Polypropylene composite mesh modified by polyurethane gel with ROS scavenging and anti-inflammatory effects for pelvic floor repair.

Development of an inflammation modulating polypropylene (PP) mesh in pelvic floor repair is an urgent clinical need. This is because PP mesh for pelvic floor repair can cause a series of complications related to foreign body reactions (FBR) in postoperative period. Therefore, we successfully prepared PP composite mesh that can scavenge reactive oxygen species (ROS) and inhibit inflammation to moderate FBR by a simple method. First, a pregel layer was formed on PP mesh by dip coating. Among them, polyurethane with polythioketal (PTK) is an excellent ROS scavenger, and dopamine methacrylamide (DMA) improves the stability of the coating and synergistically scavenges ROS. Then, a composite mesh (optimal PU50-PP) was obtained by photopolymerization. The results showed that the polyurethane gel layer was able to scavenge more than 90% of free radicals and about 75% of intracellular ROS. In vitro, PU50-PP mesh significantly scavenged ROS and resisted macrophage adhesion. After implantation in the posterior vaginal wall of rats, PU50-PP eliminated 53% of ROS, inhibited inflammation (decreased IL-6, increased IL-10), and dramatically reduced collagen deposition by about 64%, compared to PP mesh. Thus, the composite PP mesh with ROS scavenging and anti-inflammatory properties provides a promising approach for mitigating FBR.

A biocompatible polyurethane fluorescent emulsion with aggregation-induced emission for targeted tumor imaging.

The applications of fluorescence imaging in tumor detection and assistance in tumor resection have become progressively more widespread. Biocompatible fluorescent nanoparticles with high sensitivity and selectivity are a challenge for biological fluorescence imaging. Ligand-mediated targeting of nanoparticles to tumors is an appealing tactic for improving imaging efficiency. Herein, tetraphenyl ethylene (TPE) and phenylboronic acid (PBA) were introduced into polyurethane to synthesize a PU-TPE-PBA (PTP) fluorescent emulsion with aggregation-induced emission (AIE) for targeted tumor imaging. The PTP emulsion with a size of less than 50 nm shows excellent stability and high fluorescence sensitivity (extremely low TPE concentrations of 0.31 µg mL-1). Since PBA can selectively recognize and bind to sialic acid (SA) which is widely overexpressed in tumor cells, such PTP nanoparticles can be enriched in tumors and retained for longer periods due to enhanced permeability and retention (EPR) as well as active targeting effects. In addition, the PTP emulsion exhibits good biocompatibility and biosafety. Therefore, the novel PTP emulsion is promising for tumor cell imaging.

Shape-Recoverable Hyaluronic Acid-Waterborne Polyurethane Hybrid Cryogel Accelerates Hemostasis and Wound Healing.

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.