Stiffness Self‐Tuned Shape Memory Hydrogels for Embolization of Aneurysms

Abstract

An aneurysm is a life-threatening vascular disease. Embolization with shape memory (SM) hydrogel coils is promising for the treatment of the intractable aneurysms. However, single temperature-triggered SM is softened in a catheter, and delivery of multiple coils is required, which may clog the catheter and complicate operation procedure. Here, a radiopaque temperature/pH dual responsive shape memory hydrogel with self-tuned stiffness is fabricated by copolymerizing acrylonitrile (AN, dipole-dipole interaction monomer), N-acryloyl 2-glycine (ACG, pH-sensitive H-bonding monomer), and polyethylene glycol diacrylate. Under slightly acidic conditions without eliciting cytotoxicity, additional supramolecular PACG hydrogen bonds combined with cyano dipole-dipole pairings contribute to the body temperature-triggered SM effect with an unprecedented high 430 MPa (10 °C) and 16 MPa (37 °C) Young's modulus. A carotid aneurysm is created in a dog to test the embolization of this SM hydrogel. At 37 °C, the hydrogel's high stiffness ensures its smooth delivery through a catheter. After being transported into the aneurysm sac, secondary swelling occurs concurrent with appropriate decrease of stiffness upon contacting neutral blood, thus enhancing the packing density and reducing recanalization rate and delivery times. This stiffness adaptive SM hydrogel holds its great potential as permanent embolic agents for treating a variety of aneurysms.

A Solvent‐Free and Water‐Resistant Dipole–Dipole Interaction‐Based Super Adhesive

“…The setting of specific parameters was referred to the previous work. [ 28 ] The curing kinetics of PAN–PEGDA adhesives was determined on a rheometer (MCR 302, Austria) with a shearing rate of 1 s −1 at 25 °C. The morphology of PAN–PEGDA700 films was observed using a field‐emission scanning electron microscope (Hitachi S‐4800, Japan).…”

“…Previously, we demonstrated that dipole–dipole interactions in polyacrylonitrile (PAN) could tremendously increase the mechanical properties of hydrogels. [ 28,29 ] An important feature is that the dipole–dipole pairing microdomains contributed to an outstanding antiswelling ability in aqueous solution. However, these hydrogels were nonsticky possibly due to high crosslinking density of network, which restrained the dipole–dipole interaction with substrate surface.…”

An Integrated Strategy for Rapid Hemostasis during Tumor Resection and Prevention of Postoperative Tumor Recurrence of Hepatocellular Carcinoma by Antibacterial Shape Memory Cryogel

“…inevitable tissue damage and bleeding in tumor resection will greatly increase the risk of tumor recurrence by metastasis of cancer cells with blood. [28,29] Therefore, it is very important to prepare an integrated strategy that can not only stop bleeding during tumor resection, but also assist to prevent tumor recurrence after surgery. Recent studies suggest that high concentrations of reactive oxygen species (ROS) can induce oxidative damage in tumor cells, further leading to cell death.…”

Precision Embolism: Biocompatible Temperature‐Sensitive Hydrogels as Novel Embolic Materials for Both Mainstream and Peripheral Vessels

“…[ 17 ] Moreover, as utilizing unevaluated excipients, the recently reported hydrogel‐based embolic reagents are not yet available in clinical practice because of the doubtable biocompatibility. [ 18–24 ] Therefore, the development of the ideal thermosensitive hydrogel embolic reagent for TACE treatment is still needed but challenging.…”