# Novel Approaches to Combat Medical Device-Associated BioFilms
## 3 Novel Approaches to Combat Medical Device-Associated Biofilms
### Nanotechnology
The results showed a significant reduction in the bacterial load in each biofilm stage. On the peak day, i.e., the 4 th day of biofilm formation, a significant reduction of approximately 33% (MIC) and 54% (MBC) in the bacterial load of the SBT@AgNps-treated biofilms was observed compared to that of the control biofilms. A biofilm of _P. aeruginosa_ was established on a coverslip and analyzed by field emission scanning electron microscopy (FESEM) on the peak day. The results showed that the intact three-dimensional structure of the biofilm treated at the MIC and MBC was disrupted to form plaques embedded with biofilm cells. A concentration-dependent biofilm matrix structure was observed upon treatment with SBT-AgNps. In addition, the interaction of SBT@AgNps with the bacterial cell membrane and disruption of the bacterial wall were also observed. The biofilm disruption resulted from SBT@AgNps-mediated bacterial killing, and these NPs interacted with bacterial cells. Moreover, SBT@AgNps showed an excellent anti-QS ability, which may be helpful in controlling bacterial infection at initial stages by blocking bacterial communication [227]. AuNPs are also commonly used nanoparticles, and biosynthesized AuNPs from brown seaweed at sub-MICs could inhibit _P. aeruginosa_ biofilm formation by more than 80% and eradicate mature biofilms. Furthermore, sub-MICs of biosynthesised AuNPs also attenuated the production of several important virulence factors, such as pyoverdine, pyocyanin, and rhamnoids, and impaired bacterial swarming, swimming, and twitching motilities [228]. The antibacterial activity and antibiofilm potential of chitosan and its nanometer-scale derivatives have been demonstrated in a variety of microorganisms [229]. A recent study proved that chitosan NPs (CNPs) can inhibit _S. aureus_ biofilm formation, damage mature biofilms, reduce EPS production, and lower the cell surface hydrophobicity. The results showed that the biofilms were inhibited by approximately 50% upon treatment with CNPs compared to the control group. The treatment of a preformed biofilm with CNPs also resulted in a reduction of approximately 15% in the biofilm mass. Chrysin, which is a flavone constituent of the Orocylumineicum vent, has already been demonstrated to have antibacterial properties. However, its low water solubility, low bioavailability, and rapid metabolism in the body limit its therapeutic applications. Chitosan was used as a nanocarized load with chrysin to enhance the antibiofilm activity through a synergistic effect [220]. In addition to their inherent antibiofilm activity, NMs can also be used as carriers for antibiofilm agents or other biofilm scavengers. Rifampicin-conjugated silver (Rif-Ag) NPs enhance the biofilm penetrating power compared to rifampicin alone. The synthesized NPs inhibit >90% of biofilms formed by _K. pneumoniae_ and methicillin-resistant _Staphylococcus aureus_ (MRSA) at low doses and show 1.5-2 times more penetrating potential, as observed by biofilm eradication and percentage viability reduction, compared to rifampicin alone [230]. Some NMs, as response carriers, exert antibiofilm effects. For example, mesoporous poly-dopamine NPs can cooperate with PDT to combat biofilms. These NPs, when integrated on titanium surfaces with an attached indocyanine green photosensitizer, can reduce _S. aureus_ biofilm formation by 95% in murine specimens exposed to light with a wavelength of 808 nm [115]. Another study showed, that under laser irradiation, AuNPs produce vapor nanobubbles (VNB) to interfere with the structure of biofilms, promote the penetration of tobramycin, and improve the bactericidal effect [214]. Some NMs have inherent antibiofilm activity, which can prevent microorganisms from adhering to devices and the formation of biofilms, destroy EPS, and kill biofilm microorganisms through different mechanisms.