The goal of this randomized controlled trial is to evaluate the efficacy and safety of a novel hydrogel made of Carbopol® 940 functionalized with Plasma-Activated Water (PAW) in patients with chronic wounds (diabetic foot ulcers, pressure injuries, dehiscent wounds, arterial and venous ulcers). The main questions it aims to answer are:

• Does PAW-hydrogel accelerate wound closure (reduction in surface area) compared to standard advanced wound care?
• Does PAW-hydrogel reduce bacterial load in the wound bed?
• Is PAW-hydrogel safe and well-tolerated (local adverse events, pain)?

Participants will be randomly assigned to one of two groups:

• Experimental group: Topical application of PAW-hydrogel (Carbopol® 940 neutralized to pH 5.5, loaded with reactive oxygen and nitrogen species from plasma activation) 2-3 times per week.
• Control group: Standard advanced wound care (cleaning, debridement, conventional dressings).

Wound area (planimetry), bacterial load (semi-quantitative cultures), pain (Visual Analog Scale), tissue quality (Bates-Jensen scale), and adverse events will be assessed over a 12-week follow-up period.

This prospective, randomized, controlled, parallel-group trial will be conducted at the Wound Clinic and hospitalization services of the Centro Médico ISSEMYM Lic. Arturo Montiel Rojas (Metepec, State of Mexico, Mexico), in collaboration with the Instituto Nacional de Investigaciones Nucleares (ININ), which develops and characterizes the Plasma-Activated Water (PAW) and the functionalized hydrogel.

Adult patients (≥18 years) with chronic wounds of various etiologies - diabetic foot ulcers (Wagner grade 1-2), pressure injuries (grade I-III), dehiscent surgical wounds, venous ulcers, or arterial ulcers - that have failed to heal for more than 3 months and have a surface area between 2 cm² and 20 cm² will be screened. Eligible patients will be randomly allocated (1:1) to either the experimental group (PAW-hydrogel) or the active comparator group (standard advanced wound care). Randomization will be performed using a computer-generated sequence with opaque sealed envelopes.

The PAW-hydrogel intervention consists of a 1% w/v Carbopol® 940 hydrogel neutralized to pH 5.5 and functionalized with PAW generated by a dielectric barrier discharge (DBD) coaxial reactor. The hydrogel is produced under aseptic conditions at ININ, and each batch is tested for pH (5.5) and sterility before release. In the experimental arm, after standard wound cleaning with sterile saline, a uniform layer (3-5 mm thickness) of PAW-hydrogel is applied to cover the entire wound bed, followed by a sterile secondary occlusive dressing. The hydrogel is reapplied 2-3 times per week depending on exudate levels (more frequent for heavily exuding wounds). The control arm receives standard advanced wound care according to ISSEMYM protocols, which includes cleaning, mechanical debridement if needed, and application of conventional dressings (e.g., alginate, foam, or silver-based dressings as clinically indicated), without PAW-hydrogel.

The study is conducted in full compliance with the Declaration of Helsinki and Mexican health regulations (Ley General de Salud). The protocol, informed consent form, and all patient-facing materials have been approved by the Health Research and Research Ethics Committee of ISSEMYM (314/26). All participants provide written informed consent prior to any study procedure. Participants may withdraw at any time without affecting their medical care at ISSEMYM. Data confidentiality is ensured by coding patient identifiers.

Inclusion Criteria:

• Adults ≥ 18 years of age.
• Diagnosis of chronic wound (diabetic foot ulcer Wagner grade 1-2, pressure injury grade I-III, dehiscent surgical wound, venous or arterial ulcer) with duration > 3 months.
• Wound surface area between 2 cm² and 20 cm².
• For diabetic patients: HbA1c < 9% (stable metabolic control).
• Able and willing to provide written informed consent.

Exclusion Criteria:

• Clinical or radiological evidence of osteomyelitis (Wagner grade > 3).
• Severe arterial insufficiency (ankle-brachial index < 0.5).
• Use of systemic corticosteroids or immunosuppressants.
• Pregnancy or lactation.
• Known autoimmune skin disease (e.g., pemphigus, epidermolysis bullosa).
• Active malignancy or undergoing chemotherapy/radiotherapy.
• Participation in another interventional clinical trial within 30 days prior to screening.