An antidote made of nanoparticles

Another step towards creating a universal antidote

Julia Korowski, XX2 century

Different types of snakes secrete different toxins. This means that a bitten citizen needs not any, but a strictly defined antidote, and as soon as possible. Scientists from the University of California, Irvine (University of California, Irvine) We have created nanoparticles that bind not one, but several common animal toxins at once (O'Brien et al., Engineering the Protein Corona of a Synthetic Polymer Nanoparticle for Broad-Spectrum Sequestration and Neutralization of Venomous Biomacromolecules). Perhaps someday this technology will allow us to develop a universal antidote.

About 4.5 million people are bitten by venomous snakes every year, mainly in Africa and Asia. Almost 3 million of them suffer from serious consequences, more than 100,000 people die. Most episodes of snake bites occur in rural areas, where hospitals are not equipped with the necessary antidotes, and victims often receive the wrong drugs.

The production of antidotes is a complex process. First, the animal – often a horse acts in this role – is injected with small doses of diluted snake venom. The immune system of an individual begins to produce antibodies that can bind to toxins and block their activity. Then blood is taken from the animal, antibodies are isolated from it and a medicine is prepared from them. This method has significant drawbacks. Firstly, the production of antibody-based antidotes requires a lot of time and financial costs and is not very profitable for pharmaceutical companies, which leads to a shortage of drugs. Secondly, antidotes must be stored in refrigerators, which means that they are more difficult to deliver to developing countries – where they are most needed.

To solve these problems, chemist Ken Shea and his colleagues turned to nanotechnology for help. In the course of previous studies, they obtained nanoparticles that bind and remove melittin, one of the components of bee venom, from the blood. Now they set out to neutralize not one, but several toxic substances at once. The new work is devoted to a family of enzymes called phospholipase A2 (phospholipase A2, PLA2). Snakes secrete hundreds of different variants of phospholipase A2 – from low-toxic to extremely poisonous. As a rule, they are embedded in the lipid membranes of cells. Scientists have suggested that nanoparticles of "lipid-like" molecules, similar to those contained in cell membranes, will be able to bind a number of PLA2 enzymes.

However, they synthesized not one type of nanoparticles, but many hydrogel particles consisting of a carbon backbone and randomly distributed side chains. Nanoparticles with different chemical properties were incubated in the presence of blood serum and poisons, and then those of them that bound best to phospholipases A2 were isolated. After several stages of such chemical optimization, the researchers obtained nanoparticles that neutralize different types of PLA2 toxins. They called this technique the "method of directed synthetic evolution".

Shay notes that although he and his colleagues have yet to refine the results, laboratory tests show that they will be able to achieve the same strong binding to PLA2 as in the case of melittin. Animal experiments will begin next month. If they are successful, scientists will develop nanoparticles that neutralize other common poisons. "Ultimately, we would like to get a mixture of three or four types of nanoparticles that neutralize the main protein toxins," says Shay. Such synthetic "cocktails" will cost less, and in addition, they will not need to be stored in the refrigerator.

"This approach to treating snake bites seems promising," says Stephen Mackessy, a snake specialist at the University of Northern Colorado, who was not involved in the study. "If they can create a group of particles specifically binding major toxins, this approach will have great therapeutic value."

Portal "Eternal youth" http://vechnayamolodost.ru  22.12.2016