Leeches can now be used to treat Parkinson's and epilepsy

Scientists have made a breakthrough in the field of bioelectronics by successfully injecting gel polymers inside leeches and zebrafish, which organized themselves into functional electrodes. 

The study was published in Science journal. It was revealed that when the gel molecules came in contact with enzymes inside an animal's body, they became electrically conductive. 

This innovation could lead to better treatments for people with neurological conditions such as Parkinson's and epilepsy by allowing scientists to stimulate areas of the body with an external voltage. Professor Magnus Berggren at the Laboratory for Organic Electronics, LOE, at Linköping University, Sweden, noted that for decades, they have tried to create electronics that mimic biology, but now they let biology create the electronics for them.

According to Xenofon Strakosas, a researcher at LOE and Lund University, the structure of the gel is changed and made electrically conductive when it comes in contact with the body's substances. Additionally, the researchers were able to successfully create gel-based electrodes inside the bodies of live zebrafish and leeches, with electrodes being formed in each organ the gel was injected into, including the brain, heart, and tail fins of zebrafish and around the nervous tissue of medicinal leeches, as reported by Inverse. 

Encouragingly, the procedure did not seem to cause pain or discomfort in the zebrafish, and while it is harder to know about pain in the leeches, it was assumed that the same was true for them as well. The composition of the gel could be adjusted depending on the tissue, which allowed the electrical process to work properly.

The scientists involved in the study injected gel polymers inside leeches and zebrafish, which then organized themselves into functional electrodes. 

According to Xenofon Strakosas, one of the study's main authors, the contact with the body's substances changes the structure of the gel and makes it electrically conductive, which it isn't before injection. 

The researchers successfully grew gel-based electrodes inside the bodies of live zebrafish and leeches. In the study, researchers established electrode formation in the brain, heart, and tail fins of zebrafish and around the nervous tissue of medicinal leeches.

The procedure did not seem to cause pain or discomfort in the zebrafish. According to Hjort, zebrafish exhibit pain in a lot of different ways, such as firing off swimming very fast, or they can roll around. But they didn't see any of these negative effects, which is a good sign.

Professor Roger Olsson at the Medical Faculty at Lund University said that by making smart changes to the chemistry, they were able to develop electrodes that were accepted by the brain tissue and immune system. The zebrafish is an excellent model for the study of organic electrodes in brains. The scientists admit that although their results are encouraging, there is still time left for any feasible human applications.

The results of the study open up new possibilities for creating electronics that mimic biology, said Hanne Biesmans, a Ph.D. student at LOE and one of the main authors. The research could lead to better treatments for people with neurological conditions such as Parkinson's and epilepsy. While on the topic of Parkinson’s, another study found that having regular nightmares in childhood may be linked to the development of cognitive impairment or Parkinson's disease later on.

Reference: Leeches are segmented invertebrates that belong to the subclass Hirudinea. There are over 700 species of leeches found in freshwater, marine, and terrestrial habitats around the world. Leeches are best known for their ability to suck blood from their hosts, but not all species feed on blood. Some are carnivorous and feed on other invertebrates, while others are detritivores and consume decomposing organic matter.

Leeches have been used for medicinal purposes for thousands of years in various cultures around the world. In ancient Egypt, leeches were used for treating nervous system disorders, and they were also commonly used in ancient Greece for treating a range of ailments. In the 19th century, leeches became a popular medical treatment in Europe and America, particularly for treating blood-related disorders such as varicose veins.

Today, leeches are still used for medical purposes, particularly in plastic and reconstructive surgery. They secrete a substance called hirudin, which is a natural anticoagulant that can prevent blood clots from forming. Leeches are also used in some medical conditions such as arthritis and deep vein thrombosis.

Aside from their medical use, leeches play an important role in aquatic ecosystems as decomposers and as a food source for other animals. However, some species have become invasive in certain areas and can cause harm to native species.