Sequentially Moldable and Bondable Four-Dimensional Hydrogels Compatible with Cell Encapsulation

Advanced application of carbohydrate-based micro/nanoparticles for rheumatoid arthritis

Rheumatoid arthritis (RA) is a kind of synovitis and progressive joint destruction disease. Dysregulated immune cell activation, inflammatory cytokine overproduction, and subsequent reactive oxidative species (ROS) production contribute to the RA process. Carbohydrates, including cellulose, chitosan, alginate and dextran, are among the most abundant and important biomolecules in nature and are widely used in biomedicine. Carbohydrate-based micro/nanoparticles(M/NPs) as functional excipients have the ability to improve the bioavailability, solubility and stability of numerous drugs used in RA therapy. For on-demand therapy, smart reactive M/NPs have been developed to respond to a variety of chemical and physical stimuli, including light, temperature, enzymes, pH and ROS, alternating their physical and macroscopic properties, resulting in innovative new drug delivery systems. In particular, advanced products with targeted dextran or hyaluronic acid are exploiting multiple beneficial properties at the same time. In addition to those that respond, there are promising new derivatives in development with microenvironment and chronotherapy effects. In this review, we provide an overview of these recent developments and an outlook on how this class of agents will further shape the landscape of drug delivery for RA treatment.

Supramolecular Hydrogels and Water Channels of Differing Diameters from Dipeptide Isomers

Dipeptides stereoisomers and regioisomers composed of norleucine (Nle) and phenylalanine (Phe) self-assemble into hydrogels under physiological conditions that are suitable for cell culture. The supramolecular behavior, however, differs as the packing modes comprise amphipathic layers or water channels, whose diameter is defined by either four or six dipeptide molecules. A variety of spectroscopy, microscopy, and synchrotron-radiation-based techniques unveil fine details of intermolecular interactions that pinpoint the relationship between the chemical structure and ability to form supramolecular architectures that define soft biomaterials.

Chitosan, chondroitin sulfate, and hyaluronic acid based in-situ forming scaffold for efficient cell grafting

Current cell grafting techniques are majorly dependent on seeding cells on a pre-formed scaffold. However, cells grow in a 2-dimensional (2D) space in such constructs, not mimicking the tissue's 3-dimensional (3D) architecture. The present study evaluated a unique poly-electrolyte complexation (PEC) based strategy for the 3D engraftment of cells in a porous polymeric scaffold. The scaffold was synthesized using a positively charged polysaccharide chitosan (CH) and negatively charged glycosaminoglycans chondroitin sulfate (CS) and hyaluronic acid (HA). Two different scaffolds were synthesized, one using CH and CS [CH-CS] and another using CH and CS + HA [CH-(CS-HA)]. The physicochemical characterization of both the PECs confirmed electrostatic interactions, leading to a porous and viscoelastic PEC formation. Fibroblast cells were grafted and seeded in both scaffolds to evaluate the effect of different scaffold compositions and the difference between seeded and grafted cells. Imaging studies confirmed that grafting of the fibroblast cells supports cellular proliferation. The qPCR studies demonstrated increased expression of functional markers TGF-β, α-SMA, collagen-I, and fibronectin in the CH-(CS-HA) grafted cells. In summary, it was demonstrated that an in-situ forming PEC of CH, CS, and HA had good physicochemical properties for cell grafting and supported grafted cells with improved function.

Green approaches for extraction, chemical modification and processing of marine polysaccharides for biomedical applications

Over the past few decades, natural-origin polysaccharides have received increasing attention across different fields of application, including biomedicine and biotechnology, because of their specific physicochemical and biological properties that have afforded the fabrication of a plethora of multifunctional devices for healthcare applications. More recently, marine raw materials from fisheries and aquaculture have emerged as a highly sustainable approach to convert marine biomass into added-value polysaccharides for human benefit. Nowadays, significant efforts have been made to combine such circular bio-based approach with cost-effective and environmentally-friendly technologies that enable the isolation of marine-origin polysaccharides up to the final construction of a biomedical device, thus developing an entirely sustainable pipeline. In this regard, the present review intends to provide an up-to-date outlook on the current green extraction methodologies of marine-origin polysaccharides and their molecular engineering toolbox for designing a multitude of biomaterial platforms for healthcare. Furthermore, we discuss how to foster circular bio-based approaches to pursue the further development of added-value biomedical devices, while preserving the marine ecosystem.

Engineering Hydrogels for Modulation of Material-Cell Interactions

Hydrogels are a recurrent platform for Tissue Engineering (TE) strategies. Their versatility and the variety of available methods for tuning their properties highly contribute to hydrogels' success. As a result, the design of advanced hydrogels has been thoroughly studied, in the quest for better solutions not only for drugs- and cell-based therapies but also for more fundamental studies. The wide variety of sources, crosslinking strategies, and functionalization methods, and mostly the resemblance of hydrogels to the natural extracellular matrix, make this 3D hydrated structures an excellent tool for TE approaches. The state-of-the-art information regarding hydrogel design, processing methods, and the influence of different hydrogel formulations on the final cell-biomaterial interactions are overviewed herein. This article is protected by copyright. All rights reserved.

Self-glucose feeding hydrogels by enzyme empowered degradation for 3D cell culture

Hydrogels have been used in combination with cells for several biomedical and biotechnological applications. Nevertheless, the use of bulk hydrogels has exhibited severe limitations in diffusion of oxygen, nutrients, and metabolites. Here, a support for cell culture is reported where glucose is generated in situ by the own hydrogel degradation, allowing cell survival and function while promoting tissue growth. For this purpose, laminaran (or laminarin)-based hydrogels were fabricated, immobilizing the adequate enzymes to obtain structural platforms for 3D cell culture and providing glucose feeding for metabolic activity of cells through polysaccharide degradation. We demonstrate that tumor A549 cells and human mesenchymal stem cells (hMSCs) can use the glucose resultant from the hydrogel degradation to survive and grow in non-added glucose cell culture medium. Additionally, in vivo biocompatibility and biodegradability of laminaran-based hydrogels were explored for the first time. The self-feeding hydrogels exhibited high potential in cell survival compared to native cell-laden laminaran hydrogels over two weeks of sub-cutaneous implantation. Such bioscaffolds with enzyme-empowered degradation capacity can be applied in diverse biotechnological contexts such as tissue regeneration devices, biofactories, disease models, and cell delivery systems.

Recent Progress on Polysaccharide-Based Hydrogels for Controlled Delivery of Therapeutic Biomolecules

A plethora of applications using polysaccharides have been developed in recent years due to their availability as well as their frequent nontoxicity and biodegradability. These polymers are usually obtained from renewable sources or are byproducts of industrial processes, thus, their use is collaborative in waste management and shows promise for an enhanced sustainable circular economy. Regarding the development of novel delivery systems for biotherapeutics, the potential of polysaccharides is attractive for the previously mentioned properties and also for the possibility of chemical modification of their structures, their ability to form matrixes of diverse architectures and mechanical properties, as well as for their ability to maintain bioactivity following incorporation of the biomolecules into the matrix. Biotherapeutics, such as proteins, growth factors, gene vectors, enzymes, hormones, DNA/RNA, and antibodies are currently in use as major therapeutics in a wide range of pathologies. In the present review, we summarize recent progress in the development of polysaccharide-based hydrogels of diverse nature, alone or in combination with other polymers or drug delivery systems, which have been implemented in the delivery of biotherapeutics in the pharmaceutical and biomedical fields.

Polysaccharide-Based Materials Created by Physical Processes: From Preparation to Biomedical Applications

Polysaccharide-based materials created by physical processes have received considerable attention for biomedical applications. These structures are often made by associating charged polyelectrolytes in aqueous solutions, avoiding toxic chemistries (crosslinking agents). We review the principal polysaccharides (glycosaminoglycans, marine polysaccharides, and derivatives) containing ionizable groups in their structures and cellulose (neutral polysaccharide). Physical materials with high stability in aqueous media can be developed depending on the selected strategy. We review strategies, including coacervation, ionotropic gelation, electrospinning, layer-by-layer coating, gelation of polymer blends, solvent evaporation, and freezing-thawing methods, that create polysaccharide-based assemblies via in situ (one-step) methods for biomedical applications. We focus on materials used for growth factor (GFs) delivery, scaffolds, antimicrobial coatings, and wound dressings.

Modular Functionalization of Laminarin to Create Value-Added Naturally Derived Macromolecules

With society's growing awareness of climate change, novel renewable and naturally sourced materials have received increasing attention as substitutes for petroleum-based products. Laminarin (LAM-OH) is a highly abundant, nontoxic, degradable polysaccharide found in marine organisms and hence is a promising sustainable polymeric candidate. This work reports on a simple, environmentally friendly, and customizable functionalization strategy for producing a toolbox of LAM-OH derivatives under mild conditions. Herein, natural-origin macromolecules exhibiting specific chemical moieties, namely, allyl, amine, carboxylic acid, thiol, aldehyde, and catechol, were prepared and chemically characterized. Furthermore, the obtained polymers were processed into cytocompatible hydrogels, obtained by employing distinct cross-linking mechanisms, to assess their potential for biomedical purposes. The application scope of such polymers could be extended to fields such as catalysis, cosmetics, life sciences, and food packaging, which can also benefit from having sustainable, nontoxic, and degradable materials. Moreover, it is anticipated that the methodology employed to create this library of new natural-based products could be adapted to modify other polysaccharides and biopolymers in general.

Natural Polymer-based Stimuli-responsive Hydrogels

The abilities of intelligent polymer hydrogels to change their structure and volume phase in response to external stimuli have provided new possibilities for various advanced technologies and great research and application potentials in the medical field. The natural polymer-based hydrogels have the advantages of environment-friendliness, rich sources and good biocompatibility. Based on their responsiveness to external stimuli, the natural polymer-based hydrogels can be classified into the temperature-responsive hydrogel, pH-responsive hydrogel, light-responsive hydrogel, electricresponsive hydrogel, redox-responsive hydrogel, enzyme-responsive hydrogel, magnetic-responsive hydrogel, multi-responsive hydrogel, etc. In this review, we have compiled some recent studies on natural polymer-based stimuli-responsive hydrogels, especially the hydrogels prepared from polysaccharides. The preparation methods, properties and applications of these hydrogels in the medical field are highlighted.

Injectable Biomaterials for Dental Tissue Regeneration

Injectable biomaterials scaffolds play a pivotal role for dental tissue regeneration, as such materials are highly applicable in the dental field, particularly when compared to pre-formed scaffolds. The defects in the maxilla-oral area are normally small, confined and sometimes hard to access. This narrative review describes different types of biomaterials for dental tissue regeneration, and also discusses the potential use of nanofibers for dental tissues. Various studies suggest that tissue engineering approaches involving the use of injectable biomaterials have the potential of restoring not only dental tissue function but also their biological purposes.

Mechanochemical Patternable ECM-Mimetic Hydrogels for Programmed Cell Orientation

Native human tissues are supported by a viscoelastic extracellular matrix (ECM) that can adapt its intricate network to dynamic mechanical stimuli. To recapitulate the unique ECM biofunctionality, hydrogel design is shifting from typical covalent crosslinks toward covalently adaptable networks. To pursue such properties, herein hybrid polysaccharide-polypeptide networks are designed based on dynamic covalent assembly inspired by natural ECM crosslinking processes. This is achieved through the synthesis of an amine-reactive oxidized-laminarin biopolymer that can readily crosslink with gelatin (oxLAM-Gelatin) and simultaneously allow cell encapsulation. Interestingly, the rational design of oxLAM-Gelatin hydrogels with varying aldehyde-to-amine ratios enables a refined control over crosslinking kinetics, viscoelastic properties, and degradability profile. The mechanochemical features of these hydrogels post-crosslinking offer an alternative route for imprinting any intended nano- or microtopography in ECM-mimetic matrices bearing inherent cell-adhesive motifs. Different patterns are easily paved in oxLAM-Gelatin under physiological conditions and complex topographical configurations are retained along time. Human adipose-derived mesenchymal stem cells contacting mechanically sculpted oxLAM-Gelatin hydrogels sense the underlying surface nanotopography and align parallel to the anisotropic nanoridge/nanogroove intercalating array. These findings demonstrate that covalently adaptable features in ECM-mimetic networks can be leveraged to combine surface topography and cell-adhesive motifs as they appear in natural matrices.