Wound management remains a worldwide challenge. It is undeniable that patients with problems such as difficulties in wound healing, metabolic disorder of the wound microenvironment and even severely infected wounds etc. always suffer great pain that affected their quality of lives. The selection of appropriate wound dressings is vital for the healing process. With the advances of technology, hydrogels dressings have been showing great potentials for the treatment of both acute wounds (e.g., burn injuries, hemorrhage, rupturing of internal organs/aorta) and chronic wounds such as diabetic foot and pressure ulcer. Particularly, in the past decade, polysaccharide-based hydrogels which are made up with abundant and reproducible natural materials that are biocompatible and biodegradable present unique features and huge flexibilities for modifications as wound dressings and are widely applicable in clinical practices. They share not only common characteristics of hydrogels such as excellent tissue adhesion, swelling, water absorption, etc., but also other properties (e.g., anti-inflammatory, bactericidal and immune regulation), to accelerate wound re-epithelialization, mimic skin structure and induce skin regeneration. Herein, in this review, we highlighted the importance of tailoring the physicochemical performance and biological functions of polysaccharide-based hydrogel wound dressings. We also summarized and discussed their clinical states of, aiming to provide valuable hints and references for the future development of more intelligent and multifunctional wound dressings of polysaccharide hydrogels.

Immunotherapy has emerged as a promising strategy for cancer treatment, in which durable immune responses were generated in patients with malignant tumors. In the past decade, biomaterials have played vital roles as smart drug delivery systems for cancer immunotherapy to achieve both enhanced therapeutic benefits and reduced side effects. Hydrogels as one of the most biocompatible and versatile biomaterials have been widely applied in localized drug delivery systems due to their unique properties, such as loadable, implantable, injectable, degradable and stimulus responsible. Herein, we have briefly summarized the recent advances on hydrogel-by-design delivery systems including the design of hydrogels and their applications for delivering of immunomodulatory molecules (e.g., cytokine, adjuvant, checkpoint inhibitor, antigen), immune cells and environmental regulatory substances in cancer immunotherapy. We have also discussed the challenges and future perspectives of hydrogels in the development of cancer immunotherapy for precision medicine at the end.

The imbalance between osteoblasts and osteoclasts is the cause of osteoporosis. Milk-derived extracellular vesicles (mEVs), excellent drug delivery nanocarriers can promote bone formation and inhibit bone resorption. In this study, we conjugated bone-targeting peptide (AspSerSer, DSS)₆ to mEVs by click chemistry and then loaded with SRT2104, a SIRT1 (silent mating-type information regulation 2 homolog 1) agonist that was proofed to help reduce bone loss. The engineered (DSS)₆-mEV-SRT2104 had the intrinsic anti-osteoporosis function of mEVs and SRT2104 to reverse the imbalance in bone homeostasis by simultaneously regulating osteogenesis and osteoclastogenesis. Furthermore, we labelled mEVs with MnB nanoparticles that can be used for the in vivo magnetic resonance imaging (MRI) visualization. The obtained nanocomposites significantly prevented bone loss in osteoporosis mice and increased bone mineral density, exhibiting superior bone accumulation under MRI. We believe the proposed of (DSS)₆-mEV-SRT2104/MnB provides a novel paradigm for osteoporosis treatment and monitoring.