Wound
dressings that promote quick hemostasis and are highly efficient
in healing wounds are urgently needed to meet the increase in clinical
demands worldwide. Herein, a dihydrazide-modified waterborne biodegradable
polyurethane emulsion (PU-ADH) and oxidized hyaluronic acid (OHA)
were autonomously cross-linked to form a hybrid hyaluronic acid–polyurethane
(HA-PU) cryogel by hydrazone bonding at −20 °C. Through
its specific macroporous structure (which is approximately 220 μm)
constructed by aggregated PU-ADH particles and long-chain OHA, a dried
cryogel can have a dramatically compressed volume (1/7 of its original
volume) with stable fixation, and it can swell rapidly by absorbing
water or blood to approximately 22 and 16 times its dried weight,
respectively, in a few minutes. This instantaneous shape-recovering
ability favors fast hemostasis in minimally invasive surgery. Moreover,
this cryogel is superior to gauze, has excellent biocompatibility,
and quickly coagulates blood (in approximately 2 min) by activating
the endogenous coagulation system. Comparably, an injectable HA-PU
hydrogel with the same components as the HA-PU cryogel was prepared
at room temperature, and it exhibited good self-healing properties.
An in vivo evaluation of a rat liver hemostasis model
and rat skin defect model revealed that the cryogel in fast hemostasis
has great potential and superior wound-healing abilities, decreases
immune inflammation, and promotes the regeneration of angiogenesis
and hair follicles. Consequently, this work proposes a versatile method
for constructing biodegradable hybrid cryogels via autonomous cross-linking
between synthesized polymer emulsions and natural polymers. The hybrid
cryogels demonstrated great potential for applications as high-performance
wound dressings.
Living/controlled free radical copolymerization of chlorotrifluoroethene and butyl vinyl ether has been successfully achieved at room temperature under (60)Co γ-ray irradiation in the presence of S-benzyl O-ethyl dithiocarbonate. The alternating and block copolymers have been obtained with well-defined molecular weights and narrow molecular weight distributions.
Vocal fold (VF) scarring results from injury to the unique
layered
structure and is one of the main reasons for long-lasting dysphonia.
A minimally invasive procedure with injectable hydrogels is a promising
method for therapy. However, current surgical techniques or standard
injectable fillers do not yield satisfactory outcomes. In this work,
an injectable hybrid hydrogel consisting of oxide hyaluronic acid
and hydrazide-modified waterborne polyurethane emulsion was injected
precisely into the injury site and cross-linked in situ by a dynamic
hydrazone bond. The prepared hydrogel displays excellent injectability
and self-healing ability, showing favorable biocompatibility and biodegradability
to facilitate endogenous newborn cell migration and growth for tissue
regeneration. With the aim of evaluating the antifibrosis and regeneration
capacity of the hybrid hydrogel in the VF scarring model, the morphology
and vibration characteristics of VFs, inflammatory response, and healing
status were collected. The hybrid hydrogel can decrease the inflammation
and increase the ratio of collagen III/collagen I to heal damaged
scar-free tissue. Fascinatingly, the mucosal wave oscillations of
healing VF by injecting the hybrid hydrogel were vibrated like the
normal VF, achieving functional restoration. This work highlights
the utility of hybrid hydrogels consisting of synthetic biodegradable
waterborne polyurethane emulsions and natural hyaluronic acid as promising
biomaterials for scarless healing of damaged VFs.
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