28 March 2018

Healing nanofibers

A group of researchers from the Harvard School of Engineering and Applied Sciences named after John Paulson (Harvard John A. Paulson School of Engineering and Applied Sciences) has developed healing dressings that significantly accelerate the regeneration of damaged tissues.

Back in the 70s of the last century, it was discovered that the healing of wounds received before the third trimester of intrauterine development is completed without the formation of scars. This has opened up a number of possibilities for restorative medicine, but it was only now possible to reproduce the unique healing capabilities of fetal skin.

The analysis showed that the skin of an adult is different from the skin of a fetus. The protein fibronectin, which forms the extracellular substance, provides its viscosity and keeps the cells next to each other. Fetal skin contains much more fibronectin than adult skin.

Fibronectin is of two types: globular, circulating in the blood, and fibrillar (fibrous), localized in tissues. Despite the fact that the fibrillar protein showed a much more pronounced healing effect, in previous studies more attention was paid to the globular form. This is partly due to the complexity of the synthesis of fibrillar fibronectin.

Kit Parker and co-authors solved this problem with the help of their own developments. Using a special type of centrifugation (Rotary Jet-Spinning), they were able to "untangle" globular fibronectin and obtain from it individual fibers with a diameter of less than one micrometer.

Bandages were created from fibronectin fibers, which, when applied, integrate into the wound and act as a framework on which stem cells accumulate, accelerating the regeneration process. After healing, the nanofibers undergo biodegradation.

In vivo studies, fibronectin dressing showed a fairly high efficiency: within 20 days after the injury, healing was completed by 84%, while in the control group in which conventional dressings were performed, this indicator was 55.6%.

The healing rate did not affect its quality: the thickness and architecture of the epidermis and dermis were close to normal, even the hair follicles recovered.

In another article, researchers from the Wyss Institute for Biologically Inspired Engineering described soy-based healing nanofibers.

Soy protein contains estrogen-like molecules that accelerate healing, and bioactive components involved in cell construction.

In women, in the first half of the menstrual cycle, skin damage heals faster, presumably due to high levels of estrogen in the blood.

Using the same centrifugation technology as the authors of the previous article, the researchers created dressings based on soy protein and cellulose fibers. In animal experiments, they accelerated the healing process by 71% compared to wounds that were not treated, and by 21% compared to wounds that were bandaged with dressings without soy protein.

Both types of nanofiber dressings, according to the authors, have great potential in the treatment of wounds. Fibronectin bandages will preferably be used in small areas where the presence of scars is undesirable (for example, on the face or hands). Soy dressings are much cheaper, they would be suitable for treating large injuries, for example, burns.

Article C. O Chantre et al. Production-scale fibronectin nanofibers promote wound closure and tissue repair in a dermal mouse model published in the journal Biomaterials; article S. Ahn et al. Soy Protein/Cellulose Nanofiber Scaffolds Mimicking Skin Extracellular Matrix for Enhanced Wound Healing is published in the journal Advanced Healthcare Materials.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on SEAS: Drawing inspiration from plants and animals to restore tissue.

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