To adsorb or to do not adsorb? That is the question

Exposure to antibiotics for a prolonged period can lead to bacteria's ability defeat drugs. If such resistant bacteria causes an infection, there is only one way to treat it: phage, which infects specific bacteria species. It is an effective weapon against deadly diseases. However, effective treatment is dependent on factors that are not known for many years. Recent research by Professor Robert Holyst and Dr. Jan Paczesny from the Institute of Physical Chemistry in Poland, explained why some phage therapy treatments might not work. The material in which the phages are stored has a huge impact on how many they have. For many decades, antibiotics have been used to treat a variety of bacterial infections. Many diseases can now be fought more easily thanks to antibiotics. Many bacteria will develop resistance to antibiotics if they are used in medical treatment. Some bacteria can overcome all available antibiotics on the pharmaceutical market. What happens if a person infected by highly resistant bacteria is unable to take any of the available antibiotics? There is still hope for the end of this mortal battle. The solution lies in the use of bacteriophages (also known as phages). These viruses are specialized viruses that infect and kill bacteria with no adverse effects for humans. This therapy is known as Last Chance Viral Therapy. It can be used to treat chronic diseases such as urinary tract inflammation. Despite numerous clinical trials and a positive treatment, the active bacteriophages can dramatically decrease in injection solution, rendering the treatment ineffective. Recent research by the Institute of Physical Chemistry, Polish Academy of Scientists, and Professor Robert Holyst revealed that the concentration of phages in a solution depends on how the container is stored. Surprisingly, the ability of the phage to "sit" on the surface of polymers depends on which polymer was used to make them. Hydrophobicity is the key factor that governs the adhesion of phages to surfaces. Even the same set of containers from different manufacturers and suppliers can have different superficial properties. This allows the internal walls to remove all phages from bulk and reduce the concentration of the formulation. The type of container in which the phages are stored can have an impact on how active they are. These variations can be explained by additives in polymers manufacturing such as plasticizers and slip agents. Researchers tested several polypropylene-based containers for laboratory use. Dr. Paczesny comments, "We confirmed if leachables were responsible for the observed decrease in active phages within polypropylene containers. We also considered the possibility of leachables being released from unsafe tubes that could activate phages, or leachables from safe tubes that could protect them from external factors (e.g. temperature). We next looked at the mechanism behind the observed effect by examining the adsorption virions onto the walls of polypropylene containers. Uncontrolled adsorption and subsequent disappearance of phages from the solution can lead to serious errors and unrepeatable outcomes. This is crucial for phage therapy. Researchers tested different containers that were capable of standard operations such as heating or mixing active phages. The drop in active phages numbers in bulk was largely dependent on plastic properties such as wettability. They also studied the effects of phages’ physical structure and electrostatic properties on phages’ surfaces. Their results show that plastic type has a significant impact on phages' surface potential when it comes to settling onto containers' walls. Researchers proposed specific solutions to containers with certain properties, such as a treatment using a surfactant that limits phage adsorption onto the container's surface. It was shown that their agglomeration results in a drop in active phages bulk onto the containers' walls. Researchers have shown that phages prefer to adhere to hydrophobic surfaces. The aggregation of phages onto walls can be more profitable economically than their stay in the aqueous solution. This is due to the fact that water has a limited contact with hydrophobic walls if they are covered by phages. "Our findings are crucial not only for phage studies. The greatest threat to scientists is the lack of reproducibility in measurements. Scientists may not be aware that PP tube vendors might offer seemingly identical products, with significant differences from batch to batch. This can sometimes lead to incorrect conclusions. It can also, just like in the case with phages, stop the development of vital technologies because of low efficiency due to improper containers. Dr. Paczesny Scientific Reports, 1 April 2021 presents important information about the efficacy of Last Change Viral Phage Treatment. The most important aspect of the Last Change Viral Phage Therapy is the container in which the phages are kept. As you can see, this factor can have a huge impact on how many active phages are available in the treatment. For patients who struggle with bacteria that cannot be killed with phages, this small step can make a big difference. The presented data and solutions will not only solve non-repeatable infections with phages but also improve all phage-based projects. ### The National Science Centre Poland (NCN), within SONATA BIS Project No. 2017/26/E/ST4/00041