Nano oxygen chamber by cascade reaction for hypoxia mitigation and reactive oxygen species scavenging in wound healing

Progress and potential of nanobubbles for ultrasound-mediated drug delivery

INTRODUCTION

Despite much progress, nanomedicine-based drug therapies in oncology remain limited by systemic toxicity and insufficient particle accumulation in the tumor. To address these barriers, formulations responsive to external physical stimuli have emerged. One most promising system is the ultrasound stimulation of drug-loaded, gas-core particles (bubbles). Ultrasound induces bubble cavitation for cell and tissue permeabilization, triggers on-demand drug release, and provides opportunities for real-time imaging of delivery.

AREAS COVERED

Here, we focus on shell-stabilized, gas-core nanoparticles (also termed nanobubbles or ultrafine bubbles) and their role in ultrasound-mediated therapeutic delivery to tumors. This review frames the advantages of nanobubbles within the ongoing deficits in nanomedicine, describes mechanisms of ultrasound-mediated therapy, and details formulation techniques for nanobubble delivery systems. It then highlights the past decade of research in nanobubble-facilitated drug delivery for cancer therapy and anticipates new directions in the field.

EXPERT OPINION

Nanobubble ultrasound contrast agents offer a spatiotemporally triggerable therapeutic coupled with a safe, accessible imaging modality. Nanobubbles can be loaded with diverse therapeutic cargoes to treat disease and overcome numerous barriers limiting delivery to solid tumors. Close attention to formulation, characterization methods, acoustic testing parameters, and the biological mechanisms of nanobubble delivery will facilitate preclinical research toward clinical adoption.

2-Methoxyestradiol Inhibits the Oxygen-Sensing Pathway in Keloid Fibroblasts by Targeting HIF-1α/PHD

Maintaining oxygen homeostasis is a basic cellular process for adapting to physiological oxygen variations in which the oxygen-sensing pathway plays a critical role, especially in tumour progression. Little is known about the activity of the oxygen-sensing pathway in keloid tissue. In this study, key features of the oxygen-sensing pathway and its downstream effects were evaluated and compared between normal skin tissue and keloid tissue. Keloid tissue showed increased oxygen-sensing pathway activation and a higher expression of key downstream factors such as tumour necrosis factor-1α (TNF-α) and vascular endothelial growth factor (VEGF). In addition, the effects of 2-methoxyestradiol on the oxygen-sensing pathway in both hypoxic and normoxic keloid fibroblasts were evaluated. Our results suggest that 2-methoxyestradiol could be used to inhibit keloid fibroblast activity by inhibiting the oxygen-sensing pathway and its downstream effectors.

Multifunctional dynamic chitosan-guar gum nanocomposite hydrogels in infection and diabetic wound healing

Traditional wound care methods are less effective for infectious and diabetic wounds, highlighting an urgent need for effective strategies. The study aimed to design a self-healing hydrogel with antibacterial, antioxidant, and photothermal capabilities to treat infectious and diabetic wounds. Silver nanoparticles (AgNPs) were loaded into mesoporous polydopamine (MPDA) nanoparticles to form Ag@MPDA nanoparticles. Ag@MPDA was incorporated into the cationic guar gum-chitosan-boric acid (CCB) hydrogel to obtain the PA-CCB hydrogel. PA-CCB hydrogel exhibited excellent self-healing and adhesive properties, adapting well to the dynamic wound environment. PA-CCB hydrogel combined with photothermal therapy (PTT) could effectively eradicated E. coli (99.9 %) and S. aureus (99.7 %). The PA-CCB hydrogel reduced excessive reactive oxygen species and promoted the migration of fibroblasts in vitro. In the infected mouse wound models, the PA-CCB hydrogel effectively inhibited bacteria. After combining with PTT, the antibacterial ability of the PA-CCB hydrogel was further enhanced. In the diabetic mouse wound models, the PA-CCB hydrogel reduced the inflammatory level of wound tissue. In both models, after combining with PTT, the PA-CCB hydrogel exhibited further improvements in angiogenesis, collagen deposition, and re-epithelialization. By integrating multifunctional hydrogel with PTT, the PA-CCB hydrogel exhibited broad application potential for infectious and diabetic wounds.

An injectable in situ-forming hydrogel with self-activating genipin-chitosan (GpCS) cross-linking and an O2/Ca2+ self-supplying capability for wound healing and rapid hemostasis

Severe traumatic bleeding and chronic diabetic wounds require rapid hemostasis and multifunctional dressings, which remain particularly challenging, especially for non-compressible trauma and irregular wounds with dysregulated microenvironments. Chitosan (CS) can be easily cross-linked with genipin to form GpCS hydrogels. However, developing injectable GpCS hydrogels for biomedical applications faces challenges, particularly in enhancing rapid gel formation and optimizing physical properties. In this study, we present an innovative approach to improve these aspects by designing a novel injectable GpCS hydrogel, strategically enhanced through a calcium peroxide (CaO2)-activated cross-linking reaction. CaO2 played a pivotal role in promoting in situ cross-linking of the GpCS hydrogel, leading to significant improvements in its injectable in situ gel-forming ability, mechanical strength, and self-healing and bioadhesive properties. CaO2 incorporated in the hydrogels rapidly converted to oxygen when combined with catalase (CAT), thereby establishing a self-sustaining oxygen/calcium release system. This system not only promoted hyperoxia and activated the coagulation cascade, facilitating rapid blood clotting, but also significantly accelerated wound healing through enhanced angiogenesis, collagen deposition, and M2 macrophage polarization. These attributes significantly enhanced the capacity of the hydrogel to facilitate wound closure and hemostasis, highlighting its therapeutic value in accelerating recovery and improving healing outcomes in clinical wound care.

Oxygenated Exosome-Based Nanoeyedrop for Mitigating Hypoxia in Corneal Wound Healing: Impact on Healing Properties of Human Corneal Epithelial Cells

The rapid and organized healing of the cornea, while maintaining optical clarity, is essential for patient health and quality of life following corneal injuries. Oxygen plays a critical role in regulating cell migration and proliferation during wound repair, and the application of stem cell-derived exosomes offers potential therapeutic benefits due to their antioxidant and antiscarring properties. In this study, we developed oxygenated exosome-coated hemoglobin nanoparticles (OExo NPs) designed for effective oxygen delivery to enhance corneal re-epithelialization, reduce inflammation, and mitigate scarring. These OExo NPs exhibit a uniform average diameter of 130 nm and demonstrate consistent oxygen release capabilities. In vitro assays using human corneal epithelial cells-transformed (HCE-T) revealed that OExo NPs significantly promote cell proliferation and accelerate migration in scratch wound assays. Fluorescence imaging confirmed the successful internalization of OExo NPs into HCE-T cells and increased intracellular oxygen levels under hypoxic conditions. Gene expression analyses indicated a downregulation of critical wound healing markers, including HIF-1α, VEGF, IL-8, and FAK, suggesting effective alleviation of hypoxia, inhibition of angiogenesis, suppression of inflammation, and reduction of scar formation. These results highlight the potential of OExo NPs as a promising therapeutic approach for topical treatment of corneal wounds.

Recent Advancements of Nanomedicine in Breast Cancer Surgery

Breast cancer surgery plays a pivotal role in the multidisciplinary approaches. Surgical techniques and objectives are gradually shifting from tumor complete resection towards prolonging survival, improving cosmetic outcomes, and restoring the social and psychological well-being of patients. However, surgical treatment still faces challenges such as inadequate sensitivity in sentinel lymph node localization, the need to improve intraoperative tumor boundary localization imaging, postoperative scar healing, and the risk of recurrence, necessitating other adjunct measures for improvement. To address these challenges, specificity-optimized nanomedicines have been introduced into the surgical therapeutic landscape of breast cancer. In particular, this review involves starting with an overview of breast structure and the composition of the tumor microenvironment and then introducing the guiding principle and foundation for the design of nanomedicine. Moreover, we will take the order process of breast cancer surgery diagnosis and treatment as the starting point, and adaptively propose the roles and advantages of nanomedicine in addressing the corresponding issues. Furthermore, we also involved the prospects of utilizing advanced technological approaches. Overall, this review seeks to uncover the sophisticated design and strategies of nanomedicine from a clinical standpoint, address the challenges faced in surgical treatment, and provide insights into this subject matter.

Exploring the wound healing potential of dietary nitrate in diabetic rat model

Introduction

The wound healing in diabetes is hindered and prolonged due to long-term inflammation, oxidative stress damage, and angiogenesis disorders induced by high glucose status. The management of such difficult-to-treat wounds continues to pose a significant challenge in clinical treatment. Dietary nitrate, commonly found in greens such as beets and spinach, acts as a nutritional supplement and is metabolized in the body through the salivary nitrate-nitrite-NO pathway. This pathway plays a crucial role in various physiological functions, including enhancing blood flow and attenuating inflammation.

Methods

In this study, we established a diabetic rat wound model. Forty-eight rats were randomly divided into six groups (n = 8): the Con group, the Con + Nitrate group, the STZ group, the STZ + NaCl group, the STZ + rhEGF group, and the STZ + Nitrate group. Skin wound healing was assessed on the day of surgery and on postoperative days 3, 7, 10, and 14. Specimens were taken on days 7 and 14 post-surgery for relevant tests.

Results

We found that dietary nitrate could accelerate skin wound healing by promoting angiogenesis and increasing blood perfusion. Significantly, dietary nitrate also regulated glucose and lipid metabolism and exhibited anti-inflammatory and antioxidant properties.

Discussion

These findings provide a novel theoretical basis for managing wounds in diabetic individuals, indicating the broad potential of dietary nitrate in future clinical applications.

Repair and regeneration: ferroptosis in the process of remodeling and fibrosis in impaired organs

As common clinical-pathological processes, wound healing and tissue remodelling following injury or stimulation are essential topics in medical research. Promoting the effective healing of prolonged wounds, improving tissue repair and regeneration, and preventing fibrosis are important and challenging issues in clinical practice. Ferroptosis, which is characterized by iron overload and lipid peroxidation, is a nontraditional form of regulated cell death. Emerging evidence indicates that dysregulated metabolic pathways and impaired iron homeostasis play important roles in various healing and regeneration processes via ferroptosis. Thus, we review the intrinsic mechanisms of tissue repair and remodeling via ferroptosis in different organs and systems under various conditions, including the inflammatory response in skin wounds, remodeling of joints and cartilage, and fibrosis in multiple organs. Additionally, we summarize the common underlying mechanisms, key molecules, and targeted drugs for ferroptosis in repair and regeneration. Finally, we discuss the potential of therapeutic agents, small molecules, and novel materials emerging for targeting ferroptosis to promote wound healing and tissue repair and attenuate fibrosis.

Nanogels in Biomedical Engineering: Revolutionizing Drug Delivery, Tissue Engineering, and Bioimaging

Nanogels represent a significant innovation in the fields of nanotechnology and biomedical engineering, combining the properties of hydrogels and nanoparticles to create versatile platforms for drug delivery, tissue engineering, bioimaging, and other biomedical applications. These nanoscale hydrogels, typically ranging from 10 to 1000 nm, possess unique characteristics such as high water content, biocompatibility, and the ability to encapsulate both hydrophilic and hydrophobic molecules. The review explores the synthesis, structural configurations, and stimuli‐responsive nature of nanogels, highlighting their adaptability for targeted drug delivery, including across challenging barriers like the blood–brain barrier. Furthermore, the paper delves into the biomedical applications of nanogels, particularly in drug delivery systems, tissue engineering, and bioimaging, demonstrating their potential to revolutionize these fields. Despite the promising preclinical results, challenges remain in translating these technologies into clinical practice, including issues related to stability, scalability, and regulatory approval. The review concludes by discussing future perspectives, emphasizing the need for further research to optimize the properties and applications of nanogels, ultimately aiming to enhance their efficacy and safety in clinical settings.

Nanozymes for the Therapeutic Treatment of Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are chronic, refractory wounds caused by diabetic neuropathy, vascular disease, and bacterial infection, and have become one of the most serious and persistent complications of diabetes mellitus because of their high incidence and difficulty in healing. Its malignancy results from a complex microenvironment that includes a series of unfriendly physiological states secondary to hyperglycemia, such as recurrent infections, excessive oxidative stress, persistent inflammation, and ischemia and hypoxia. However, current common clinical treatments, such as antibiotic therapy, insulin therapy, surgical debridement, and conventional wound dressings all have drawbacks, and suboptimal outcomes exacerbate the financial and physical burdens of diabetic patients. Therefore, development of new, effective and affordable treatments for DFU represents a top priority to improve the quality of life of diabetic patients. In recent years, nanozymes-based diabetic wound therapy systems have been attracting extensive interest by integrating the unique advantages of nanomaterials and natural enzymes. Compared with natural enzymes, nanozymes possess more stable catalytic activity, lower production cost and greater maneuverability. Remarkably, many nanozymes possess multienzyme activities that can cascade multiple enzyme-catalyzed reactions simultaneously throughout the recovery process of DFU. Additionally, their favorable photothermal-acoustic properties can be exploited for further enhancement of the therapeutic effects. In this review we first describe the characteristic pathological microenvironment of DFU, then discuss the therapeutic mechanisms and applications of nanozymes in DFU healing, and finally, highlight the challenges and perspectives of nanozyme development for DFU treatment.

Hydrogel-Based Oxygen and Drug Delivery Dressing for Improved Wound Healing

Herein, we propose a Carbopol hydrogel-based oxygen nanodelivery "nanohyperbaric" system as a wound dressing material for an enhanced wound healing process. Oxygen nanobubbles (ONBs) were used to supply oxygen, and collagenase was added in the gel as a drug model. Both oxygen and collagenase would benefit the wound healing process, and the Carbopol hydrogel serves as the matrix to load ONBs and collagenase in the wound dressing. The obtained ONB-embedded Carbopol hydrogel with collagenase (ONB-CC) could provide 12.08 ± 0.75 μg of oxygen from 1 mL of ONB-CC and exhibited a notable capacity to prolong the oxygen holding for up to 3 weeks and maintained the enzymatic activity of collagenase at more than 0.05 U per 0.1 mL of ONB-CC for up to 17 days. With HDFa cells, the ONB-CC did not show a notable effect on the cell viability. In a scratch assay, the oxygen from ONBs or collagenase aided cell migration; further, the ONB-CC induced the most obvious scratch closure, indicating an improvement in wound healing as a cocktail in the ONB-CC. The mRNA expression further demonstrated the effectiveness of the ONB-CC. Studies in rats with punched wounds treated with the ONB-CC dressing showed improved wound closure. Histopathological images showed that the ONB-CC dressing enhanced re-epithelization and formation of new blood vessels and hair follicles. The proposed ONB-CC has excellent potential as an ideal wound dressing material to accelerate wound healing by integration of multiple functions.

Exosome-coated oxygen nanobubble-laden hydrogel augments intracellular delivery of exosomes for enhanced wound healing

Wound healing is an obvious clinical concern that can be hindered by inadequate angiogenesis, inflammation, and chronic hypoxia. While exosomes derived from adipose tissue-derived stem cells have shown promise in accelerating healing by carrying therapeutic growth factors and microRNAs, intracellular cargo delivery is compromised in hypoxic tissues due to activated hypoxia-induced endocytic recycling. To address this challenge, we have developed a strategy to coat oxygen nanobubbles with exosomes and incorporate them into a polyvinyl alcohol/gelatin hybrid hydrogel. This approach not only alleviates wound hypoxia but also offers an efficient means of delivering exosome-coated nanoparticles in hypoxic conditions. The self-healing properties of the hydrogel, along with its component, gelatin, aids in hemostasis, while its crosslinking bonds facilitate hydrogen peroxide decomposition, to ameliorate wound inflammation. Here, we show the potential of this multifunctional hydrogel for enhanced healing, promoting angiogenesis, facilitating exosome delivery, mitigating hypoxia, and inhibiting inflammation in a male rat full-thickness wound model.