Preparation of multilayer films using the negative charge of phenylboronic acid and its response to pH change, fructose, and hydrogen peroxide

ROS-responsive supramolecular antimicrobial peptides-based nanoprodrugs for cervical cancer therapy

Although antimicrobial peptides (AMPs) as a promising natural drugs can efficiently inhibit cervical cancer, poor bioavailability, low tumor selectivity, and non-selective toxicity still hinder its further application in vivo. In order to effectively address these challenges, we have developed a reactive oxygen species (ROS)-responsive targeting nanoprodrug designed for selective therapy of cervical cancer. Such nanoprodrugs (CEC-OxbCD) are fabricated by the supramolecular self-assembly of the modified β-cyclodextrin (β-CD) and AMPs. Antimicrobial peptide, CecropinXJ (CEC), is a cationic antibacterial peptide isolated from 3rd instar larvae of Bombyx mori from Xinjiang, China. OxbCD is an oxidation-responsive β-cyclodextrin material. CEC-OxbCD were synthesized using the nanoprecipitation/self-assembly method. Subsequently, the particle size distribution, morphology, drug loading efficiency, and release behaviour of CEC-OxbCD were characterised. In vitro and in vivo anti-cancer activities were also evaluated. Nanoprodrugs can be effectively disassembled under stimuli of the tumor- endogenous ROS, resulting in a rapid and on-demand release of antimicrobial peptides (AMPs) with a release rate of 90 %. Furthermore, both in vitro and in vivo experimental results demonstrate that our nanoprodrugs exhibit remarkable therapeutic efficacy against cervical cancer. This work not only provides an effective and promising therapeutic strategy for cervical cancer, but also explores a novel application for AMPs.

Hyaluronic Acid-Based Dynamic Hydrogels for Cartilage Repair and Regeneration

Hyaluronic acid (HA), an important natural polysaccharide and meanwhile, an essential component of extracellular matrix (ECM), has been widely used in tissue repair and regeneration due to its high biocompatibility, biodegradation, and bioactivity, and the versatile chemical groups for modification. Specially, HA-based dynamic hydrogels, compared with the conventional hydrogels, offer an adaptable network and biomimetic microenvironment to optimize tissue repair and the regeneration process with a striking resemblance to ECM. Herein, this review comprehensively summarizes the recent advances of HA-based dynamic hydrogels and focuses on their applications in articular cartilage repair. First, the fabrication methods and advantages of HA dynamic hydrogels are presented. Then, the applications of HA dynamic hydrogels in cartilage repair are illustrated from the perspective of cell-free and cell-encapsulated and/or bioactive molecules (drugs, factors, and ions). Finally, the current challenges and prospective directions are outlined.

Dynamic Alginate Hydrogel as an Antioxidative Bioink for Bioprinting

3D bioprinting holds great potential for use in tissue engineering to treat degenerative joint disorders, such as osteoarthritis. However, there is a lack of multifunctional bioinks that can not only support cell growth and differentiation, but also offer protection to cells against injuries caused by the elevated oxidative stress; this conditions is a common characteristic of the microenvironment of the osteoarthritis disease. To mitigate oxidative stress-induced cellular phenotype change and malfunction, an anti-oxidative bioink derived from an alginate dynamic hydrogel was developed in this study. The alginate dynamic hydrogel gelated quickly via the dynamic covalent bond between the phenylboronic acid modified alginate (Alg-PBA) and poly (vinyl alcohol) (PVA). It presented good self-healing and shear-thinning abilities because of the dynamic feature. The dynamic hydrogel supported long-term growth of mouse fibroblasts after stabilization with a secondary ionic crosslinking between introduced calcium ions and the carboxylate group in the alginate backbone. In addition, the dynamic hydrogel showed good printability, resulting in the fabrication of scaffolds with cylindrical and grid structures with good structural fidelity. Encapsulated mouse chondrocytes maintained high viability for at least 7 days in the bioprinted hydrogel after ionic crosslinking. Most importantly, in vitro studies implied that the bioprinted scaffold could reduce the intracellular oxidative stress for embedded chondrocytes under H₂O₂ exposure; it could also protect the chondrocytes from H₂O₂-induced downregulation of extracellular matrix (ECM) relevant anabolic genes (ACAN and COL2) and upregulation of a catabolic gene (MMP13). In summary, the results suggest that the dynamic alginate hydrogel can be applied as a versatile bioink for the fabrication of 3D bioprinted scaffolds with an innate antioxidative ability; this technique is expected to improve the regenerative efficacy of cartilage tissues for the treatment of joint disorders.

Dynamic hyaluronic acid hydrogel with covalent linked gelatin as an anti-oxidative bioink for cartilage tissue engineering

In the past decade, cartilage tissue engineering has arisen as a promising therapeutic option for degenerative joint diseases, such as osteoarthritis, in the hope of restoring the structure and physiological functions. Hydrogels are promising biomaterials for developing engineered scaffolds for cartilage regeneration. However, hydrogel-delivered mesenchymal stem cells or chondrocytes could be exposed to elevated levels of reactive oxygen species (ROS) in the inflammatory microenvironment after being implanted into injured joints, which may affect their phenotype and normal functions and thereby hinder the regeneration efficacy. To attenuate ROS induced side effects, a multifunctional hydrogel with an innate anti-oxidative ability was produced in this study. The hydrogel was rapidly formed through a dynamic covalent bond between phenylboronic acid grafted hyaluronic acid (HA-PBA) and poly(vinyl alcohol) and was further stabilized through a secondary crosslinking between the acrylate moiety on HA-PBA and the free thiol group from thiolated gelatin. The hydrogel is cyto-compatible and injectable and can be used as a bioink for 3D bioprinting. The viscoelastic properties of the hydrogels could be modulated through the hydrogel precursor concentration. The presence of dynamic covalent linkages contributed to its shear-thinning property and thus good printability of the hydrogel, resulting in the fabrication of a porous grid construct and a meniscus like scaffold at high structural fidelity. The bioprinted hydrogel promoted cell adhesion and chondrogenic differentiation of encapsulated rabbit adipose derived mesenchymal stem cells. Meanwhile, the hydrogel supported robust deposition of extracellular matrix components, including glycosaminoglycans and type II collagen, by embedded mouse chondrocytesin vitro. Most importantly, the hydrogel could protect encapsulated chondrocytes from ROS induced downregulation of cartilage-specific anabolic genes (ACAN and COL2) and upregulation of a catabolic gene (MMP13) after incubation with H₂O₂. Furthermore, intra-articular injection of the hydrogel in mice revealed adequate stability and good biocompatibilityin vivo. These results demonstrate that this hydrogel can be used as a novel bioink for the generation of 3D bioprinted constructs with anti-ROS ability to potentially enhance cartilage tissue regeneration in a chronic inflammatory and elevated ROS microenvironment.