Bi-Layer Wound Dressings with Tranexamic Acid and Nitric Oxide: Hemostatic and Antibacterial Breakthroughs

Study Background and Research Question

Uncontrolled hemorrhage and wound infection are the two leading contributors to early mortality following traumatic injury. Despite advances in trauma management, these challenges persist in both civilian and battlefield contexts, accounting for a substantial proportion of preventable deaths within the first hours and days after injury. Traditional wound dressings often lack the dual functionality required to immediately halt bleeding and protect against infection. In this context, the reference study (Nguyen et al., 2024) addresses a critical research gap: can a single wound dressing effectively combine rapid clot formation with potent antibacterial action to improve outcomes in trauma care?

Key Innovation from the Reference Study

The central innovation of the work is the design and fabrication of a bi-layer wound dressing capable of instant clot formation and sustained antibacterial activity. The dressing incorporates three synergistic components:

• Tranexamic Acid (TXA): An established antifibrinolytic agent, TXA is used here to stabilize the developing clot by inhibiting fibrin degradation.
• S-nitroso-N-acetylpenicillamine (SNAP): This nitric oxide (NO) donor is embedded in the base layer to provide continuous NO release, leveraging its broad-spectrum antibacterial and wound healing properties.
• Propolis: A natural resinous material with bioadhesive, antibacterial, and anti-inflammatory effects, used as a scaffold for TXA delivery.

This strategic bi-layer configuration allows for immediate hemostasis at the wound interface while the underlying NO-releasing layer combats infection and supports tissue regeneration. Such integration of antifibrinolytic and antimicrobial mechanisms is a substantial step forward in wound care biomaterials.

Methods and Experimental Design Insights

The study's fabrication process involves two distinct layers:

• The wound-contact layer consists of TXA uniformly suspended within a propolis matrix, with propolis concentrations tested at 2.5%, 5.0%, and 7.5% by volume.
• The base layer is composed of the NO donor SNAP embedded within a Carbosil® copolymer (polycarbonate urethane and silicone), positioned furthest from the wound bed to allow gradual NO release.

To characterize the dressing, the researchers conducted:

• A lactate dehydrogenase-based platelet adhesion assay to assess clot formation and fibrin activation.
• Scanning electron microscopy (SEM) for visualization of the fibrin network and clot morphology.
• Antibacterial testing against Staphylococcus aureus and multidrug-resistant Acinetobacter baumannii to quantify reductions in colony-forming units (CFUs).

This robust experimental design enables a comprehensive evaluation of both hemostatic and antimicrobial performance.

Protocol Parameters

• Propolis concentration in wound-contact layer: 2.5%, 5.0%, or 7.5% v/v; higher concentrations (7.5%) demonstrated greater clot stability and fibrin activation within 15 minutes.
• Tranexamic Acid loading: Uniform distribution within the propolis matrix; precise concentrations tailored to achieve immediate antifibrinolytic effect at the wound interface.
• NO donor (SNAP) embedding: Incorporated in Carbosil® base layer for controlled NO release and antibacterial coverage.
• Platelet adhesion assay: Lactate dehydrogenase quantification, 15-minute exposure to assess rapid clot formation.
• SEM imaging: Post-clot formation, samples fixed and dehydrated for morphological analysis.
• Antibacterial efficacy: CFU reduction measured after NO/propolis exposure against both Gram-positive and Gram-negative pathogens.

Core Findings and Why They Matter

The study reports several key outcomes with direct translational relevance:

• Instant Clot Formation: The 7.5% propolis-TXA layer achieved rapid and dense fibrin network formation, as confirmed by both biochemical and SEM analyses, within the first 15 minutes of application (Nguyen et al., 2024).
• Stabilization of Hemostasis: Tranexamic Acid acts as a competitive inhibitor of plasminogen activation, preventing fibrinolysis and promoting clot stability directly at the wound site.
• Robust Antibacterial Activity: The NO-releasing layer, combined with propolis, resulted in a 98.9% and 99.4% reduction in S. aureus and multidrug-resistant A. baumannii CFUs, respectively, within a clinically relevant timeframe.
• Dual-Action Synergy: The combination of antifibrinolytic and antimicrobial strategies addresses the two primary causes of trauma-related morbidity, potentially reducing the need for multiple interventions.

These findings underscore the potential of bi-layered, multifunctional dressings to transform emergency wound care, especially in prehospital or resource-limited environments.

Comparison with Existing Internal Articles

This reference study aligns with and extends insights from several recent internal resources. For instance, Tranexamic Acid in Fibrinolysis Research: Protocols & Innovations emphasizes the versatility of TXA as an antifibrinolytic agent in both in vitro and advanced wound models, supporting its inclusion in bi-layer dressings for translational hemostasis. Similarly, Instant Clot-Forming NO-Releasing Dressings with Tranexamic Acid and Instant Clotting and Antibacterial Dressings with TXA–NO–Propolis discuss the integrative approach of pairing antifibrinolytic and NO-mediated antibacterial functions. This convergence of evidence reinforces the practical relevance of TXA-centered dual-action dressings for both research and translational care.

Limitations and Transferability

While the study demonstrates efficacy in vitro and in preclinical models, some limitations must be acknowledged. First, the dressing's performance in complex, contaminated wound environments and under dynamic physiological conditions remains to be validated in large animal models or clinical trials. The optimal TXA and propolis concentrations may also vary depending on wound size, bleeding severity, and microbial burden. Moreover, long-term biocompatibility and potential immunogenicity of the dressing components, particularly with repeated or prolonged use, require further investigation. Finally, the scalability and manufacturability of the bi-layer configuration need to be addressed for widespread adoption.

Research Support Resources

Researchers interested in replicating or extending these workflows may benefit from high-purity Tranexamic Acid as a foundation for antifibrinolytic studies. Tranexamic Acid (SKU B1858, APExBIO) is suitable for both in vitro and translational research applications, with supporting documentation and quality control data available. Careful attention to dosing, solubility, and storage—as outlined in the product specifications—can help maximize reproducibility in clot formation and plasmin-induced neutrophil adherence assays. This resource supports continued innovation in fibrinolysis research and advanced wound dressing development.