreds of micrometers in diameter that come together to fill macroscopic areas.

Random and oriented electrospun fibers based on a multicomponent, in situ clickable elastin-like recombinamer system for dermal tissue engineering.

Unlabelled: Herein we present a system to obtain fibers from clickable elastin-like recombinamers (ELRs) that crosslink in situ during the electrospinning process itself, with no need for any further treatment to stabilize them. These ELR-click fibers are completely stable under in vitro conditions. A wrinkled fiber morphology is obtained.

Biocompatibility of two model elastin-like recombinamer-based hydrogels formed through physical or chemical cross-linking for various applications in tissue engineering and regenerative medicine.

Biocompatibility studies, especially innate immunity induction, in vitro and in vivo cytotoxicity, and fibrosis, are often lacking for many novel biomaterials including recombinant protein-based ones, such as elastin-like recombinamers (ELRs), and has not been extensively explored in the scientific literature, in contrast to traditional biomaterials. Herein, we present the results from a set of experiments designed to elucidate the preliminary biocompatibility of 2 types of ELRs that are able to form extracellular matrix-like hydrogels through either physical or chemical cross-linking both of which are intended for different applications in tissue engineering and regenerative medicine. Initially, we present in vitro cytocompatibility results obtained upon culturing human umbilical vein endothelial cells on ELR substrates, showing optimal proliferation up to 9 days.

Regeneration of hyaline cartilage promoted by xenogeneic mesenchymal stromal cells embedded within elastin-like recombinamer-based bioactive hydrogels.

Over the last decades, novel therapeutic tools for osteochondral regeneration have arisen from the combination of mesenchymal stromal cells (MSCs) and highly specialized smart biomaterials, such as hydrogel-forming elastin-like recombinamers (ELRs), which could serve as cell-carriers. Herein, we evaluate the delivery of xenogeneic human MSCs (hMSCs) within an injectable ELR-based hydrogel carrier for osteochondral regeneration in rabbits. First, a critical-size osteochondral defect was created in the femora of the animals and subsequently filled with the ELR-based hydrogel alone or with embedded hMSCs.