It is known that adsorption of extr

It is known that adsorption of extracellular polymeric sub- stances occurs as the first event on submerged substrata in seawater [28], promoting in turn the diatom to settle. Herein, con- trolling the protein adsorption is a key to mediating the settlement behavior of diatoms. In this study, the protein adsorption on differ- ent substrates was quantized with a BCA kit. It is found that PDMS benefits the protein adsorption (Fig. 5). This is why many methods have been attempted to modify the PDMS surface chemically to minimize the protein absorption [5,29,30]. In this study, the effect of the modification by the micropatterning or the pSB functionaliza- tion of the PDMS surfaces was investigated. Significantly weakened adsorption of BSA proteins was realized on the flat Al-PDMS-pSB surface as compared to that on the flat Al-PDMS surface (Fig. 5). This could be attributed mainly to the higher hydrophilicity of the samples after the additional pSB modification. In this case, the “sur- face hydration” theory likely prevails, suggesting a tightly bound water layer formed around the hydrophilic surface [31]. In addi- tion, the electrostatic interaction between BSA and dipole moments of sulfobetaine groups in the zwitterionic polymer as observed by other researchers [32,33] could also account for the antifouling per- formances. Similar adsorption of albumin was also observed for the micropatterned Al-PDMS and the micropatterned Al-PDMS-DOPA- pSB. The pSB modified samples exhibit similar tendency (Fig. 5). This could explain the constrained settlement of the diatoms on the pSB treated samples.