Mechanically Tunable Hydrogels with Self-Healing and Shape Memory Capabilities from Thermo-Responsive Amino Acid-Derived Vinyl Polymers

A Pro-Healing and Antibacterial Bio-Based Hydrogel Barrier for the Prevention of Intestinal Anastomotic Leakage

Postoperative leakage at the colorectal anastomosis is recognized as a significant and serious complication. Its pathogenic factors are complex, the onset process is hidden, and it is often complicated with severe abdominal infection, which leads to sepsis and even multiple organ failure. In order to develop a new type of multifunctional biomaterial which can prevent intestinal bacterial translocation, intestinal fluid spillage and promote the healing of intestinal anastomosis, we prepared a multifunctional temperature-sensitive extracellular matrix hydrogel with the extracellular matrix (ECM) of porcine small intestinal submucosa (SIS) physically modified by boric acid and 4-ARM-PEG-SC as raw materials, in order to avoid abdominal infection and prevent anastomotic leakage. A series of experiments showed that the prepared hydrogel had stable structure, could resist the erosion of digestive juice in physiological range and had good tissue adhesion and mechanical properties, excellent antiexplosion ability and self-healing. Combined with its injectability, it could effectively seal the anastomosis. In vitro experiments showed that the hydrogel had effective antidigestion ability, good antibacterial properties, excellent cell and blood compatibility, as well as antioxidant and anti-inflammatory capabilities. Experiments revealed that the hydrogel could effectively optimize the local microenvironment of the anastomosis, promote the tissue repair of the anastomosis and effectively reduce the incidence of colonic anastomotic leakage in rats by promoting the key factors of cell proliferation, facilitating vascular formation and curtailing the expression of pro-inflammatory factors. The findings of this study pave the way for novel strategies in creating multifunctional materials designed to prevent and manage anastomotic leakage.

Recent advancements in natural polymers-based self-healing nano-materials for wound dressing

The field of wound healing has witnessed remarkable progress in recent years, driven by the pursuit of advanced wound dressings. Traditional dressing materials have limitations like poor biocompatibility, nonbiodegradability, inadequate moisture management, poor breathability, lack of inherent therapeutic properties, and environmental impacts. There is a compelling demand for innovative solutions to transcend the constraints of conventional dressing materials for optimal wound care. In this extensive review, the therapeutic potential of natural polymers as the foundation for the development of self-healing nano-materials, specifically for wound dressing applications, has been elucidated. Natural polymers offer a multitude of advantages, possessing exceptional biocompatibility, biodegradability, and bioactivity. The intricate engineering strategies employed to fabricate these polymers into nanostructures, thereby imparting enhanced mechanical robustness, flexibility, critical for efficacious wound management has been expounded. By harnessing the inherent properties of natural polymers, including chitosan, alginate, collagen, hyaluronic acid, and so on, and integrating the concept of self-healing materials, a comprehensive overview of the cutting-edge research in this emerging field is presented in the review. Furthermore, the inherent self-healing attributes of these materials, wherein they exhibit innate capabilities to autonomously rectify any damage or disruption upon exposure to moisture or body fluids, reducing frequent dressing replacements have also been explored. This review consolidates the existing knowledge landscape, accentuating the benefits and challenges associated with these pioneering materials while concurrently paving the way for future investigations and translational applications in the realm of wound healing.

Novel Photothermal Graphene-Based Hydrogels in Biomedical Applications

In the last decade, photothermal therapy (PTT) has attracted tremendous attention because it is non-invasive, shows high efficiency and antibacterial activity, and minimizes drug side effects. Previous studies demonstrated that PTT can effectively inhibit the growth of bacteria and promotes cell proliferation, accelerating wound healing and tissue regeneration. Among different NIR-responsive biomaterials, graphene-based hydrogels with photothermal properties are considered as the best candidates for biomedical applications, due to their excellent properties. This review summarizes the current advances in the development of innovative graphene-based hydrogels for PTT-based biomedical applications. Also, the information about photothermal properties and the potential applications of graphene-based hydrogels in biomedical therapies are provided. These findings provide a great potential for supporting their applications in photothermal biomedicine.

Self-healing amino acid-bearing acrylamides/n-butyl acrylate copolymers via multiple noncovalent bonds

Four amino acid-bearing acrylamides, N-acryloyl-l-threonine (AThrOH), N-acryloyl-l-glutamic acid (AGluOH), N-acryloyl-l-phenylalanine (APheOH), and N-acryloyl-l, l-diphenylalanine (APhePheOH), were selected for copolymerization with n-butyl acrylate (nBA) to develop amino acid-based self-healable copolymers. A series of copolymers comprising amino acid-bearing acrylamides and nBA with tunable comonomer compositions and molecular weights were synthesized by free radical and reversible addition-fragmentation chain-transfer copolymerization. Self-healing and mechanical properties originated from the noncovalent bonds between the carboxyl, hydroxyl, and amide groups, and π-π stacking interactions among the amino acid residues in the side chains were evaluated. Among these copolymers, P(nBA-co-AGluOH) with suitable comonomer compositions and molecular weights (nBA : AGluOH = 82 : 18, Mn = 18 300, Mw/Mn = 2.58) exhibited good mechanical properties (modulus of toughness = 17.3 MJ m-3) and self-healing under ambient conditions. The multiple noncovalent bonds of P(nBA-co-AGluOH)s were also efficient in improving the optical properties with an enhanced refractive index and good transparency.