Flexible PVDF based piezoelectric nanogenerators

Biodegradable cryogel wound dressing which can stop deep noncompressible hemorrhage and simultaneously promote wound healing is a highly promising biomaterial in clinics. Here, we prepared a series...

Degradable Gelatin-Based IPN Cryogel Hemostat for Rapidly Stopping Deep Noncompressible Hemorrhage and Simultaneously Improving Wound Healing

Polymeric tissue adhesives provide versatile materials for wound management and are widely used in a variety of medical settings ranging from minor to life-threatening tissue injuries. Compared to the traditional methods of wound closure (i.e., suturing and stapling), they are relatively easy to use, enable rapid application, and introduce minimal tissue damage. Furthermore, they can act as hemostats to control bleeding and provide a tissue-healing environment at the wound site. Despite their numerous current applications, tissue adhesives still face several limitations and unresolved challenges (e.g., weak adhesion strength and poor mechanical properties) that limit their use, leaving ample room for future improvements. Successful development of next-generation adhesives will likely require a holistic understanding of the chemical and physical properties of the tissue-adhesive interface, fundamental mechanisms of tissue adhesion, and requirements for specific clinical applications. In this review, we discuss a set of rational guidelines for design of adhesives, recent progress in the field along with examples of commercially available adhesives and those under development, tissue-specific considerations, and finally potential functions for future adhesives. Advances in tissue adhesives will open new avenues for wound care and potentially provide potent therapeutics for various medical applications.

Polymeric Tissue Adhesives.

Bacterial infection can cause chronic nonhealing wounds, which may be a great threat to public health. It is highly desirable to develop an injectable wound dressing hydrogel with multifunctions including self‐healing, remodeling, antibacterial, radical scavenging ability, and excellent photothermal properties to promote the regeneration of damaged tissues in clinical practice. In this work, dopamine‐modified gelatin (Gel‐DA) is employed for the first time as a biotemplate for enhancing the biomineralization ability of gelatin to synthesize dopamine‐modified gelatin@Ag nanoparticles (Gel‐DA@Ag NPs). Further, the prepared Gel‐DA@Ag NPs with antioxidant activity and near‐infrared (NIR) laser irradiation synergistic antibacterial behavior are fixed in the guar gum based hydrogels through the formation of borate/didiol bonds to possess remolding, injectable, and self‐healing performance. In addition, the multifunctional hydrogels can completely cover the irregular wound shape to prevent secondary injury. More importantly, these hydrogel platforms under NIR can significantly accelerate wound healing with more skin appendages like hair follicles and blood vessels appearing. Therefore, it is expected that these hydrogels can serve as competitive multifunctional dressings in biomedical field, including bacteria‐derived wound infection and other tissue repair related to reactive oxygen species overexpression.

Multifunctional Injectable Hydrogel Dressings for Effectively Accelerating Wound Healing: Enhancing Biomineralization Strategy

Piezoelectric materials are widely referred to as "smart" materials because they can transduce mechanical pressure acting on them to electrical signals and vice versa. They are extensively utilized in harvesting mechanical energy from vibrations, human motion, mechanical loads, etc., and converting them into electrical energy for low power devices. Piezoelectric transduction offers high scalability, simple device designs, and high-power densities compared to electro-magnetic/static and triboelectric transducers. This review aims to give a holistic overview of recent developments in piezoelectric nanostructured materials, polymers, polymer nanocomposites, and piezoelectric films for implementation in energy harvesting. The progress in fabrication techniques, morphology, piezoelectric properties, energy harvesting performance, and underpinning fundamental mechanisms for each class of materials, including polymer nanocomposites using conducting, non-conducting, and hybrid fillers are discussed. The emergent application horizon of piezoelectric energy harvesters particularly for wireless devices and self-powered sensors is highlighted, and the current challenges and future prospects are critically discussed.

Piezoelectric Materials for Energy Harvesting and Sensing Applications: Roadmap for Future Smart Materials

Commercial or clinical tissue adhesives are currently limited due to their weak bonding strength on wet biological tissue surface, low biological compatibility, and slow adhesion formation. Although catechol-modified hyaluronic acid (HA) adhesives are developed, they suffer from limitations: insufficient adhesiveness and overfast degradation, attributed to low substitution of catechol groups. In this study, we demonstrate a simple and efficient strategy to prepare mussel-inspired HA hydrogel adhesives with improved degree of substitution of catechol groups. Because of the significantly increased grafting ratio of catechol groups, dopamine-conjugated dialdehyde-HA (DAHA) hydrogels exhibit excellent tissue adhesion performance (i.e., adhesive strength of 90.0 ± 6.7 kPa), which are significantly higher than those found in dopamine-conjugated HA hydrogels (∼10 kPa), photo-cross-linkable HA hydrogels (∼13 kPa), or commercially available fibrin glues (2-40 kPa). At the same time, their maximum adhesion energy is 384.6 ± 26.0 J m-2, which also is 40-400-fold, 2-40-fold, and ∼8-fold higher than those of the mussel-based adhesive, cyanoacrylate, and fibrin glues, respectively. Moreover, the hydrogels can gel rapidly within 60 s and have a tunable degradation suitable for tissue regeneration. Together with their cytocompatibility and good cell adhesion, they are promising materials as new biological adhesives.

Dopamine-Modified Hyaluronic Acid Hydrogel Adhesives with Fast-Forming and High Tissue Adhesion.

Enhanced piezoelectric performance of BiCl3/PVDF nanofibers-based nanogenerators

The invention relates to medical equipment, particularly a medical scaffold with an inner coating film, and a preparation method for the medical scaffold, and belongs to the field of medical equipment. In the medical scaffold with the inner coating film, a non-woven inner coating film of which fibers are distributed on the axial direction of the medical scaffold is prepared on the inner surface of an inner film by an electrospinning method by taking a coating film scaffold as a basis, wherein the coating film scaffold consists of a netlike scaffold which is formed by weaving medical alloy wires, an electrospinning non-woven inner film and an electrospinning non-woven outer film; and the thickness of the inner coating film is 2 to 6 mu m. During preparation of the medical scaffold with the inner coating film, the inner coating film, the inner film and the outer film are prepared sequentially, and the inner coating film in the medical scaffold improves the biocompatibility with tract tissues of a human body, facilitates adhesion, migration and reproduction of endothelial cells at two ends of the medical scaffold, promotes quick endothelialization of the medical scaffold, and prevents the medical scaffold from becoming narrow again. The preparation method for the medical scaffold is simple, convenient to operate, and low in cost, and suitable for preparation of medical scaffolds with different diameters and lengths.

Medical scaffold with inner coating film, and preparation method for medical scaffold

The invention relates to a ligament support containing silk fibroin compound oriented nanofiber and a preparation method thereof, and belongs to the technical field of medical apparatus and instruments. The ligament support is prepared from oriented fiber combining silk fibroin with a medical high molecular synthetic material and has a porous three dimensional structure, the mass ratio of the silk fibroin and medical high molecular synthetic material in the compound oriented fiber is (1-20):(1-1), the diameter of the compound oriented fiber is 500nm-10000nm, the thickness of the ligament is 1mm-10mm, and the width of the ligament is 1mm-15mm. The ligament support has a uniform microstructure and good biocompatibility, provides a matrix structure for growing of ligament cells, and can be used for increasing the tensile strength of the ligament due to the compound fiber orientated structure. The ligament support is simple in preparation method and convenient to operate, the preparation process is controllable, and the preparation method is suitable for preparing the ligament supports of various sections and lengths.

Ligament support and preparation method thereof

The invention relates to a preparation method of a hydrogel matrix, especially a preparation method of an alginic acid hydrogel matrix for UV 3D printing, and belongs to the technical field of biological material preparation. According to the preparation method, alkenyl groups are grafted on the molecular chains of sodium alginate prepared by a freeze-dry method, and after dissolving and mixing, the alginic acid hydrogel matrix for UV 3D printing is obtained. The preparation method adopts a freeze-drying technology under mixed solvent environment, the grafting rate of sodium alginate is largely improved, and the problem that the UV curing speed is slow due to low grafting rate is completely solved. The prepared alginic acid hydrogel matrix can rapidly solidify under the irradiation of UV light, the solid state can be maintained, moreover, in the presence of low concentration metal halides, the system can be further solidified, the hydrogel strength is improved, and the problems of conventional 3D printing hydrogel such as difficult moulding, collapse, and the like are overcome. The preparation method is simple, the cost is low, and the preparation method can be applied to industry easily.

Tao Yongzhen

Papers

Dopamine-Modified Hyaluronic Acid Hydrogel Adhesives with Fast-Forming and High Tissue Adhesion.

Enhanced piezoelectric performance of BiCl3/PVDF nanofibers-based nanogenerators

Medical scaffold with inner coating film, and preparation method for medical scaffold

Ligament support and preparation method thereof

Preparation method of alginic acid hydrogel matrix for UV 3D printing