Extension of microscale surface ion conduction (μSIC) to the sensing of charged small molecules: application to per- and poly-fluoroalkyl substances (PFASs)
Year: 2025
Type: article
Abstract: Surface ion conduction-based sensing, which detects changes in ionic conductivity upon target binding, has been widely used for molecular detection. However, many sensors in this class, such as chemically modified solid-state nanopores, face challenges related to complex fabrication and inconsistent immobilization of target-specific probes at the nanoscale. In contrast, we previously introduced the microscale surface ion conduction (μSIC) sensor as a solution for detecting biological analytes. In this work, we demonstrate the adaptability of the μSIC sensor for organic pollutant detection, specifically targeting per- and polyfluoroalkyl substances (PFASs) in drinking and brackish waters. By integrating C18 reversed-phase silica gel chromatographic beads as a solid substrate, we enable label-free, non-optical detection of PFASs. This approach offers several advantages, including being labor-efficient, portable, and cost-effective, compared to conventional detection methods. By integrating an additional preconcentration step using faradaic ion concentration polarization (fICP) with a lateral flow assay (LFA) (fICP-LFA), the sensor's sensitivity was increased almost 77 times while the limit of detection (LOD) of perfluorooctane sulfonic acid (PFOS) was improved 1137-fold. It was also observed that the shift in current (signal) produced by the sensor does not change significantly over a range of background electrolyte (BGE) concentrations spanning three orders of magnitude. This work is significant as it implements a chromatographic solid phase as a substrate for label-free sensing, creating an avenue to develop a new class of sensors or to monitor chromatographic interactions. Further, we demonstrate that the μSIC sensor can be adopted for non-biological molecules, and to the best of our knowledge, this work is the first surface charge-based detection of PFASs.
Source: The Analyst
DOI: 10.1039/d5an00584a
Authors: Md Ruhul Amin, Beatrise Berzina, Umesha Peramune, Robbyn K. Anand
Institution: Iowa State University
Language: English
Subfield: Electrochemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Awards: NSF Convergence Accelerator Track K: Electrokinetic water purification system for point-of-use applications, CAREER: Advancing Ion Concentration Polarization to Enrich New Classes of Analytes from Complex Media and to Interface with Analysis: Breaking the Glass Ceiling on Enrichment, G5245109432, G6671297155
OpenAlex ID: W4413002017