RESUMEN
The study explores the impact of biomimetic surfaces on bacterial attachment and biofilm formation. Specifically, it investigates the effects of topographic scale and wetting behavior on the attachment and growth of Staphylococcus aureus and Escherichia coli on four different biomimetic surfaces: rose petals, Paragrass leaves, shark skin, and goose feathers. Using soft lithography, epoxy replicas with surface topographies similar to those of the natural surfaces were created. The static water contact angles of the replicas exceeded the hydrophobic threshold of 90°, while the hysteresis angles were found to be in the order of goose feathers, shark skin, Paragrass leaves, and rose petals. The results showed that bacterial attachment and biofilm formation were the lowest on rose petals and the highest on goose feathers, regardless of the bacterial strain. Additionally, the study revealed that surface topography had a significant impact on biofilm formation, with smaller feature sizes inhibiting biofilm formation. Hysteresis angle, rather than static water contact angle, was identified as a critical factor to consider when evaluating bacterial attachment behavior. These unique insights have the potential to lead to the development of more effective biomimetic surfaces for the prevention and eradication of biofilms, ultimately improving human health and safety.
Asunto(s)
Biomimética , Tiburones , Animales , Adhesión Bacteriana , Biopelículas , Escherichia coli , Interacciones Hidrofóbicas e Hidrofílicas , Propiedades de Superficie , Agua/química , HumectabilidadRESUMEN
The particle concentration effect on Kd values of radionuclides has been observed but the underlying mechanism remains controversial. The hope is to use the relationship between particle concentration, adsorption-desorption isotherms and reversibility, in combination with surface component activity of model (SCA model), to solve this issue. 137Cs, 60Co, 90Sr were used as tracers, batch experiments were conducted in freshwater-sediment and seawater-sediment. The experiment of each radionuclide was designed with five different particle concentrations Cp, and for each Cp there were seven different initial concentrations C0. After adsorption experiments, four consecutive desorption experiments were carried out. At the fourth desorption experiment, radionuclide concentrations in the supernatant and sediment were measured. The results showed that adsorption and single desorption data of 137Cs, 60Co, 90Sr might be described by linear isotherms. 137Cs was reversible in the seawater-sediment, so hysteresis angles of the five-particle concentration were approximately 0°, all adsorption and desorption data could be classified into one line. In the remaining systems, besides the adsorption and single desorption isotherms moved upward with the decrease of particle concentration, hysteresis angles and irreversibility also increased, thus, the particle concentration effect was obvious. The reversible and resistant component concentrations calculated by adsorption, single desorption and consecutive desorption isotherm were linear functions of equilibrium concentration Ce1, respectively. Data from adsorption and desorption experiments with particle concentration effect could be classified into the same line using the Freundlich-SCA model. The results of this study indicate that the particle concentration effect is related to reversibility. When adsorption isotherm and single desorption isotherm are both linear, consecutive desorption isotherm, reversible and resistant component concentrations approach linearity too. After the Freundlich-SCA model eliminated the particle concentration effect on adsorption and desorption data, the data can be used to predict the adsorption, single desorption isotherm and Kd value at any particle concentration.