Surface structure change properties: Auto-soft bionic fibrous membrane in reducing postoperative adhesion

Light-Operated Transient Unilateral Adhesive Hydrogel for Comprehensive Prevention of Postoperative Adhesions

Dislocation of anti-adhesion materials, non-specific tissue adhesion, and the induction of secondary fibrinolysis disorders are the main challenges faced by postoperative anti-adhesion materials. Herein, a self-leveling transient unilateral adhesive hydrogel is custom-designed to conquer these challenges with a theoretically calculated and dual-step tailored gellan gum (GG) as the sole agent. First, the maximum gelation temperature of GG is lowered from 42-25 °C through controlled perturbation of intra- and inter-molecular hydrogen bonds, which is achieved by employing the methacrylic anhydride as a "hydrogen bond's perturbator" to form methacrylate GG (MeGG). Second, the "self-leveling" injectability and wound shape adaptably are endowed by the formation of borate-diol complexed MeGG (BMeGG). Finally, the transient unilateral tissue-adhesive hydrogel (BMeGG-H) barrier is prepared through photo-controlled cross-linking of reactive alkenyl groups. This degradable hydrogel demonstrates favorable rheological properties, light-controlled unilateral adhesion properties, biocompatibility, anti-fibrin adhesion, and anti-cell adhesion properties in vitro. Comprehensive regulation of the fibrinolysis balance toward non-adhesion is conformed in a rat model after intra-abdominal surgery via anti-autoinflammatory response, intestinal wall integrity repair, and Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) balance adjustment. Notably, the 14th day anti-adhesion effective rate is 100%, indicating its significant potential in clinical applications for postoperative anti-adhesion.

Effect of Compressive Modulus of Porous PVA Hydrogel Coating on the Preventing Adhesion of Polypropylene Mesh

PP mesh is a widely used prosthetic material in hernia repair. However, visceral adhesion is one of the worst complications of this operation. Hence, an anti-adhesive PP mesh is developed by coating porous polyvinyl alcohol (PVA) hydrogel on PP surface via freezing-thawing process method. The compressive modulus of porous PVA hydrogel coating is first regulated by the addition of porogen sodium bicarbonate (NaHCO3) at various quality ratios with PVA. As expected, the porous hydrogel coating displayed modulus more closely resembling that of native abdominal wall tissue. In vitro tests demonstrate the modified PP mesh show superior coating stability, excellent hemocompatibility, and good cytocompatibility. In vivo experiments illustrate that PP mesh coated by the PVA4 hydrogel that mimicked the modulus of native abdominal wall could prevent adhesion effectively. Based on this, the rapamycin (RPM) is loaded into the porous PVA4 hydrogel coating to further improve anti-adhesive property of PP mesh. The Hematoxylin and eosin (H&E) and Masson trichrome (MT) staining results verified that the resulting mesh could alleviate the inflammation response and reduce the deposition of collagen around the implantation zone. The biomimetic mechanical property and anti-adhesive property of modified PP mesh make it a valuable candidate for application in hernioplasty.

Simulation and Structural Analysis of a Flexible Coupling Bionic Desorption Mechanism Based on the Engineering Discrete Element Method

Soil adhesion is one of the important factors affecting the working stability and quality of agricultural machinery. The application of bionic non-smooth surfaces provides a novel idea for soil anti-adhesion. The parameters of sandy loam with 21% moisture content were calibrated by the Engineering Discrete Element Method (EDEM). The final simulated soil repose angle was highly consistent with the measured soil repose angle, and the obtained regression equation of the soil repose angle provides a numerical reference for the parameter calibration of different soils. By simulating the sinusoidal swing of a sandfish, it was found that the contact interface shows the phenomenon of stress concentration and periodic change, which reflects the effectiveness of flexible desorption and soil anti-adhesion. The moving resistance of the wedge with different wedge angles and different serrated structures was simulated. Finally, it was found that a 40° wedge with a high-tail sparse staggered serrated structure on the surface has the best drag reduction effect, and the drag reduction is about 10.73%.

Nanofibrous scaffolds for the healing of the fibrocartilaginous enthesis: advances and prospects

With the current developmental advancements in nanotechnology, nanofibrous scaffolds are being widely used. The healing of fibrocartilaginous enthesis is a slow and complex process, and while existing treatments have a certain effect on promoting their healing, these are associated with some limitations. The nanofibrous scaffold has the advantages of easy preparation, wide source of raw materials, easy adjustment, easy modification, can mimic the natural structure and morphology of the fibrocartilaginous enthesis, and has good biocompatibility, which can compensate for existing treatments and be combined with them to promote the repair of fibrocartilaginous enthesis. The nanofibrous scaffold can promote the healing of fibrocartilaginous enthesis by controlling the morphology and ensuring controlled drug release. Hence, the use of nanofibrous scaffold with stimulative response features in the musculoskeletal system has led us to imagine its potential application in fibrocartilaginous enthesis. Therefore, the healing of fibrocartilaginous enthesis based on a nanofibrous scaffold may be a novel therapeutic approach.

Advanced hydrogels: New expectation for the repair of organic erectile dysfunction

Organic erectile dysfunction (ED) is a type of sexual disorder in men that is usually associated with illness, surgical injury, normal aging and has a high incidence across the globe. And the essence of penile erection is a neurovascular event regulated by a combination of factors. Nerve and vascular injury are the main causes of erectile dysfunction. Currently, the main treatment options for ED include phosphodiesterase type 5 inhibitors (PDE5Is), intracorporeal injections and vacuum erection devices (VEDs), which are ineffective. Therefore, it is essential to find an emerging, non-invasive and effective treatment for ED. The histopathological damage causing ED can be improved or even reversed with hydrogels, in contrast to current therapies. Hydrogels have many advantages, they can be synthesized from various raw materials with different properties, possess a definite composition, and have good biocompatibility and biodegradability. These advantages make hydrogels an effective drug carrier. In this review, we began with an overview of the underlying mechanisms of organic erectile dysfunction, discussed the dilemmas of existing treatments for ED, and described the unique advantages of hydrogel over other approaches. Then emphasizing the progress of research on hydrogels in the treatment of ED.

Biodegradable Polymer Electrospinning for Tendon Repairment

With the degradation after aging and the destruction of high-intensity exercise, the frequency of tendon injury is also increasing, which will lead to serious pain and disability. Due to the structural specificity of the tendon tissue, the traditional treatment of tendon injury repair has certain limitations. Biodegradable polymer electrospinning technology with good biocompatibility and degradability can effectively repair tendons, and its mechanical properties can be achieved by adjusting the fiber diameter and fiber spacing. Here, this review first briefly introduces the structure and function of the tendon and the repair process after injury. Then, different kinds of biodegradable natural polymers for tendon repair are summarized. Then, the advantages and disadvantages of three-dimensional (3D) electrospun products in tendon repair and regeneration are summarized, as well as the optimization of electrospun fiber scaffolds with different bioactive materials and the latest application in tendon regeneration engineering. Bioactive molecules can optimize the structure of these products and improve their repair performance. Importantly, we discuss the application of the 3D electrospinning scaffold's superior structure in different stages of tendon repair. Meanwhile, the combination of other advanced technologies has greater potential in tendon repair. Finally, the relevant patents of biodegradable electrospun scaffolds for repairing damaged tendons, as well as their clinical applications, problems in current development, and future directions are summarized. In general, the use of biodegradable electrospun fibers for tendon repair is a promising and exciting research field, but further research is needed to fully understand its potential and optimize its application in tissue engineering.

Self-Assembling Peptide-Based Hydrogels for Wound Tissue Repair

Wound healing is a long-term, multistage biological process that includes hemostasis, inflammation, proliferation, and tissue remodeling and requires intelligent designs to provide comprehensive and convenient treatment. The complexity of wounds has led to a lack of adequate wound treatment materials, which must systematically regulate unique wound microenvironments. Hydrogels have significant advantages in wound treatment due to their ability to provide spatiotemporal control over the wound healing process. Self-assembling peptide-based hydrogels are particularly attractive due to their innate biocompatibility and biodegradability along with additional advantages including ligand-receptor recognition, stimulus-responsive self-assembly, and the ability to mimic the extracellular matrix. The ability of peptide-based materials to self-assemble in response to the physiological environment, resulting in functionalized microscopic structures, makes them conducive to wound treatment. This review introduces several self-assembling peptide-based systems with various advantages and emphasizes recent advances in self-assembling peptide-based hydrogels that allow for precise control during different stages of wound healing. Moreover, the development of multifunctional self-assembling peptide-based hydrogels that can regulate and remodel the wound immune microenvironment in wound therapy with spatiotemporal control has also been summarized. Overall, this review sheds light on the future clinical and practical applications of self-assembling peptide-based hydrogels.

Mechanisms Affecting Physical Aging and Swelling by Blending an Amphiphilic Component

Polymer blending is a promising method to overcome stability obstacles induced by physical aging and swelling of implant scaffolds prepared from amorphous polymers in biomedical application, since it will not bring potential toxicity compared with chemical modification. However, the mechanism of polymer blending still remains unclearly explained in existing studies that fail to provide theoretical references in material R&D processes for stability improvement of the scaffold during ethylene oxide (EtO) sterilization, long-term storage, and clinical application. In this study, amphiphilic poly(ethylene glycol)-co-poly(lactic acid) (PELA) was blended with amorphous poly(lactic-co-glycolic acid) (PLGA) because of its good miscibility so as to adjust the glass transition temperature (Tg) and hydrophilicity of electrospun PLGA membranes. By characterizing the morphological stability and mechanical performance, the chain movement and the glass transition behavior of the polymer during the physical aging and swelling process were studied. This study revealed the modification mechanism of polymer blending at the molecular chain level, which will contribute to stability improvement and performance adjustment of implant scaffolds in biomedical application.