Composite Tissue Adhesive Containing Catechol-Modified Hyaluronic Acid and Poly‑l‑lysine

Commercial tissue adhesives such as fibrin, albumin-glutaraldehyde, and cyanoacrylates often suffer from the limitations of adverse inflammatory reactions, lack of bioactivity, and/or weak wet adhesion. There is a need to develop advanced tissue adhesives which possess adequate wet adhesion and appropriate biodegradability and biocompatibility. The wet adhesion of the catechol group to a variety of substrates is well-known. Further, it undergoes Michael addition with an amine or thiol group, which makes catechol-containing polymers appealing as tissue adhesives because there are abundant amine and thiol groups in native tissue. We present here a composite tissue adhesive based on a catechol-modified polymer that utilizes poly-l-lysine (PLL) as a bridging molecule to promote the interfacing with cells and tissues. Hyaluronic acid (HA) was chosen here as the polymer backbone for functionalization with catechol moieties, which is attributable to its multiple biological activities. The cross-linking conditions of catechol-functionalized HA (HACA) were optimized, and the swelling and degradation behavior of the cross-linked hydrogels were characterized. The PLL/HACA-based adhesive demonstrated good adhesion to hydrogels derived from collagen and gelatin that act as a simplified soft tissue model, and to porcine skin tissue. Moreover, the adhesive supported culture of a human umbilical vein endothelial cell line (HUV-EC-C) with high cell viability and formation of capillary-like structure. This may bring added benefit by means of promoting angiogenesis, therefore promoting the integration between host tissue and implant. Our results indicate that PLL/HACA could be a promising tissue adhesive for multiple internal uses

Fabrication and Characterization of an Electro-Compacted Collagen/Elastin/Hyaluronic Acid Sheet as a Potential Skin Scaffold

The development of biomimetic structures with integrated extracellular matrix (ECM) components represents a promising approach to biomaterial fabrication. Here, an artificial ECM, comprising the structural protein collagen I and elastin (ELN), as well as the glycosaminoglycan hyaluronan (HA), is reported. Specifically, collagen and ELN are electrochemically aligned to mimic the compositional characteristics of the dermal matrix. HA is incorporated into the electro-compacted collagen-ELN matrices via adsorption and chemical immobilization, to give a final composition of collagen/ELN/HA of 7:2:1. This produces a final collagen/ELN/hyaluronic acid scaffold (CEH) that recapitulates the compositional feature of the native skin ECM. This study analyzes the effect of CEH composition on the cultivation of human dermal fibroblast cells (HDFs) and immortalized human keratinocytes (HaCaTs). It is shown that the CEH scaffold supports dermal regeneration by promoting HDFs proliferation, ECM deposition, and differentiation into myofibroblasts. The CEH scaffolds are also shown to support epidermis growth by supporting HaCaTs proliferation, differentiation, and stratification. A double-layered epidermal-dermal structure is constructed on the CEH scaffold, further demonstrating its ability in supporting skin cell function and skin regeneration

Mediating Zn Ions Migration Behavior via β‑Cyclodextrin Modified Carbon Nanotube Film for High-Performance Zn Anodes

Metallic Zn is considered as a promising anode material because of its abundance, eco-friendliness, and high theoretical capacity. However, the uncontrolled dendrite growth and side reactions restrict its further practical application. Herein, we proposed a β-cyclodextrin-modified multiwalled carbon nanotube (CD-MWCNT) layer for Zn metal anodes. The obtained CD-MWCNT layer with high affinity to Zn can significantly reduce the transfer barrier of Zn2+ at the electrode/electrolyte interface, facilitating the uniform deposition of Zn2+ and suppressing water-caused side reactions. Consequently, the Zn||Zn symmetric cell assembled with CD-MWCNT shows a significantly enhanced cycling durability, maintaining a cycling life exceeding 1000 h even under a high current density of 5 mA cm–2. Furthermore, the full battery equipped with a V2O5 cathode displays an unparalleled long life. This work unveils a promising avenue toward the achievement of high-performance Zn metal anodes

3D printing of highly flexible, cytocompatible nanocomposites for thermal management

Highly flexible biocompatible materials that are both thermally conductive and electrically insulating are important for implantable and wearable bioelectronics applications. The ability to thermally process these materials into useful structures using additive manufacturing approaches opens up new opportunities for its use in bespoke structures. Here we investigate the three-dimensional (3D) printing of a medical-grade thermoplastic polyurethane (PU) elastomer, which is thermally insulating and enhance its thermal and mechanical properties through the incorporation of boron nitride (BN) as a filler. Via a simple solution compounding approach, a highly flexible and thermally conductive BN nanoparticle/ PU composite has been developed and subsequently processed into simple bio-scaffolds structures via a 3D pneumatic melt extrusion printing process. The addition of up to 20% w/w of BN to the PU significantly enhances the tensile modulus by 659%, from 1.74 to 13.2 MPa, while supporting high mechanical flexibility. The thermal conductivity of 20% w/w BN/PU composite increases by 74% with respect to the unmodified PU. The 3D printed BN/PU composite scaffolds exhibit good biocompatibility and cell attachment enhancement with L929 fibroblast cells. Graphical abstract: [Figure not available: see fulltext.