# Novel Approaches to Combat Medical Device-Associated BioFilms
## 3 Novel Approaches to Combat Medical Device-Associated Biofilms
### Antimicrobial Peptides
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**AMP** & **Pathogen** & **Infection Model** & **MIC** & **MBIC/EC** & **Effects and Mechanism of Action** & **Reference** \\ \hline P1 (S) & _S. mutans_ & in vitro & NP & 25 ug/mL & Disturb the biofilm architecture, resulting in a drastic reduction in attached biofilm biomass & [192] \\ Hppedidin 20 (S) & _S. epidermidis_ & in vitro & \textgreater{}50 \(\upmu\)M & 25 \(\upmu\)M & Reduce the mass of the extracellular matrix and change the structure of biofilms by targeting PIA & [193] \\ HBD-3 (N) & _S. epidermidis_ & in vivo & 4 ug/mL & 40 ug/mL & Inhibit biofilm formation & [176] \\  & _S. aureus_ & 8 ug/mL & 60 \(\upmu\)M & Reduce the expression of adhesion protein and inhibit & [175] \\ TRP-1-GCGC-HBD-3 & _S.tilis_ & 320 ug/mL & 60 \(\upmu\)M & Reduce the expression of adhesion protein and inhibit & [175] \\ (S) & _S. gondii_ & in vitro & 500 ug/mL & 800 ug/mL & \\ HPDFs-Co (M) & _P. aeruginosa_ & in vitro & 32 \(\upmu\)M & 2 \(\upmu\)M & Destroy extracellular DNA & [194] \\ Cl62G (S) & _S. mutans_ & in vitro & -5 \(\upmu\)M & 20 \(\upmu\)M & Kill bacteria through disruption of the cell membrane & [170] \\ In-SB056-1 & _P. aeruginosa_ PAO1 & ex vivo & 19.25 \(\upmu\)M & 19.25 \(\upmu\)M & [195] \\ Polymyrin B (N) & _V. cholerae_ & in vitro & 100 ug/mL & 25 \(\upmu\)M & Affect flagella, reduce motility, inhibit biofilm formation & \\ BF & & & & 2.5 ug/mL & \\ Pc-CATH1 & C. albicans & in vivo & 1-16 ug/mL & NP & Inhibit biofilm formation, destroy preformed biofilms & [171] \\ Ce-CATH2 & & & & NP & \\ \hline \end{tabular} Note: N: naturally occurring AMP; M: modification of naturally occurring AMP; S: synthetic AMP; MSSA: methicillin-resistant Stribylococcus aureus; PIA: polysaccharide intercellular adhesive; ROS: reactive oxygen species; MIC: minimum inhibitory concentration; MBC: minimal biofilm inhibitory concentration; EC: experimental concentration; NP: not provided.  
\end{table} 
Table 3: _Cort._AMPs represent promising compounds for antibiofilm strategies. However, the activity of AMPs is related to many factors, including the size, sequence, charge, structure, conformation, hydrophobicity, and amphiphilicity, which may lead to toxicity and side effects on host cells under some conditions [11]. Although these AMPs have good antibiofilm activity in vitro, their potential toxicity and poor stability under physiological conditions limit their application in the clinical treatment of biofilm infections [201]. To date, many studies have examined the relationship between the structure of AMPs and their antibiofilm activity and safety. The structure with the best antibacterial activity is determined through the artificial modification and synthesis of AMPs, with the aim of seeking suitable AMPs for clinical application. Many methods have been adopted, for example, substitution, cyclization, hybridization techniques, or modification of the C- and N-termini via acetylation and myristoylation [173; 202; 203; 204; 205; 206]. The bactericidal activity of some AMPs can be increased by truncating or increasing the overall positive charge [172; 207]. In addition, the application of some drug delivery systems can not only help AMPs increase the antibacterial activity, but also improve their stability under physiological conditions and reduce their cytotoxicity [168]. For example, the conjugation of AMPs with nanoparticles (NPs) leads to the higher penetration of biofilms and improves the antibacterial activity. At the same time, NPs provide protection to AMPs, preventing their degradation in different environments, such as enzymatic degradation [208]. In conclusion, AMPs have a variety of active antibiofilm mechanisms and have potential applications in clinical treatment to remove biofilms.