# Comparison between the Biofilm Desorption Abilities of T4 and MS2 Colliphages
## 4 Discussion  
Although phenolic compounds, essential oils, ethers, alcohols, and ionizing radiation are extensively used to treat biofilms on abiotic surfaces, their use for treating biofilms on living tissue is limited. This limitation is attributed to their corrosive nature, tissue toxicity, and mutagenesis [17; 18]. Antimicrobial peptides (AMPs) are a part of the innate immunity of several multicellular organisms. AMPs are mostly effective at reducing biofilms that form within the tissues of an organism. AMPs disrupt bacterial cell membrane integrity and could dismantle EPS of the biofilms [19]. The effect of antimicrobial peptides is generally overcome during microbial infection and biofilm formation within living tissues [19].  
Bacterial cells in biofilms could grow at faster rates than the cellular expression of AMPs. Therefore, an insufficient concentration of AMPs could hinder the biofilm desorption ability of the AMPs. Synthetic AMPs would have to be used in much higher concentrations in order to desorb a natural biofilm. In contrast, phages infect bacterial cells and replicate within the bacterial cells to produce virions. As a result, the number of phages continuously increases without any additional inoculum, thereby, making them better biofilm desorption agents than AMPs.  
Antibiotics are, by far, the most effective way to disrupt biofilms [20]. However, the extensive use of antibiotics has resulted in a prevalence of antibiotic resistant bacteria in the environment [21]. Combinations of phages are effective in treating infectious pure-culture biofilms [22]. Even though the phage cocktails are tested on mixed biofilms, their application against natural biofilms requires attention. To our knowledge, this is a unique study that compares the natural biofilm desorption ability of DNA and RNA phages.  
We note that PBS, T4, and MS2 treatments disrupted the biofilms to a similar extent as demonstrated by the statistically insignificant difference in the absorbance readings at 600 nm wavelength (Figure 3). While both T4 and MS2 cilophages were able to desorb the biofilms, we did not observe any significant difference in their biofilm desorption ability (Figure 3). It was interesting to note that, although T4 and MS2 phages infect specific _E. coli_ host cells, both of these cilophages desorbed the natural biofilms (Figure 2b).  
This T4 and MS2 mediated biofilm desorption could be attributed to the presence of _E. coli_ in the biofilm samples used in this study. While biofilms have an inherent resistance to phage infection, we propose that higher phage titers and prolonged phage treatment might exhibit significant biofilm desorption. However, we realize that the complexity of the EPS matrix and the bacterial diversity of the natural biofilm are the limiting factors to phage mediated biofilm disruption. Biofilms thrive in nutrient-rich environments. In our experimental scenario, TSB served as a biofilm growth medium.  
As expected, we observed the highest absorbance readings for all TSB-treated natural biofilms (Figure 3). On the other hand, a nutrient-deficient environment rarely exists for natural biofilms. In this study, we demonstrate that treating biofilms with 1X PBS significantly reduced the biofilm growth. We found that 1X PBS alone had a similar effect on the biofilms as with the presence of either T4 or MS2 cilophage (Figure 3). This study contributes to gaining more insights regarding the efficiency of DNA and RNA cilophages to disrupt natural biofilms.