Research Topic: Photonic Micro-Patterned Silicon Chip for Selective Bacterial Spatial Colonization
Abstract: ** Lecture will be given in English**
Bacterial adhesion to solid surfaces is governed by a complex interplay between bacterial characteristics, environmental conditions, and surface physicochemical properties. Understanding these interactions is important for elucidating early bacterial colonization and for the rational design of surfaces that can modulate bacterial attachment and spatial organization.
In this work, we developed a platform that integrates a silicon photonic chip, with a well-defined micropore geometry, into a multichannel polydimethylsiloxane (PDMS) microfluidic device, enabling controlled flow experiments and real-time monitoring of bacterial attachment using phase-shift reflectometric interference spectroscopy (PRISM). The photonic chip functions both as an optical transducer and as a substrate for bacterial attachment. Using this platform, we investigated the roles of surface chemistry and biochemical recognition in bacterial attachment and colonization.
Several silicon chemistries were examined, including silicon oxide (OX), amine-terminated (AMINE), and lectin- functionalized surfaces. Lectins are carbohydrate-binding proteins that recognize specific glycan motifs on bacterial cell surfaces through their carbohydrate-recognition domains, and we hypothesized that they may enable selective bacterial capture based on differences in surface glycosylation. First, the interactions of several lectins with Listeria innocua and Escherichia coli, used as Gram-positive and Gram-negative model bacteria, respectively, were characterized. Based on these results, Wheat Germ Agglutinin (WGA) was selected and immobilized on the microstuctured chip. Bacterial interactions with the different surfaces were subsequently characterized by PRISM and microscopy. L. innocua exhibited substantial attachment to all tested surfaces, with pronounced bacterial accumulation on the AMINE- and WGA-functionalized surfaces. In contrast, E. coli displayed a clearer preference for the WGA-functionalized surface. These findings show that surface chemistry modulates bacterial attachment can in a species-dependent manner. However, WGA did not provide sufficient selectivity to clearly distinguish between the two bacterial species based on the PRISM response.
Overall, the developed platform provides a versatile framework for investigating how different surface and environmental cues can influence bacteria–surface interaction under controlled conditions. The platform can be further adapted with alternative surface chemistries, capture probs or surface topography to improve bacterial differentiation and spatially selective colonization.
