Biofilm prevention
Biofilm formation occurs when free floating microorganisms attach themselves to a surface.
Biofilms secrete extracellular polymeric substance that provides a structural matrix and facilitates adhesion for the microorganisms; the means of prevention have thus concentrated largely on two areas: killing the microbes that form the film, or preventing the adhesion of the microbes to a surface.
Because biofilms protect the bacteria, they are often more resistant to traditional antimicrobial treatments, making them a serious health risk.
[1] For example, there are more than one million cases of catheter-associated urinary tract infections (CAUTI) reported each year, many of which can be attributed to bacterial biofilms.
Antibiotics, biocides, and ion coatings are commonly used chemical methods of biofilm prevention.
The antimicrobial property of silver is known as an oligodynamic effect, a process in which metal ions interfere with the growth and function of bacteria.
[4] Several in vitro studies have confirmed the effectiveness of silver at preventing infection, both in coating form and as nanoparticles dispersed in a polymer matrix.
The highly purified water showed a sharp decrease in bacteria colony adherence.
Water purification methods are being scrutinized here because it is in this state that contamination is thought to occur and biofilms are formed.
[6] To avoid the undesirable effects of leaching, antimicrobial agents can be immobilized on device surfaces using long, flexible polymeric chains.
One in vitro study found that when N-alkylpyridinium bromide, an antimicrobial agent, was attached to a poly(4-vinyl-N-hexylpyridine), the polymer was capable of inactivating ≥ 99% of Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa bacteria.
[7] Dispersion forces between the polymer chains and the bacterial cells prevent bacteria from binding to the surface and initiating biofilm growth.
Ozone targets extracellular polysaccharides, a group of bacterial colonies on a surface, and cleaves them.
The ozone cuts through the skeleton of the biofilm at a rapid pace thus dissolving it back to harmless microscopic fragments.
Ozone is so effective because it is a very strong oxidant and it encounters biofilms in much larger concentrations than most disinfectants like chlorine.
[8] Modification of the surface charge of polymers has also proven to be an effective means of biofilm prevention.
The hydrophobicity and the charge of polymeric chains can be controlled by using several backbone compounds and antimicrobial agents.
Positively charged polycationic chains enables the molecule to stretch out and generate bactericidal activity.
[7] The free energy of adhesion can be determined by measuring the contact angles of the substances in question.
Studies have shown that there is a threshold value of surface roughness (Ra = 2 μm) below which biofilm adhesion will reduce no further.
The device delivers periodic rectangular pulses through an actuator holding a thin piezo plate.
Aryl rhodanines inhibit the adhesion of bacterial cell such as: staphylococcus aureus and enterococci in the first step of biofilm formation, because it prevents the initial interaction between bacterial cells and adhesion surface, the mechanism of inhibit biofilm by these molecules exhibit the physical interaction between aryl rhodanine and adhesine which are located on the bacterial cell surface.
[15] Ionic liquid is a group of low melting point salts containing anions and cations.
