Cancer diseases are one of the main causes of the high mortality rate, which is related to the late detection of neoplastic changes and the low effectiveness of standard treatments. Biomedical imaging, one of the key pillars of modern cancer diagnosis and treatment, is tightly integrated into clinical decision making. Early diagnosis is known to be a major factor in reducing mortality, treatment costs and hospital stays. Imaging probes are a key component of molecular imaging and must offer high sensitivity, low background noise, low toxicity and relative stability.

Application of nanoparticles in molecular imaging techniques enables earlier detection and treatment of tumors by increasing sensitivity of signals and targeting of contrast agents directly into cancer cells. Several studies have shown that nanoparticles known as aptamers are among the best imaging tools due to their high stability, target specificity and affinity. 

The aim of the project is to develop a universal molecular probe for the PD-L1 protein (programmed death receptor -1 ligand), which will facilitate the diagnosis of various types of cancer. PD-L1 is a protein found on the surface of many cancer cells, enabling them to bypass the immune system's natural defines system.

One of the components of the immune system are T cells, which recognize and attack cancer cells. These cells have structures called receptors on their outer surface, which act as keys to lock onto the molecules of attacking organisms. This molecular recognition is a major component of the immune response. One of the elements of this mechanism are so-called "checkpoints", which prevent T cells from attacking normal cells. A key part of this mechanism is the PD-L1 / PD-1 system. PD-L1 on normal cells recognizes and attaches to PD-1 on T cells, preventing them from attacking healthy cells. Unfortunately, some cancers have learned to produce large amounts of PD-L1 in order to trick the immune system into avoiding detection. Hence, the designed probes target PD-L1 binding and will be able to detect and locate neoplastic cells at a very early stage of the disease. These probes can be used in early diagnosis, increasing the chances of disease detection and treatment.

The development of a universal probe would create the possibility of imaging various types of tumors depending on their ability to overexpress PD-L1 and would provide a tool / finished product as a probe for future diagnostic and even therapeutic clinical trials.