Changes in nanomechanical properties and adhesion dynamics of algal cells during their growth

Abstract

Nanomechanical and structural characterizations of algal cells are of key importance for understanding their adhesion behavior at interfaces in the aquatic environment. We examine here the nanomechanical properties and adhesion dynamics of the marine, unicellular, green flagellate Dunaliella tertiolecta in laboratory culture. Mechanical properties of motile cells are hard to access while keeping cells viable, and studies to date are limited. Immobilization of negatively charged cells to a positively charged substrate enables high-resolution imaging and nanomechanical measurements. Cells in exponential phase possess a large cell volume as imaged by AFM, in agreement with the large amount of amperometrically measured displaced charge at the interface. Cells are stiffer and more hydrophobic in exponential than in the stationary phase. Differences in the critical interfacial tensions of adhesion of cells in exponential and stationary phase show the analogy with adhesion of hydrophobic droplets of organic liquids. Differences in the kinetics of adhesion and spreading of cells at the interface are attributed to their volume and nanomechanical properties that vary during cell aging. In the future, cell mechanical properties could be considered as a marker for environmental stress in order to better understand viability and adaptation strategies of algal populations in aquatic systems.

Transpicuous-Cum-Fouling Resistant Copolymers of 3-Sulfopropyl Methacrylate and Methyl Methacrylate for Optronics Applications in Aquatic Medium and Healthcare

“…These cells were centrifuged and washed with distilled water. The optical density was set at 0.5 for the spectrophotometer [29]. The adhesion studies were carried out using Dictyosphaerium on prepared antifouling copolymers P(SPMA-co-MMA), and comparative analysis was made by using each type of copolymer.…”

“…Antibacterial activity against E. coli and S. aureus has been probed by the disk diffusion method, and further bacterial biofilm has been analyzed by SEM [28]. Algal biofilm for Dictyosphaerium species has been examined by optical microscopy [29]. The results of the current work are significant and provide a facile approach to develop functional antifouling polymers by optimizing transparency for potential applications in various areas including healthcare.…”

Structural Features of the Algal Cell Determine Adhesion Behavior at a Charged Interface

“…This unexpected behavior could derive from the surface properties of C. vulgaris in the log phase of growth. Change of surface properties during the exponential and stationary growth phases of D. tertiolecta was studied [36]. The results showed that D. tertiolecta was hydrophobic during the exponential growth phase as for the C. vulgaris .…”

“…The algal cell D. tertiolecta possesses a 9 nm thick plasma membrane modified on the surface with glycoproteins forming glycocalyx [19,36]. The nanomechanical characterization of D. tertiolecta in the exponential and stationary growth phases was studied [36].…”

“…The algal cell D. tertiolecta possesses a 9 nm thick plasma membrane modified on the surface with glycoproteins forming glycocalyx [19,36]. The nanomechanical characterization of D. tertiolecta in the exponential and stationary growth phases was studied [36]. The results showed that cells were significantly more hydrophobic and stiffer in the exponential than in the stationary growth phase, probably due to the molecular modification of the cell envelope (31 kPa, 19 kPa, respectively).…”