In a biosensing device, the sensing performance is governed by the biotic/abiotic interface, where the biorecognition element (BRE) needs to interact with both the abiotic transducer and the target of interest to trigger a desired response. The morphology of the BRE at the biotic/abiotic surface is a result of numerous interactions that strongly influence which conformation the BRE will assume on the substrate surface. Presumably, this conformation impacts target/BRE interactions and therefore subsequent responses in the transducer, ultimately dictating sensor performance. As such, the biotic/abiotic interface is the most critical part of biosensor development because a well-engineered interface will be responsible for the biosensor’s stability, sensitivity, and accuracy. A proper interface characterization is challenging due to all possible physicochemical interactions between those two players. Still, it is mandatory to understand their role to make the BREs adopt a specific orientation after the attachment.<br/>In this presentation, we used near edge X-Ray absorption fine structure (NEXAFS) spectroscopy to investigate the bio interface between peptide sequences with known binding affinity to volatile organic compounds (VOCs) and carbon nanotubes (CNT). We modified the original sequences designed for VOC binding by replacing predicted key amino acids with non-interacting moieties to probe sequence-dependent sensing performance. NEXAFS is sensitive to the molecular alignment of those modified peptide sequences because this technique relies on the prevalence and overall orientation of unoccupied molecular orbitals, measuring the change in absorbance after varying the incident angle of synchrotron light. Furthermore, NEXAFS was performed after dosing with VOCs, providing key insights into how morphological/orientation changes occur as a function of the peptide sequence. Overall, this work suggests that NEXAFS is a relevant tool to correlate molecular alignment and performance of functionalized surfaces, contributing to the development of biofunctionalized materials.

Validating residues influence on peptide/carbon nanotube interface and VOCs sensing performance using Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.