Chronic wounds affect millions of people worldwide. Diabetic wounds are especially difficult to treat. Due to the growing number of people suffering from diabetes worldwide, wounds in diabetics account for a significant proportion of the global burden.
Conventional wound dressings contain antimicrobial chemicals such as iodine which may contaminate the environment. For chronic wound treatment, antibiotics are used. Large scale use of antibiotics leads to the development of antibiotic-resistant strains. Moreover, changing the wound dressing is often painful.
To overcome these challenges, researchers have come up with pastes, emulsions, hydrogels and oleogels that are less painful to patients, as well as less harmful to the environment.
Recently, researchers at the Pushpagiri College of Dental Sciences, Thiruvalla, Keralam collaborated with researchers in Italy to develop such an alternative that heals wounds effectively.
They thought of neem oil – it has antimicrobial and antifungal properties. But in some cases it may cause skin irritation. So they thought of adding hypericum oil, which is soothing. Oil from a flower called hypericum has antimicrobial, anti-inflammatory and antioxidant properties. It also facilitates the proliferation and migration of cells from surrounding tissues and promotes the growth of blood vessels to carry nutrients and oxygen to growing cells in the wound area.
Suspensions of such oils have been used for wound healing experiments earlier. However, when applied directly to the skin, the emulsion tends to run off due to its low viscosity, resulting in limited residence time at the application site. So the researchers thought of adding one more component – cellulose. They reasoned that cellulose would hold the suspension together and make the action more sustained.
To test the idea, the researchers combined neem oil and hypericum oil. Then they added emulsifiers and prepared an oil-in-water emulsion by homogenisation.
The researchers chose bacterial cellulose as the scaffold for holding the bioactive agents. Compared to plant cellulose, which may be contaminated with hemicellulose and lignin, it is easier to extract pure cellulose from bacteria. Bacterial cellulose has a nanofibrillar structure that resembles the extracellular matrix – useful for healing wounds. It also has hydroxyl groups that form hydrogen bonds with bioactive agents and water, to hold together the bioactive compounds while creating a moist environment for faster wound healing.
They prepared the bacterial cellulose by culturing Komagataeibacter xylinus, a well-studied source of cellulose. When cultured under static conditions for 7 to 10 days, a pellicle, a white layer, is formed on top. The pellicle is then washed with sodium hydroxide and hydrogen peroxide to obtain pure white cellulose.
Using transmission electron microscopy, the researchers examined the bacterial cellulose. The bacterial cellulose exhibited a fibre-like structure. The oil-in-water emulsion showed oil droplets dispersed throughout the aqueous phase. The paste exhibited a uniform distribution of the oil droplets within the nanofibrous cellulose matrix.
The researchers then evaluated the wound-healing efficacy of the paste using an in vivo rat model. Circular wounds were surgically created and treated with the cellulose-emulsion paste.
Another set of rats were treated with commercial collagen as positive control, and yet another was left untreated as the negative control group.
Compared with the commercial collagen group, wound healing was faster in the group treated with the paste. By the third day, 65% of the wound area was closed, whereas only 45% of wound closure was achieved in the group treated with the conventional collagen. The untreated group did not show wound closure.
Is this treatment toxic to the cells? The researchers subjected mouse fibroblasts to increasing concentrations of the cellulose-emulsion paste to assess its cytotoxicity. Cell viability remained above 85% even at high concentrations of the paste.
But does the paste have adverse effects on internal organs? To check for organ toxicity in rats whose skin wounds were treated with the paste, the researchers examined the histology of heart, liver, and kidney tissues from rats treated with the paste. They were similar to normal tissues.
Thus, the paste is safe for use.
The cellulose-emulsion paste overcomes the limitations of conventional wound dressings, such as the need for frequent changing of wound dressings and the potential development of antibiotic resistance.
International Journal of Pharmaceutics, 702: 127247 (2026)
DOI: 10.1016/j.ijpharm.2026.127247
Reported by Deepika Baskaran
Sastra Deemed University, Thanjavur
This report was written in a workshop for capacity building of PhD scholars
organised by scienceandmediaworkshops.
The reports on this site are free-to-use for Indian media houses.
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