Surface treatment to overcome phage adsorption during storage

Bacterial resistance to antibiotics, also called antibioresistance, is increasing and “could cause 10 billion deaths each year by 2050” according to the World Health Organization. Phagotherapy is a promising alternative to antibiotics, but as soon as bacteriophages are specific to bacterial hosts, a phage library at our disposal is needed to treat a maximum of bacterial infections. However, some preliminary studies confirmed the essential role of the container material's surface properties which impacts phages concentration by decreasing by several decades the infectious titer over time.

The aim of the study is to develop vials with antibiofouling coating that prevents bacteriophages adsorption. We decided to focus on surface treatment by developing antibiofouling films on Glass and silicon substrates. PEG-like and zwitterion compounds are usually cites as having a well antifouling aptitude. Once having measured the coating thickness by ellipsometry and evaluated its integrity during immersion, the film is tested as bacteriophages antifoulant. One method to conclude on the coating ability to be antibiofouling is the Quartz Cristal Microbalance. First, a buffer flow is used as reference, then phages with high concentration are introduced before washing with buffer again. Each coating is compared to a pristine substrate, so if the frequency signal comes back to reference frequency but the uncoated substrate does not, the coating is antifoulant. PEG-like and zwitterion films have been studied in that way and seems to be promising candidates to overcome bacteriophages adsorption.

Moreover, by doing QCM tests, we ask us the following question: do we adsorb only bacteriophages or are there other substances as Lipopolysaccharides ?

During the presentation the contact between coatings and bacteriophages will be discussed using graphs obtained by QCM. Two methods used to respond to the LPS issue will be detailed by introducing bacteriophages purification and the measure of endotoxins level. Complementary analysis such as phages concentration in the post-QCM solution will support results.