Reduced Biofilm Formation at the Air–Liquid–Solid Interface via Introduction of Surfactants

Abstract

Reduced biofilm formation is highly desirable in applications ranging from transportation to separations and healthcare. Biofilms often form at the three-phase interface where air, liquid, and solid coexist due to the close proximity to nutrients and oxygen. Reducing biofilm formation at the triple interface presents challenges because of the conflicting requirements for hydrophobicity at the air−solid interface (for selfcleaning properties) and for hydrophilicity at the liquid−solid interface (for reduced foulant adhesion). Meeting those needs simultaneously likely entails a dynamic surface, capable of shifting the surface energy landscape in response to wetting conditions and thus enabling hydrophobicity in air and hydrophilicity in water.Here, we designed a facile approach to render existing surfaces resistant to biofilm formation at the triple interface. By adding trace amounts (∼0.1 mM) of surfactants, biofilm formation of Pseudomonas aeruginosa (known to form biofilm at the triple interface) was reduced on all surfaces tested, ranging from hydrophilic to hydrophobic, polar to nonpolar. That reduced fouling was not a result of the known antimicrobial effects. Instead, it was attributed to the surface-adsorbed surfactants that dynamically control surface energy at the triple interface. To further understand the effect of surfactant−surface interactions on biofilm reduction, we systematically varied the surfactant charge type and surface properties (surface energy and charge). Electrostatic interactions between surfactants and surfaces were identified as an influential factor when predicting the relative fouling reduction upon introduction of surfactants. Nevertheless, biofilm formation was reduced even on the charge-neutral, fluorinated surface made of poly(1H, 1H, 2H, 2H-perfluorodecyl acrylate) by more than 2-fold simply via adding 0.2 mM dodecyl trimethylammonium chloride or 0.3 mM sodium dodecyl sulfate. Given its robustness, this strategy is broadly applicable for reducing fouling on existing surfaces, which in turn improves the cost-effectiveness of membrane separations and mitigates contaminations and nosocomial infections in healthcare.

An imidazolium-based zwitterionic polymer for antiviral and antibacterial dual functional coatings

“…In the first step, iCVD deposition of vinyl imidazole (VI; monomer) and divinylbenzene (DVB; cross-linker) was performed. The coating of copolymers was subsequently treated using a vapor of 1,3-propanesultone in a second step to obtain the imidazolium-based zwitterionic polymer ( 26 , 27 ).…”

“…Previous research has indicated that zwitterionic polymers synthesized using the two-step vapor-based method can have a mild negative charge (e.g., ζ potential was around −13 mV for a pyridinium-based zwitterionic polymer in a 100 mM NaCl standard solution at the pH of 7) ( 26 ). Although negative surface charge is desirable because virus particles are also believed to be negatively charged ( 45 ), we do not anticipate electrostatic repulsion to be the primary reason for the reduction of viral adhesion, as charge neutrality is a prerequisite for the antibiofouling behavior demonstrated by the imidazolium zwitterionic polymers reported here.…”

Surfaces with antifouling-antimicrobial dual function via immobilization of lysozyme on zwitterionic polymer thin films

“…PVC was chosen as a benchmark for an “uncoated” surface because it is commonly used in microbiology studies as the material for culture plates. 23…”

“…19 For example, poly(sulfobetaine) (pSB) 20 has demonstrated an ultralow level of nonspecific protein adsorption, 21 bacterial adhesion, 22 and biofilm formation. 23 Hence, zwitterionic materials have been used in a wide range of biological and medical applications, including antibiofouling coatings for biomedical devices, 24 efficient drug nanocarriers, 25 biocompatible tissue scaffolds, 26 and stabilizers for enzymes. 27…”

Characterization of Magnesium-Polylactic Acid Films Casted on Different Substrates and Doped with Diverse Amounts of CTAB

“…The surfactant will be cetyltrimethylammonium bromide (CTAB). This cationic surfactant is relatively safe and frequently used in disinfection and cleaning procedures because of its antimicrobial properties [ 23 , 24 ], in addition to the fact that even a trace amount of surfactant provides an effective strategy to reduce biofilm formation [ 25 ].…”