Microscale adhesion patterns for the precise localization of amoeba

Abstract

In order to get a better understanding of amoeba-substrate interactions in the processes of cellular adhesion and directional movement, we engineered glass surfaces with defined local adhesion characteristics at a micrometric scale. Amoeba ( Dictyostelium dicoideum) are capable to adhere to various surfaces independently on the presence of extracellular matrix proteins. This paper describes the strategy used to create selective adhesion patterns using an appropriate surface chemistry and shows the first results of locally confined amoeba adhesion. The approach is based on the natural ability of Dictyostelium to adhere to various types of surfaces (hydrophilic and hydrophobic) and on its inability to spread on inert surfaces, such as the block copolymer of polyethylene glycol and polypropylene oxide, named Pluronic. We screened diverse alkylsilanes, such as methoxy, chloro and fluoro silanes for their capacity to anchor Pluronic F127 efficiently on a glass surface. Our results demonstrate that hexylmethyldichlorosilane (HMDCS) was the most appropriate silane for the deposition of Pluronic F127. A complex dependence between the physico-chemistry of the silanes and the polyethylene glycol block copolymer attachment was observed. Using this method, we succeed in scaling down the micro-fabrication of Pluronic-based adhesion patterns to the amoeba cell size (10 μm). This original Pluronic patterning method should prove useful as a tool for controlling cell adhesion and directional movement in amoeba.