Turning an adversary into an ally: Self-assembled amyloid-like fibril aerogel packed 3D-printed microfluidic sample pre-treatment device for elemental analysis.

In this study, we transformed well-known disease-causing amyloid fibrils into a functional ally. Instead of using Alzheimer's disease associated amyloid-beta fibrils we employed synthetic lysozyme derived amyloid-like fibrillar aggregates. We developed a simple and effective method for enriching and detecting various toxic elements in complex serum samples. This method employs a reusable 3D-printed microfluidic sample pre-treatment device, packed with a bio-based aerogel elemental ion extractant composed of self-assembled amyloid-like lysozyme fibrillar aggregates (AF), graphitic carbon nitride nanosheets (g-C₃N₄ NSs), and polyethyleneimine (PEI). The developed setup is integrated with inductively coupled plasma mass spectrometry (ICP-MS), enabling accurate elemental analysis without interference from the sample matrix. The synthesized elemental ion extractant aerogel is rich in diverse functional groups, significantly enhances the element extraction efficiency compared to conventional toxic element sorbents lacking structured amyloid-like networks. The established method yielded significant detection limits ranging from 1 to 100 μg L-1 for Ag+, Cr3+ and Se IV over other elements with relative standard deviations (RSDs) between 2.1 and 4.6 %. Specifically, the approach achieved a limit of detection (LOD) of 0.2 μg L-1 for Cr, 0.4 μg L-1 for Se, and 1.1 μg L-1 for Ag. High recovery rates ranging from 85 to 102 % were achieved in spiked complex serum matrices. Moreover, the proposed multifunctional 3D-printed microfluidic approach significantly enhanced the selective extraction and detection of toxic elements in complex serum samples, demonstrating robust performance over seven adsorption-desorption cycles and representing a sustainable and significant analytical advancement.