A hydrogel dressing with tunable critical temperature and photothermal modulating melittin release for multiply antibacterial treatment

Tunable thermoresponsive hydrogels for temperature regulation and warning in fruit and vegetables preservation

Fresh fruit and vegetables usually suffer from quality deterioration when exposed to inappropriate temperatures. Common energy-input temperature regulation is widely applied but there remain challenges of increasing energy consumption. Passive temperature management regulates the heat transfer without energy consumption, showing a sustainable strategy for food preservation. Here, thermoresponsive hydrogels were constructed by incorporating NaCl and sodium dodecyl sulfate (SDS) micelles into a poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAM-co-AM)) network. Due to the excellent mechanical properties and reversible thermochromism at 14 °C and 37 °C, Gel-8 wt%-NaCl could inhibit temperature rise and avoid sunburn damage to peppers under direct sunlight by blocking the input of solar energy and accelerating moisture evaporation. Additionally, hydrogels could act as a feasible sensor by providing real-time visual warnings for inappropriate temperatures during banana storage. Based on the self-adaptive thermoresponsive behaviour, the prepared hydrogels showed effective performance of temperature regulation and quality preservation of fruit and vegetables.

Mussel-inspired tissue adhesive composite hydrogel with photothermal and antioxidant properties prepared from pectin for burn wound healing

Biodegradable self-healing hydrogels with antibacterial property attracted growing attentions in biomedication as wound dressings since they can prevent bacterial infection and promote wound healing process. In this research, a biodegradable self-healing hydrogel with ROS scavenging performance and enhanced tissue adhesion was fabricated from dopamine grafted oxidized pectin (OPD) and naphthoate hydrazide terminated PEO (PEO NH). At the same time, Fe3+ ions were incorporated to endow the hydrogel with near-infrared (NIR) triggered photothermal property to obtain antibacterial activity. The composite hydrogel showed good hemostasis performance based on mussel inspired tissue adhesion with biocompatibility well preserved. As expected, the composition of FeCl3 improved conductivity and endowed photothermal property to the hydrogel. The in vivo wound repairing experiment revealed the 808 nm NIR light triggered photothermal behavior of the hydrogel reduced the inflammation response and promoted wound repairing rate. As a result, this composite FeCl3/hydrogel shows great potential to be an excellent wound dressing for the treatment of infection prong wounds with NIR triggers.

Stimuli-responsive peptide assemblies: Design, self-assembly, modulation, and biomedical applications

Peptide molecules have design flexibility, self-assembly ability, high biocompatibility, good biodegradability, and easy functionalization, which promote their applications as versatile biomaterials for tissue engineering and biomedicine. In addition, the functionalization of self-assembled peptide nanomaterials with other additive components enhances their stimuli-responsive functions, promoting function-specific applications that induced by both internal and external stimulations. In this review, we demonstrate recent advance in the peptide molecular design, self-assembly, functional tailoring, and biomedical applications of peptide-based nanomaterials. The strategies on the design and synthesis of single, dual, and multiple stimuli-responsive peptide-based nanomaterials with various dimensions are analyzed, and the functional regulation of peptide nanomaterials with active components such as metal/metal oxide, DNA/RNA, polysaccharides, photosensitizers, 2D materials, and others are discussed. In addition, the designed peptide-based nanomaterials with temperature-, pH-, ion-, light-, enzyme-, and ROS-responsive abilities for drug delivery, bioimaging, cancer therapy, gene therapy, antibacterial, as well as wound healing and dressing applications are presented and discussed. This comprehensive review provides detailed methodologies and advanced techniques on the synthesis of peptide nanomaterials from molecular biology, materials science, and nanotechnology, which will guide and inspire the molecular level design of peptides with specific and multiple functions for function-specific applications.

Current status of development and biomedical applications of peptide-based antimicrobial hydrogels

Microbial contamination poses a serious threat to human life and health. Through the intersection of material science and modern medicine, advanced bionic hydrogels have shown great potential for biomedical applications due to their unique bioactivity and ability to mimic the extracellular matrix environment. In particular, as a promising antimicrobial material, the synthesis and practical biomedical applications of peptide-based antimicrobial hydrogels have drawn increasing research interest. The synergistic effect of peptides and hydrogels facilitate the controlled release of antimicrobial agents and mitigation of their biotoxicity while achieving antimicrobial effects and protecting the active agents from degradation. This review reports on the progress and trends of researches in the last five years and provides a brief outlook, aiming to provide theoretical background on peptide-based antimicrobial hydrogels and make suggestions for future related work.

Recent advances of hydrogels as smart dressings for diabetic wounds

Chronic diabetic wounds have been an urgent clinical problem, and wound dressings play an important role in their management. Due to the design of traditional dressings, it is difficult to achieve adaptive adhesion and on-demand removal of complex diabetic wounds, real-time monitoring of wound status, and dynamic adjustment of drug release behavior according to the wound microenvironment. Smart hydrogels, as smart dressings, can respond to environmental stimuli and achieve more precise local treatment. Here, we review the latest progress of smart hydrogels in wound bandaging, dynamic monitoring, and drug delivery for treatment of diabetic wounds. It is worth noting that we have summarized the most important properties of smart hydrogels for diabetic wound healing. In addition, we discuss the unresolved challenges and future prospects in this field. We hope that this review will contribute to furthering progress on smart hydrogels as improved dressing for diabetic wound healing and practical clinical application.

CuS@TA-Fe Nanoparticle-Doped Multifunctional Hydrogel with Peroxide-Like Properties and Photothermal Properties for Synergistic Antimicrobial Repair of Infected Wounds

Bacterial infection is a critical factor in wound healing. Due to the abuse of antibiotics, some pathogenic bacteria have developed resistance. Thus, there is an urgent need to develop a non-antibiotic-dependent multifunctional wound dressing for the treatment of bacteria-infected wounds. In this work, a multifunctional AOCuT hydrogel embedded with CuS@TA-Fe nanoparticles (NPs) through Schiff base reaction between gelatin quaternary ammonium salt - gallic acid (O-Gel-Ga) and sodium dialdehyde alginate (ADA) along with electrostatic interactions with CuS@TA-Fe NPs is prepared. These composite hydrogels possess favorable injectability, rapid shape adaptation, electrical conductivity, photothermal antimicrobial activity, and biocompatibility. Additionally, the doped NPs not only impart fast self-healing properties and excellent adhesion performance to the hydrogels, but also provide excellent peroxide-like properties, enabling them to scavenge free radicals and exhibit anti-inflammatory and antioxidant capabilities via photothermal (PTT) and photodynamic (PDT) effects. In an S. aureus infected wound model, the composite hydrogel effectively reduces the expression level of wound inflammatory factors and accelerates collagen deposition, epithelial tissue, and vascular regeneration, thereby promoting wound healing. This safe and synergistic therapeutic system holds great promise for clinical applications in the treatment of infectious wounds.