Hybrid Double-Sided Tape with Asymmetrical Adhesion and Burst Pressure Tolerance for Abdominal Injury Treatment.

Patients with open abdominal (OA) wounds have a mortality risk of up to 30%, and the resulting disabilities would have profound effects on patients. Here, we present a novel double-sided adhesive tape developed for the management of OA wounds. The tape features an asymmetrical structure and employs an acellular dermal matrix (ADM) with asymmetric wettability as a scaffold. It is constructed by integrating a tissue-adhesive hydrogel composed of polydopamine (pDA), quaternary ammonium chitosan (QCS), and acrylic acid cross-linking onto the bottom side of the ADM. Following surface modification with pDA, the ADM would exhibit characteristics resistant to bacterial adhesion. Furthermore, the presence of a developed hydrogel ensures that the tape not only possesses tissue adhesiveness and noninvasive peelability but also effectively mitigates damage caused by oxidative stress. Besides, the ADM inherits the strength of the skin, imparting high burst pressure tolerance to the tape. Based on these remarkable attributes, we demonstrate that this double-sided (D-S) tape facilitates the repair of OA wounds, mitigates damage to exposed intestinal tubes, and reduces the risk of intestinal fistulae and complications. Additionally, the D-S tape is equally applicable to treating other abdominal injuries, such as gastric perforations. It effectively seals the perforation, promotes injury repair, and prevents the formation of postoperative adhesions. These notable features indicate that the presented double-sided tape holds significant potential value in the biomedical field.

Fabrication of gelatin-based printable inks with improved stiffness as well as antibacterial and UV-shielding properties.

Gelatin-based inks have a broad range of applications in bioprinting for tissue engineering and regenerative medicine due to their biocompatibility, ease of modification, degradability, and rapid gelation induced by low temperature. However, gelatin-derived inks prepared through low-temperature treatment have poor mechanical properties that limit their applications. To solve this problem, we designed polyacrylamide/gelatin/silver nanoparticle (PAAm-GelatinAgNPs) ink to improve gelatin-based hydrogels. The ink is based on double networks, in which the physically cross-linked gelatin as the first network and covalently cross-linked PAAm as the second network. It was found that the presence of PAAm increased the tensile and compression strength of the gelatin-based ink. Moreover, silver nanoparticles endowed the antibacterial properties to the gelatin-based ink and were able to shield the UV irradiation and damages to rat skin. In addition, this ink showed the shear thinning property; Consequently it succeeded in printing complex 3D scaffolds such as the cube, five-pointed star, flower, and university logo of "SEU". In summary, this ink presents a new strategy for the modification of gelatin and offers new potential applications for customized therapy of antimicrobial and anti-UV damage to tissues.

Biomaterials and biosensors in intestinal organoid culture, a progress review.

As an emerging technology, intestinal organoids are promising new tools for basic and translational research in gastroenterology. Currently, culture of intestinal organoids relies mostly on a type of tumor-derived scaffolds, namely Matrigel, which may pose tumorigenic risks to organoid implantation. Apart from the traditional detection methods, such as tissue slicing and fluorescence staining, the monitoring of intestinal organoids requires real-time biosensors that can adapt to their three-dimensional dynamic growth patterns. In this review, we summarized the recent advances in developing definite hydrogel scaffolds for intestinal organoid culture and identified key parameters for scaffold design. In addition, classified by different substrate compositions like pH, electrolytes, and functional proteins, we concluded the existing live-imaging biosensors and elucidated their underlying mechanisms. We hope this review enhances the understanding of intestinal organoid culture and provides more practical approaches to investigate them.

Engineering an adhesive based on photosensitive polymer hydrogels and silver nanoparticles for wound healing.

Hemostasis, wound closure and prevention of infection are critical to wound healing after an injury. Skin adhesives have been used to seal incisions, thus aiding primary wound healing, as well as creating a barrier to microbes. We constructed a skin adhesive with antibacterial and hemostatic activities (AHAs) for wound management. The adhesive was made by using methacrylated hyaluronan-polyacrylamide (MHA-PAAm) hydrogels, integrated with silver nanoparticles (AgNPs) and bonded to gelatin. Because of the three-dimensional network structure of the hydrogels, nanoscale particles can be encapsulated into their voids; the AgNPs, through sustained delivery of silver ions, endow the adhesives with sustained broad-spectrum antibacterial activity. Furthermore, due to the introduction of MHA which can be crosslinked by visible light, the polyacrylamide hydrogel matrix can be formed through photo crosslinking. In addition, gelatin can be bonded to both the hydrogel matrix and host tissues because of the interaction between carboxyl and amino-moieties. Our animal studies demonstrated that the AHAs which possess tissue adhesive and antibacterial properties were easy to stretch, and were able to stop bleeding in rat tail amputation and liver injury models. AHAs enhance wound granulation tissue formation, vascular tissue formation, and collagen formation, as well as alleviate inflammation. These properties promoted wound closure in rat wound infection models, promising great potential for applying AHAs in clinical uses.