Gentamicin-thioctic acid multifunctional hydrogel for accelerating infected wound healing

Facile Solvent-Free Fabrication of All-Small-Molecule Supramolecular Photothermal Bioadhesive for Sutureless Wound Closure

Achieving underwater adhesion possesses a significant challenge, primarily due to the presence of interfacial water, which restricts the potential applications of adhesives. In this study, we present a straightforward and environmentally friendly one-pot approach for synthesizing a solvent-free supramolecular TPFe bioadhesive composed of thioctic acid, proanthocyanidins, and FeCl3. The bioadhesive exhibits excellent biocompatibility and photothermal antibacterial properties and demonstrates effective adhesion on various substrates in both wet and dry environments. Importantly, the adhesive strength of this bioadhesive on steel exceeds 1.2 MPa and that on porcine skin exceeds 100 kPa, which is greater than the adhesive strength of most reported bioadhesives. In addition, the bioadhesive exhibits the ability to effectively halt bleeding, close wounds promptly, and promote wound healing in the rat skin wound model. Therefore, the TPFe bioadhesive has potential as a medical bioadhesive for halting bleeding quickly and promoting wound healing in the biomedical field. This study provides a new idea for the development of bioadhesives with firm wet adhesion.

The Unprecedented Biodegradable Polyzwitterion: A Removal-Free Patch for Accelerating Infected Diabetic Wound Healing

Zwitterionic polymers have emerged as an important class of biomaterials to construct wound dressings and antifouling coatings over the past decade due to their excellent hydrophilicity. However, all the reported zwitterionic polymers as wound dressings are nondegradable because of noncleavable carbon─carbon bonding backbones, and must be removed periodically after treatment to avoid hypoxia in the wound, thus leading to potential secondary injury. In this work, a biodegradable polyzwitterion patch is fabricated for the first time by ring-opening polymerization of carboxybetaine dithiolane (CBDS), which is self-crosslinked via inter-amide hydrogen bonds and zwitterionic dipole-dipole interactions on the side chains. The unprecedented polyCBDS (PCBDS) patch demonstrates enough ductility owing to the intermolecular physical interactions to fully cover irregular wounds, also showing excellent biodegradability and antifouling performance resulted from the existence of disulfide bonds and carboxybetaine groups. Besides, the PCBDS degradation-induced released CBDS owns potent antioxidant and antibacterial activities. This PCBDS patch is used as a diabetic wound dressing, inhibiting bacterial adhesion on the external surface, and its degradation products can exactly kill bacteria and scavenge excessive reactive oxygen species (ROS) at the wound site to regulate local microenvironment, including regulation of cytokine express and macrophage polarization, accelerating infected diabetic wound repair, and also avoiding the potential secondary injury.

Mechanical Stimulation of Anti-Inflammatory and Antioxidant Hydrogels for Rapid Re-Epithelialization

The epithelium, an essential barrier to protect organisms against infection, exists in many organs. However, rapid re-epithelialization to restore tissue integrity and function in an adverse environment is challenging. In this work, a long-term anti-inflammatory and antioxidant hydrogel with mechanical stimulation for rapid re-epithelialization, mainly composed of the small molecule thioctic acid, biocompatible glycine, and γ-Fe2O3 nanoparticles is reported. Glycine-modified supramolecular thioctic acid is stable and possesses outstanding mechanical properties. The incorporating γ-Fe2O3 providing the potential contrast function for magnetic resonance imaging observation, can propel hydrogel reconfiguration to enhance the mechanical properties of the hydrogel underwater due to water-initiated release of Fe3+. In vitro experiments show that the hydrogels effectively reduced intracellular reactive oxygen species, guided macrophages toward M2 polarization, and alleviated inflammation. The effect of rapid re-epithelialization is ultimately demonstrated in a long urethral injury model in vivo, and the mechanical stimulation of hydrogels achieves effective functional replacement and ultimately accurate remodeling of the epithelium. Notably, the proposed strategy provides an advanced alternative treatment for patients in need of large-area epithelial reconstruction.

A Visible Light Cross-Linked Underwater Hydrogel Adhesive with Biodegradation and Hemostatic Ability

Hydrogel adhesives with integrated functionalities are still required to match their ever-expanding practical applications in the field of tissue repair and regeneration. A simple and effective safety strategy is reported, involving an in situ injectable polymer precursor and visible light-induced cross-linking. This strategy enables the preparation of a hydrogel adhesive in a physiological environment, offering wet adhesion to tissue surfaces, molecular flexibility, biodegradability, biocompatibility, efficient hemostatic performance, and the ability to facilitate liver injury repair. The proposed one-step preparation process of this polymer precursor involves the mixing of gelatin methacryloyl (GelMA), poly(thioctic acid) [P(TA)], poly(acrylic acid)/amorphous calcium phosphate (PAAc/ACP, PA) and FDA-approved photoinitiator solution, and a subsequent visible light irradiation after in situ injection into target tissues that resulted in a chemically-physically cross-linked hybrid hydrogel adhesive. Such a combined strategy shows promise for medical scenarios, such as uncontrollable post-traumatic bleeding.

An Injectable, Adhesive, and Self-Healing Hydrogel with Inherently Antibacterial Property for Wound Dressing

Antibacterial hydrogel has emerged as an excellent candidate for wound dressing with the ability to eliminate infection and promote wound healing. Herein, a dynamic hydrogel is developed by Schiff base reaction of mixed charged polypeptides and oxidized dextran (ODex). Specifically, biodegradable polypeptides of 1-(propylthio)acetic acid-3-butylimidazole-modified poly(L-lysine) (PLL-PBIM) and adipate dihydrazide-modified poly(L-glutamic acid) (PLG-ADH) are achieved with tunable substitution and charge. By mixing with ODex, charged polypeptides of PLL-PBIM and PLG-ADH led to an injectable and self-healing hydrogel in seconds. The injectable and self-healing performances of the hydrogels are ascribed to the reversible imine and hydrazone bonds formed between polypeptides and ODex. The positively charged hydrogels exhibited over 95% antibacterial activity against E. coli and S. aureus. An optimized balancing of PLG-ADH and PLL-PBIM significantly reduced the hemolysis rate and cytotoxicity of hydrogels. Therefore, the dynamic hydrogel with excellent biocompatibility and inherently antibacterial ability can have potential application for wound dressing.

Super Adhesive Fluorescent Materials for Encrypted Messages, Underwater Leak Repair, and Their Potential Application in Fluorescent Tattoos

Achieving high-performance luminescence for underwater bonding remains a significant challenge in materials science. This study addresses this issue by synthesizing a luminescent material based on an aggregation-induced emission (AIE) monomer and copolymerizing it with lipoic acid (LA) to create an AIE supramolecular polymer. The resulting copolymer exhibits strong fluorescence under ultraviolet (UV) irradiation at 365 nm due to the AIE of TPEE and enables underwater adhesion. The P(LA-TPEE) polymer demonstrates potential for digital encryption and decryption of quick response (QR) codes underwater. Furthermore, it can dissolve well in anhydrous ethanol, producing an environment-friendly and super waterproof adhesive. Most notably, the P(LA-TPEE) solution can be sprayed on human skin, creating an invisible tattoo that only became visible under UV light due to the hydrogen bond (H-bond) and π-π structures. This smart tattoo can be quickly wiped away with alcohol, avoiding the painful and harmful process of tattoo removal. It can also be repeatedly applied to draw the preferred tattoo pattern. This AIE supramolecular polymer shows great potential in underwater adhesion and repair, underwater message encryption, and non-toxic and painless invisible tattooing. Overall, this study provides a valuable approach for material design in the future.

A multifunctional PAN/PVP nanofiber sponge wound dressing loaded with ZIF-8-derived carbon nanoparticles with adjustable wetness for rapid wound disinfection and exudate management

Rapid and safe disinfection and exudate management are two major challenges in infected wound care. Therefore, in this work, we developed a novel wound dressing via encapsulating ZIF-8-derived carbon nanoparticles in a hydrophilic nanofiber sponge to address severe wound infection and heavy exudate problems. The dressing can effectively kill bacteria through chemo-photothermal synergistic therapy. Meanwhile, the hydrophilic nanofiber sponge can quickly absorb wound exudate around the wound and accelerate the evaporation rate of liquid through the photothermal effect and its own structure; therefore, it is possible to remove excess liquid and regulate its wetness. In this way, it prevents the problem of wound overhydration often caused by hydrophilic dressings. In our experiment, the dressing showed good antibacterial performance and biocompatibility in vitro and could effectively control wound infection, absorb wound exudate and promote skin wound healing in vivo. Its good therapeutic effect is not only due to effective infection control and wound exudate management, but also because the structure of nanofibers similar to an extracellular matrix provides basic physical support and structural  signals conducive to skin tissue regeneration.

Self-healing, self-adhesive, and stretchable conductive hydrogel for multifunctional sensor prepared by catechol modified nanocellulose stabilized poly(α-thioctic acid)

Self-healing, self-adhesive, and stretchable bio-based conductive hydrogels exhibit properties similar to those of biological tissues, making them an urgent requirement for emerging wearable devices. The primary challenge lies in devising straightforward strategies to accomplish all the aforementioned performances and achieve equilibrium among them. This study used the natural compound thioctic acid (TA) and modified cellulose to prepare conductive hydrogels with stretchability, healing, and self-adhesion through a simple one-step strategy. Metastable poly(TA) was obtained through ring-opening polymerization of lithiated TA, followed by the introduction of dopamine-grafted cellulose nanofibers (DCNF) to stabilize poly(TA) and prepare PTALi/DCNF hydrogels with the aforementioned properties. The hydrogels demonstrated remarkable conductivity, attributed to the existence of Li + ions, with a maximum conductivity of 17.36 mS/cm. The self-healing capacity of the hydrogels was achieved owing to the presence of disulfide bond in TA. The introduction of DCNF can effectively stabilize poly(TA), endow the hydrogel with self-adhesion ability, improve the mechanical properties, and further enhance the formability of hydrogels. Generally, bio-based PTALi/DCNF hydrogels with stretchability, self-healing, self-adhesion, and conductivity are obtained through a simple strategy and used as a sensor with a wide response range and high sensitivity. Hydrogels have significant potential for application in wearable electronic devices, electronic skins, and soft robots.

Underwater luminescent labeling materials constructed from a supramolecular approach

Underwater labeling under complicated conditions is challenging for modern adhesive materials. In this work, a series of supramolecular polymer adhesives were successfully prepared via the non-covalent copolymerization of low-molecular-weight monomers (thioctic acid (TA) and tetraphenylethene derivatives (TPEs)). Strong adhesion effects were observed under various conditions. The poly(TA-TPE)s showed long-term stability in underwater labeling. Due to the aggregation-induced emission (AIE) behavior of TPEs, poly(TA-TPE)s showed great potential as fluorescent labeling materials in water. Complicated and cryptographic information can be stored in labeling structures, and analyzed under ultraviolet (UV) irradiation. Supramolecular labeling showed excellent distinguishability in complex backgrounds. Meanwhile, fluorescent adhesives exhibited a number of advantages over visible colored labels.