Researchers have explored methods for delivering medications to tumors using blood cells.

Nanomedicine is an emerging field that utilizes various nanoparticles for diagnosis and therapy. These particles assist in delivering drugs directly to tumors, but achieving the required concentration is a challenging task. One solution to the delivery problem is the use of neutrophils.

“There are two approaches: the first is to load the cells with nanoparticles outside the body and then return them; the second is to introduce nanoparticles directly into the body so that the cells can capture them and deliver them to the tumor. Neutrophils are considered promising 'couriers.' This type of leukocyte, which makes up a large part of the immune system, can penetrate through blood vessels and travel long distances in response to inflammation or a tumor,” said Maxim Abakumov, PhD, head of the 'Biomedical Nanomaterials' laboratory at NITU MISIS.

However, there are challenges: some coatings on nanoparticles may hinder the functioning of neutrophils. The material, size, and shape significantly affect the interaction with leukocytes—certain types of particles can damage them. Additionally, blood cells have a short lifespan, so they need to be quickly collected, loaded with medication, and returned to the patient’s body.

“The three most promising types of nanoparticles are liposomes, magnetite, and biodegradable copolymers of lactic and glycolic acids (PLGA). Low-toxicity liposomes degrade naturally and can carry a large amount of the drug. Copolymers allow for controlling the release rate of drugs, while magnetite nanoparticles are useful not only for drug delivery but also for tumor visualization,” noted Anastasia Garina, first-category engineer at the 'Biomedical Nanomaterials' laboratory at NITU MISIS.

Researchers from MISIS University, the N.I. Pirogov Russian National Research Medical University, the V.P. Serbsky National Medical Research Center for Psychiatry and Narcology, and D.I. Mendeleev University of Chemical Technology studied the effects of various types of nanoparticles on neutrophils both in laboratory conditions and within living organisms. They found that magnetite nanoparticles exit blood vessels and can be captured by neutrophils for transport to tumors.

Copolymer nanoparticles accumulate near the walls of blood vessels and are also gathered by blood cells. However, neutrophils do not capture liposomes, but the leukocytes themselves facilitate the delivery of spheres to tumors through micro- and macro-leakage mechanisms—disruptions in the integrity of the vascular walls of neoplasms, allowing drug substances to enter the tissues directly. Details of the study are described in the scientific journal Pharmaceuticals (Q1).

Each type of nanoparticle behaves differently in blood vessels. As a result, the speed and efficiency of drug delivery to tumors with neutrophils varies. In the future, scientists plan to determine the key parameters of nanoparticles that will define the mechanism of interaction with neutrophils.

This work was supported by a grant from the Russian Science Foundation.