Preparation and Application of Biomass-based Sprayable Hydrogels

Hydrogels have three-dimensional network structures that have been widely applied owing to their high water content,excellent biocompatibility,and physicochemical properties.Compared with conventional hydrogels,sprayable hydrogels exhibit excellent temporal and spatial controllability.Biomass materials offer easy accessibility,biocompatibility,biodegradability,and other physicochemical properties that are extensively used in the formation of sprayable hydrogels.In situ formed biomass-based sprayable hydrogels are realized by chemical or physical crosslinking.Rapid spray filming,in situ drug delivery,high permeability,and flexible portability enable biomass-based sprayable hydrogels to show great potential for topical drug delivery,wound healing,and other applications.This review describes in detail the status of research on the preparation and application of biomassbased sprayable hydrogels and suggests prospects for their future development.

Sprayable Immunotherapy Gel on Surgical Site Reduces Cancer Recurrence and Metastasis

A large portion of cancer patients will undergo some types of surgery to treat their disease.Despite the continuous improvement in surgical techniques over the past decades,many patients still develop tumor recurrence,which leads to severe mortality[1-3].Immunotherapy provides a new promise to cure cancer.Macrophages are major components of the innate immunity,and phagocytize foreign substances.However,cancer cells can escape macrophage recognition through displaying“don’t eat me”signal via up-regulation of CD47 protein on their surface[4-5].Several ongoing clinical trials are looking at ways to block CD47,but the side effects such as anemia and thrombocytopenia caused by systemic administration can not be ignored,since the red blood cells also express CD47 on their surface.Avoiding these severe side effects are essential to make CD47-blocking immunotherapies clinically applicable[6-7].In addition,the macrophages within tumor tissues are M2-like phenotype,and exert pro-tumourigenic activities.

Advancing homogeneous networking principles for the development of fatigue-resistant,low-swelling and sprayable hydrogels for sealing wet,dynamic and concealed wounds in vivo

Effective sealing of wet,dynamic and concealed wounds remains a formidable challenge in clinical practice.Sprayable hydrogel sealants are promising due to their ability to cover a wide area rapidly,but they face limitations in dynamic and moist environments.To address this issue,we have employed the principle of a homogeneous network to design a sprayable hydrogel sealant with enhanced fatigue resistance and reduced swelling.This network is formed by combining the spherical structure of lysozyme(LZM)with the orthotetrahedral structure of 4-arm-polyethylene glycol(4-arm-PEG).We have achieved exceptional sprayability by controlling the pH of the precursor solution.The homogeneous network,constructed through uniform cross-linking of amino groups in protein and 4-arm-PEG-NHS,provides the hydrogel with outstanding fatigue resistance,low swelling and sustained adhesion.In vitro testing demonstrated that it could endure 2000 cycles of underwater shearing,while in vivo experiments showed adhesion maintenance exceeding 24 h.Furthermore,the hydrogel excelled in sealing leaks and promoting ulcer healing in models including porcine cardiac hemorrhage,lung air leakage and rat oral ulcers,surpassing commonly used clinical materials.Therefore,our research presents an advanced biomaterial strategy with the potential to advance the clinical management of wet,dynamic and concealed wounds.

Sprayable nanodrug-loaded hydrogels with enzyme-catalyzed semiinter penetrating polymer network(Semi-IPN)for solar dermatitis

Solar dermatitis is an acute or chronic high incidence of skin injury caused by ultraviolet(UV)radiation based on strong sunlight,which seriously endangers people's health.In this study,we designed and demonstrated enzyme-catalyzed semi-inter penetrating polymer network(Semi-IPN)sprayable nanodrug-loaded hydrogels based on gelatin,3-(4-hydroxyphenyl)propionic acid(HPA),polyvinyl alcohol(PVA),glycerol,and dexamethasone sodium phosphate(DEXP)for solar dermatitis.The hydrogels had high water content,excellent biocompatibility,effective encapsulation and sustained release of nanodrugs,antiinflammatory,and strong anti-ultraviolet B(anti-UVB)radiation properties based on glycerol and phenol functional groups,but also controllable spray gelation mode to make them adhere well on the dynamic skin surfaces and achieve continuous transdermal drugs delivery for solar dermatitis.The sprayable nanodrug-loaded hydrogel systems could be used as a highly effective therapeutic method for solar dermatitis,and also provide a good strategy for designing novel nanodrug-loaded hydrogel delivery systems.

Strengthening of the concrete face slabs of dams using sprayable strain-hardening fiber-reinforced cementitious composites

In this study,sprayable strain-hardening fiber-reinforced cementitious composites(FRCC)were applied to strengthen the concrete slabs in a concrete-face rockfill dam(CFRD)for the first time.Experimental,numerical,and analytical investigations were carried out to understand the flexural properties of FRCC-layered concrete slabs.It was found that the FRCC layer improved the flexural performance of concrete slabs significantly.The cracking and ultimate loads of a concrete slab with an 80 mm FRCC layer were 132%and 69%higher than those of the unstrengthened concrete slab,respectively.At the maximum crack width of 0.2 mm,the deflection of the 80-mm FRCC strengthened concrete slab was 144%higher than that of the unstrengthened concrete slab.In addition,a FE model and a simplified analytical method were developed for the design and analysis of FRCC-layered concrete slabs.Finally,the test result of FRCC leaching solution indicated that the quality of the water surrounding FRCC satisfied the standard for drinking water.The findings of this study indicate that the sprayable strain-hardening FRCC has a good potential for strengthening hydraulic structures such as CFRDs.

Recent advances on thermosensitive hydrogels-mediated precision therapy

Precision therapy has become the preferred choice attributed to the optimal drug concentration in target sites,increased therapeutic efficacy,and reduced adverse effects.Over the past few years,sprayable or injectable thermosensitive hydrogels have exhibited high therapeutic potential.These can be applied as cell-growing scaffolds or drug-releasing reservoirs by simply mixing in a free-flowing sol phase at room temperature.Inspired by their unique properties,thermosensitive hydrogels have been widely applied as drug delivery and treatment platforms for precision medicine.In this review,the state-of-theart developments in thermosensitive hydrogels for precision therapy are investigated,which covers from the thermo-gelling mechanisms and main components to biomedical applications,including wound healing,anti-tumor activity,osteogenesis,and periodontal,sinonasal and ophthalmic diseases.The most promising applications and trends of thermosensitive hydrogels for precision therapy are also discussed in light of their unique features.