Hydrogen peroxide (H2 O2 ) has received increasing attention because it is not only a mild and environmentally friendly oxidant for organic synthesis and environmental remediation but also a promising new liquid fuel. The production of H2 O2 by photocatalysis is a sustainable process, since it uses water and oxygen as the source materials and solar light as the energy. Encouraging processes have been developed in the last decade for the photocatalytic production of H2 O2 . In this Review we summarize research progress in the development of processes for the photocatalytic production of H2 O2 . After a brief introduction emphasizing the superiorities of the photocatalytic generation of H2 O2 , the basic principles of establishing an efficient photocatalytic system for generating H2 O2 are discussed, highlighting the advanced photocatalysts used. This Review is concluded by a brief summary and outlook for future advances in this emerging research field.

Production of Hydrogen Peroxide by Photocatalytic Processes

Infection is a major obstacle to wound healing. To enhance the healing of infected wounds, dressings with antibacterial activities and multifunctional properties to promote wound healing are highly desirable. Herein, gelatin-grafted-dopamine (GT-DA) and polydopamine-coated carbon nanotubes (CNT-PDA) were used to engineer antibacterial, adhesive, antioxidant and conductive GT-DA/chitosan/CNT composite hydrogels through the oxidative coupling of catechol groups using a H2O2/HRP (horseradish peroxidase) catalytic system. The addition of the antibiotic doxycycline endowed the hydrogels with antimicrobial activity to treat infected full-thickness defect wounds. Additionally, CNT-PDA endowed these hydrogels with an excellent photothermal effect, leading to good in vitro and in vivo antibacterial activities against Gram-positive and Gram-negative bacteria. The catechol group and polydopamine imparted tissue adhesiveness, and the hemostatic and antioxidant abilities of these hydrogels were also investigated. The porosity, degradability, swelling, rheological, mechanical, and conductive behaviors of these hydrogels were finely regulated by changing the concentration of CNT-PDA. Hemolysis and cytocompatibility tests using L929 fibroblast cells confirmed the good biocompatibility of these hydrogels. The wound closure, collagen deposition, histomorphological examination and immunofluorescence staining results demonstrated the excellent effects of these hydrogels in an infected full-thickness mouse skin defect wound. In summary, the adhesive antibacterial and conductive GT-DA/chitosan/CNT hydrogels showed great potential as multifunctional bioactive dressings for the treatment of infected wounds.

Mussel-inspired, antibacterial, conductive, antioxidant, injectable composite hydrogel wound dressing to promote the regeneration of infected skin.

Bacterial infection is one of the top ten leading causes of death globally and the worst killer in low-income countries. The overuse of antibiotics leads to ever-increasing antibiotic resistance, posing a severe threat to human health. Recent advances in nanotechnology provide new opportunities to address the challenges in bacterial infection by killing germs without using antibiotics. Antibiotic-free antibacterial strategies enabled by advanced nanomaterials are presented. Nanomaterials are classified on the basis of their mode of action: nanomaterials with intrinsic or light-mediated bactericidal properties and others that serve as vehicles for the delivery of natural antibacterial compounds. Specific attention is given to antibacterial mechanisms and the structure-performance relationship. Practical antibacterial applications employing these antibiotic-free strategies are also introduced. Current challenges in this field and future perspectives are presented to stimulate new technologies and their translation to fight against bacterial infection.

https://espace.library.uq.edu.au/view/UQ:83fdbcc/UQ83fdbcc_OA.pdf

Antibiotic-Free Antibacterial Strategies Enabled by Nanomaterials: Progress and Perspectives.

Diabetic wound healing remains a critical challenge due to its vulnerability to multidrug-resistant (MDR) bacterial infection, as well as the hyperglycemic and oxidative wound microenvironment Herein, an injectable multifunctional hydrogel (FEMI) was developed to simultaneously overcome these hurdles The FEMI hydrogel was fabricated through a Schiff-based reaction between e-polylysine (EPL)-coated MnO2 nanosheets (EM) and insulin-loaded self-assembled aldehyde Pluronic F127 (FCHO) micelles Through a synergistic combination of EPL and "nanoknife-like" MnO2 nanosheets, the FEMI hydrogel exhibited extraordinary antimicrobial capacities against MDR bacteria The MnO2 nanoenzyme reshaped the hostile oxidative wound microenvironment by decomposing the endogenous H2O2 into O2 Meanwhile, the pH/redox dual-responsive FEMI hydrogel achieved a sustained and spatiotemporal controlled release of insulin to regulate the blood glucose Our FEMI hydrogel demonstrated an accelerated MDR bacteria-infected diabetic wound healing in vivo and represents a versatile strategy for healing a broad range of tissue damages caused by diabetes

Nanoenzyme-Reinforced Injectable Hydrogel for Healing Diabetic Wounds Infected with Multidrug Resistant Bacteria.

Conductive biomaterials based on conductive polymers, carbon nanomaterials, or conductive inorganic nanomaterials demonstrate great potential in wound healing and skin tissue engineering, owing to the similar conductivity to human skin, good antioxidant and antibacterial activities, electrically controlled drug delivery, and photothermal effect. However, a review highlights the design and application of conductive biomaterials for wound healing and skin tissue engineering is lacking. In this review, the design and fabrication methods of conductive biomaterials with various structural forms including film, nanofiber, membrane, hydrogel, sponge, foam, and acellular dermal matrix for applications in wound healing and skin tissue engineering and the corresponding mechanism in promoting the healing process were summarized. The approaches that conductive biomaterials realize their great value in healing wounds via three main strategies (electrotherapy, wound dressing, and wound assessment) were reviewed. The application of conductive biomaterials as wound dressing when facing different wounds including acute wound and chronic wound (infected wound and diabetic wound) and for wound monitoring is discussed in detail. The challenges and perspectives in designing and developing multifunctional conductive biomaterials are proposed as well.
Highlights:
1 The design and application of conductive biomaterials for wound healing are comprehensively reviewed, including versatile conductive agents, the various forms of conductive wound dressings, and different in vivo applications.2 Three main strategies of which conductive biomaterials realizing their applications in wound healing and skin tissue engineering are discussed.3 The challenges and perspectives in designing multifunctional conductive biomaterials and further clinical translation are proposed.

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering.

The emergence and global spread of bacterial resistance to currently available antibiotics underscore the urgent need for new alternative antibacterial agents. Recent studies on the application of nanomaterials as antibacterial agents have demonstrated their great potential for management of infectious diseases. Among these antibacterial nanomaterials, carbon-based nanomaterials (CNMs) have attracted much attention due to their unique physicochemical properties and relatively higher biosafety. Here, a comprehensive review of the recent research progress on antibacterial CNMs is provided, starting with a brief description of the different kinds of CNMs with respect to their physicochemical characteristics. Then, a detailed introduction to the various mechanisms underlying antibacterial activity in these materials is given, including physical/mechanical damage, oxidative stress, photothermal/photocatalytic effect, lipid extraction, inhibition of bacterial metabolism, isolation by wrapping, and the synergistic effect when CNMs are used in combination with other antibacterial materials, followed by a summary of the influence of the physicochemical properties of CNMs on their antibacterial activity. Finally, the current challenges and an outlook for the development of more effective and safer antibacterial CNMs are discussed.

Antibacterial Carbon-Based Nanomaterials.

The development of high-efficiency peroxidase mimetics is highly desirable in view of high cost and low stability of natural enzymes. From the perspective of mimicking active site microenvironment at low cost, we herein report a novel histidine-functionalized graphene quantum dot (His-GQD)/hemin complex, which exhibits the highest catalytic rate for the peroxidase-based chromogenic reaction among the hemin-containing mimetics reported so far. Also, our peroxidase mimetic shows excellent tolerance to strongly acidic conditions and can function in a wide temperature range. Lineweaver-Burk plots and comprehensive electron paramagnetic resonance analysis reveal a ping-pong type catalytic mechanism for this mimetic. In addition, His-GQD/hemin demonstrates high efficiency and accuracy in detecting H2O2 and blood glucose. Our work provides an effective design of artificial enzymes for practical applications.

Mimicking peroxidase active site microenvironment by functionalized graphene quantum dots

Preparation of blue- and green-emissive nitrogen-doped graphene quantum dots from graphite and their application in bioimaging.

Facts can be exchanged in multiple fields with the help of disease-specific ontologies. A range of diverse values can be produced by mining ontological approaches for demonstrating disease mechanisms. Alzheimer’s disease (AD) is an incurable neurological brain illness. An early diagnosis of AD can be helpful for better treatment and the prevention of brain tissue destruction. Researchers have used machine learning techniques to predict the early detection of AD. However, Alzheimer’s disorders are still underexplored in the knowledge domain. In the biomedical field, the illustration of terminologies and notions is essential. Multiple methods are adopted to represent these notions, but ontologies are the most frequent and accurate. Ontology construction is a complex and time-consuming process. The designed ontology relies on Disease Ontology (DO), which is considered the benchmark in medical practice. Ontology reasoning mechanisms can be adopted for AD identification. In this paper, a deep convolutional neural network-based approach is proposed to diagnose Alzheimer’s disease, using an AD dataset acquired from Kaggle. Machine learning-based approaches (logistic regression, gradient boosting, XGB, SGD, MLP, SVM, KNN, random forest) are also used for a fair comparison. The simulation results are generated using three strategies (default parameters, 10-cross validation, and grid search), and MLP provides superior results on a default parameter strategy with an accuracy of 92.12%. Furthermore, the deep learning-based approach convolutional neural network (CNN) achieved an accuracy of 94.61%. The experimental results indicate that the construction of ontology, with the help of deep learning knowledge, can produce better results where the robustness and scalability can be enhanced. In comparisons to other methods, the CNN results are excellent and encouraging.

/pdf/constructing-domain-ontology-for-alzheimer-disease-using-3tie50fq.pdf

Asmat Nawaz

Papers

Antibacterial Carbon-Based Nanomaterials.

Mimicking peroxidase active site microenvironment by functionalized graphene quantum dots

Preparation of blue- and green-emissive nitrogen-doped graphene quantum dots from graphite and their application in bioimaging.

Constructing Domain Ontology for Alzheimer Disease Using Deep Learning Based Approach

Allelopathic Potential of Soliva sessilis Ruiz & Pav. on Wheat