A MgAl-LDH-CuS nanosheet-based thermo-responsive composite hydrogel with nir-responsive angiogenesis inhibitor releasing capability for multimode starvation therapy

The rapid proliferation of tumors is highly dependent on the nutrition supply of blood vessels. Cutting off the nutrient supply to tumors is an effective strategy for cancer treatment, known as starvation therapy. Although various hydrogel-based biomaterials have been developed for starvation therapy through glucose consumption or intravascular embolization, the limitations of single-mode starvation therapy hinder their therapeutic effects. Herein, we propose a dual-function nutrition deprivation strategy that can block the nutrients delivery through extravascular gelation shrinkage and inhibit neovascularization through angiogenesis inhibitors based on a novel NIR-responsive nanocomposite hydrogel. CuS nanodots-modified MgAl-LDH nanosheets loaded with angiogenesis inhibitor (sorafenib, SOR) are incorporated into the poly(n-isopropylacrylamide) (PNIPAAm) hydrogel by radical polymerization to obtain the composite hydrogel (SOR@LDH-CuS/P). The SOR@LDH-CuS/P hydrogel can deliver hydrophobic SOR with a NIR-responsive release behavior, which could decrease the tumor vascular density and accelerate cancer cells apoptosis. Moreover, the SOR@LDH-CuS/P hydrogel exhibits higher (3.5 times) compressive strength than that of the PNIPAAm, which could squeeze blood vessels through extravascular gelation shrinkage. In vitro and in vivo assays demonstrate that the interruption of nutrient supply by gelation shrinkage and the prevention of angiogenesis by SOR is a promising strategy to inhibit tumor growth for multimode starvation therapy.

An injectable multifunctional thermo-sensitive chitosan-based hydrogel for periodontitis therapy

Bacteria are recognized as the driving factors of periodontitis. However, excessive reactive oxygen species (ROS) can harm periodontal tissue while also causing an uncontrolled inflammatory response. Hence, eliminating excessive ROS and blocking ROS-induced abnormal inflammatory response by antioxidants are achieving remarkable results in periodontitis therapy. Moreover, influenced by the deep and irregular periodontal pockets, injectable thermo-sensitive chitosan-based hydrogels have attracted a lot of attention. This study aimed to formulate an antibacterial and antioxidant therapeutic regimen by incorporating antimicrobial peptides (Nal-P-113) and/or antioxidants (polydopamine nanoparticles, PDNPs) into chitosan-based hydrogels. The hydrogel was characterized in vitro and finally examined in rats using the experimental periodontitis model. The release kinetics showed that the hydrogel could stably release Nal-P-113 and PDNPs for up to 13 days. The scavenging activity of the hydrogel against DPPH was about 80 % and the antibacterial ratio against Streptococcus gordonii (S. gordonii), Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) was about 99 %. Importantly, it was examined that the hydrogel had the ability to prevent periodontal tissue damage. Thus, chitosan-based hydrogels may provide a basis for designing multifunctional local drug delivery biomaterials for the treatment of periodontitis.

Multifunctional thermo-sensitive hydrogel for modulating the microenvironment in Osteoarthritis by polarizing macrophages and scavenging RONS

Osteoarthritis (OA) is a common degenerative joint disease that can lead to disability. Blocking the complex malignant feedback loop system dominated by oxidative stress and pro-inflammatory factors is the key to treating OA. Here, we develop a multifunctional composite thermo-sensitive hydrogel (HPP@Cu gel), which is utilized by Poloxamer 407 (P407) and hyaluronic acid (HA) mixture as the gel matrix, then physically mixed with copper nanodots (Cu NDs) and platelet-rich plasma (PRP). Cu NDs is a novel nano-scavenger of reactive oxygen and nitrogen species (RONS) with efficient free radical scavenging activity. HPP@Cu gel is injected into the articular cavity, where it form an in situ gel that slowly released Cu NDs, HA, and PRP, prolonging the duration of drug action. Our results indicate that HPP@Cu gel could efficiently remove RONS from inflammatory sites and promote repolarization of macrophages to an anti-inflammatory phenotype. The HPP@Cu gel therapy dramatically reduces cartilage degradation and inflammatory factor production in OA rats. This study provides a reliable reference for the application of injectable hydrogels in inflammatory diseases associated with oxidative stress.

Novel fusion peptides deliver exosomes to modify injectable thermo-sensitive hydrogels for bone regeneration

Injectable thermo-sensitive hydrogels composed of small intestinal submucosa (SIS) with exosomes derived from bone marrow mesenchymal stem cells (BMSCs) are desired for bone regeneration. However, poor mechanical properties limit the clinical application of SIS hydrogels. Herein, the mechanical properties of SIS hydrogels incorporated with 3-(3,4-dihydroxyphenyl) propionic acid (CA) are assessed. The results show that the mechanical properties of SIS hydrogels are improved. In addition, the retention and stability of exosomes over time at the defect site are also challenges. Fusion peptides are designed by connecting collagen-binding domines (CBDs) of collagen type I/III with exosomal capture peptides CP05 (CRHSQMTVTSRL) directly or via rigid linkers (EAAAK). In vitro experiments demonstrate that fusion peptides are contribute to promoting the positive effect of exosomes on osteogenic differentiation of BMSCs. Meanwhile, the results of hydrogels combining exosomes and fusion peptides in the treatment of rat skull defect models reveal that fusion peptides could enhance the retention and stability of exosomes, thereby strengthen the therapeutic effect for skull defects. Therefore, SIS hydrogels with CA modified by fusion peptides and exosomes appear to be a promising strategy in bone regenerative medicine.