Interfacing Authentic Cell Membranes with 2D Materials for Biological Sensing

Abstract

Phospholipids (PLs) driven liquid phase exfoliation of graphene is a sustainable approach for graphene processing, with promising applications in the field of bioelectronics. This work introduces a new approach to produce few-layer graphene (FLG) dispersions investigating PLs with organic solvents of varying polarities to elucidate the effect of polarity on the resulting structures and dispersion. The interaction between alcohols and PLs regulated the fluidity, conformation, orientation, and species formations of the PLs. These properties emerged as key experimental parameters resulting in superior dispersibility, exfoliation yield, and distinct lipid fingerprints on the resulting graphene surface. Among the tested solvents, Ethanol (EtOH) provided superior graphene dispersibility compared to methanol (MetOH) and isopropanol (IPA), with EtOH being the most effective solvent for long-term graphene dispersion. The EtOH-PLs resulted in a more robust and stable PL-coated graphene layer, compared to MetOH-PLs, enhancing the compatibility of EtOH-PLs exfoliated graphene flakes in aqueous environments over extended periods. The resulting dispersion was tested with interfacing on biological bacterial membranes and synthetic membranes. Besides it is used as an ink to coat a hydrogel-based stretchable substrate highlighting its excellent film-forming properties and wettability and used to record Electrocardiogram (ECG) signals from the skin surface. This study advances state-of-the-art exfoliation methods by using PLs as biomolecules for exfoliation, demonstrating their critical role in yield, dispersion stability, and surface properties. Moreover, it reveals that alcohol interactions can modify PL properties, mimicking that of other PLs, and highlights how the bare surface of nanomaterials like graphene can trigger the formation of a slowly exchanging layer of surrounding molecules depending on the physiochemical state of a biomolecule in media, offering new insights into controlling these processes for cell-membrane related applications.

Date of Award	12 Dec 2024
Original language	American English
Supervisor	Anna-Maria Pappa (Supervisor)