Self-redox reaction driven in situ formation of Cu2O/Ti3C2Tx nanosheets boost the photocatalytic eradication of multi-drug resistant bacteria from infected wound

Engineered MXene Biomaterials for Regenerative Medicine

MXene-based materials have attracted significant interest due to their distinct physical and chemical properties, which are relevant to fields such as energy storage, environmental science, and biomedicine. MXene has shown potential in the area of tissue regenerative medicine. However, research on its applications in tissue regeneration is still in its early stages, with a notable absence of comprehensive reviews. This review begins with a detailed description of the intrinsic properties of MXene, followed by a discussion of the various nanostructures that MXene can form, spanning from 0 to 3 dimensions. The focus then shifts to the applications of MXene-based biomaterials in tissue engineering, particularly in immunomodulation, wound healing, bone regeneration, and nerve regeneration. MXene's physicochemical properties, including conductivity, photothermal characteristics, and antibacterial properties, facilitate interactions with different cell types, influencing biological processes. These interactions highlight its potential in modulating cellular functions essential for tissue regeneration. Although the research on MXene in tissue regeneration is still developing, its versatile structural and physicochemical attributes suggest its potential role in advancing regenerative medicine.

MXene-Derived Multifunctional Biomaterials: New Opportunities for Wound Healing

The process of wound healing is frequently impeded by metabolic imbalances within the wound microenvironment. MXenes exhibit exceptional biocompatibility, biodegradability, photothermal conversion efficiency, conductivity, and adaptable surface functionalization, demonstrating marked potential in the development of multifunctional platforms for wound healing. Moreover, the integration of MXenes with other bioactive nanomaterials has been shown to enhance their therapeutic efficacy, paving the way for innovative approaches to wound healing. In this review, we provide a systematic exposition of the mechanisms through which MXenes facilitate wound healing and offer a comprehensive analysis of the current research landscape on MXene-based multifunctional bioactive composites in this field. By delving into the latest scientific discoveries, we identify the existing challenges and potential future trajectories for the advancement of MXenes. Our comprehensive evaluation aims to provide insightful guidance for the formulation of more effective wound healing strategies.

Advancing diabetic wound care: The role of copper-containing hydrogels

Diabetic wounds pose a significant challenge in healthcare due to their complex nature and the difficulties they present in treatment and healing. Impaired healing processes in individuals with diabetes can lead to complications and prolonged recovery times. However, recent advancements in wound healing provide reasons for optimism. Researchers are actively developing innovative strategies and therapies specifically tailored to address the unique challenges of diabetic wounds. One focus area is biomimetic hydrogel scaffolds that mimic the natural extracellular matrix, promoting angiogenesis, collagen deposition, and the healing process while also reducing infection risk. Copper nanoparticles and copper compounds incorporated into hydrogels release copper ions with antimicrobial, anti-inflammatory, and angiogenic properties. Copper reduces infection risk, modulates inflammatory response, and promotes tissue regeneration through cell adhesion, proliferation, and differentiation. Utilizing copper nanoparticles has transformative potential for expediting diabetic wound healing and improving patient outcomes while enhancing overall well-being by preventing severe complications associated with untreated wounds. It is crucial to write a review highlighting the importance of investigating the use of copper nanoparticles and compounds in diabetic wound healing and tissue engineering. These groundbreaking strategies hold the potential to transform the treatment of diabetic wounds, accelerating the healing process and enhancing patient outcomes.

Two-dimensional nanomaterials: A multifunctional approach for robust for diabetic wound repair

Diabetic wounds pose a clinical challenge due to persistent inflammation, severe bacterial infections, inadequate vascularization, and pronounced oxidative stress. Current therapeutic modalities fail to provide satisfactory outcomes in managing these conditions, resulting in considerable patient distress. Two-dimensional nanomaterials (2DNMs), characterized by their unique nanosheet structures, expansive surface areas, and remarkable physicochemical properties, have garnered considerable attention for their potential in therapeutic applications. Emerging 2DNMs can be loaded with various pharmacological agents, including small molecules, metal ions, and liposomes. Moreover, they can be integrated with various biomaterials such as hydrogels, microneedles, and microspheres, thus demonstrating unprecedented advantages in expediting the healing process of diabetic wounds. Moreover, 2DNMs exhibit exceptional performance characteristics, including high biocompatibility, effective antimicrobial properties, optimal phototherapeutic effects, and enhanced electrostimulation capabilities. These properties enable them to modulate the wound microenvironment, leading to widespread application in tissue repair with remarkable outcomes. This review delineates several emerging 2DNMs, such as graphene and its derivatives, black phosphorus, MXenes, and transition metal dichalcogenides, in the context of diabetic wound repair. Furthermore, it elucidates the translational challenges and future perspectives of 2DNMs in wound healing treatments. Overall, 2DNMs present a highly promising strategy for ameliorating diabetic wounds, thus providing novel avenues for diagnostic and therapeutic strategies in diabetic wound management.

A 4D printed nanoengineered super bioactive hydrogel scaffold with programmable deformation for potential bifurcated vascular channel construction

Four-dimensional (4D) printing of hydrogels enabled the fabrication of complex scaffold geometries out of static parts. Although current 4D fabrication strategies are promising for creating vascular parts such as tubes, developing branched networks or tubular junctions is still challenging. Here, for the first time, a 4D printing approach is employed to fabricate T-shaped perfusable bifurcation using an extrusion-based multi-material 3D printing process. An alginate/methylcellulose-based dual-component hydrogel system (with defined swelling behavior) is nanoengineered with carbonized alginate (∼100 nm) to introduce anti-oxidative, anti-inflammatory, and anti-thrombotic properties and shape-shifting properties. A computational model to predict shape deformations in the printed hydrogels with defined infill angles was designed and further validated experimentally. Shape deformations of the 3D-printed flat sheets were achieved by ionic cross-linking. An undisrupted perfusion of a dye solution through a T-junction with minimal leakage mimicking blood flow through vessels is also demonstrated. Moreover, human umbilical vein endothelial and fibroblast cells seeded with printed constructs show intact morphology and excellent cell viability. Overall, the developed strategy paves the way for manufacturing self-actuated vascular bifurcations with remarkable anti-thrombotic properties to potentially treat coronary artery diseases.

Progress in the development of piezoelectric biomaterials for tissue remodeling

Piezoelectric biomaterials have demonstrated significant potential in the past few decades to heal damaged tissue and restore cellular functionalities. Herein, we discuss the role of bioelectricity in tissue remodeling and explore ways to mimic such tissue-like properties in synthetic biomaterials. In the past decade, biomedical engineers have adopted emerging functional biomaterials-based tissue engineering approaches using innovative bioelectronic stimulation protocols based on dynamic stimuli to direct cellular activation, proliferation, and differentiation on engineered biomaterial constructs. The primary focus of this review is to discuss the concepts of piezoelectric energy harvesting, piezoelectric materials, and their application in soft (skin and neural) and hard (dental and bone) tissue regeneration. While discussing the prospective applications as an engineered tissue, an important distinction has been made between piezoceramics, piezopolymers, and their composites. The superiority of piezopolymers over piezoceramics to circumvent issues such as stiffness mismatch, biocompatibility, and biodegradability are highlighted. We aim to provide a comprehensive review of the field and identify opportunities for the future to develop clinically relevant and state-of-the-art biomaterials for personalized and remote health care.

MXene-Mediated Catalytic Redox Reactions for Biomedical Applications

Reactive oxygen species (ROS) play a crucial role in orchestrating a myriad of physiological processes within living systems. With the advent of materdicine, an array of nanomaterials has been intricately engineered to influence the redox equilibrium in biological milieus, thereby pioneering a distinctive therapeutic paradigm predicated on ROS-centric biochemistry. Among these, two-dimensional carbides, nitrides, and carbonitrides, collectively known as MXenes, stand out due to their multi-valent and multi-elemental compositions, large surface area, high conductivity, and pronounced local surface plasmon resonance effects, positioning them as prominent contributors in ROS modulation. This review aims to provide an overview of the advancements in harnessing MXenes for catalytic redox reactions in various biological applications, including tumor, anti-infective, and anti-inflammatory therapies. The emphasis lies on elucidating the therapeutic mechanism of MXenes, involving both pro-oxidation and anti-oxidation processes, underscoring the redox-related therapeutic applications facilitated by self-catalysis, photo-excitation, and sono-excitation properties of MXenes. Furthermore, this review highlights the existing challenges and outlines future development trends in leveraging MXenes for ROS-involving disease treatments, marking a significant step towards the integration of these nanomaterials into clinical practice.

Photodynamic and nitric oxide therapy-based synergistic antimicrobial nanoplatform: an advanced root canal irrigation system for endodontic bacterial infections

BACKGROUND

The main issues faced during the treatment of apical periodontitis are the management of bacterial infection and the facilitation of the repair of alveolar bone defects to shorten disease duration. Conventional root canal irrigants are limited in their efficacy and are associated with several side effects. This study introduces a synergistic therapy based on nitric oxide (NO) and antimicrobial photodynamic therapy (aPDT) for the treatment of apical periodontitis.

RESULTS

This research developed a multifunctional nanoparticle, CGP, utilizing guanidinylated poly (ethylene glycol)-poly (ε-Caprolactone) polymer as a carrier, internally loaded with the photosensitizer chlorin e6. During root canal irrigation, the guanidino groups on the surface of CGP enabled effective biofilm penetration. These groups undergo oxidation by hydrogen peroxide in the aPDT process, triggering the release of NO without hindering the production of singlet oxygen. The generated NO significantly enhanced the antimicrobial capability and biofilm eradication efficacy of aPDT. Furthermore, CGP not only outperforms conventional aPDT in eradicating biofilms but also effectively promotes the repair of alveolar bone defects post-eradication. Importantly, our findings reveal that CGP exhibits significantly higher biosafety compared to sodium hypochlorite, alongside superior therapeutic efficacy in a rat model of apical periodontitis.

CONCLUSIONS

This study demonstrates that CGP, an effective root irrigation system based on aPDT and NO, has a promising application in root canal therapy.

Potential Biosafety of Mxenes: Stability, Biodegradability, Toxicity and Biocompatibility

MXenes are two-dimensional nanomaterials with unique properties that are widely used in various fields of research, mostly in the field of energy. Fewer publications are devoted to MXene application in biomedicine and the question is: are MXenes safe for use in biological systems? The sharp edges of MXenes provide the structure of "nanoknives" which cause damage in direct physical contact with cells. This is effectively used for antibacterial research. However, on the other hand, most studies in cultured cells and rodents report that they do not cause obvious signs of cytotoxicity and are fully biocompatible. The aim of our review was to consider whether MXenes can really be considered non-toxic and biocompatible. Often the last two concepts are confused. We first reviewed aspects such as the stability and biodegradation of MXenes, and then analyzed the mechanisms of toxicity and their consequences for bacteria, cultured cells, and rodents, with subsequent conclusions regarding their biocompatibility.

Transition Metal Oxide-Decorated MXenes as Drugless Nanoarchitectonics for Enriched Nanocatalytic Chemodynamic Treatment

Despite their unique characteristics, 2D MXenes with sole photothermal conversion ability are required to explore their superfluous abilities in biomedicine. The small-molecule-based chemotherapeutics suffer from various shortcomings of time-consuming and expensiveness concerning theoretical and performance (preclinical/clinical) checks. This study demonstrates the fabrication of Ti3C2 MXene nanosheets (TC-MX NSs) and subsequent decoration with transition metal oxides, that is, copper oxide (Cu2O/MX, CO-MX NCs) as drugless nanoarchitectonics for synergistic photothermal (PTT)-chemodynamic therapeutic (CDT) efficacies. Initially, the monolayer/few-layered TC-MX NSs are prepared using the chemical etching-assisted ultrasonic exfoliation method and then deposited with Cu2O nanoconstructs using the in situ reduction method. Further, the photothermal ablation under near-infrared (NIR)-II laser irradiation shows PTT effects of CO-MX NCs. The deposited Cu2O on TC-MX NSs facilitates the release of copper (Cu+) ions in the acidic microenvironment intracellularly for Fenton-like reaction-assisted CDT effects and enriched PTT effects synergistically. Mechanistically, these deadly free radicals intracellularly imbalance the glutathione (GSH) levels and result in mitochondrial dysfunction, inducing apoptosis of 4T1 cells. Finally, the in vivo investigations in BALB/c mice confirm the substantial ablation of breast carcinoma. Together, these findings demonstrate the potential synergistic PTT-CDT effects of the designed CO-MX NCs as drugless nanoarchitectonics against breast carcinoma.

A Synergistic Antibacterial Study of Copper-Doped Polydopamine on Ti3C2Tx Nanosheets with Enhanced Photothermal and Fenton-like Activities

In response to the trend of drug-resistant and super bacteria, the existing single antibacterial methods are not sufficient to kill bacteria, and the development of multifunctional antibacterial nanomaterials is urgent. Our study aims to construct copper-doped polydopamine-coated Ti3C2Tx (CuPDA@Ti3C2Tx) with an enhanced photothermal property and Fenton-like activity. The nanocomposite hydrogel consisting of CuPDA@Ti3C2Tx and alginate can improve the antioxidant activity of two-dimensional MXene nanosheets by coating them with a thin layer of PDA nanofilm. Meanwhile, Cu ions are adsorbed through the coordination of PDA-rich oxygen-containing functional groups and amino groups. Calcium ions were further used to crosslink sodium alginate to obtain antibacterial hydrogel materials with combined chemotherapy and photothermal therapy properties. The photothermal conversion efficiency of CuPDA@Ti3C2Tx is as high as 57.7% and the antibacterial rate of Escherichia coli reaches 96.12%. The photothermal effect leads to oxidative stress in bacteria, increases cell membrane permeability, and a high amount of ROS and copper ions enter the interior of the bacteria, causing protein denaturation and DNA damage, synergistically leading to bacterial death. Our study involves a multifunctional synergistic antibacterial nanodrug platform, which is conducive to the development of high-performance antibacterial agents and provides important research ideas for solving the problem of drug-resistant bacteria.

Multifunctional MXene-Based Bioactive Materials for Integrated Regeneration Therapy

The reconstruction engineering of tissue defects accompanied by major diseases including cancer, infection, and inflammation is one of the important challenges in clinical medicine. The development of innovative tissue engineering strategies such as multifunctional bioactive materials presents a great potential to overcome the challenge of disease-impaired tissue regeneration. As the major representative of two-dimensional nanomaterials, MXenes have shown multifunctional physicochemical properties and have been diffusely studied as multimodal nanoplatforms in the field of biomedicine. This review summarized the recent advances in the multifunctional properties of MXenes and integrated regeneration-therapy applications of MXene-based biomaterials, including tissue regeneration-tumor therapy, tissue regeneration-infection therapy, and tissue regeneration-inflammation therapy. MXenes have been recognized as good candidates for promoting tissue regeneration and treating diseases through photothermal therapy, regulating cell behavior, and drug and gene delivery. The current challenges and future perspectives of MXene-based biomaterials in integrated regeneration-therapy are also discussed well in this review. In summary, MXene-based biomaterials have shown promising potential for integrated tissue regeneration and disease treatment due to their favorable physicochemical properties and bioactive functions. However, there are still many obstacles and challenges that must be addressed for the regeneration-therapy applications of MXene-based biomaterials, including understanding the bioactive mechanism, ensuring long-term biosafety, and improving their targeting therapy capacity.

Drug delivery strategies for antibiofilm therapy

Although new antibiofilm agents have been developed to prevent and eliminate pathogenic biofilms, their widespread clinical use is hindered by poor biocompatibility and bioavailability, unspecific interactions and insufficient local concentrations. The development of innovative drug delivery strategies can facilitate penetration of antimicrobials through biofilms, promote drug dispersal and synergistic bactericidal effects, and provide novel paradigms for clinical application. In this Review, we discuss the potential benefits of such emerging techniques for improving the clinical efficacy of antibiofilm agents, as well as highlighting the existing limitations and future prospects for these therapies in the clinic.

Nanophotocatalysts in biomedicine: Cancer therapeutic, tissue engineering, biosensing, and drug delivery applications

Photocatalysis can be considered as a green technology owing to its excellent potential for sustainability and fulfilling several principles of green chemistry. This process uses light radiation as the primary energy source, preventing or reducing the requirement for artificial light sources and exogenous catalytic entities. Photocatalysis has promising applications in biomedicine such as drug delivery, biosensing, tissue engineering, cancer therapeutics, etc. In targeted cancer therapeutics, photocatalysis can be employed in photodynamic therapy to form reactive oxygen species that damage cancerous cells' structure. Nanophotocatalysts can be used in targeted drug delivery, showing potential applications in nuclear-targeted drug delivery along with specific delivery of chemotherapeutics to cancer cells or tumor sites. On the other hand, in tissue engineering, nanophotocatalysts can be employed in designing scaffolds that promote cell growth and tissue regeneration. However, some important challenges pertaining to the performance of photocatalysis, large-scale production of nanophotocatalysts, optimization of reaction/synthesis conditions, long-term biosafety issues, stability, clinical translation, etc. still need further explorations. Herein, the most recent advancements pertaining to the biomedical applications of nanophotocatalysts are reflected, focusing on drug delivery, tissue engineering, biosensing, and cancer therapeutic potentials.

MXene-based composites against antibiotic-resistant bacteria: current trends and future perspectives

Today, finding novel nanomaterial-based strategies to combat bacterial resistance is an important field of science. MXene-based composites have shown excellent antimicrobial potential owing to their fascinating properties such as excellent photothermal effects, highly active sites, large interlayer spacing, unique chemical structures, and hydrophilicity; they have great potential to damage the bacterial cells by rupturing the bacterial cell membranes, enhancing the permeability across the membrane, causing DNA damages, reducing the metabolic activity, and generating oxidative stress. After inserting into or attaching on the surface of pathogenic bacteria, these two-dimensional structures can cause bacterial membrane disruption and cell content leakage owing to their sharp edges. Remarkably, MXenes and their composites with excellent photothermal performance have been studied in photothermal antibacterial therapy to combat antibiotic-resistant bacteria and suppress chronic wound infections, thus providing new opportunities for multidrug-resistant bacteria-infected wound healing. But, details about the possible interactions between MXene-based nanosystems and bacterial cell membranes are rather scarce. Also, the mechanisms of photothermal antibacterial therapy as well as synergistic tactics including photothermal, photodynamic or chemo-photothermal therapy still need to be uncovered. This review endeavors to delineate critical issues pertaining to the application of MXene-based composites against antibiotic-resistant bacteria, focusing on their photocatalytic inactivation, physical damage, and photothermal antibacterial therapy.

This review endeavors to delineate critical issues pertaining to the application of MXene-based composites against antibiotic-resistant bacteria.